Issues with renewable energy accounting – Editor
Critics of various published renewable energy analyses have pointed out that modern renewable energy technologies are often dependent upon fossil fuel and other energy sources, and have cautioned that the energy accounting costs might not adequately reflect that dependency. An additional consideration is the associated environmental and social costs. Thus while the cost statistics reported in the above article are interesting, the possibility that they do not fully account for hidden costs in the manufacture and use of polysilicon solar panels and for waste products disposal must be considered.
The problem is analysed in an import- ant paper by Weißbach et al [1] in terms of the energy return on energy invested, or EROEI – the ratio of the energy produced over the life of a power plant to the energy that was required to build it and any extraneous energy sources that might be involved in its operation. It takes energy to make a power plant – to manufacture its components, mine the fuel, and so on. The power plant needs to make at least this much energy to break even. A break-even powerplant has an EROEI of 1. But such a plant would pointless, as there exists no energy surplus for doing the useful things we use energy for.
There is a minimum EROEI, greater than 1, that is required for an energy source to be able to run society. An energy system must produce a surplus large enough to sustain things like food production, hospitals, and universities to train the engineers to build the plant, transport, construction, and all the elements of the civilization in which it is embedded.
One problem here is that some models for solar energy plants limit their life cycle or EROEI analysis to just the solar panels themselves, and there is a danger in this simplistic approach that the solar energy generated could represent half or less of the overall energy entailed in the construction and use of these plants.
1. The Weißbach et al paper is downloadable from the following less technical review:
http://bravenewclimate.com/2014/08/22/catch-22-of-energy-storage/
