Hydropower's Biogenic Carbon Footprint

• Published in: PloS one Vol. 11; no. 9; p. e0161947
• Main Authors: Scherer, Laura, Pfister, Stephan
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 14.09.2016; Public Library of Science (PLoS)
• Subjects: Air pollution; Alternative energy sources; Carbon dioxide; Carbon footprint; Carbon Footprint - statistics & numerical data; Carbon sequestration; Clean energy; Climate change; Climate Change - statistics & numerical data; Climate change mitigation; Dams; Datasets; Earth Sciences; Ecological footprint; Ecology and Environmental Sciences; Electric power generation; Electric power plants; Electricity; Electricity generation; Emergency preparedness; Emissions; Emissions (Pollution); Energy; Energy consumption; Energy resources; Energy sources; Engineering and Technology; Environmental engineering; Environmental impact; Floods; Generalized linear models; Global warming; Global warming potential; Greenhouse effect; Greenhouse gases; Hydroelectric plants; Hydroelectric power; Hydroelectric power plants; Industrial plant emissions; Methane; Mitigation; Models, Statistical; Natural gas; Physical Sciences; Power plants; Power Plants - statistics & numerical data; Renewable energy; Thermal power; Thermal power plants; Variables; Water Movements; Working groups; New York; United Kingdom > UK; United States > US; Switzerland
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0161947

Global warming is accelerating and the world urgently needs a shift to clean and renewable energy. Hydropower is currently the largest renewable source of electricity, but its contribution to climate change mitigation is not yet fully understood. Hydroelectric reservoirs are a source of biogenic greenhouse gases and in individual cases can reach the same emission rates as thermal power plants. Little is known about the severity of their emissions at the global scale. Here we show that the carbon footprint of hydropower is far higher than previously assumed, with a global average of 173 kg CO2 and 2.95 kg CH4 emitted per MWh of electricity produced. This results in a combined average carbon footprint of 273 kg CO2e/MWh when using the global warming potential over a time horizon of 100 years (GWP100). Nonetheless, this is still below that of fossil energy sources without the use of carbon capture and sequestration technologies. We identified the dams most promising for capturing methane for use as alternative energy source. The spread among the ~1500 hydropower plants analysed in this study is large and highlights the importance of case-by-case examinations.