Yet Another Cycling Forum
General Category => The Knowledge => OT Knowledge => Topic started by: Joe.B on 09 April, 2022, 05:23:42 pm
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Calling all those with PV on the roof!
I’ve been quoted £11K for a PV installation and I’m now trying to gauge whether that is a fair price. I’d be interested in hearing from other YACF’s with PV about how much their systems cost.
A bit of background:
My roof is in 3 sections, facing East, West & North. Obviously the North is out of the picture so we’re looking at an E-W array, there is also a bit of shading from two chimney stacks.
Before receiving the proposal from the installer I made a few stipulations about the system:
· To minimise shading losses I stipulated that I wanted panels with embedded bypass diodes.
· Panels to be wired in parallel rather than series to minimise shading losses, (installers usually default to series as it uses significantly less wiring).
· I asked for a Multi Power Point Tracking (MPPT) inverter/controller rather than a cheaper PWM device.
· I want LiFePO battery storage rather than Li-Ion.
Our household consumption for March this year was rather typical for us:
• Car Charging = 225KWh
• Hot Tub = 275KWh
• Rest of House = 310KWh
Given that we’ll be using the PV to charge the home battery, heat the immersion and run the hot tub, I don’t envisage having any surplus to sell back on the grid. (I’m currently building a diy solar thermal system for the hot tub which I’ll post about once complete).
They have come back to me with a proposal for a 10 x 380W (split 50-50 E/W), installation with a 5.8KWh battery. Cost £11K.
I’ve looked up the specified panels, inverter & battery on sparky trade sites and these items can be bought for £4500. Allowing another £1000 for other required components, we’ll assume £5.5K on parts.
That leaves £5.5K for survey’s, scaffolding, installation and commissioning. This is the bit that I’m not sure about so I’d be grateful to hear what others here have paid.
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I've been quoted just over £5.4k for a 5kw array and £4.8k for a 4kw array
And £4400 for a 5.2kw Givenergy battery system
This was before the VAT change
I really need to get back on the case.
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· To minimise shading losses I stipulated that I wanted panels with embedded bypass diodes.
· Panels to be wired in parallel rather than series to minimise shading losses, (installers usually default to series as it uses significantly less wiring).
· I asked for a Multi Power Point Tracking (MPPT) inverter/controller rather than a cheaper PWM device.
Our household consumption for March this year was rather typical for us:
• Car Charging = 225KWh
• Hot Tub = 275KWh
• Rest of House = 310KWh
With panels in parallel, the panels will be kept at the same voltage. If a panel is shaded, that will cause its voltage to drop, and it won't supply any current, which makes the bypass diodes pointless. The bypass diodes are useful when a panel will still be delivering current with some parts of it shaded.
I think that dealing with shading is best done with separate inverters for each panel. Dave from the EEVblog (https://www.eevblog.com/ (https://www.eevblog.com/)) had some issues with shading and his latest installation has micro inverters on each panel IIRC.
MPPT stands for Maximum Power Point Tracking. It continually adjusts the panel voltage to get the maximum power.
Have you got a heat pump for the hot tub?
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Just accepted a local authority auction quote of £6.4 k for a 14 panel 4.7kw array. Additional costs will include a diverter for the immersion heater of £450. Battery is unnafordable atm.
Edit. Also extra for the pidgeon netting.
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Just accepted a local authority auction quote of £6.4 k ...
How does that work?
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Thanks for the reply's folks. On the face of it my quote seems a bit on the expensive side, although given that I have specified particular preferences regarding panels/inverter/battery and the fact that I will require scaffolding on both sides of the house perhaps I should expect it to be a bit on the high side.
I did think about specifiing micro-inverters on each panel but in the end decided that they presented a bit of a challenge in the event of any repair/replacement that might be required. Of course it could be argued that a single inverter results in a single point of failure.
When I finally gave in to Mrs B and ordered a hot tub I talked to the supplier about a heat pump but decided that it wasn't worth the extra cost. That was back when we were paying 15p/KWh and I do rather wish we'd paid extra for the heat pump now but I should soon have a solar thermal panel plumbed into the tub which should help reduce costs.
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When considering the cost of the parts versus total installed cost, don't underestimate the cost of the panel mounting hardware. In discussion with my installer, it became evident that this is a large part of the cost, if a decent system is used. The design of this also needs to be calculated and verified.
My own 4kWp system was £5700 in 2018, including the solar iBoost unit, to power the immersion heater from surplus PV generation. It uses Canadian Solar 335w panels, and a Solax X1 twin mppt inverter.
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Just accepted a local authority auction quote of £6.4 k ...
How does that work?
Combine of several local authorities runs an auction with pre vetted installers. Households register interest and receive an individual proposal which they then have a month to think about. A small deposit then follows and all is subject to detailed survey. Price actually seems to be about current average, although a 30% discount is being claimed. YMMV.
https://www.cambridgeshire.gov.uk/residents/climate-change-energy-and-environment/how-you-can-take-action/home-energy/solar-together-cambridgeshire (https://www.cambridgeshire.gov.uk/residents/climate-change-energy-and-environment/how-you-can-take-action/home-energy/solar-together-cambridgeshire)
Well this is all beginning to turn into a bit of a disaster. This company does not communicate, return emails, use the telephone call back facility and is not following the procedures set out in its marketing bumpf, presumably agreed as part of the Local Authority procurement process.
Scaffolding is supposed to be erected up to seven days before installation and written confirmation provided that the agreed install date is still good up to four days before due installation date.
My installation was due on the 5th August, agreed when the major financial deposit was taken. No communications has been received since then. No scaffold has been erected. Materials arrived on the early evg of 3rd of Aug with no notice. The 'call' centre is extremely difficult to contact (other than sales, surprise surprise) spent 20 mins on their arrange installation option yesterday during which time I went from 4th in the Queue to 3rd then gave up.
This bunch also seem to have been awarded another contract in Devon.
The final installation price with extras for what is basically a 4kw array is £5400 ish including some extras such as pidgeon netting and a diverter but no battery. I would sooner pay a bit more for a decent service. Does not bode well at all for after sales. Screams lack of resources or possible financial difficulty to me, having worked in the construction industry for 40 years.
Oh dear I have just read these, wish I had done so beforehand. May be time to seek an alternative. So much for having Local Authority sponsors. Now would I have good title to the delivered kit I wonder?
https://uk.trustpilot.com/review/www.solartogether.co.uk?page=3 (https://uk.trustpilot.com/review/www.solartogether.co.uk?page=3)
Edit.
In accordance with the the terms and cons have cancelled this. But as expected no acnowledgement. I have received an invoice for an installation I have not had. You could not make this up! There is slapdash and there is incompetent. ISO 9001 oh really!. When chased for the payment I actually received a direct line to a human being. Told her that installation has not taken place. That was last monday. Nothing since.
A quick google produces a report from the London Mayors office highlighting 385 complaints being made about this company, very much in line with my own and other's experience. And yet, they are still being awarded further concessions. Something is very not right here.
https://www.london.gov.uk/questions/2022/2589 (https://www.london.gov.uk/questions/2022/2589)
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It's legitimate to ask the company why it will cost that much and to ask whether their price is negotiable.
Something that you might consider as a preliminary stage is dropping any chimney stacks no longer in use and making good. The chimney brickwork would terminate below roof tiles, with the rafters/tiles then augmented to cover the gap. I've had quotes of £600 for that job.
The rationale for dropping the chimneys is that future maintenance on a chimney stack would become more expensive where the contractor needs to work around a PV installation. And your PV cells would receive more light.
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Hi,
Rather a new interloper here as I'm not a serious cyclist, but I came across this thread (via another excellent one) and perhaps can contribute. Sorry if after nearly 4 months I'm too late, so I'll keep this moderately short (for me). First my credentials are that we had an 8 panel system installed last November, also via a Solar Together "Auction" (Surrey), which cost around £4k for the installed panels, etc. and +£2k for a LiFePO4 battery (3kwh) with upgrade to a Hybrid Inverter, etc. That seemed a reasonable price but I'm not sure it would have been at +30%. We had planned for 10 panels (which didn't change the cost much) but the shape of our otherwise "optimum" roof (South-facing at 37 degrees slope) couldn't accept more than 8.
Therefore, the quote of £11k seems high for what appears to have been offered. However, IMHO your specification/stipulations seem "wrong". Embedded diodes won't do anything in a Parallel-connected panel arrangement, but that seems inappropriate for an on-grid/domestic system. Parallel-wired would give around 100 Amps at 35 volts (compared with 10 Amps at 350 volts for Series), which will be much less efficient (and probably unreliable) in generating the Inverter's internal ~400 volt bus. An inverter of over 3 kW will probably have dual MPPT inputs, ideal for your separate E/W panels.
Whilst I appreciate your concern about locating "optimisers" directly at the panels (I felt the same), a diode effectively "writes off" any power from an affected panel, whilst the optimiser converts it to a useful voltage. We were quoted £50 for individual panel optimisers or £30 each for the whole roof; since we have 1-2 panels occasionally shaded by a chimney stack, I specified just one optimiser for the more affected panel as an "experiment" and the overall power does seem significantly reduced when the shadow strikes the other panel. I believe most domestic Inverters are MPPT now and LiFePO4 are (or were) actually cheaper (and better) than Li-Ion, but their lower energy density makes them less ideal for EVs. Sadly the price of LiFePO4 battery packs seems to have almost doubled in the last few months, and personally I have a rather reactionary view to consider Lead Acid batteries if the Inverter can be located in a garage, but I won't expound on this at the moment.
My main reason for contributing is that your electricity consumption at 810 kw/month is unusually high; to generate that in March on a South-facing roof is likely to need more than 20 panels! I haven't calculated how much worse would be E+W facing panels, but remember that if the elevation of the sun is lower than the slope of the roof (e.g. throughout the winter in UK), then the sun will be "behind" one of the sets of panels. PV panels need direct sunshine and not at too much of a "glancing" angle; it's true that they do deliver "some" output under cloudy skies, but in the same way that you may make some progress to your destination if you carry your punctured bike on your back, compared with riding it? Typically, in a UK winter, the panels will deliver about 25% of their daily summer output and last December our system generated only 10% of their summer output (just 5 kWh per panel in the whole month). Personally, I've found the following PV System Calculator very comprehensive and apparently quite accurate (seems to include localised Cloud Cover data):
https://re.jrc.ec.europa.eu/pvg_tools/en/tools.html
There's more I could say, but this must be enough for now.
Cheers, Alan.
