Energy Return on Energy Input (EROI)

The EROI (Energy Return on Energy Input, or ERoEI) is an index for the amount of energy gained for each unit of investment to extract it. The EROI for oil has fallen since 1900 from over 100 to less than 15 today, reflecting the passing of the age of easy oil.

In the case of power generating plant, the various fuels have ERoEI of: Nuclear = 5-15 (optimised plants up to 24), Photovoltaic (P/V) 3-7, Wind 16-25, Hydro = 10-270 (very dependent on location). Some reports claim the ERoEI for a new generation of nuclear power plant could be in the hundreds, but for now this remains theoretical.

EROI for different energy sources

SourceEROI for USA
Domestic oil11-14
Imported oil17-31
Coal40-80
Natural gas10-16
Nuclear5-16
Hydroelectric20-40
Wood30
Wind energy28
Photovoltaic8
Biodiesel3

Source:

The EROI (Energy Return on Energy Input) is an index for the amount of energy gained for each unit of investment to extract it.