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Comment by fenixnuke | Hacker News Reader

They are likely operating on the wholesale markets, which are market priced. For the western grid there is a significantly wider price range of prices. On peak days in the summer, prices can go up above $1,000/mwh in the late afternoon for several days. During the late fall/early spring, there are negative prices in the late morning (like $20-$50/mwh) due to extremely high solar production and low demand, so utilities are literally paying you to use electricity. It's not inconceivable to get to $1 million a year on 1 mwh of storage.

Take a look at the price maps and historical pricing data if you are curious https://www.caiso.com/todaysoutlook/Pages/prices.html

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A lot of people look at these and think "that doesn't seem like it'd be remotely worth it for something that size" but it's really hard to explain just how badly California has painted itself into a corner on distant generation, huge variance between excess renewable capacity and peak load, and transmission congestion. The numbers don't make sense to people.

Pretty much all the solar plants we're putting in now have combined battery storage systems either for voltage support or "peaker" sales opportunities. In some places (like literal islands) it's about capacity smoothing or resilience, but the driving force behind all the investment is the US western interconnect with arbitrage opportunism starting to make real money and looking to make much, much more over the next decade.

If government-sachs is betting on this, they've probably got an even more pessimistic take on the CAISO market than I do.

> it's really hard to explain just how badly California has painted itself into a corner on distant generation

source needed if you're making such a bold statement

Just read the constant stream of news about it? They keep shutting down power plants in the name of the environment, but just shift the generation outside of the state. It's a numbers game that's meaningless as long as they still consume power, but it lets them virtue signal all over the place to people who don't pay attention to details - which sadly is most of us. How many times when we are give stats do we really wonder about the context around them?

Im familiar with energy markets. Im also familiar with the fact that any serious seller or buyer of energy locks in yearly pricing contracts and is unaffected by these swings. Any serious datacenter or industrial buyer is not relying on spot pricing. These energy markets also dont exist in every state.

If you are familiar with energy markets then by all means tell us the percentage breakdown of electricity consumed that is covered by long term contracts vs the spot market.

How can you make a storage system that only slurps power off of another grid that "literally pays you to use electricity"? during those times?

Buy low and sell high. They can find surplus power and buy it cheap, then wait until there are unmet demands and sell high.

These crazy things called computers make creating and automating markets like that pretty easy :)

It's win win - the people with surplus power can at least get some money for energy that would otherwise likely go to waste (large base load power plants can't ramp up and down on a dime) and on the flip side if you have an energy provider that only occasionally needs capacity in excess of their inherent generation even though the immediate cost is higher for spot power, it can still be far cheaper in the long term than building more base load generation (often fossil fuel because renewable still isn't a viable replacement for base loads). And running base load generation under capacity is wasteful for emissions and overall efficiency.

Once we start to crack the whole energy storage thing renewables will be A LOT more valuable since we will be able to start to use them for base load. Storage allows you to create reliable energy delivery that's predictable - that's essential if we ever want to eject fossil fuels from the grid. Or we could stop being childish about nuclear power - frankly I think we can solve the storage problem long before we can convince people to be rational about nuclear :p

It probably seems crazy for the uninitiated, but there are a lot of efficiencies in markets that occur naturally over time. You see distortions in the market from CA's stupid and politically motivated choices - what seems crazy to you is the market adapting to the model that CA is forcing. Is it nuts? Yup. Is it necessary? Nope - these wounds are entirely self inflicted. Pretending the world is different than it actually is doesn't solve anything and the people of CA are paying a hell of a lot more for electricity because they are trying to live in a pipe dream for where we are today.

There are times where the rooftop solar and base load generation for a utility is greater than the total electricity demand. Demand and supply for the grid have to be balanced, or else you will end up tripping plants and/or damaging equipment. Since they can't "turn off" rooftop and most grid scale solar generation, and they can't really turn off and on their base load plants throughout the day, their best option is to try to sell the excess electricity on the wholesale market. The problem is that the other utilities are in the same situation, and they need to offload electricity. Since no one wants the electricity, wholesale prices will actually go negative. Basically a utility will pay another utility to turn off a base load plant and take the excess electricity from them.

This is why grid scale energy storage is such a hyped technology - if you can store that energy when supply is way too high and dispatch it when renewable generation is low (no wind/solar), you can maintain high renewable percentage in the generation mix. Without it, you can only really go up to a certain percentage of renewables.

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