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Just cancelled the order for the PV panels (Statutory cooling period of only 14 days which commences when materials are delivered but before installation) and will go with one of the main energy providers instead I think. If this involves a significant wait so be it. Have been in touch with the LA and it seems I am not alone in experiencing problems with this particular firm. Shame, its such a good idea.
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Can anyone point me towards a PV panels on the roof basics introduction?
Recently moved in to my (final?) home, work to do, fine with that, south facing bungalow at top of a slope so sun shining bright on me just now.
Thinking about solar panels. But have no knowledge on subject. Would like to understand the basic principles before contacting potential providers, so I at least understand what they're talking about.
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Post 1 of er, many.
I can help you here but it's best to explain things with how technology has evolved.
Back in the dark ages of solar PV, perhaps as much as 20 years ago :o solar PV was wired like this:
(https://www.solarquotes.com.au/img/solar-panel-array-DC.jpg)
This is a bit of an exaggeration as under load a PV panel produces 34 ish or 39 ish volts. So the 'string' 6 panels under load would produce 207 to 234 volts. But. If your One Big Ass Inverter is not consuming what the panels are potentially producing the panels get grumpy & frustrated and their output voltage rises. Think of it as pressure in a pipe. Each panel is trying to pump water, if each one can shuffle their water load on to the next panel they are all happy. But if there is a blockage the panels get angry and try to force their water through, each panel pushing hard as it can against the next. If the inverter doesn't take the load the back pressure becomes interesting.
You could have one hell of a big pile of voles at the input terminals to the OBAI. 600V DC as the picture shows will ruin your day if you come into contact with it.
Despite the big hairy ass voltages in your roof this was an ok system. Simple to wire as the panels very quickly gained a simple, standardised, good quality connector. Plug one to the next to the next & the installers were happy & the consumers ignorant.
There was a down side though. Shade. If a fat bar steward pigeon sat on one panel shading some of those little squares (more than one but less than half a panel) the output of the entire string dropped. If one panel fell to 50% so did all the other panels in the string. Imagine the fat pigeon has it's knarly, deformed talons crimped around the cable of that one panel crushing the cable for all it is worth. Because the vole flow for that one cable is restricted so is the vole flow for all the other panels in the string. In Canada, where the bears live, a big maple leaf landing on one panel could knock an entire string down to 50%. So few chestnut leaves or the shade of a chimney on a UK panel.
Something had to be done. So it was.
To be continued...
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This is interesting, I await the next instalment :)
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Part deux of many.
Pretty much every component in the string inverter system above is a single point of failure. Whatever breaks or fails, the whole system output is hit. So what if instead one one big ass system you had lots of independent small ones?
Enter the micro-inverter:
(http://soretween.altervista.org/misc/Microinverters.jpg)
Each micro-inverter converts the DC from one panel into 240VAC. Wiring is dead simple, the same standardised connectors are used on the DC side and the multi-drop cable on the AC side comes pre-made.
The micro-inverters live on your roof under the panels:
(https://external-content.duckduckgo.com/iu/?u=http%3A%2F%2F4.bp.blogspot.com%2F_GbVfHUmEcfA%2FS-c8cVed5HI%2FAAAAAAAAADU%2F2RoeTRIHKys%2FS724%2Fmy%2Bsolar%2Bpics%2B050.jpg&f=1&nofb=1)
If a leaf falls on one panel only that panel is affected versus losing output from your whole string:
(https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fres.cloudinary.com%2Fdxkmfveis%2Fw_1024%2Ch_1024%2Cc_fit%2Frksolar%2F2019%2F04%2Fmicro_string_comparison.jpg&f=1&nofb=1)
The down side is that there is more to go wrong. But really, who cares? If a panel fails in a string setup your whole system output is zero until you can get the panel replaced. If your string inverter fails zero output again. With microinverters no one component can bring down the whole system, you might be down one panels worth of output for a while but the rest keep doing their thing. No single point of failure - almost, bah :-( I'll get to that in part 3.
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This is a bit of an exaggeration as under load a PV panel produces 60 ish or 72 ish volts. So the 'string' 6 panels under load would produce 360 to 432 volts. But. If your One Big Ass Inverter is not consuming what the panels are potentially producing the panels get grumpy & frustrated and their output voltage rises.
Interesting thread.
Minor point of order here. PV panels will self-limit their voltage, and that voltage is only 20 - 30 % higher than the voltage at which they produce the maximum power. So if the inverter isn't taking current, there is a larger voltage, but it's not massively larger. 6 panels in series will produce enough voltage to kill you, whether they are running normally or no load is being taken.
The shading issue is a real problem.
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Thanks ST. When's the next lesson? 😊
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PV cells sound a bit like bike dynamos, also trying to push a constant current.
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Part C.
There is one more component required in a micro-inverter system not shown above, a controller. The controller does two things, first it tells the micro-inverters what to do, what voltage and frequency to output and so on. Second it interrogates the micro-inverters to see how much power they are producing and report that on to the cloud or a local PC. A controller is required by law but it wasn't always so. Once you could have a system installed & the installer would use a temporary controller to program up the micro-inverters and then be on his way. The only reporting your owner got was from a meter measuring the system output. Now all systems must have an on site controller fitted at all times. This is good for the customer because they can get panel level monitoring. It also means the profile of the micro-inverters can be adjusted quickly, the electricity company can ask the manufacturer to push out a minor adjustment to better match the grid profile. When I installed my small system I downloaded the list of profiles and there were hundreds of them, far more than just the variants of 220, 230, 240 & 110VAC in combination with 50 or 60 Hz. The bad news is that micro-inverters must shut down if they do not hear from a controller, I have no idea how long they will continue to produce if your controller goes silent.
(http://soretween.altervista.org/misc/Microinverters2.jpg)
Some controllers communicate wirelessly with the microinverters, others piggy back the control over the top of the mains. Whatever, the controller is a single point of failure in an otherwise very resilient arrangement. The good news is it will be fitted somewhere easily accessible, near your meter probably. 10 minute job to replace if that single point of failure does so in the middle of winter!
Aside:
I've just realised I've mixed up one thing. I incorrectly recalled the significance of the numbers 60 or 72 as being the output voltage, that is wrong. Panels usually have 60 or 72 cells in them, other variants exist too such as 54 or 96 but 60 cell & 72 cell are the most common. It is not a simple one cell to one volt relationship. I'll look it up the correct typical output voltages and make appropriate corrections. Sorry about that.
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Doesn't an individual solar cell give you (when open circuit) the usual P-N junction voltage of 0.6V or so?
Panels are presumably made up of series-parallel strings, akin to large batteries.
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Figures updated. Refresh your browser if you still see 72V in the part deux image.
Doesn't an individual solar cell give you (when open circuit) the usual P-N junction voltage of 0.6V or so?
Yes (for engineering values of yes which is more accurately yes-ish). A quick check of a few panel datasheets (https://www.pluginsolar.co.uk/?product_cat=standard-solar-panels) gives about .55 - .57 per cell under optimal load and .65 - .68 open circuit.
Panels are presumably made up of series-parallel strings, akin to large batteries.
Solid yes. The most common panels are actually 120 or 144 cells made up of two parallel strings so 2x60 or 2x72. That is why output drops to half in the one leaf scenario, one of the parallel strings is not producing.
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Part iv.
In the two systems above microinverters have a huge advantage which meant string inverter manufacturers were in danger of losing their lunch. Something needed to be done about one leaf or a bit of shade halving or even knocking out all production from a string. So optimisers were invented. These are basically bypass valves that allow power from unshaded panels to bypass a shaded or faulty panel. They sit in the system like this:
(http://soretween.altervista.org/misc/Optimisers.jpg)
The optimisers live on the roof under the panels just the same as the micro-inverters do. They are generally more than just a bypass valve, they also provide panel level monitoring. The sting inverter communicates with the optimisers via a signal piggy backed onto the high voltage DC loop. So now string systems have most of the advantages of a micro-inverter system. Shading only affects one panel, a faulty panel doesn't knock out the string, and you have panel level monitoring. However, the optimisers are now single points of failure for the string instead.
So that's the three main types of system. Dumb string systems still have their place as they are obviously the cheapest, solar parks & industrial roofs where shading isn't an issue. Commercial installation don't need panel level monitoring, if a string is under performing they'll send a person to investigate. Most domestic installations ought to be micro-inverter or string with optimiser, unless it really does have zero deciduous trees in the vicinity and zero shading year round.
Next I'll have explain a bit more about the life cycle of panels.
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Im reading this with interest.
Can you also touch on the issue where the inverters need an existing supply to sync to, and whether they can run standalone in the case of a power cut (Island mode?), thx..
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Hi,
Another feature of the PV/Forward Silicon Diode voltage issue is that the ~600 mV has a negative temperature coefficient of ~2 mV/degree C. That's why all Panels lose about 0.3% of their output voltage/power for each degree C rise in temperature.
No, the "surprising" answer is that most PV systems must "shut down" if a power cut occurs. It's primarily a "safety" requirement to prevent any locally generated power being sent out to the "National Grid" where people may be attempting to repair the cables! I don't know how or if the MicroInverters can handle this situation, but our "Hybrid" (combined PV and Battery) Inverter does have a separate "Un-Interruptable" output facility up to 3 kW (for one 13A socket). Sadly, our installer didn't even offer to connect this up as an option, which I probably would have accepted, if the price had been reasonable. However, it is only primarily intended to run a PC or Router, etc., it's not going to keep the Lights on, or the Pump and Gas valve running in a typical Central Heating system. :( Incidentally, we did have a (very rare) power cut recently and not only did the PV system "stop", but because the Router and all the communications also failed, the (one hour) event is still almost "invisible" on our data logs.
Perhaps it's also worth mentioning that there are separate "ac" and "dc" parts of the system. The PV panels themselves generate dc (typically 200 - 350 volts) and so does an (optional) battery (typically 48 volts) whilst the (National) "Grid" is ac. ALL other ac power, e.g. from the Inverter(s), must be perfectly synchronised to the 50 Hz Grid, or there will be a very big bang. :) Thus a fundamental difference between MicroInverters and Optimisers (or basic PV panels) is that the "downlead" from the roof will carry ac instead of dc. I guess that optimisers are far cheaper than MicroInverters since they only need to handle ~50v dc compared with ~230v ac (rms, so ~700v peak-peak). Similarly, I believe that some battery packs interface with ac rather than dc.
