I was listening to a new article on Radio 5 last evening about the great power cut of Friday 9th August when two power generating stations failed within 2 minutes. One guest was bemoaning the use of "inflexible renewable wind power" so much so I thought he was going to demand the re-opening of the pits and coal powered stations (according to Grid watch, Coal generated no power at 9.30pm last night, while wind was up there at 35% of the total produced).
There is truth in the claim that renewables and micro generation make the grid harder to manage. But the reality is, NG are doing great at managing that. Wind generation didn't cause the issue on Friday.
Two large power plants disconnected in quick succession. One was gas, one was wind, but the second could equally have been coal, or nuclear, or gas. The thing with the wind one disconnecting is that the turbines were still spinning, there just was no connection to the grid. Which is an interesting failure mode.
Something was then said which interested me about the fact that there is a company out there who are currently building a 2GW storage facility and that a lot of storage is currently available at home in the batteries of mobile cars.
Grid scale storage is a thing. The UK has had that for decades. We call it pump hydro. It's a battery in so far as it stores energy, tho it stores it in the form of water at height, rather than lithium ions in a chemical matrix. But it's still energy storage.
Grid scale storage came to many peoples attention due to a publicity stunt by Elon Musk in Australia. He pledged to build what was then a massive (possibly worlds largest[citation needed]) 129MWh battery in southern Australia, and to do so in an insanely short time scale, or it would be free.
That 2GW storage bank seems a interesting claim. That's the same as 20000 Tesla P100 vehicles. That's a lot of battery. At least, if they mean 2GWh, not 2GW. Which is where things start to get a bit of a murky mess. I can build a unit with a 5KW inverter capable of pumping 5KW into my home power, but as it's connected to an old 12AH battery I have under the desk (from a UPS), it would only supply that 5KW for a matter of seconds. So it could be that they have a single battery with a capacity of 2GWh, or it could be a 100MWh battery, with an inverter capable of pumping it into the grid at 2GW.
Now given the UK already has a 50MW battery in hertfordshire (no data on if that's 50MW or 50MWh grumble grumble), adding a 2GWh storage seems... far fetched...
This latter point surprised me as the Cowboys who fitted my EV home charge point didn't mention that to me, or show me how to do so in emergencies. So, did I miss hear? Also, I have 4kw power solar panels on my roof. If we get a power cut on a summer's day, will this power my house on minimal or indeed normal usage until the mains are restored? All the power cuts we have had recently have been at night.
Finally, does anyone have a power wall? I was wondering if it was worth getting one before our stupid Government increases VAT on them to 20%. Why would anyone with half a brain do that?!
Sorry if these are stupid questions but in my half asleep mind I may have misunderstood some simple points the guest made.
So, vehicle-to-grid, v2g. It's been coming Real Soon Now™ for a while now. In theory it's a fantastic idea, it allows for proper demand side management, it allows you to make use of really cheap electricity etc... *BUT* It's not there yet.
There is a company in the UK that has demonstrated it as working for Nissan Leaf vehicles. They had a nice demo of vehicle to tea at Fully Charged Live. But as far as I am aware, there's not yet a proper standard for it, and it's not been fully realised as available.
The thing is, when it is, it'll be FANTASTIC. You can drive to work, charge up on the work charger in the work car park, drive home, and with the range left in the battery, cook dinner, and power your house, then drive back to work the following day and charge up... Or you can charge at 3am when electricity is practically free, and then even out the spike at 1800 when everyone turns their oven on...
How does it work? well you basically need to trick the car into connecting the internal battery to the pins of the charging cable, and the you need to work out how to turn the DC in the car, into 230v AC for your house. It's not simple. Take a look at your charging cable. Two of those pins carry power (assuming chadamo), the rest carry data signals to allow the car to talk to the charger. If you have CCS, or CCS2, then it gets even more complex as you have a mix of AC pins, DC pins, and data pins. It's not quite as simple as siphoning the petrol out the tank of the old dinosaur burner to power your generator.
As to the solar, if you have a simple grid tie inverter, then you're unlikely to be able to disconnect from the mains and power the house on a sunny day directly. Apart from anything else, a single cloud could drop production, causing a brownout which could really mess with devices plugged in. For this to work, you really want something battery like to buffer in vs out. The way you describe the cowboys who have done your installs suggests this wasn't even a consideration. Fitting a battery, be it a power wall or some other solution may require a new inverter.
On to the power wall. I've tried to do the maths on it. I can't find a way to make it cost effective on it's own, but then I don't have solar. If you do have solar, then the maths is a bit better, but there may be other products that are more cost effective than a tesla branded one. If you're only looking at it to cover the occasional power cut, then actually the most environmentally friendly approach is probably a second hand generator off ebay, and run it on diesel you keep for emergencies. Nothing new has been created, and the amount you will actually burn, will be negligible (plant a tree to offset each power cut).
Electricity, the Grid, and vehicles are going to change dramatically in the next few years, it's gonna be interesting to watch!
J
PS, Grid watch claims no coal was burning on Friday. This is actually wrong. No DOMESTIC coal generation. The UK has power interconnects (at least until the end of October), with a couple of it's neighbours, all of which (apart from France) have substantial coal generation as part of their mix. Unfortunately due to the way power from these interconnects is provided we have no means to see if the power coming in from Belgium is coal or gas or nuclear or whatever. Meaning that we can claim no domestic coal generation, we can't be 100% certain the UK used no coal power at all.