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To add some other points - rooftop solar being the future is untested. Most of the installations were done in an environment where solar wasn't really commercia

by roenxi 3y ago

To add some other points - rooftop solar being the future is untested. Most of the installations were done in an environment where solar wasn't really commercially viable and people were trying to push water uphill with a shovel. Which can be done, mind you. There are cases like Germany where they seem to have done a lot of damage to their own energy supply. But now that solar seems to be a viable option it is unclear what the equilibrium point is. For coal, it didn't make sense to give everyone a generator. Even coal-powered fireplaces in homes turned out to be noncompetitive for heating, which is a bit of an unexpected outcome. So since rooftop solar is dangerous to install and comes with a maintenance burden as well as presumably increased risk to consumers, it might still turn out that the best approach is a big centralised solar farm with huge economies of scale. Keep maintaining and using a distribution grid. Grids are expensive, so it could shake out either way. But I don't think the public knows what will happen yet.

tialaramex 3y ago
> which is a bit of an unexpected outcome I don't see it. Coal fireplaces are relying on the same idea as the ICE car, this fuel is so cheap to use that it won't matter if we use it inefficiently. But unlike cars, your house isn't going anywhere. One thing people tend to get wrong about heating is that because of the laws of thermodynamics it seems as though any method must always be 100% efficient and thus it can't matter. But actually we care what gets heated. Fireplaces heat the air in the chimney well but you don't live there - you live in the rest of the house. As little as 20% of the thermal energy in the coal is converted into a warm living space, and that makes it pretty easy for electrical solutions to compete. Something like a gas boiler heating water for radiators still can't deliver the same point of use efficiency (as resistive heating) because the burned gas is toxic, so we need to put that warm gas outside (otherwise what you've made is a death trap, not a warm home), yet we'd like to capture as much of the warmth as possible, the result is we're maybe 80% efficient. It's much easier to add radiators than chimneys, so the result is much better, but far from perfect.
- roenxi 3y ago
  We're burning coal - which burns really hot. Nobody has managed to come up with a more economically efficient approach than burning that coal kilometers away from the place that needs to be heated. And not for clever chemical reactions, we're still burning it for heat. So it turns out that the most effective way to heat a space is to burn coal for heat but jam a ridiculous amount of stuff between that and the eventual heated space. Obviously you've got all the details, but if those details are what turned out to be true for coal then we as the public have no idea at all what the details are going to be for solar. Possibly even the insiders don't know yet. There is a pretty good chance here that centralised solar installations win the economic battle.
  - tialaramex 3y ago
    > Nobody has managed to come up with a more economically efficient approach than burning that coal kilometers away from the place that needs to be heated. Have you tried not burning the coal? The coal was fine where it was, leave it there and save on extracting it, then burning it and then cleaning up the tremendous resulting mess.

by roenxi 3y ago

tialaramex 3y ago

> which is a bit of an unexpected outcome I don't see it. Coal fireplaces are relying on the same idea as the ICE car, this fuel is so cheap to use that it won't matter if we use it inefficiently. But unlike cars, your house isn't going anywhere. One thing people tend to get wrong about heating is that because of the laws of thermodynamics it seems as though any method must always be 100% efficient and thus it can't matter. But actually we care what gets heated. Fireplaces heat the air in the chimney well but you don't live there - you live in the rest of the house. As little as 20% of the thermal energy in the coal is converted into a warm living space, and that makes it pretty easy for electrical solutions to compete. Something like a gas boiler heating water for radiators still can't deliver the same point of use efficiency (as resistive heating) because the burned gas is toxic, so we need to put that warm gas outside (otherwise what you've made is a death trap, not a warm home), yet we'd like to capture as much of the warmth as possible, the result is we're maybe 80% efficient. It's much easier to add radiators than chimneys, so the result is much better, but far from perfect.

roenxi 3y ago
We're burning coal - which burns really hot. Nobody has managed to come up with a more economically efficient approach than burning that coal kilometers away from the place that needs to be heated. And not for clever chemical reactions, we're still burning it for heat. So it turns out that the most effective way to heat a space is to burn coal for heat but jam a ridiculous amount of stuff between that and the eventual heated space. Obviously you've got all the details, but if those details are what turned out to be true for coal then we as the public have no idea at all what the details are going to be for solar. Possibly even the insiders don't know yet. There is a pretty good chance here that centralised solar installations win the economic battle.
- tialaramex 3y ago
  > Nobody has managed to come up with a more economically efficient approach than burning that coal kilometers away from the place that needs to be heated. Have you tried not burning the coal? The coal was fine where it was, leave it there and save on extracting it, then burning it and then cleaning up the tremendous resulting mess.