Even relatively small batteries can be a large added cost to the installation, so it's worth considering their benefits. At best, the most you will be paid for any energy you "Export" (via the "Smart Export Guarantee") will be about 25% of what you have to pay to buy the same energy, and a recent quote I got from BG was nearer 5%. Thus it makes sense to store energy to use overnight (or alternatively charge the battery from lower cost overnight energy after "dull" days). Also, in winter, early morning, late evening or "overcast" weather, etc., the PV system may be only "ticking over" at perhaps 0.2 - 1 kW, so the battery can handle any "surge" load such as boiling a kettle (3kW), Microwave Oven, etc., without needing to pull in any expensive power from the Grid. Sadly, there's nothing that a battery can do about the considerable over-generation in summer (e.g. the last 10 days) and severe under-generation through most of the winter, in UK.
Cheers, Alan.
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On my relatively small panel installation (6 panels) the calculated payback time of a cheap battery storage system was around 20 years.
I've decided against, but I suspect that the technology isn't quite mature for battery backup at prices households can afford.
Sent from my moto g(30) using Tapatalk
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Battery storage payback varies massively with consumption/size/solar performance and with the delta between overnight rate and day rate electricity (assuming you can get overnight cheap rates).
Also, if you are getting solar PV, then the battery is at the same VAT rate (0 or 5%, can't remember), but if the battery is a standalone then you pay all the VAT. A 9kWh battery install is about 5-6 grand at the moment (including VAT), if you can find someone who has one they can install. I've not updated my payback math since the latest electricity price rise speculation, but on current prices, if you can charge it at 7.5p per kWh, and that means you don't need to use the day rate of 40p per kWh, that's £2.80 or so a day, or around a grand a year. NB that's a super simple calculation - if you have solar you could save more, but batteries are often limited in terms of output power, so if your battery limits at 5kW and your shower pulls 10kW, you're using 5kW of 40p electricity for the duration of your shower.
I think our solar system cost 5 grand about 5 years ago. It's old enough to not have microinverters, but it seems to be relatively reliable in terms of the output curve, I don't think pigeons bother it all that much (east/west, so where the sun is makes a massive difference). If you get panels, make sure to get anti-pigeon stuff installed at the same time - we've had a real issue getting stuff installed to try to stop them rattling around under the panels!
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My troubles with the Solar Together nominated provider for this geographic Local Authority area continue. This firm is called Green Energy Together (GET) of Ware Herts. Avoid at all costs!!!!
They have just invoiced me for my new installation. But, the problem is, I do not have a new installation, the component parts are sitting where the delivery guy put them on the 3rd August. I cancelled the order by email on the 11th August (with hard copy recorded del to their head office) as they did not install on the 5th as scheduled and have not communicated at all since. I cancelled in accordance with the terms and cons (within the cooling off period) as I did not want to lose my ability to cancel. They do not seem to read emails, return phone calls, or make call backs when agreeing to do so. I spent 40 mins odd on the phone today to no avail by not moving in the queue at all. ( I find this highly suspect tbh).
With baited breath I have sent them photos, taken today, of the uninstalled kit about my premises asking them to remove same asap.
It would seem they have confused me with someone else, whom presumably, they have not invoiced for a new installation. British industry at its finest. Strewth.
The sooner these guys are out of my life the better.
Solar Together seem completely toothless but they do communicate well. I have copied them into every email attempt I have made with GET but I am still where I am today. Their ability to hold the contractor to account for compliance seems somewhat limited or perhaps non existent.
Even if I do get my deposit back this experience will still have cost me £150 for the survey.
Solicitors beckon methinks.
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Just cancelled the order for the PV panels (Statutory cooling period of only 14 days which commences when materials are delivered but before installation) and will go with one of the main energy providers instead I think.
Hi, hope your issues with the original company are being sorted. Who are you planning to go with?
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For those of you who went over + batteries, how much space did you need for the batteries and where did you store them?
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I don't think anyone here has - as I have mentioned on another thread, they are not yet economical for domestic use where you have a reliable connection to the mains.
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OVO are asking for expressions of interest atm so may well see how it goes with them as and when. OVO Australia already install. Eon install, but seem a bit spendy. Batteries in the UK are still prohibitively expensive. Big Battery.com in the US illustrates just how much more expensive, when they can supply a 7plus KWh battery with 10 year guarantee for $2499 plus inverter, this including auto heat detection and suppression. Also, I am not that keen on having a battery internally due to fire risk, which will further increase the cost of any installation, particularly if housed externally in a suitable cabinet.Heat pumps don't appear to make economic or practical sense for me atm.
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There's an article in today's Guardian on Solar PV. https://www.theguardian.com/money/2022/aug/20/solar-panels-how-to-fix-your-energy-bills-while-the-sun-shines
My interest was piqued by the suggestion of using your excess generation to run an immersion heater, rather than exporting for the crap return you are offered these days. 'That's a good idea' I thought. Though it seems it's not really very practical to use this in combination with a combi boiler. I suppose I could in theory get a future new hot water shower (i.e. not electric) installed and just have that (and maybe the bathroom sink tap) running off the immersion. (Though assuming the water heats during the day would it stay warm long enough to have a shower with it early the next morning?)
(And I suppose if we were to go the whole hog eventually and get ASHP that would negate the immersion idea).
Hmmmm
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You can pre-heat the cold feed to a combi. How much the boiler will tolerate depends on its ability to modulate down sensibly. MIL's former house (solar thermal) had a thermostatic mixer valve feeding water to the combi at about 40C, which was meh.
Alternatively, I suppose you could use a combi boiler to heat the water in the tank as if it were another central heating zone...
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I would have thought that if you wanted to heat water you would do it direct, not via pv. You could use pv to run a hp though, running in reverse in summer to cool your house.
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Yebbut the point is that if you get solar water you don't get any voles. This way you get voles and anything extra you get free HW.
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You can pre-heat the cold feed to a combi. How much the boiler will tolerate depends on its ability to modulate down sensibly. MIL's former house (solar thermal) had a thermostatic mixer valve feeding water to the combi at about 40C, which was meh.
Alternatively, I suppose you could use a combi boiler to heat the water in the tank as if it were another central heating zone...
The articles I was reading suggested that only certain boilers could accept preheated water.
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You are correct, Mrs P.
Whilst using PV to heat water may seem illogical, its actually cheaper and more reliable, and you have the flexibility of using your excess voles in the way you want. 95% of our water is heated this way, its just on particularly crap winter days we may need to let the oil boiler do a bit of water heating. This is in rural mid-Wales, where is is often cloudy (I mean we are in the clouds because of altitude, not the sky is cloudy, which is NFW).
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Interesting to know, thanks Wombat. Are you heating your water with excess PV or is that the primary use for it? How long does it stay hot for - can you have an early morning shower using the previous days' HW?
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In our owned house we ran hot water on a separate circuit with a massive tank in the attic and the immersion connected to the PV. The only hot water heating for a lot of the year was the immersion heater and was perfectly hot enough for the morning. This was though with a large tank, very well insulated.
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Hi,
For those of you who went over + batteries, how much space did you need for the batteries and where did you store them?
For us it was almost a no-brainer, the Inverter went inside the garage on the wall beside the Electricity meter and with the (3kWh) Battery below. I'd expected it to be hung on the wall but it just sits "upright" on the floor; it's basically like a "19 inch rack" (45 x 40 x 15 cms) which would have been stacked up if we'd ordered more of the 3kWh modules. Each module was priced at about £1000 but that appears to have doubled in the last 6 months. 3kWh is not really large enough, but at present prices the law of diminishing returns may make it "about right".
The first use of the battery is for short bursts of energy (less than 1 kWh) for kettle, toaster, washing machine, etc. when the PV may be only ticking over at <1kW in early morning and winter, etc., and avoids buying in full-priced electricity. The next use is to power the house overnight on "free" electricity in summer, or in winter to charge overnight on low(er) cost electricity to use during the day. 3 kWh is not really enough to do that fully but it's only a part-year feature. However, even a large battery won't do much to get over the three or more consecutive days of generally either "sunny" or "overcast" weather common in our UK climate. Also it probably won't help much with an electric (only) shower (~10 kW) which is why I'm looking at installing a thermostatic "power shower" to run from the HW tank.
As I hinted in my post on 1 August, if I were buying the system now, I would consider requesting Lead Acid batteries (Deep Cycle, Leisure or Marine type) for which £1000 could buy around 10 kWh. All that can't be used continuously, but 50% DOD will give 5kW and maybe more for the occasional "unusual" conditions. Those batteries may not last more than 5 years but by then, the LiFePO4s may be better value or you may have a "battery with wheels" (aka an EV) when the concept of the car supplying stored power to the house will be more mature. ;)
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A standard "foam" covered HW tank probably won't keep its temperature particularly well; I've just set our Immersion heater to run in/until the late afternoon to use the PV, but the water is noticeably cooler by the morning. So I plan to add a low-cost Immersion "Jacket" which (the reviews suggest) should help considerably. It depends greatly on how much hot water you use, but we're actually "losing" more energy from the tank than the hot water used. But that's still more economical than exporting the electricity (even to Octopus at 7.5p/kWh) and of course in winter the energy is not really "lost" if it helps to heat the house.
Cheers, Alan.
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Cheers allycat, I was wondering how we could put a water tank and batteries in the loft, but looks like batteries are not as big as I thought.
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Hi,
If PV panels are installed at the same time as the battery (which I believe saves VAT and was mandatory for the much larger Tesla Powerwall), then a "Hybrid" Inverter may be installed, that converts the dc from the panels AND the battery to ac. Maybe a little larger and more expensive than a normal Inverter, but I don't know the situation for MicroInverters, or if a PV system is already installed.
You can give yourself a fright by looking for "Pylontech" (LiFePO4 batteries) on ebay, where the price almost doubled within a few months. The size (and number) of battery modules will depend greatly on your electricity usage (quantity and daily pattern) but I'd suggest aiming for about 18 hours of storage at your average consumption (i.e. 3/4 day) if the price looks "realistic". Hybrid Inverters generally accept 48 volts dc such as from Pylontech (and other brands) OR from Lead Acid, e.g. 4 x "car type" batteries connected in series. Each 120 Ah "Leisure/Marine" battery is probably equivalent to about 0.75 kWh taking into account the recommended 50% Depth Of Discharge.
Cheers, Alan.
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Life. Don't it just get in the way.
So, solar panel life cycles, what's that all about? Put simply - they degrade, they all degrade and a sales person telling you theirs are super-duper producing the same after 25 years as on day 1 is probably lying. Hmmm, how can we have 'probably' and the assertion that all panels degrade in the same sentence? Let me explain.
Here's a typical Warranty graph:
(https://www.germansolarusa.com/wp-content/uploads/2017/03/GermanSolar-panel-linear-warranty.png)
First the dark grey part - this is how warranties on solar panels used to work (and some still do). From day 1 through to the end of the 10th year the manufacturer only guaranteed 90% of rated output dropping to 80% years 11-25. That's a bit crap, your 250 watt panels might only produce 225 on the day you switched them on. Your string of ten could have produced only 2.25kW instead of 2.5 kW on day one. From year 11 on you might only see 2kW on those rare bright & sunny days.
