[belorn]

The price difference between wind energy when the supply is high and nuclear when the supply is low is well over 10 times here in northern Europe.

If I can choose the time and place for when to do the trade, I would make a huge profit trading 2 units of energy and getting 1 unit back later at my specified time and place. The top price is around 40cent per kwh when the wind is still and demand is at its peak, compared to ~3c kwh when the wind is at the maximum production and demand is at the lowest. paying 6c worth of wind power and getting 40c when I specific it would be massive profit.

Green hydrogen if burned for energy would cost about 3-10 times that of nuclear per kwh. In the future that cost might go down but for now that is a bit (which is why no one are producing green hydrogen in order to produce energy). Again, if you are willing to sell green hydrogen for the price of nuclear, eating the loss, then sign me up. I will happy buy that and sell it for minimum 3x of what I pay for it since there are plenty of industries that want energy when demand is high and supply is low.

The cost of energy is not determined by how much it cost to produce. It is determined by the time and place it is delivered. 1 unit of energy produced today is not fungible for 1 unit of energy produced tomorrow. Only energy produced at the same time can be evaluated based on how much they cost to produce.

[fallingknife]

The fact that there is a 10x price arbitrage available in the market is proof that storage is not economically possible currently.

[bshipp]

Isn't it the opposite? A 10x variation would be an incentive to invest in storage systems that capture energy at night and release it during the day.

Think a high-altitude reservoir where water is pumped up all night and then released all day when it's required.

[belorn]

Storage that has a reliable 365 charge/discharge cycles each year can be economical viable, especially when the discharge window of peak price is just a few hours. Solar + lithium battery work great in countries where the primary source of energy can be solar every day of the year.

Wind power doesn't work like that. Instead of a daily pattern of high and low supply, you get random amount of weeks and days of high supply followed by random amount of weeks and days of low supply.

Storage need to discharge in order to generate profits. If you get 30-50 discharge cycles each year, then those periods need to provide profits for the cost of 365 days of operations and it also need to repay the original investment.

One way to get around this is with subsidies. This is how some fossil fuel plants operate, called "reserve energy". When the wind blow they don't run the generator, but they still get paid through tax money. Then they start the engines when the wind isn't blowing and demand exceed supply. This scheme helps to reduce the peak price in northern Europe, through obviously it isn't really that cheap. It mostly just hide the true price behind subsidies.

[fallingknife]

Yes, the fact that such a strong incentive exists, and yet it hasn't been done, shows that cost is so much that even a 10x price difference isn't enough to pay for it.

[bshipp]

I'm pretty sure it's done quite frequently. It's a pretty simple battery system with--apparently--an 80+% round-trip efficiency to it.

The biggest problem is getting permission to move that much water around. I live next to a lake and shudder at the regulatory hurdles I'd encounter building something like this. There'd be at least 4 government agencies before I even negotiated to sell to the public utility.

https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit...

[ncmncm]

It would be obviously stupid to build storage that there is not enough renewable power to charge up from, yet. So, its not having been built yet only proves money is better spent on generating capacity.

[fallingknife]

Makes no difference what generates it. OP said that power prices vary by 10x from peak to trough. If you charge from the grid when cheap you can make 10x per cycle selling it back.

[ncmncm]

Then it is expected the situation will not last long enough to make a profit from.