When considering the greenhouse gas emissions associated with any energy source, it is important to look at the total life cycle emissions both from the direct use of the energy source and from the indirect emissions associated with building the system, producing and transporting fuels and other supplies and, ultimately, decommissioning the system. Taking all of this into consideration is necessary in order to have a full accounting of the carbon impact of power sources.
Some critics of wind and solar energy have tried to make the case that indirect greenhouse gas emissions greatly reduce the value of those technologies in reducing greenhouse gas emissions. However, a recent comprehensive study has refuted that argument.
The study, conducted by an international team of scientists, was published in the journal Nature Energy. It looked at a wide range of energy systems from the perspective of overall life-cycle greenhouse gas emissions. It even analyzed life-cycle emissions of potential fossil fuel power plants equipped with carbon capture and sequestration technology, such as so-called clean coal plants.
The results of the study were that not only are wind and solar energy more favorable when it comes to life-cycle emissions, but that a full decarbonization of the global power sector by scaling up these technologies will result in only modest indirect greenhouse gas emissions.
As a general principle, wind and solar energy provide a superior greenhouse gas balance because they do not require additional energy for the production and transport of fuels, and the technologies themselves can be produced in large part using decarbonized electricity. And, in fact, during the transition to a clean power supply, life-cycle emissions from building wind and solar plants are smaller than the emissions from remaining fossil power plants.
Photo, posted September 20, 2008, courtesy of Jeff Kubina via Flickr.