Manufacturing techniques improved and reduced the variability out of the factory, also manufacturers started to 'bin' their panels, by which I mean they would test them and then sell them as 260 watt, 250, 240, 230 etc depending on their actual performance rather than 'we're trying to make 250 watt panels so we'll sell them all as that'. These two changes allowed linear warranties to be introduced, the orange area. Panels still degrade just the same but it's more predictable and steady.
All panels have a production warranty, ask to see yours before you buy. The above slope is 0.8% per year. The Canadian Solar panels I bought for my experimental array are 0.6% per year. LG produce some (https://www.pluginsolar.co.uk/?product=lg-neonh-375w-all-black-mono-solar-panel) that are warrantied at 0.25% per year, naturally these are more expensive up front.
So does this mean we are stuck with buying systems that only produce 'boilerplate' power when brand new (if at all) and get steadily crapper over time? No, we over-spec the panels to account for it.
Take for example Enphase IQ7a micro-inverters (https://enphase.com/store/microinverters/iq7-series/iq7a-microinverter). These are specified to work with panels ranging from 350 to 460+W which is a huge variability. So which panels do you choose? Although the input power is widely variable the output power, what the electronics can handle, is limited to 366W1. So if we size our panels so that after x years they still produce 366W we're golden? Yes we are. Panels degrade but electronics do not, they either work or they fail. So choose panels that can run your inverter flat out for whatever the payback time of the system is. This is what the salesman who swears his magic panels don't degrade is doing, he's over-specking the panels so the customer doesn't see the degradation. Or he's not that clever and flat lying to you.
String inverters are the same, here's the data sheet for Growatt string inverters (https://www.pluginsolar.co.uk/wp-content/uploads/2019/08/growatt-mtl-s-datasheet-9.pdf). For inverters with max rated power output of 2500W they allow up to 2900W panel arrays. I get the feeling looking at the numbers the margins are not quite so generous on these string inverters, I could be wrong & I don't have the spoons right now to fully dive in.
After the system has paid for it who cares if there's degradation? Your system might produce 100% power for 10 years and pay for itself. In year 11 it starts to degrade by 0.8, 0.6 or even 0.25% per year, its still 100% free power, you are not going to match your household load that closely that such a small percentage makes a material difference. Sure you could have bought better quality or higher power panels up front but that would have cost more. The cost benefit relationship in that part of the system life is very hard to gauge. The CO2 manufacturing payback on solar panels, by the way, is so short it's not even a factor. Less than a couple of years (https://www.renewableenergyhub.co.uk/main/solar-panels/solar-panels-carbon-analysis/) even if they are shipped half way round the world.
1Actually the spec is 366VA. Converting from VA to W is complicated and requires an understanding of power factors and imaginary power. No really, imaginary power is a real thing. Imaginary but real. That makes perfect sense. For simplicity I'm going to assume W=VA which in a lot of loads at home is near as makes no odds true.
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Interesting to know, thanks Wombat. Are you heating your water with excess PV or is that the primary use for it? How long does it stay hot for - can you have an early morning shower using the previous days' HW?
A good modern hot water tank should keep warm for almost a week. A friends solar install he's using the hotwater as a dump load, his tank was installed a couple of years ago, and it loses about 1kwh of heat per day. So next day should be no problem if you've put enough energy into it.
J
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I don't think anyone here has - as I have mentioned on another thread, they are not yet economical for domestic use where you have a reliable connection to the mains.
A battery (even without solar) can be economical if you have dual rate electricity and can charge the battery on the cheap rate and don't need to use the expensive rate. Obviously it depends on the amount you use, the rate at which you use it and the delta between the cheap and expensive rates.
The ability to fire the immersion heater based on whether or not you are exporting to the grid has been a thing since at least 2016 when we got our panels. The system we had was called iBoost, but if I were you I'd look around and see what alternatives there are - it expired after about 4 years, and the warranty was only 3, so we had to pay for an entirely new unit to be installed. We've been having issues with our thermostat tripping out this year, and we've had a new thermostat which hasn't fixed the issue - maybe the immersion has done something odd, or maybe it's some sort of iBoost effect.
SoreTween - are Autarco still offering guaranteed output? When we had ours installed, they guaranteed a total amount to be generated over the first 5/10 years, and if it falls short of this number then they will pay you what you would have got from the FIT had it hit the spec. It's not exactly generous, and FIT has gone now, but I don't know if there are suppliers who are prepared to stand behind their products and guarantee an output over the medium term?
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Is an immersion/HW tank in the loft (insulated but in the bottom, not the top) a really bad idea?
(Probably a sensible place to put it would be our bathroom, but I won't be refitting the bathroom the same year we get solar...)
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I don't think anyone here has - as I have mentioned on another thread, they are not yet economical for domestic use where you have a reliable connection to the mains.
A battery (even without solar) can be economical if you have dual rate electricity and can charge the battery on the cheap rate and don't need to use the expensive rate. Obviously it depends on the amount you use, the rate at which you use it and the delta between the cheap and expensive rates.
I'm not convinced, please show your working
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I'm not convinced, please show your working
If daily usage is 10kwh. If you can store that power in a 12kwh battery, which you charge at night at 20p/kwh rather than 30p/kwh, that means you're paying £2 per day, rather than £3 per day. If your battery setup costs you 365 quid, then it's gonna be money back at one year. Obviously it's not going to be so cheap, but cost of battery in pounds, is number of days until it pays back.
Nooow, if you had enough solar on the roof that you could get 10kwh of energy per day from the sun, then you are now saving yourself approx £3 per day. So pay back is now 3 times as quick if it's the same price...
IMHO, the issue with a lot of solar installs is they are just too small.
J
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SoreTween - are Autarco still offering guaranteed output? When we had ours installed, they guaranteed a total amount to be generated over the first 5/10 years, and if it falls short of this number then they will pay you what you would have got from the FIT had it hit the spec. It's not exactly generous, and FIT has gone now, but I don't know if there are suppliers who are prepared to stand behind their products and guarantee an output over the medium term?
Never heard of autarco, will dig when I can.
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I'm not convinced, please show your working
If daily usage is 10kwh. If you can store that power in a 12kwh battery, which you charge at night at 20p/kwh rather than 30p/kwh, that means you're paying £2 per day, rather than £3 per day. If your battery setup costs you 365 quid, then it's gonna be money back at one year. Obviously it's not going to be so cheap, but cost of battery in pounds, is number of days until it pays back.
Nooow, if you had enough solar on the roof that you could get 10kwh of energy per day from the sun, then you are now saving yourself approx £3 per day. So pay back is now 3 times as quick if it's the same price...
IMHO, the issue with a lot of solar installs is they are just too small.
J
Yep, that's exactly what I was looking for.
So a decent deep cycle lead acid battery, 115 Ah per unit @ 12V is around £150. If you cycle them to 50%, that's 115 x 12 / 2 = 690 Wh. For your 10 kWh you need 14.5 of them = £2,173. Divide by 365 = 5.95 years.
At 50% daily discharge an AGM battery will last 3-5 years.
3 to 5 < 5.95
therefore it's not economical, QED.
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And that doesn't include the fact you'll need some clever control electronics if you want to store and later use exactly 10 kWh every day, plus an inverter (which will also be lossy) all of which cost £thousands.
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<snip>maffs I is not arguing wiff</snip>
therefore it's not economical, QED.
until the next price rise.
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Hi,
Is an immersion/HW tank in the loft (insulated but in the bottom, not the top) a really bad idea?
I'm not a plumber but as nobody else has answered, I'll suggest 3 factors which need to be considered:
Firstly, water is heavy so don't get carried away by very large tanks (which might not pass through a loft hatch either?).
Secondly, HW tanks are usually "tall" (so that hotter water can rise to the top) but (at least with a conventional system) the water level in the Cold Water (feeder) tank needs to be at least 1 metre higher than the top. I don't know if there are any regulations that determine how small the CW tank can be (e.g. to ensure that the HW tank can't "run dry"). Note that there are some very "exotic" HW tanks being offered now with multiple heaters (at different levels), etc, but AFAIK at a considerable price.
Sorry, but I think a little "theory" is required: Water systems have two independent parameters, Volume and Pressure (plus of course temperature and flow rate, etc.). Volume is usually measured in litres, easy to relate to a bottle of milk in size and weight. A typical Hot Water Tank is about 100 - 150 litres), which you can relate to how many or how long you can shower from a tankful. Such a tank needs about 6 - 10 kW.hours to heat all the water from cold to hot. The "flow rate" should be specified or measurable (typically 5 litres/min for a shower) but you may need to take into account the ratio of Hot to Cold if a (thermostatic) mixer is being used.
Pressure is best considered in "Bars" (about 14 psi in old money), where 1 Bar is atmospheric pressure (i.e. 1000 milliBars) and equivalent to a "column" of 10 metres of water, e.g. at the base of a pipe full of water running from a basement to the roof of a fairly large house. "Mains" Water pressure is usually at least several Bars because it needs to push water to the top of the highest house in the neighbourhood. The importance of pressure is that it can determine the flow rate (in association with pipe diameters and lengths, etc.) so a shower in an upstairs room with the (CW) tank on the loft floor may have only a small fraction of a Bar pressure and poor (natural) flow rate (hence the application of pumped power showers). Thus there can be merit in mounting the CW tank "high" in the loft (and physically it doesn't need to have a large volume).
The third issue is that "bought in" electricity is an expensive way to heat water (if you have any alternatives). Rarely will you have any "surplus" PV generation in the winter months (and I'm not even expecting any today). Therefore, I have no intention of disabling our existing "indirect" water heating from the gas boiler. However, I have fitted a "Solar" (Low Power, 1kW) Immersion Heater as a cheaper option to a "Diverter" (which I may eventually "roll my own") and plan to add a power shower to complement/replace the existing direct mains (water and electricity) shower. I've also just bought a HW Cylinder "jacket", which suddenly seem to have become in short supply. ;)
Finally, if choosing between adding a 6kW HW tank or a 6kW battery pack to a PV system, I would consider it a complete no-brainer to go for the battery; Lower losses and far more flexible.
Cheers, Alan
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Can you link to this HW jacket you refer to? Is it just insulation or something fancier?
I am only entertaining an immersion to be heated via excess PV, not paid for voles. Don't have a cold water tank either. I bet a tank with a solar diverter is a lot cheaper than a battery!
