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Right. When we generate electricity via solar or wind, the heat involved has (essentially) been shifted from elsewhere. That energy was going to reach our pl

Right. When we generate electricity via solar or wind, the heat involved has (essentially) been shifted from elsewhere. That energy was going to reach our planet either way. Whether we use a solar panel to shift it somewhere we can use it, or if it just heats the whatever it would have otherwise ran into, we aren't adding energy to the system by shifting it around. The waste heat from solar panels is just the energy from the sun, less whatever gets turned into electricity. No new energy was created - if there was, you could just create a perpetual motion machine to solve the problem.

EGreg 9y ago
So then, isn't fossil fuel energy "just" stored sun energy too? If it hadn't wound up underground, our planet would have been slightly hotter already.
- lostapathy 9y ago
  Yes, it's just stored energy from the past. But when we release it now, we get heat now. When we leave it in the ground, we avoid that heat.
- cestith 9y ago
  Fossil fuel is stored chemical energy. Burning it releases the energy. Photovoltaic solar power is converting one type of energy (light) into another (electricity), with the waste heat being the same waste heat the light would've created by shining on something else. Solar thermal energy is using the heat from the sun to do work (which may include heating oils, air, or water to drive a turbine to generate electricity) or to generate electricity (using, say, thermal-piezo conversion). The only effective ways we have to store solar power are batteries, supercapacitors (once they're viable), large heat masses (such as stone or water), growing plants, or putting energy into chemicals for later storage (electrolysis and storing the hydrogen, forming artificial hydrocarbons, recycling aluminum for aluminum/air power cells, pumping water uphill to power a turbine later, pressurizing gases to later drive a turbine, stuff like that). Not all of the things I mentioned work at every scale. Some of them are more efficient than others. They may all have advantages and drawbacks.

EGreg 9y ago

So then, isn't fossil fuel energy "just" stored sun energy too? If it hadn't wound up underground, our planet would have been slightly hotter already.

lostapathy 9y ago
Yes, it's just stored energy from the past. But when we release it now, we get heat now. When we leave it in the ground, we avoid that heat.
cestith 9y ago
Fossil fuel is stored chemical energy. Burning it releases the energy. Photovoltaic solar power is converting one type of energy (light) into another (electricity), with the waste heat being the same waste heat the light would've created by shining on something else. Solar thermal energy is using the heat from the sun to do work (which may include heating oils, air, or water to drive a turbine to generate electricity) or to generate electricity (using, say, thermal-piezo conversion). The only effective ways we have to store solar power are batteries, supercapacitors (once they're viable), large heat masses (such as stone or water), growing plants, or putting energy into chemicals for later storage (electrolysis and storing the hydrogen, forming artificial hydrocarbons, recycling aluminum for aluminum/air power cells, pumping water uphill to power a turbine later, pressurizing gases to later drive a turbine, stuff like that). Not all of the things I mentioned work at every scale. Some of them are more efficient than others. They may all have advantages and drawbacks.