Follows on from Technology is Social

Energy Return on Energy Input (EREI)
Understanding this concept is fundamental to understanding what is possible with energy technology. Basically, any production of energy takes energy to make. In the fossil fuel world, the ratio of energy input to energy output has been said to be of the order of 1:100. Even today when it has become much harder to find and extract useable oil the ratio is still around 1:20 or more. Easy to access fields of fossil fuels, with little energy use, and little ecological destruction, will tend to be consumed first. There are inevitably declining returns on EREI from resources, and therefore declining availability of energy, without some massive new source of energy being discovered, and this does not happen that often.

The closer the EREI ratio gets to 1:1 or lower, the more the amount of energy used to produce energy gets to resemble the amount of energy produced. The smaller the ratio, the less energy is available for free action, or action that is not tied into energy production. If the ratio goes below 1:1, then energy is essentially being wasted to make energy.

That energy is being wasted and consumed in order to make energy, does not mean the system cannot continue for a while, making things worse. Energy ‘non-production’ can be supported by the taxpayer (as the State considers it important for national functioning); by weird financial schemes or straightforward Ponzi schemes in which more and more people are persuaded to put money into the ventures while return declines (as many people suggest is the actual dynamic behind fracking); by taking energy from a better functioning part of the system; by using cheaper energy such as slave labour; and by increasing unrepairable environmental destruction. Just as we can pursue declining fish stocks with more energy and ruthlessness until they are all gone, so we can pursue low EREI until we collapse. Money acts as an ersatz source of energy as it allows human focus and activity stripped from reality but, eventually, if it does not have some relationship to available energy, the currency will collapse. The point is such practices suck energy from the necessary transition, and eventually disrupt the society in a probably catastrophic way.

Renewable energies, and any potential ‘clean fossil fuels,’ have much lower EREI, than dirty fossil fuels. Most of the renewables are also intermittant, So we need more of them and more energy production, than we needed of fossil fuel energy supplies – and again that takes lots of free energy.

This lower EREI severely limits what can be done and unfortunately, we need a truly massive energy transformation in a time of apparent declining energy availability (and particularly low ecologically destructive energy) to produce machines with lower EREI, which makes transition harder.

Continues in Problems of Transition 05: The problem of pace and size