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My 300l stored hot water cylinder (Megaflow) does not have a Cold Water header tank in the loft, it is mains-pressure, and so the whole height thing goes away. Incoming mains pressure is around 3 bar, and that's fine for showers on both floors. Yes, upstairs will have slightly lower pressure due to the hydrostatic head between the incoming mains and the elevation of the upstairs shower. But much better than showers you will get from the hydrostatic head from a CW tank in the loft. (Unless you have a loft 30m up above you...) These legacy systems *will* require a pump to provide a decent shower, and *will* need a tank with sufficient volume not to be sucked dry by it! On the other hand, a CW tank can produce a higher flow rate via a pump than most mains supplies can sustain, but only until the tank is emptied...
It's also fully insulated from the factory to such an extent that the airing cupboard it occupies is no longer warm compared to the crappy old open vented cylinder it replaced, which was insulated with some thin blown foam around it, and then a wrap-around duvet effort. Water heated the previous evening will still be hot enough for a shower the next morning. There's no need to add any additional insulation or jackets to a modern decent cylinder.
It has space for two immersion heaters, but only one is installed.
(I think the design intent here is the lower one is for heating the full cylinder with cheap voles, and the upper one to provide a 'boost' of required using more expensive voles.)
I've only used the immersion during times when the gas boiler has been hors de combat, because this cylinder also has an indirect coil in it.
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Ta.
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Mains water pressure hot water tanks require heavy duty engineering plus regs and roolz for annual inspection - and the hot water temperature is delivery temperature. Vented low pressure thermal storage, at higher than delivery temperature with a mains pressure plate heat exchanger is current practice for hot water energy storage
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Mains water pressure hot water tanks require heavy duty engineering
Really? what might that be?
All it requires is to follow the manufacturer's installation instructions.
Heatrae Sadia provide detailed installation instructions for the Megaflo tanks which are not hard to follow.
Basically, use the supplied fill and expansion relief valves, the over-temperature/pressure relief valve, piped to a tundish to a drain.
Keep the pipework within the specs.
Nothing heavy duty about that.
plus roolz for annual inspection - special qualifications required..
That might be correct, I think installation needs to be done by a competent person and there may be a requirement for inspection.
<shrug> I did all of this myself, and I do inspect it. To date, no-one has welded the relief valves shut.
Mains pressure hot water is standard almost everywhere else in the world. It's really not a steam bomb waiting to go off, unless you've *really* fucked it up by welding all the safety valves closed!
low pressure hot water storage with a mains pressure plate heat exchanger as described up thread is current practice
It is *a* current practice, but certainly not the only one. Megaflo and similar installations are not uncommon.
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I'm not convinced, please show your working
If daily usage is 10kwh. If you can store that power in a 12kwh battery, which you charge at night at 20p/kwh rather than 30p/kwh, that means you're paying £2 per day, rather than £3 per day. If your battery setup costs you 365 quid, then it's gonna be money back at one year. Obviously it's not going to be so cheap, but cost of battery in pounds, is number of days until it pays back.
Nooow, if you had enough solar on the roof that you could get 10kwh of energy per day from the sun, then you are now saving yourself approx £3 per day. So pay back is now 3 times as quick if it's the same price...
IMHO, the issue with a lot of solar installs is they are just too small.
J
Yep, that's exactly what I was looking for.
So a decent deep cycle lead acid battery, 115 Ah per unit @ 12V is around £150. If you cycle them to 50%, that's 115 x 12 / 2 = 690 Wh. For your 10 kWh you need 14.5 of them = £2,173. Divide by 365 = 5.95 years.
At 50% daily discharge an AGM battery will last 3-5 years.
3 to 5 < 5.95
therefore it's not economical, QED.
I don't understand why you are dividing the cost of the batteries by the number of days in the year. Surely you should take the cost and divide it by the amount saved? Or are you using QGs 20p and 30p prices to get £1 per day?
Let's use actual numbers from Octopus Go. 7.5p overnight, 43p daily -> 75p vs £4.30 per day, so £3.55 delta. £1295 saving per year, with a £5k install, the payback time is under 4 years, and there is a 10 year warranty on the battery and inverter.
That's the ideal energy use, but assuming no free energy from solar.
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I don't understand why you are dividing the cost of the batteries by the number of days in the year. Surely you should take the cost and divide it by the amount saved? Or are you using QGs 20p and 30p prices to get £1 per day?
Cos with my maths, that's the what the difference in cost is. As you save £1 per day, it's an easy one to see that it saves you £365 per year.
Let's use actual numbers from Octopus Go. 7.5p overnight, 43p daily -> 75p vs £4.30 per day, so £3.55 delta. £1295 saving per year, with a £5k install, the payback time is under 4 years, and there is a 10 year warranty on the battery and inverter.
That's the ideal energy use, but assuming no free energy from solar.
I was using the numbers from my British gas bill adjusted to the nearest 10p to make maths easy.
J
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Any of Écossaises on here have experience of the Scottish Power Solar enquiry / quote system? Just lodged an enquiry with them - they're busy, surprise surprise - and will get some cost and savings estimates back from them, 6-8 weeks turnround vs 2 weeks in more normal times, for PVs with and without battery option.
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I don't understand why you are dividing the cost of the batteries by the number of days in the year. Surely you should take the cost and divide it by the amount saved? Or are you using QGs 20p and 30p prices to get £1 per day?
Yes, as QG said, I was using the bit in her post I highlighted. As the delta was 1 I didn't need to think about whether to multiply or divide by it :)
Let's use actual numbers from Octopus Go. 7.5p overnight, 43p daily -> 75p vs £4.30 per day, so £3.55 delta. £1295 saving per year, with a £5k install, the payback time is under 4 years, and there is a 10 year warranty on the battery and inverter.
That's the ideal energy use, but assuming no free energy from solar.
That gets more interesting.
However... the day rate on a split night/day tariff is much higher than a flat rate. The octopus rate back home is 26.31p currently giving only £1.88 saving by going to split tariff, less the extra you pay if you have to use any of the higher day rate. Under ideal conditions where you used exactly 10 kWh every single day, it's over 7 years payback, you'd probably struggle to break even. But it's getting there. Battery prices will come down and energy prices go up.
For a real-world example, I use an average of 600 Wh a day. I have three 115 Ah 12V batteries. This is over-specced for "ideal" conditions, but I need the headroom to be able to run the washing machine on some days and to cover dark winter days. As they are shallow-cycled they will hopefully last much longer, but at 26.31p it will be around 10 years for the cost of the batteries alone to match the 26.31p of piped electricity. And I inherited the solar panels, controller and inverter.
ETA: no, sorry, that's bollocks. There's the standing charge, which at such low usage is more than the unit price. The batteries will work out cheaper than being on the mains well within their lifetime, assuming the panels or electronics don't cark it in the meantime.
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Good point about needing to compare day/overnight with the regular price. I doubt you can get a contract with 26p as the 24/7 rate at the moment (it's really hard to get Octopus to give you a rate at all), but everything is going to be a much bigger number soon anyway.
It will be interesting to do the math again after October.
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Any of Écossaises on here have experience of the Scottish Power Solar enquiry / quote system? Just lodged an enquiry with them - they're busy, surprise surprise - and will get some cost and savings estimates back from them, 6-8 weeks turnround vs 2 weeks in more normal times, for PVs with and without battery option.
No, but 2 of my colleagues have had speedy service recently from an outfit in Glasgow, I will enquire on Monday if I remember.
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All a bit frustrating at the moment. I’ve been trying and failing to get solar PV and a heat pump installed. Today I’ve had my gas boiler repaired on the grounds that a heat pump, even if I can get one installed, is unlikely to improve CO2 emissions over winter running on marginal coal fired electricity unless I can also get the solar PV.
No doubt the contractor will call me tomorrow…
We currently have gas fixed at 4.3p/kWh and 25ppd standing charge to Sept 23. Electricity is Intelligent Octopus beta - c50ppd standing and 7.5p/kWh for 6 hours at night and 33.75p/kWh daytime. If I could post a picture directly I could show you the impact of load shifting - which works until the bairn decides she needs to run the 2.9kW over for half and hour to cook 4 fishfingers. I should get her to use the gas oven I think, and it’s probably lower carbon assuming similar thermal efficiency for each cavity (yes, an unusual cooker).
Mike
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..the bairn decides she needs to run the 2.9kW over for half and hour to cook 4 fishfingers.
Mike
Under a grill in minutes? In a microwave in seconds?
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Under a grill in minutes? In a microwave in seconds?
Microwaved they'll be horrible and soggy. Eew
J
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..the bairn decides she needs to run the 2.9kW over for half and hour to cook 4 fishfingers.
Mike
Under a grill in minutes? In a microwave in seconds?
No microwave.
Frying pan on the induction would be best.
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Oops wrong thread.
J
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until the bairn decides she needs to run the 2.9kW over for half and hour to cook 4 fishfingers.
Except, the 2.9kw oven shouldn't be using 1.45kwh of energy over that 30 mins to cook said fish. Once it's up to temp, it should then only turn on intermittently to keep it at that temp. If it takes 5 minutes to heat to temp, then you're looking at 0.242kwh to get it to temp, then a few seconds every now and then to boost it back to temp.
Where as an electric grill keeps the heat at the same level the whole time (at least the ones I've used), so even if you could bring the cooking time down to 15 mins by using a grill, you may in fact use more power (0.725kwh) by doing so.
This assumes the oven has a modicum of insulation around it, and a proper thermostatic regulator. Which the various electric ovens I've used, have had.
J
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until the bairn decides she needs to run the 2.9kW over for half and hour to cook 4 fishfingers.
Except, the 2.9kw oven shouldn't be using 1.45kwh of energy over that 30 mins to cook said fish. Once it's up to temp, it should then only turn on intermittently to keep it at that temp. If it takes 5 minutes to heat to temp, then you're looking at 0.242kwh to get it to temp, then a few seconds every now and then to boost it back to temp.
Where as an electric grill keeps the heat at the same level the whole time (at least the ones I've used), so even if you could bring the cooking time down to 15 mins by using a grill, you may in fact use more power (0.725kwh) by doing so.
This assumes the oven has a modicum of insulation around it, and a proper thermostatic regulator. Which the various electric ovens I've used, have had.
J
Yep, I know it cycles but it does take longer than 5 minutes to get up to temp. To be fair, she doesn’t preheat it, but I’d still prefer her to fry on the induction hob.
I can see the useage peak in my half hourly octopus history:(. Although it doesn’t compare to charging the car, running the immersion and washing clothes and pots at the same time of night! I have seen >6kWh in half an hour.
