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EROEIEnergy Return on Energy Invested (alternative energy sources)
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Whilst I agree that a more technically literate discussion is vital to all parts of the debate regarding our future energy mix I was staggered to find not a single mention of EROEI in any of the material on the subject of fracking.
If the average EROEI of our energy system falls below a critical threshold, then our society will be at serious risk of collapse, because the governing energy equation is reciprocal: the higher the proportion of our currently available energy supply that we spend on obtaining our future energy supply, the lower the proportion of our currently available energy supply that remains available for everything else that society wants to do with it.
If the EROEI is effectively cut in half, that is comparable to cutting production in half.
According to Tullett Prebon, an EROEI of five to one will cripple economies by gobbling up one sixth of global GDP.
"Declining EROEI could bomb societies back into the pre-industrial age," adds the Tullett report, cheerfully.
If we were to combine a fertility rate of only one child per female (1CPF) plus a concurrent reduction in per-capita energy consumption of one percent per year, we could be on a downward trajectory that will reduce the total demand for energy, including food, similar to the decline in energy availability, as dominated by decreasing oil (shown in the curve "no", the net oil energy after energy input for extraction, EROEI).
The best we could hope for is to slightly increase all renewable energy sources to about 10% of our present total energy consumption in the next 50 years as net petroleum output EROEI declines steadily.
The argument that by means of sophisticated, often digitally enhanced production, it is possible to generate the same output using less material throughput, readily succumbs to the EROEI effect, for the full cost of manufacturing the new technology itself is rarely factored in.
By many calculations, working with solar panels and wind turbines, you're often getting close to zero on your EROEI. And you're trying to do it eighty stories up.
In the technologies involved with energy resource extraction, such costs are often reflected in the ratio of energy return on energy invested (EROEI).
Regarding the article, there are no references to energy returned on energy invested (EROEI).
Not all depletion or emissions activists support the large-scale development of biofuels (ethanol, butanol, and biodiesel), which are the only realistic renewable replacements for liquid transport fuels, because of the low energy profit ratio (energy returned on energy invested, or EROEI) entailed in making these fuels, and because these substitutes imply worrisome tradeoffs with food production.