EROEI - energy return on energy investment blarney

The EROEI (energy return on energy investment) is a measure that is often used by humans to judge the effectiveness of technological systems, such as wind farms, in supplying energy. ER, the energy return is the output of this energy flow process. The energy input is not included because it is presumed to be free! EI is the separate embedded energy flow that drives the system. Thus EROEI is only a measure of the energy effectiveness of the system. It does not take into account:

• the transformation in the form of energy during the flow is often coupled with the transformation of material to waste. The production of the greenhouse gas emissions (contributing to climate change) as thermal energy is extracted from the fossil fuels is but one example of this association.
• the technological systems have a limited life due to the wear and tear of natural forces, including various forms of friction so their ultimate destiny is as waste material, even when there is recycling
• the energy input to technological systems from fossil fuels or uranium is not truly free as there are limited supplies of these materials so their usage is a divestment of natural material wealth so future generations will have to cope with this unsustainable process

Ironically the natural systems that have used energy to power development over eons do not have any of these failings. Society has the fallacious belief that they can devise systems that emulate the natural sustainable processes.