Knowing the greenhouse gas emissions of a certain energy source spread over its entire life cycle, from conception to deactivation, is important for investors who must consider the costs of their investment over decades.
Generally the accuracy of estimating emissions has been very low, with huge ranges offering uncertain and sometimes conflicting information; however a new analysis by the US Department of Energy’s (DOE) National Renewable Energy Laboratory (NREL) uses a different method to determine the emissions per kilowatt hours from raw material, manufacturing, transportation, operation, and decommissioning, in order to provide the most accurate comparisons. By harmonising the results of over 2,000 different studies the NREL were able to reduce the range of estimates by as much as 90 percent in some cases.
The new study tries to be as impartial as possible, noting that in the past some estimates have been influenced depending on the method of the analysis, or the vested interests of the party analysing the data.
The study showed the greenhouse gas emissions from photovoltaic installations came in at a median of 45 grams of CO2 per kilowatt hour of electricity generated. This 45 gram median contrasts with the 1,001 grams of CO2 created by coal.
Despite their newer, more accurate methods of calculating the emissions, the numbers for nuclear energy still varies greatly from between 4-110 grams.
Concentrated solar projects release 26 grams with parabolic trough plants, or 38 grams for the concentrated solar towers.
Thin film solar cells release very low levels of greenhouse gases; with a median of 20 grams for amorphous silicon, 14 for cadmium-telluride, and 26 for copper indium gallium diselenide.
Wind power relases between 2-45 grams per kilowatt hour.
By. Joao Peixe of Oilprice.com
Joao is a writer for Oilprice.com