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Yep, I know it cycles but it does take longer than 5 minutes to get up to temp. To be fair, she doesn’t preheat it, but I’d still prefer her to fry on the induction hob.
I can see the useage peak in my half hourly octopus history:(. Although it doesn’t compare to charging the car, running the immersion and washing clothes and pots at the same time of night! I have seen >6kWh in half an hour.
Then be fair to the offspring. Judge not based on the 2.9kw, but the more realistic amount it uses.
Also how slow is your oven. My electric oven would get to 200° in 7 minutes.
J
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All a bit frustrating at the moment. I’ve been trying and failing to get solar PV and a heat pump installed. Today I’ve had my gas boiler repaired on the grounds that a heat pump, even if I can get one installed, is unlikely to improve CO2 emissions over winter running on marginal coal fired electricity unless I can also get the solar PV.
Solar PV makes marginal difference at best during the winter. Our system produced 54kWh in January and 116kWh in Feb this year (compared to 521kWh in June).
When combined with a battery it might allow you to timeshift your electricity consumption, which would probably reduce the CO2.
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All a bit frustrating at the moment. I’ve been trying and failing to get solar PV and a heat pump installed. Today I’ve had my gas boiler repaired on the grounds that a heat pump, even if I can get one installed, is unlikely to improve CO2 emissions over winter running on marginal coal fired electricity unless I can also get the solar PV.
Solar PV makes marginal difference at best during the winter. Our system produced 54kWh in January and 116kWh in Feb this year (compared to 521kWh in June).
When combined with a battery it might allow you to timeshift your electricity consumption, which would probably reduce the CO2.
Thanks Duncan, that’s useful to know. What’s the peak output rating of your installation?
Mike
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Plus we’re further north than you, DuncanM, so shorter winter days could worsen that position…
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Hi,
Solar PV makes marginal difference at best during the winter. Our system produced 54kWh in January and 116kWh in Feb this year (compared to 521kWh in June).
What’s the peak output rating of your installation?
Certainly Solar PV is unsuitable for general heating applications in winter (far more appropriate for Air Conditioning in "summer") but that ratio of winter to summer energy does seem rather poor; our first year suggests a ratio of about 1:4. However, our first month (December 2021) was particularly low (~40 kWh), perhaps because the MPPT had not optimised itself? The system is rated at about 2.8 kWp (8 x 350 watt panels) with the highest month (July) totaling just under 400 kWh. The web calculator that I linked on page 1 of this thread seems quite a good predictor, generally within about +/- 10% :
https://re.jrc.ec.europa.eu/pvg_tools/en/tools.html
Just drag the map to your location, set a peak power and slope (to horizontal) if unusual. Adjust the Azimuth (+/-), where South-facing is defined as zero degrees! Then Click "Visualise Results" and scroll down. For an E-W orientation you may need to add two separate calculations. The other defaults seem good enough, but it's worth trying "Optimise Slope/Azimuth" as a sanity check.
However, as for the "economics", how can one predict the cost of energy over the next 10+ years? But I find it hard to believe that Octopus will be able to continue with their "overnight" energy at 7.5p/kWh when/if more than 50% continues to be generated from gas.
Cheers, Alan.
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Interesting, that calculator reckons 75-100kwh in winter and 400-500 in summer here for 3.8kwp. (No idea if that is the right size we would get)
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Interesting, that calculator reckons 75-100kwh in winter and 400-500 in summer here for 3.8kwp. (No idea if that is the right size we would get)
Measure the width of the roof at ground level. Assume 1m x 2m for a panel, they're in that ballpark. 400w per panel is not bleeding edge any more so sane cost wise. Count the number of full tile rows to get the vertical. Look up the type on a roofing merchant to get the full size, if I recall correctly about 45% of each full tile/slate will be visible? That figure comes from dark and ancient corners of the memory so could well be wrong, hopefully someone will correct me. You should be able to get a feel for only one row / maybe two / easy two & be within a panel on the horizontal.
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If you have a gable end counting bricks, horizontal and courses to ridge would give you an idea of roof size and pitch
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Hi,
Solar PV makes marginal difference at best during the winter. Our system produced 54kWh in January and 116kWh in Feb this year (compared to 521kWh in June).
What’s the peak output rating of your installation?
Certainly Solar PV is unsuitable for general heating applications in winter (far more appropriate for Air Conditioning in "summer") but that ratio of winter to summer energy does seem rather poor; our first year suggests a ratio of about 1:4. However, our first month (December 2021) was particularly low (~40 kWh), perhaps because the MPPT had not optimised itself? The system is rated at about 2.8 kWp (8 x 350 watt panels) with the highest month (July) totaling just under 400 kWh.
Our system is an E-W split 7 and 8 panels (each a nominal 285W), and I think the total is supposedly 3.6kW. December is rubbish - it has been under 50kWh each year since we had it installed in 2016. On the other hand, this summer has been especially good - over 400kWh April and August, and over 500kWh in June and July.
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Our system is an E-W split 7 and 8 panels (each a nominal 285W), and I think the total is supposedly 3.6kW. December is rubbish - it has been under 50kWh each year since we had it installed in 2016. On the other hand, this summer has been especially good - over 400kWh April and August, and over 500kWh in June and July.
Cosine angles are screwing you over.
The optimal angle in summer is pretty much flat. The sun is high in the sky, and you get optimal return when it's close to flat. In winter, the optimal angle for say, Birmingham, is about 80°. In fact running at 90° (i.e. vertical), represents only an approx 8% drop in yield). Most roof pitches are in the 30-50° range. Which actually represents a good compromise across the whole year. But in winter it reduces what you're likely to get. In an ideal world you'd have a mechanism to tilt the panels to the optimal angle for the day. But that uses energy and it's often not worth the ROI.
As a ball park figure, in January/December expect to get about 0.6kwh per day, for every 1kw of panels installed on a south facing roof in the middle of the UK.
J
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We have a really shallow pitch on our roof, I don't know if that's good or bad! :)
I've not seen any roof based solar with moveable panels, I just don't think the extra cost and complexity give a good enough return. It's easy to make sturdy systems where rails bolt into the roof and the panels attach to the rails - trying to make he whole thing pivot/rotate would be a pita. And the pigeons would probably screw the thing up anyway.
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I suppose anything that tracks the sun automagically means complexity and moving parts, the economics of which compares unfavourably to installing a greater number of static panels. Possibly this could change if space becomes the limiting factor, rather than cost.
If the panels are somewhere more accessible[1] than a typical BRITISH roof, it wouldn't seem unreasonable to have some course manual angle adjustment that could be tweaked a few times a year. But that sort of thing doesn't play well with fit-and-forget marketing materials.
[1] Which probably means ground level. Obviously no manufacturer wants to be responsible for someone doing a Rod Hull.
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Yay to solar furnaces on roofs. When the neighbours piss you off, a few remote adjustments can melt their Corsa with the popping exhaust, incinerate the "Gin O'Clock" sign in the front garden, or cremate their yapping dog.
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Hi,
We have a really shallow pitch on our roof, I don't know if that's good or bad! :)
According to the calculator it's good because you have an E-W alignment. For that, the "optimum" slope is zero degrees, whilst for South-facing it's around 40 degrees (since the maximum UK sun elevation is ~60 degrees). The nature of the Cosine Law is that very little is lost by the first 10-20 degrees "off-axis" (which reaches 14% loss at 30 degrees and then changes rapidly). Thus the primary reason for using a truly horizontal or vertical PV alignment is aesthetic, not performance. Another disadvantage of pure horizontal mounting is that rain probably won't wash the panels clean (it's not worth considering snow here).
AFAIK the calculator maximises the total power generated over the whole year, which might be appropriate for a solar farm supplying electricity at a fixed price, but in the real world, electricity at some times is far more "valuable" than at others. In particular, any "surplus" electricity that a domestic user must sell back to a supplier will be bought at only 5 - 25% of the price paid to import the same electrons. Hence the merits of a battery or "diverter" (to hot water tank) storage, but at best this can be for a period of only a few days. Thus my inclination is to aim for a steeper PV slope on south-facing PV panels (when possible). The panels (and Inverters) should receive slightly less "surplus" energy in mid-summer, potentially keeping them cooler (more reliable and efficient) and increasing the "valuable" energy in winter.
... it wouldn't seem unreasonable to have some coarse manual angle adjustment that could be tweaked a few times a year.
I think the main benefit is in daily sun-following with an Az-El or Equatorial motor drive, but that's only realistic (and acceptable) at ground level (or a flat roof). However, the price of PV panels is such that (for some years now) it's not been considered generally worthwhile to introduce any "mechanical" complications (including pumps, etc. in solar-thermal systems). However, I am surprised that solar farm operators don't appear to pay somebody to spend a day or two adjusting their thousands of simple ground-level PV frames between say 70 and 40 degrees twice a year (spring and autumn). I assume it's because increasing the "sod all" generated in winter, even if by +50%, just isn't profitable?
Cheers, Alan.
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My troubles with the Solar Together nominated provider for this geographic Local Authority area continue. This firm is called Green Energy Together (GET) of Ware Herts. Avoid at all costs!!!!
They have just invoiced me for my new installation. But, the problem is, I do not have a new installation, the component parts are sitting where the delivery guy put them on the 3rd August. I cancelled the order by email on the 11th August (with hard copy recorded del to their head office) as they did not install on the 5th as scheduled and have not communicated at all since. I cancelled in accordance with the terms and cons (within the cooling off period) as I did not want to lose my ability to cancel. They do not seem to read emails, return phone calls, or make call backs when agreeing to do so. I spent 40 mins odd on the phone today to no avail by not moving in the queue at all. ( I find this highly suspect tbh).
With baited breath I have sent them photos, taken today, of the uninstalled kit about my premises asking them to remove same asap.
It would seem they have confused me with someone else, whom presumably, they have not invoiced for a new installation. British industry at its finest. Strewth.
The sooner these guys are out of my life the better.
Solar Together seem completely toothless but they do communicate well. I have copied them into every email attempt I have made with GET but I am still where I am today. Their ability to hold the contractor to account for compliance seems somewhat limited or perhaps non existent.
Even if I do get my deposit back this experience will still have cost me £150 for the survey.
Solicitors beckon methinks.
Same company
https://www.independent.co.uk/voices/solar-panels-sadiq-khan-green-energy-bills-b2162593.html?amp
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This evening I've been doing some number crunching. Our current electricity consumption is about 5.8kwh/day in midsummer and 8.93kwh/day in winter. Based on the figures from the calculator above that estimates we would generate approx 13.3/day in summer and 2.5 in winter. According to my calcs if we got an ASHP we'd be consuming an extra 20kwh/day in the winter months.
