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This is calculated in energy return on energy invested (EROI). Solar is doing.. ok in that regard: http://rameznaam.com/2015/06/04/whats-the-eroi-of-solar/ http

by brrt 11y ago

This is calculated in energy return on energy invested (EROI). Solar is doing.. ok in that regard: http://rameznaam.com/2015/06/04/whats-the-eroi-of-solar/ http://rameznaam.com/2015/06/04/whats-the-eroi-of-solar/ The comparable number for fossil fuels (in this case, oil) is 'well to tank efficiency', which amounts to about 25% for oil, if i recall correctly. So 1/4th of energy contained in oil is already spent to bring it to market. Notably, wind energy has a far more favorable EROI than solar does (currently), but wind power is a relatively limited resource.

542458 11y ago
Wow. I suppose it should have been obvious, but it's still interesting to see nuclear's numbers so high, considering the enormous material requirements for reactors. Only makes me more sad that the world seems to be closing down nuclear rather than opening it up.
- brrt 11y ago
  A large problem with current generation nuclear is that the easily obtainable uranium isotopes are in the process of running out (in no small part due to artificial limitations on e.g. reprocessing of fuel). We'll probably continue to have enough for some time to come, but a large-scale switch to nuclear energy is actually quite unlikely at this stage. I don't mean to say that this is the primary reason for nuclear's demise - it isn't - but it is a real hurdle against increasing deployments. Of course, there are very exciting new developments in nuclear technology that solve this - breeding, reprocessing, etc - but they are all (still) at an experimental stage. That's the catch-22 of nuclear: there's an existing, mature industry, which uses it's fuel unsustainably, and there are developments to sustainably use nuclear power, which is quite far from being an industry.
lost_name 11y ago
To be clear, the article you link is arguing against the graph at the top. > Solar panels, according to Weißbach, generate four times as much energy over their lifetimes as it takes to manufacture them. Unfortunately, Weißbach also claims that an EROI of 7 is required to support a society like Europe. [...] For solar, which I know better, this paper is an outlier. > If we used only the estimates from 2010 on, we’d find an EROI for poly-Si solar of around 15. If we used only the 2013 estimate, we’d find an EROI of around 25. > In summary: The Weißbach paper is, with respect to solar, an outlier. A more realistic estimate of poly-Si solar EROI, today, is somewhere above 10, and probably above 15. And it’s rising. Solar panels generate many times more energy over their lifetimes than is used to construct them and their associated hardware.

by brrt 11y ago

542458 11y ago

Wow. I suppose it should have been obvious, but it's still interesting to see nuclear's numbers so high, considering the enormous material requirements for reactors. Only makes me more sad that the world seems to be closing down nuclear rather than opening it up.

brrt 11y ago
A large problem with current generation nuclear is that the easily obtainable uranium isotopes are in the process of running out (in no small part due to artificial limitations on e.g. reprocessing of fuel). We'll probably continue to have enough for some time to come, but a large-scale switch to nuclear energy is actually quite unlikely at this stage. I don't mean to say that this is the primary reason for nuclear's demise - it isn't - but it is a real hurdle against increasing deployments. Of course, there are very exciting new developments in nuclear technology that solve this - breeding, reprocessing, etc - but they are all (still) at an experimental stage. That's the catch-22 of nuclear: there's an existing, mature industry, which uses it's fuel unsustainably, and there are developments to sustainably use nuclear power, which is quite far from being an industry.

lost_name 11y ago

To be clear, the article you link is arguing against the graph at the top. > Solar panels, according to Weißbach, generate four times as much energy over their lifetimes as it takes to manufacture them. Unfortunately, Weißbach also claims that an EROI of 7 is required to support a society like Europe. [...] For solar, which I know better, this paper is an outlier. > If we used only the estimates from 2010 on, we’d find an EROI for poly-Si solar of around 15. If we used only the 2013 estimate, we’d find an EROI of around 25. > In summary: The Weißbach paper is, with respect to solar, an outlier. A more realistic estimate of poly-Si solar EROI, today, is somewhere above 10, and probably above 15. And it’s rising. Solar panels generate many times more energy over their lifetimes than is used to construct them and their associated hardware.