In writing Wednesday’s post ERoEI for Beginners, I prepared a number of charts that were not used and these are presented here. Where it has been measured and according to the literature, the net energy of oil, natural gas and coal is falling everywhere. Surface mined US coal has one of the highest energy returns of any fuel and is substantially higher than deep mined Chinese coal. In electricity equivalent (Eeq) form, Chinese coal is marching towards the Net Energy Cliff edge while US coal remains far from it. The image shows part of a 50 km long queue of coal trucks in China.
Estimates of ERoEI for solar PV are all over the place (1 to 12) because different analysts set different system boundaries, the energy return is latitude and site specific and its possible that the literature based on historic deployed panels is not up to date with most recent advances.
Sugarcane ethanol in Brazil has ERoEI of 8 to 10 at the refinery gate which at face value seems OK [1]. But to be equitable with its FF cousins this needs to be reduced to 3 to 4 in Eeq form and is barely viable. Temperate latitude biofuels are not viable in liquid form at the refinery gate and converting them to Eeq cripples them completely. But I suppose burning them to make electricity is no less crazy than burning them in an internal combustion engine sat idle at traffic lights.
No comments:
Post a Comment