I'm not exactly sure where I'm going with this...
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Hi,
As I said at the top of this page (4) Solar PV is NOT appropriate for general UK heating requirements. Any electricity generated between say November and January should be considered as just a "bonus" to cover some of your normal electricity needs. But at least the electricity will be "worth" your normal kW rate and not the pittance paid for any excess generation fed back to the grid in summer. :(
Most "Renewables" are not a "reliable" energy source for homeowners, nor arguably even for the Country. There still may be days in summer when you will need to import some electricity from the grid, even assuming you have a battery to supply your own electricity overnight (and at some other times). Personally, I've also "invested" in a Ripple Wind Farm to add some complementary energy, but only as a token effort, not a serious attempt to be Green or self-sufficient (nor a recommendation).
Yesterday evening I considered posting that the Grid was currently generating just 2.5% of the modest weekend load (25 GW compared with a typical weekday 35-40 GW) from Wind (and none from Solar of course). The other Renewables were 2.5% hydro (including Pumped Storage) and 7% biomass (which is not zero-carbon). The 17% Nuclear is not strictly a renewable, but better than the 59% Gas and over 5% COAL at the time! That doesn't quite total 100% due to "Other" and Imports.
Cheers, Alan.
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For those of you who went over + batteries, how much space did you need for the batteries and where did you store them?
Hi,
caveat, we are located in Bermuda. high humidity, quite a lot of sun and high temperature so not directly applicable to UK requirements.
We have a pretty substantial system with 2 electrical feeds to the grid.
One services the main house and office with 35 panels and a 20 KW battery
The other system services workshops, art studio, and two vacation cottages with 21 panels and a 10kw battery. (there is room for an additional 2.5 kw battery add on for an up charge)
We love the battery back up and in a locale that is subject to power outages from weather systems they are good insurance.
We do have plenty of room, but the batteries are not small and they are noisy.
I have the workshop/cottage battery in my art studio and its noticeable when it kicks in. (I like the sound as I associate it with saving money and carbon). The other we have stored in an out building, cognisant of the fact that we have vascation rentals and didn't want to disturb guests with ambient noise.
Related to the noise and space issue, we are replacing water heaters with hybrid systems that are much more efficient but larger and noisier. One is under a wooden floor in a back bedroom and could be an issue for a light sleeper. They do also have the advantage of drying out their surroundings if damp is an issue.
It was a costly system to install but our power bills are running at a fraction of what they were.
Bermuda has the highest cost of electricity on the Globe at over 41c KWH
Purely on costing we would have nixed the batteries in terms of ROI but we wanted to reduce our carbon footprint and have redundancy so bit the bullet.
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We have a pretty substantial system with 2 electrical feeds to the grid.
One services the main house and office with 35 panels and a 20 KW battery
The other system services workshops, art studio, and two vacation cottages with 21 panels and a 10kw battery.
Given your location the size of your solar arrays and batteries your inverters must have fan cooling. On the flip side fans rather than passive heatsinks maybe cheaper and allow installers to use less space.
I have a (modest) 3kW inverter with a massive passive heatsink. The installation instructions specify 250mm ventilation clearance. But it is silent..
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We have a pretty substantial system with 2 electrical feeds to the grid.
One services the main house and office with 35 panels and a 20 KW battery
The other system services workshops, art studio, and two vacation cottages with 21 panels and a 10kw battery.
Given your location the size of your solar arrays and batteries your inverters must have fan cooling. On the flip side fans rather than passive heatsinks maybe cheaper and allow installers to use less space.
I have a (modest) 3kW inverter with a massive passive heatsink. The installation instructions specify 250mm ventilation clearance. But it is silent..
Ahh right, that will be the sound then. They are about the size of a smallish cabinet. Sonnen. There was some spec about airflow too.
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I was just on the Octopus website reading about their export tariffs, when a little Octopodal bubble appeared telling me that carbon footprint of electricity is currently high and that as my device is over 80% charged I might want to consider unplugging.
Creepy.
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Further to posts upthread. Green Energy Together of Ware Herts have had their MCS accreditation suspended. (Guardian revised article 14th March) HIES are also withdrawing accreditation as GET were apparently not registering deposits therefore denying customers the 10 year insurance based installation guarantee or indeed security of deposit return (sort of Escrow'ish arrangement). All of which is in breach of the terms and conditions of contract. Of note there is another company at the same postal address installing Heat pumps which still has valid accreditation. Some serious questions should be being asked behind closed doors concerning the promotion of this scheme by Local Authorities and the associated procurement process by Solar Together and its holding company iChoosr together with subsequent contract administration. ST are customer friendly but are as much use as a chocolate teapot if problems are being experienced. I am happy to say that following this debacle which in the end cost me £450 for absolutely nothing, I found a really good local contractor and now have a fully functional 5.8Kw/p array with diverter for immersion heating. (impressive piece of kit). All at the price quoted which was very competitive and within the forecast timescale restoring my faith in British contractors somewhat. Incidentally, Octopus are accepting new customers again.
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Glad you got sorted eventually. Sounds stressful.
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It was. I have a near neighbour who has a significant deposit with this contractor waiting for an installation nearly one year on. It seems that the scheme is not covered by the Local Government Ombudsman scheme which I find to be somewhat bizarre, as they promoted it in the first place. My neighbour received an email today from ST informing them that the firm's MCS accreditation has been withdrawn. They had an installation 'appointment' for April.
Edit a warning.
From Trust Pilot: A former employee.
They are now trading under a new name ‘Sustain Solar’. They thought they were smart by changing the director from Nick to one of their other directors Jullie Elliot (who is just as bad as the Elbournes) but if you search GET on companies house you’ll find all the details linking it back to GET.
This is not the first time the company has run into issues and changed their names due to this so if that doesn’t scream dodgy then i don’t know what will !
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Got a quote from Greener Energy Group today. We only have room for 6 panels so 2.61kW. That and a 5kW battery was £11600.
The guy said a year ago it would have been about 3 grand cheaper.
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I was just on the Octopus website reading about their export tariffs, when a little Octopodal bubble appeared telling me that carbon footprint of electricity is currently high and that as my device is over 80% charged I might want to consider unplugging.
Creepy.
And pretty much pointless purple-wash. If your device is over 80% charged, it's reasonable to conclude that: a) It's a phone, fondleslab or at least a laptop, and therefore optimised to be reasonably energy-efficient and b) It's not drawing very much current.
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Got a quote from Greener Energy Group today. We only have room for 6 panels so 2.61kW. That and a 5kW battery was £11600.
The guy said a year ago it would have been about 3 grand cheaper.
I accepted the quote on Thursday though it didn't officially go through until today cos of the deposit. They then phoned me at lunchtime and asked if I'd like them to be installed this Thursday! Er, no, geez a chance to get my shit together... (need the rest of the funds to liquify and to book the cats into borstal for the day, and presumably the power will be off for some of the day so need to work around that).
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Got a quote from Greener Energy Group today. We only have room for 6 panels so 2.61kW. That and a 5kW battery was £11600.
The guy said a year ago it would have been about 3 grand cheaper.
I accepted the quote on Thursday though it didn't officially go through until today cos of the deposit. They then phoned me at lunchtime and asked if I'd like them to be installed this Thursday! Er, no, geez a chance to get my shit together... (need the rest of the funds to liquify and to book the cats into borstal for the day, and presumably the power will be off for some of the day so need to work around that).
I've had nada contact from ScottishPower since November, when it was 'sorry for the delay, we're busy', just prompted them again as the roofers due to start Thursday on the retiling so soon ready for action.
Would I be better going the GEG route?
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Based on my experience so far, yes. The bloke who came to survey said it could be on my roof in 2 to 3 weeks for a 'cash' sale, a few months if funding through HES. I didn't really expect them to offer me an install date 3 days after paying the deposit.
2 happy GEG punters at my workplace too.
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Thanks. I'll do the registration thing and take it from there.
I'm in (the scorchio for past 2 weeks) D&G, have a 50s bungalow with a longish roof facing SW / 220 degrees so PVs plus battery seems the way to go. 👍
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Point to note. Installations below 4kw/p the MCS registered installer can give the power distributor a couple of weeks notice. Above 4kw/p a formal proposal using different pro forma has to be made to the power distributor which needs to be approved before installation takes place and this can take some weeks. (it may also be refused for various reasons but rare.). If exporting later your electricity company will ask to see evidence of the approval.
My installation at 5.8kw/p was around the £7.5k mark without battery. I indicated that I will not have a battery in the roof space in any future installation due to fire hazard so a hybrid inverter was not installed. This will make it more expensive later if I decide to subsequently install a battery. I can not make the sums work for a battery atm.
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Any pointers to a cost benefit do the sums site / tool for solar PVs plus battery plus air source heat pump?
The current gas boiler - age unknown, serial # sent to Worcester - may (soon?) be coming to replacement time.
Could I move to an air source heat pump fed by a battery fed by solar panels and topped up by off peak unit rates in the winter phase? Given latitude / roof orientation / building config / weather patterns? Plus a couple of woodburners either end of the house.
I've found and been linked to sites various but all a bit generic.
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Scaffolding went up Tuesday. Panels on Wednesday (took all of an hour), sparky today (he was here for several hours). All done, just need to wait for MCS cert to get a new tariff off Octopus. Though I may stick with the fixed import rate til it expires in Sept. Will see what the charts say while I'm away for the next fortnight.
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Any pointers to a cost benefit do the sums site / tool for solar PVs plus battery plus air source heat pump?
The current gas boiler - age unknown, serial # sent to Worcester - may (soon?) be coming to replacement time.
Could I move to an air source heat pump fed by a battery fed by solar panels and topped up by off peak unit rates in the winter phase? Given latitude / roof orientation / building config / weather patterns? Plus a couple of woodburners either end of the house.
I've found and been linked to sites various but all a bit generic.
It's worth reading Monbiot on woodburners. https://www.theguardian.com/commentisfree/2022/dec/27/wood-burning-stove-environment-home-toxins
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Ah, sorry for poor sentence structuring. The woodburners already exist. This is about me understanding the full costings of poss moving off grid from mains gas.
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Scaffolding went up Tuesday...
Scaffolding still in place ::-)
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Graphs, we haz them.
(https://live.staticflickr.com/65535/52991174797_5871b8027d.jpg) (https://flic.kr/p/2oJDC5M)
graph_02 (https://flic.kr/p/2oJDC5M) by The Pingus (https://www.flickr.com/photos/the_pingus/), on Flickr
(https://live.staticflickr.com/65535/52992140145_ff26218b00_z.jpg) (https://flic.kr/p/2oJJz3H)
graph_01 (https://flic.kr/p/2oJJz3H) by The Pingus (https://www.flickr.com/photos/the_pingus/), on Flickr
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:thumbsup:
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Hmm those are impressive figures.
