The Downside of Heat Cogeneration at Coal Power Plants
A coal plant in China. Photo: Wikipedia, CC
Don't Turn Off the Heat Please
Both the US and China have many coal plants (producing about 45% of the power in the US and 75% in China). One difference is that in China, it is more common for the waste heat from those power plants to be recovered and used to heat local residential buildings or for industrial purposes. On the face of it, this is a good thing, but as Kevin Bullis points out, this also has a perverse effect that will probably make it harder for China to move away from coal.
Photo: USGS, public domain.
Indeed, if a coal plant only produces electricity, if you want to shut it down you just have to find another source of electricity. But if it also produces useful heat, you now also have to figure out how to replace that heat, and that's not something that renewables can do with just a bolt on replacement.
This also can conflict with wind power; if there's a big spike, but you can't turn down coal plants because the heat is used, you have to find another way to do something with your wind energy (if you have a lot of hydro with sufficiently big reservoirs, you can use those, but not all regions have access to this). Another way to do it - once we have a smart grid - would be to use demand-response with big industrial users or residential water heaters (more on this here).
Cleaning up the grid isn't as simple as it first may seem, but it's still a necessary task.
Via Technology Review
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