Indeed. This is why Dinorwig (the Welsh power station) is profitable. When electricity is cheap they buy it, and put electricity in and it pumps water up to an artificial lake, when prices rise they stop, and when the price rises still further that's their cue to drop water from the lake back through the system to make electricity for sale.
You can do the maths "Hmm, we need to make £2 per MWh of electricity at least once per day for this business to make sense" and look at price charts and say "Yup, that's feasible, today we will buy any time it's below £30 until we're full and we'll sell any time it's above £35 until we're empty" and make plenty of money. If only conveniently located mountain lakes were more common we'd probably have these everywhere.
The price decisions are tricky though, imagine you decide you should sell for £40 today, and then the wind just doesn't stop blowing at sea and offshore wind turbines (which will sell for any price at any time since their power is basically free) keep the price below £38 all day. You end the day with zero income. Not a game for people with limited capital reserves. Or you decide to buy once it falls below £40 on another day, but then every AC unit in the country is running non-stop and the cloud sit, unmoving but blocking the sun, prices sit above £50 all day. Again no income.
It wasn't built to make a profit, the government built it because it's a Black Start facility, ie it's one way to "boot up" the electricity grid if it fails and you need to start over from no electricity. But now it's privately owned by a French corporation and increasing use of renewables means more minute-by-minute price fluctuations to profit from.
You can do the maths "Hmm, we need to make £2 per MWh of electricity at least once per day for this business to make sense" and look at price charts and say "Yup, that's feasible, today we will buy any time it's below £30 until we're full and we'll sell any time it's above £35 until we're empty" and make plenty of money. If only conveniently located mountain lakes were more common we'd probably have these everywhere.
The price decisions are tricky though, imagine you decide you should sell for £40 today, and then the wind just doesn't stop blowing at sea and offshore wind turbines (which will sell for any price at any time since their power is basically free) keep the price below £38 all day. You end the day with zero income. Not a game for people with limited capital reserves. Or you decide to buy once it falls below £40 on another day, but then every AC unit in the country is running non-stop and the cloud sit, unmoving but blocking the sun, prices sit above £50 all day. Again no income.
It wasn't built to make a profit, the government built it because it's a Black Start facility, ie it's one way to "boot up" the electricity grid if it fails and you need to start over from no electricity. But now it's privately owned by a French corporation and increasing use of renewables means more minute-by-minute price fluctuations to profit from.