I just stumbled across a paper on EROI from 2011 (revised February 2015). Some of you will have copped it before but for those who haven't, it's here. Hope it's of some use to someone here.
From the abstract:
EROI for finding oil and gas decreased exponentially from 1200:1 in 1919 to 5:1 in 2007.
The EROI for production of the oil and gas industry was about 20:1 from 1919 to 1972, declined to about 8:1 in 1982 when peak drilling occurred, recovered to about 17:1 from 1986–2002 and declined sharply to about 11:1 in the mid to late 2000s.
I experience pleasure and pains, and pursue goals in service of them, so I cannot reasonably deny the right of other sentient agents to do the same - Steven Pinker
For me EROEI is one of the known unknowns. We know it is valid concept, we know it is a critical factor in sustaining our society and population, we know it is declining for all fossil fuels, new technology notwithstanding, and we know it is approaching a tipping point where net energy is/will be declining faster than the global economy can become more energy efficient, or build out renewable energy sources to replace net energy. We know energy production is facing a Seneca cliff leading to collapse of industrial civilisation, and even if fossil fuels was no the primary cause, one of the other limits to growth would do the same job in a few decades time.
But we cannot actually and reliably measure what the EROEI is in the real world. Too many variables.
