Oh that old saw... we get so much energy from the sun it's all hunky dory. The challenge of converting that energy to a usable form at the kind of scale needed to power a civilization is not mechanically simple. The supply chain and energy inputs (including fossil fuels) required for photo-voltaic are non-trivial. Conc-solar is still not proven at scale and again requires natural resource and energy inputs to build and maintain the systems. Energy return on energy investment is the key metric here and one that is not well understood by many, nor favourable for a lot of the proposed solutions.
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Oh that old saw... we get so much energy from the sun it's all hunky dory. The challenge of converting that energy to a usable form at the kind of scale needed to power a civilization is not mechanically simple. The supply chain and energy inputs (including fossil fuels) required for photo-voltaic are non-trivial. Conc-solar is still not proven at scale and again requires natural resource and energy inputs to build and maintain the systems. Energy return on energy investment is the key metric here and one that is not well understood by many, nor favourable for a lot of the proposed solutions.
This is a critical point. Energy return on energy invested (EROEI) is a concept everyone should be familiar with.
I suggest beginning with the work of Professor Charles Hall of SUNY-ESF.
http://www.esf.edu/efb/hall/energy.htm