bjn wrote: ↑Thu Mar 13, 2025 12:45 pm
Grumble wrote: ↑Thu Mar 13, 2025 12:41 pm
bjn wrote: ↑Thu Mar 13, 2025 11:53 am
The Energy Transition Show podcast has just finished a 3 episode series on the energy transition in the UK. The last one has a long interview with the chief engineer at the National Energy System Operator. Basically, we are acing it when it comes to decarbonising electricity generation. The expectation is that by 2030 gas generation will be down to around 5%, from around 30% today. Well worth a listen.
https://xenetwork.org/ets/
I’ll definitely try to listen to that. Do they discuss the other side of the problem, electrifying everything to take advantage of our cleaner generation?
They talk about space heating and transportation and the need to increase electrification of both and the impact that will have on demand, though they don't drill into it very deeply.
I don't sit listening to long podcasts. If you can find any written version...
As we have noted, gas is on 98% of the time in Britain atmo. Which is making our electricity very expensive. So getting it down to 5% should mean we are greatly increasing the amount of no-gas hours. That's quite tricky, due to the way we have managed our system over the last 30-40 years.
Meanwhile I had a look at NESO's
Future Energy Scenarios. Which apparently gets gas down very rapidly, but not quite that rapidly. It doesn't discuss all the issues. BUt what I do see there are quite enormous quantities of electricity storage supposed to come online over the next 5 years. See p121. Storage quantities need to increase about 3-4 times in both GW and GWh over the next 5 years. Currently pumped storage is about 30% of the GW but 80% of the GWh. There is limited scope to expand pumped storage. So that means GWh in batteries have to increase about 20-fold in the next 5 years. So these are really huge expansions in batteries, as well as at least doubling pumped storage in the next 5 years.
I do tend to wonder if this is another "now we have to really go very fast, look we can still do it" moment that we have had with every previous release of these reports. But it never happens. Or whether these quantities of storage are actually being procured. I am aware that there is now a large pot of money earmarked for getting people to install longer term storage - batteries with run-times longer than an hour, more pumped storage. What I don't know is if it is enough.
The main issues in getting gas down to this low level - which will have really good consequences for our electricity market - are:
-balancing demand and supply when there isn't much wind/solar about
-inertia, which is about keeping the frequency close to 50Hz when some large generator trips out, because if you don't do that it all falls down
Now the main reasons we have gas nearly always on (at least 98% of the time) in Britain these days are about:
-flexibility - ie responding to short term (under a day) unexpected imbalances, and
-inertia
On flexibility, we used to need a lot of spinning reserve - that is, gas (and previously coal) stations that are switched on, but running at a minimum amount, so that they can be turned up quickly - seconds, minutes - if needed. Because if it isn't on, it takes an hour to 4 hours, mostly, to turn a gas station on. It isn't a precise science how long it takes to turn on. But they have been getting better at switching them on within an hour rather than 4 hours. An issue with spinning reserve is the minimum amount of generation that comes from them while spinning, which used to be like 1/4 or 1/3 of their capacity, but apparently they have got that down of late. But of course, on is on, and that's an issue. We need to be able to have extended time when none of it is on.
Now the need for spinning reserve - for flexibility - has been greatly reduced by batteries, which can fill that one hour gap while you try to turn gas power stations on. Another issue is how well do you know the wind output 4 hours out. The error in that has reduced, and that has also reduced the need for reserve. And turning the gas stations on quicker has meant we can look more to 1 hour out rather than 4 hours out, where the uncertainty is much less.
But then there's inertia. There tends to be very little discussion of this in energy scenario papers, which are mostly about adding up quantities of energy in different hours. But inertia is actually a really big issue in practice. We need enough inertia, or when something large falls over, it pushes trips lots of other things out and we have huge large-area black-outs, that take a few hours to fix, like when that large wind-farm tripped out a few years ago. Wind and solar don't provide inertia, not naturally anyway. On the continent, they can rely considerably on inertia from their neighbours, but DC interconnectors don't provide inertia. It mostly comes from gas, biomass, nuclear and hydro. They have been developing ways of getting "synthetic inertia" from wind, but it needs to be fitted to the wind-farms. And I'm not sure of the extent of it - it was pretty small when I last checked. I've also just done a google, and apparently there are now "green inertia" projects, where people are paid to have things like flywheels running which aren't actually generating, but can use the flywheel to generate with inertia at a moment's notice when called. Also batteries can be connected via "grid-forming inverters" which not only convert the battery to AC but give some inertia as well. So explicit things have to be done to get the inertia we need. But what you don't see in scenarios are tables of "green inertia" quantities to know how well they are doing and whether it is consistent with getting to these targets.
