There is no such thing as a ‘free’ lunch, some one always pays. Wind and sun may be free, the occasional power they produce is anything but.
The economic choices we make (and the policies that surround, support or reflect them) are driven by a simple equation: that the economic cost should be outweighed by the benefits on offer. And, until very recently, that equation applied with equal force to energy use and production.
As Euan Mearns puts it: “The Energy Return on Energy Invested (ERoEI or EROI) of any energy-gathering system is a measure of that system’s efficiency. The concept was originally derived in ecology and has been transferred to analyse human industrial society. In today’s energy mix, hydroelectric power ± nuclear power have values >50. At the other end of the scale, solar PV and biofuels have values <5. It is assumed that ERoEI >5 to 7 is…
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Utopia, you are standing in it! 
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