Comment by jillesvangurp
1 year ago
People always forget that batteries also absorb power. Having a lot of renewables means there are energy spikes far exceeding what can be used in that moment. Without batteries, that energy is lost. Having batteries means that energy can be buffered and used later (e.g. in the evening). So they improve the capacity factor of existing installed renewables. Add domestic batteries, EV batteries, etc. to the mix and you also get the potential for demand shaping where you charge those when renewable energy production is spiking and prices are low. And of course even though that is currently not utilized on a large scale, all those EVs could technically provide energy back to the grid as well.
Another point is that batteries like this are not actually intended for long term storage. They are instead about stabilizing the grid and dealing with short term spikes and dips in supply and demand of energy. Unlike a coal or gas plant, a battery can respond in milliseconds and be very cost effective for that. Spinning up coal and gas plants is expensive and slow. And they cost money when they are not running.
And while that single coal plant was able to provide so-called baseload; it would only have been able to do so if it was up and running 24/7/365. And that wouldn't be true. They are very reliable but occasionally coal plants have to be down for maintenance, repairs, etc. and this can take quite some time (weeks/months). Same with nuclear plants. So, relying on that to not happen was never a good plan.
Long term storage is always assumed to be needed to compensate for a lack of this baseload. However, baseload is actually a fuzzy notion until you express it in gwh and gw. Hawaii seems to be in the process of proving this might be a lot less than some people seem to assume. At least I'm not aware of them having any long term storage. They'll probably add more battery and resilience to their grid over time in the form of more wind and solar generation and additional batteries. But if these people modeled this correctly and did their homework, this might actually be fine as is. We'll find over time I guess.
Do we currently have enough renewables installed in (eg) the the UK for batteries to increase capacity factor? Is there ever enough renewable production that energy is lost?
Yes, but it's at a local level.
One of the benefits of batteries is that they can be spread around and used to alleviate bottlenecks. Building transmission is very expensive, so this is a good early market for them.
These are called Non-Tranmissikn Alternatives or Non-Wires Alternatives:
NTAs are programs and technologies that complement and improve operation of existing transmission systems that individually or in combination defer or eliminate the need for upgrades to the transmission system.
Wind farms often get turned off because there is too much Wind, solar is also often throttled. There is a lot of "lost" power that could rather find its way into batteries or H2-electrolyzers.
They get turned off to avoid damage in too much wind, not to avoid overproduction. We only have a few GW of installed solar capacity so it's not hugely important to the overall picture.
In the UK it's easy to see that Wind and CCGT plants operate in inverse of one another, when it's windy most of our power comes from the wind and the CCGT are switched off. And conversely when it's calm the CCGTs produce most of the power.