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The energy delivered by a solar panel is overwhelmingly more than needed to make it. The gain is enormous. There is simply no contest. Consider that makers of

by ncmncm 4y ago

The energy delivered by a solar panel is overwhelmingly more than needed to make it. The gain is enormous. There is simply no contest. Consider that makers of solar panels, and of the materials that go into them, get no break on their power bills. Each and every kWh that goes into making the panel is paid for, and necessarily has its cost folded into the price of the panel. Otherwise they would be paying power out of their own pocket, to give it to you for free. Furthermore, the fraction of the energy used in making the panel that comes from renewables goes up every year, as their share of the total generated increases. The same argument applies to wind turbines, tidal turbines, wave engines, dams, and (in their way) storage media.

dv_dt 4y ago
One could look for more direct sources, but the summary is that energy payback happens in 1-4 years out of current 25 year "life". And that 25 years is typically a warranty to 80% of original capacity. Year 26 of operation is not a sudden drop. https://www.solarmelon.com/faqs/solar-panels-use-energy-manufacture-actually-produce/ https://www.solarmelon.com/faqs/solar-panels-use-energy-manu...
- ncmncm 4y ago
  Yes, panels at 80% have good resale value. If you have room, you just add 20% more. If not, you sell them and buy more.
- Schroedingersat 4y ago
  Costs have dropped an order of magnitude since that study. Many of which scale with energy. 4 years is now a massive overestimate. Depending on how much you include (frames, inverter, grid tie in etc) 0.5-2 is more realistic.
- Yoric 4y ago
  Unless I'm mistaken, that's based on the assumption that you're in position to use 100% of the energy produced during the day, exactly when it's produced. I'm sure that there are scenarios in which that's true (e.g. keep the refrigerator on all day long, use some other energy source for the night) but if your main use for the energy is not correlated with the sun being up (e.g. power your computer when you're back home in the evening), you need to add the actual energy cost of storage, which is typically really bad. This considerably increases the time to energy payback. Still probably worth it, though.
  - ncmncm 4y ago
    Panels are so cheap now that they pay even if you waste most of what they could have produced. A smallish battery that captures only some of the excess, and delivers it when you need it, suffices. Battery cost is still falling fast as new chemistries come online. Hydrogen synthesis and storage might displace batteries for domestic use, particularly if hydrogen-fueled cars succeed. (Advice: keep all that equipment outside!) If not, zinc/bromine battery tech looks strong.
    - Yoric 4y ago
      Are you tokey of monetary cost or the total amount of energy needed to actually build/deliver/install/maintain/dispose of these technologies? If the former, you are clearly right. If the latter, I'm not so sure (with current tech).
      - ncmncm 4y ago
        Monetary cost, as already noted, reveals an exact upper bound on the amount of energy needed to build and deliver the goods: people doing those get no discount on their power bill. The price also includes labor, administrative and marketing costs, tariffs, taxes, and whatever profit was taken, less any public subsidy or loss-leader discount.

by ncmncm 4y ago

dv_dt 4y ago

One could look for more direct sources, but the summary is that energy payback happens in 1-4 years out of current 25 year "life". And that 25 years is typically a warranty to 80% of original capacity. Year 26 of operation is not a sudden drop. https://www.solarmelon.com/faqs/solar-panels-use-energy-manufacture-actually-produce/ https://www.solarmelon.com/faqs/solar-panels-use-energy-manu...

ncmncm 4y ago
Yes, panels at 80% have good resale value. If you have room, you just add 20% more. If not, you sell them and buy more.
Schroedingersat 4y ago
Costs have dropped an order of magnitude since that study. Many of which scale with energy. 4 years is now a massive overestimate. Depending on how much you include (frames, inverter, grid tie in etc) 0.5-2 is more realistic.
Yoric 4y ago
Unless I'm mistaken, that's based on the assumption that you're in position to use 100% of the energy produced during the day, exactly when it's produced. I'm sure that there are scenarios in which that's true (e.g. keep the refrigerator on all day long, use some other energy source for the night) but if your main use for the energy is not correlated with the sun being up (e.g. power your computer when you're back home in the evening), you need to add the actual energy cost of storage, which is typically really bad. This considerably increases the time to energy payback. Still probably worth it, though.
- ncmncm 4y ago
  Panels are so cheap now that they pay even if you waste most of what they could have produced. A smallish battery that captures only some of the excess, and delivers it when you need it, suffices. Battery cost is still falling fast as new chemistries come online. Hydrogen synthesis and storage might displace batteries for domestic use, particularly if hydrogen-fueled cars succeed. (Advice: keep all that equipment outside!) If not, zinc/bromine battery tech looks strong.
  - Yoric 4y ago
    Are you tokey of monetary cost or the total amount of energy needed to actually build/deliver/install/maintain/dispose of these technologies? If the former, you are clearly right. If the latter, I'm not so sure (with current tech).
    - ncmncm 4y ago
      Monetary cost, as already noted, reveals an exact upper bound on the amount of energy needed to build and deliver the goods: people doing those get no discount on their power bill. The price also includes labor, administrative and marketing costs, tariffs, taxes, and whatever profit was taken, less any public subsidy or loss-leader discount.