3 ms·

Your figure of 15W/sq foot assumes no gaps between panels - hard to imagine on a 50mile+ array. The bigger problem is that it assumes overhead, direct sunlight.

by ppf 8y ago

Your figure of 15W/sq foot assumes no gaps between panels - hard to imagine on a 50mile+ array. The bigger problem is that it assumes overhead, direct sunlight. You'd have to cut that at least in half ;) Yes, the UK does have issues by these metrics, and the US is in the unique position of a huge per capita energy consumption and huge land reserves. Therefore, it is somewhat feasible in the US to just keep building wind and solar farms. However, I wonder how the economics of the non-renewable minerals needed would affect the price. It also doesn't (as far as I know) take into account all the extra infrastructure required to support the fluctuating nature of renewable energy sources.

ppf 8y ago
Also, with a higher cost to manufacture these energy sources, it's inevitable that the cost to consumers will rise.
- nostrademons 8y ago
  The gaps easily get canceled out by using newer solar panels; I took the low end of commercial solar power outputs I found on the web, many of the more recent ones do 20W/sq foot or more. 25% gaps seems generous. I thought about the rare-earth issue, but there's a simple solution that bypasses both it and the energy-storage issue: use solar-thermal plants instead of photovoltaics. These require only mirrors and steam turbines, both made out of abundant materials. Efficiency is actually higher than photovoltaics (30% or so), and energy can be stored as heat for up to 5 hours before it's used. (Ironically, they have the same issues relative to photovoltaics that photovoltaics have over fossil fuels; in theory they're simpler and more environmentally friendly, but implementing the theory correctly requires solving a number of engineering problems that together make them cost more and generate more hiccups than photovoltaics have.) The higher cost isn't actually true anymore, for photovoltaics and wind at least. Solar hit grid parity with fossil fuels in late 2015, and is now actually cheaper than coal power plants. This (rather than subsidies) is why the coal industry is in deep shit: it just doesn't make economic sense anymore, and the electric industry is rapidly switching over to renewables & natural gas.

by ppf 8y ago

ppf 8y ago

Also, with a higher cost to manufacture these energy sources, it's inevitable that the cost to consumers will rise.

nostrademons 8y ago
The gaps easily get canceled out by using newer solar panels; I took the low end of commercial solar power outputs I found on the web, many of the more recent ones do 20W/sq foot or more. 25% gaps seems generous. I thought about the rare-earth issue, but there's a simple solution that bypasses both it and the energy-storage issue: use solar-thermal plants instead of photovoltaics. These require only mirrors and steam turbines, both made out of abundant materials. Efficiency is actually higher than photovoltaics (30% or so), and energy can be stored as heat for up to 5 hours before it's used. (Ironically, they have the same issues relative to photovoltaics that photovoltaics have over fossil fuels; in theory they're simpler and more environmentally friendly, but implementing the theory correctly requires solving a number of engineering problems that together make them cost more and generate more hiccups than photovoltaics have.) The higher cost isn't actually true anymore, for photovoltaics and wind at least. Solar hit grid parity with fossil fuels in late 2015, and is now actually cheaper than coal power plants. This (rather than subsidies) is why the coal industry is in deep shit: it just doesn't make economic sense anymore, and the electric industry is rapidly switching over to renewables & natural gas.