We’ve been seeing some price spikes in power supply over the last few days. Ought we to blame those intermittent power generators, who can’t be relied on to generate at times of need and sit idle 80% of the time?
I am referring to gas turbines, of course.
Renewables are dismissed too often as intermittent. It is a particularly harsh judgement when offshore wind farms offshore are operating between 40% and 50% of the time, while some gas turbines are down in the 20% range.
Wind farms have been idle recently, but they reliably generate when the wind blows. Weather forecasting has been improving, and it is fairly clear a few days ahead when they are not going to generate and very clear a few hours ahead. And if the wind is there, we can rely on the power being there.
Gas-fired plant is a different matter. They only generate when the price is right. At bottom, that means they generate when the electricity price beats the price of their gas fuel, and is high enough to pass whatever other startup costs and profit requirement the owner might have.
Other operators can take a guess, but they can’t be sure that a gas-fired plant will come into operation. The EU’s REMIT rules (now reflected in the UK) mean the company must say whether the plant will be in the market. But it can be a fast changing situation: plant can come back into the market late on, once the price has spiked high enough to pass internal thresholds.
If intermittency caused by price is less predictable than that caused by weather, is it materially different in the fact that eventually it responds to high prices? That depends on what price is regarded as completely unacceptable.
Most power generation is intermittent or variable in one way or another (and those that are not, present their own problems). But in practice, power generation should not be considered on its own but as part of an energy system that combines variable supply with variable demand.
The great opportunity of these two types of intermittency working together is the opportunity it gives for enabling other ways of managing the system. I have written elsewhere about how price spikes are necessary to bring forward demand response, because it opens up a market, and this applies equally to storage. Storage allows demand to be time-shifted, but we should make sure that we take advantage of storage of all types – that includes building insulation, which allows heating times to be shifted. Let’s try to translate these recent price spikes into thinking about the system, not specific plant types.