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Comment by ploxiln | Hacker News Reader

Electrical power is fungible, but the time it is available is not. There is usually near-peak power usage just after sun-down. So while a large amount of "clean" power was generated in the middle of the day and sold to other states, after sun-down a significant portion of the power used in the state was "un-clean".

Even if California made it the final 3% to reach 100% renewable energy (by the headline metric), it will still depend on a significant amount of non-renewable energy for significant parts of every single day (or else it will have blackouts).

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It's not like you can ramp a coal-fired or nuclear power station up and down on a whim either though. It takes time and planning to modify the output if you don't have storage capacity. Power companies do a lot of predictive analysis to forecast demand and make sure they're running a little ahead. Here in the UK we even have a term called "TV pickup" where the electricity demand for the country increases significantly immediately after popular TV shows when we all go and put our kettles on for another cup of tea[1].

Power demand varies a lot, and in a reasonably predictable way, so you're fine so long as you have a mix of generation technologies. For most places that'll end up being solar, wind and nuclear, with extensive storage capacity.

[1] https://en.wikipedia.org/wiki/TV_pickup

TV pick-up used to be a thing when 17 million people watched Corrie in real time.

Those types of real time viewing figures are limited to live England matches in the euros/World Cup, and very unusual events like the PM’s covid broadcast back in 2020

I’m surprised the US doesn’t have the phenomenon during the super bowl. I guess the lack of kettles and the main attraction of the Super Bowl being the adverts dampens it down though.

We have the Super Flush... when everyone goes to the bathroom at half-time and at the end of the game.

> It's not like you can ramp a coal-fired or nuclear power station up and down on a whim either though.

At least nuclear you can relatively fast. In terms of KW/min change rate faster then most gas peaker plants. It is not done much outside of France though as the operating costs of a nuclear power plant are pretty much identical when operating at 5% or 100% output.

edit:

German nuclear power plants also used to do load matching.

https://www.oecd-nea.org/upload/docs/application/pdf/2021-12...

Source for the KW/min change rate of nuclear vs CCGT/coal

https://snetp.eu/wp-content/uploads/2020/05/SNETP-Factsheet-...

Coal is also able react relatively quickly to flex up/down within a range once running but has relatively high start costs and minimum run time (startup/shutdown takes longer). In the UK, the remaining coal fired plants still regularly participated in the balancing mechanism over the winter, for example (at sometimes eye-watering prices due to those factors along with high emissions costs).

> It's not like you can ramp a coal-fired or nuclear power station up and down on a whim either though.

You can with nuclear: thermally it is kept running, but the steam bypasses the generators and so there is no electrical production.

That's true but no one is suggesting they stop now right? This is just a milestone.

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