How big is your array?
General question; what happens if your grid connection goes down and you don't have a battery system?
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Can we talk guarantees? Do you (les pingus or others) have one from the manufacturer, or is it only via the installer (who would then claim from the manufacturer, if the installer still exists)?
We had panels put up a couple of weeks ago, and the installers voided the manufacturer's warranty before even leaving the roof, by drilling holes for the pigeon netting rather than using the proper clips. The installer blithely suggested he would of course underwrite the warranty, which is very much not the point. Negotiations for a replacement are now being conducted through our roofer.
But would you accept this?
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I personally wouldn't, and I'd want a warranty against damage from windspeeds over 100knots.
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Hmm those are impressive figures.
How big is your array?
Got a quote from Greener Energy Group today. We only have room for 6 panels so 2.61kW. That and a 5kW battery...
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Scaffolding went up Tuesday...
Scaffolding still in place ::-)
Still there. We should be charging for storage.
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Can we talk guarantees? Do you (les pingus or others) have one from the manufacturer, or is it only via the installer (who would then claim from the manufacturer, if the installer still exists)?
We had panels put up a couple of weeks ago, and the installers voided the manufacturer's warranty before even leaving the roof, by drilling holes for the pigeon netting rather than using the proper clips. The installer blithely suggested he would of course underwrite the warranty, which is very much not the point. Negotiations for a replacement are now being conducted through our roofer.
But would you accept this?
Sounds well dodgy.
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No contact yet para mi 3 weeks in from GreenerEnergyGroup, and again nowt from ScottishPower Solar. My roof retiling is now 2/3rds of the way through, guys doing a good job, so almost ready for the PVs. If I can gain a place in the queue. Maybe phone calls required to prod.
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Umming and ahhing about the Surrey scheme. We have a big, usefully orientated roof that would get the sun all day on those days when we get sun. On the other hand, it seems like a potential palaver with blokes who will break stuff. Plus we'll be spending money on stuff we don't understand, which is a bit like that time I bought some magic beans.
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Umming and ahhing about the Surrey scheme. We have a big, usefully orientated roof that would get the sun all day on those days when we get sun. On the other hand, it seems like a potential palaver with blokes who will break stuff. Plus we'll be spending money on stuff we don't understand, which is a bit like that time I bought some magic beans.
Recommend Gary Does Solar you tube channel
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I read the leaflet and it made me feel a bit tired.
I gather there's some kind of solar auction scheme, you sign up and eventually get a non-binding quote. Since I can't, apparently [my wife], use the roof as a dry ski slope (it would be brill till you hit next door's chimney), it may be a use. Though it does sound most days like the squirrels have taken up my suggestion. I have a feeling that squirrels may be the larval form of bears. I wonder how many solar fix-it men they can eat. Given the paucity of postal service, it seems they've over-indulged on the previous Royal Mail buffet. New snacks might be required.
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I'm sure squirrels are perfectly capable of playing innocent until the system is installed and all the expensive scaffolding put away, before moving in to make their own special nut-based modifications to the thermal design and/or wiring. See Youtube videos of engineers opening microwave antennas passim.
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So far the tree rats of Surrey have failed to kill the PV installation on the roof of Fort Larrington, but I'm sure it’s only a matter of time.
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Judging by the installation across the road it'll be the scurries* that'll be reducing the flow of voles in Furryboottton.
*Other shitehawks are available.
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Can we talk guarantees? Do you (les pingus or others) have one from the manufacturer, or is it only via the installer (who would then claim from the manufacturer, if the installer still exists)?
We had panels put up a couple of weeks ago, and the installers voided the manufacturer's warranty before even leaving the roof, by drilling holes for the pigeon netting rather than using the proper clips. The installer blithely suggested he would of course underwrite the warranty, which is very much not the point. Negotiations for a replacement are now being conducted through our roofer.
But would you accept this?
As far as I can tell, the manufacturers guarantees are set out in my installation contract and I would claim via the installer. I am surprised that the installer would install without clips as they are relatively inexpensive and simple to fit. You should be given a customer satisfaction pro forma to complete in due course where you may express your disatisfaction directly to MCS.
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Scaffolding went up Tuesday...
Scaffolding still in place ::-)
Still there. We should be charging for storage.
And that's the scaffolders taking it down.
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Scaffolding went up Tuesday...
Scaffolding still in place ::-)
Still there. We should be charging for storage.
And that's the scaffolders taking it down.
People in my road had their loft extension completed just before Xmas 2022.
The scaff is still surrounding the house....
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AIUI scaffolders generally don’t have much storage space and like to move scaffolding directly from one job to another, so if they don’t have a new job in your area it’s hard work getting them to collect it.
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AIUI scaffolders generally don’t have much storage space and like to move scaffolding directly from one job to another, so if they don’t have a new job in your area it’s hard work getting them to collect it.
Thing is, having added value to your property, you'd be a bit stuffed if you were trying to sell it.
Can't see 48mm Ø galvanised pipe surrounding the place as a strong selling point.
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I'm sure if you threatened to dismantle it yourself and flog it on ebay they’d be round quickly enough :demon:
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I'm sure if you threatened to dismantle it yourself and flog it on ebay they’d be round quickly enough :demon:
I was getting to that point.
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After a series of missed calls from a Glasgow #, is what happens when one leaves one's phone inside while one is outside, got an assessor from Greener Energy Group coming Monday to go over the property. I know I need to up the loft insulation plus there is zero cavity wall insulation. Will be good to get some actual numbers to ponder.
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Son had half a scaffolding job done to inspect / repair the roof. Told them it was inadequate so not paying but they repeatedly failed to take it away. Roofer came and added to it, did the roof, and took the lot away! Result!
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Starting to roll. Liked how the Greener Energy Group put down real numbers, explain how A works vs B, how support funding (should?) apply and how to proceed. Button pressed. PVs, battery, hybrid ASHP and smart diverter tech box thing a-comin'. Once the cavity in the walls is no longer a great big empty space.
Sums say payback in 7 years. But that's based on the usage projections from my minimising gas usage over last winter, running low room temps and excludes the ~£450 or so spent on firewood to run the cozy woodburner on every evening from end September through to April. Real breakeven prob more like 4 years.
Next phase of The Project starts...
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Good luck dealing with Home Energy Scotland.
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Was at choir Mus Dir's house yesterday, rehearsing my part for our forthcoming concert. I arrived whilst a sales person/technical bod was there, talking about solar panels. Colin (Mus Dir) was glad to get rid of him. He told me he's had his panels so long (2011 or whatever) that the feed-in tariff is still worth £1500 a year to him.
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3 weeks after sending the DNO paperwork and applying for Octopus Outgoing I hadn't heard anything (though forums suggest the DNO doesn't inform the supplier when they've processed the export notification and they have to keep checking themselves) so I DM'd Octopus on Twitter when I'd finished work and a couple of hours later we're on the export tariff.
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After some research with Prof Google, I decided it might actually be possible to request remote control of the inverter (not very well advertised) rather than heaving myself up the step ladder to an unlit loft with the hairy spiders to control it.
Without much expectation I raised a ticket with Solis late Sat afternoon and lo and behold, a couple of hours later they emailed to say we now had remote control.
Being the wrong side of a beer or two at the time I left it until now. After a bit of playing around I seem to have got the directions round the not very intuitive interface and done a quick experiment to see if we can tell the battery to charge from the grid at a certain time, and to tell the battery to discharge to the grid at a certain time.
That all seemed to go as requested so I guess I can ask the Octopods to put us onto the Octopus Flux tariff now....
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After some research with Prof Google, I decided it might actually be possible to request remote control of the inverter (not very well advertised) rather than heaving myself up the step ladder to an unlit loft with the hairy spiders to control it.
Without much expectation I raised a ticket with Solis late Sat afternoon and lo and behold, a couple of hours later they emailed to say we now had remote control.
Being the wrong side of a beer or two at the time I left it until now. After a bit of playing around I seem to have got the directions round the not very intuitive interface and done a quick experiment to see if we can tell the battery to charge from the grid at a certain time, and to tell the battery to discharge to the grid at a certain time.
That all seemed to go as requested so I guess I can ask the Octopods to put us onto the Octopus Flux tariff now....
Thanks that's really helpful. When we get to the winter months I want to set our battery to partially charge on the overnight tariff, which will effectively keep us on cheaper rate electricity for the 2-3 hours until the sun is high enough to start the panels meeting our needs.
Our inverter is in the garage, so not difficult to access, but even so changing settings should be easier on my PC than fiddling around with the Inverter three button interface. I've submitted a ticket this morning.
I'm also with Octopus & found them very quick to sort our SEG (unlike OVO who basically spent 6 months ignoring us). For the last 3 months are SEG payments have been more than our import bill. That will change as the days shorten and when our storage heaters go on, but one year into PV ownership we think it was a good decision.
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:thumbsup:
Glad my witterings have been useful to someone.
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Finally, after a loooong process now got approval for renewables funding for PVs, battery and after a go / no go kerfuffle over hybrid ASHP a go for it on full ASHP. 10k grant and a lot of 0% loan funding, in high inflation / interest rate times. 👍
PVs likely to be fitted in 2 weeks time, right on for summer sunshine....
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I now have PVs on the roof, batteries and inverter in the loft, techie box stuff in abundance and a (data received via China 🤔) app on the iPad showing wots gahn on. Will be learning. Next is the full tech assessment this Saturday re will ASHP work. Tbd.
I'm off grid tonight.
And Greener Energy Group are 👍 re suppliers and installers.
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Good stuff.
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Ooh, you're moving faster than us. PV has been on the roof since June (reinstalled by the same firm but a rather better work team than the first clowns who installed the wrong units, invalidated the guarantee, broke our roof tiles, tried to cover it up, and lied about it all), but we're still waiting on the battery and commissioning. The heat pump has been sitting in the garden for even longer.
All the insulation works, though. The place is just about as warm as our flat, despite not being either heated or lived in yet.
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The roofers / panel fitters were late arriving, their van broke down, had to wait for 3 hours for AA then van swop, but v quick, fitted the 12 panels in little over an hour. Missed the birdproofing, will fit that tomorrow. They asked me for spare roof tiles (I have lots) as 2 corners chipped.
The sparkies were here for 8+ hours, putting it all together, even had a call out to local network provider to check poss mains earthing too high test numbers, engineer came out in pm, all fine.
This late October, a few sunny spells day has generated 8.4 kWh. The immersion heater is on!