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Comment by wumpus | Hacker News Reader

How does this work with solar panels and wind turbines?

I know that fossil fuel plants have a lot of waste heat that enables cogeneration, but I've never heard of that with solar or wind.

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A fossil fuel plant will burn fuel to produce heat. Some of this heat will be used for generation, and the remainder is waste heat. A solar panel or wind turbine, on the other hand, does not produce significant amounts of heat in operation - a PV solar panel would only get somewhat warm, a wind turbine would only achieve some friction heating - to where it is not economical to harness this relatively small amount of energy (compared to waste heat from an exothermic generation process, like nuclear fission or hydrocarbon combustion)

Solar panels are super thermally inefficient generally speaking, collecting about 20% of the energy that hits the panel. They are dark, and this leaves a lot of heat available for the gathering. You can get solar systems that heat water as well, especially in rooftop solar. This also cools the panels down and makes them more efficient. Not much, but measurably. Something like this. [1]

Of course, in the winter in Canada, you have to bleed the system otherwise the water will freeze in the tubes and they'll burst.

There's no free heat from a wind turbine.

[1] https://dualsun.com/en/product/hybrid-panel-spring/

Actually, wind turbines do produce heat but we generally let it dissipate. It may be that it is not really usable, but wind turbines that only produce heat are a thing historically:

https://www.lowtechmagazine.com/2019/02/heat-your-house-with...

I think the issue is you can’t really move heat too far physically, and turbines are located usually pretty far from houses themselves. Certainly relative to rooftop solar.

No argument here, I was just being a pedant really

I appreciated your comment because I hadn’t actually thought about that before!

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