An international team of scientists has amassed the largest data set to date on greenhouse gas emissions from hydroelectric reservoirs. Their analysis, published today in the online version of Nature Geoscience, posits that these human-made systems emit about 1/6 of the carbon dioxide and methane previously attributed to them.
Prior studies based on more limited data cautioned that hydroelectric reservoirs could be a significant and large source of both carbon dioxide and methane to the atmosphere.
Through an analysis of 85 globally-distributed hydroelectric reservoirs, the authors revealed that these systems emit 48 million metric tons of carbon annually, a downgrade from earlier estimates of 321 million metric tons. Further putting things in perspective, hydroelectric reservoirs are responsible for less than 16% of the total carbon dioxide and methane emissions from all types of human-made reservoirs combined.
When rivers are dammed to make the reservoirs needed for hydroelectricity, flooding creates lake-like conditions that generate carbon dioxide and methane. Emissions are the highest following reservoir construction, due to decomposing vegetation and soil organic matter. As reservoirs age, emissions decline, with cold-water systems stabilizing more rapidly than their warm-water counterparts.
Lead author MSc. Nathan Barros, of the Federal University of Juiz de Fora further explains, "The bottom line is that per unit of energy, hydroelectric generation produces much less carbon dioxide and methane emissions than previously thought, but impacts are not equal across all landscapes."
The amount of greenhouse gases generated by hydroelectric reservoirs depends on where they are built, with the team's analysis indicating that emissions are correlated with latitude and the amount of biomass in the watershed. With Barros adding, "Reservoirs in tropical locations, such as the Amazon, emit more methane and carbon throughout their lifecycles."
Hydroelectricity supplies an estimated 20% of the world's electricity and accounts for more than 85% of electricity from renewable sources. Future development is expected globally.
The paper's authors urge careful consideration of site location and design. "During the environmental impact phase, it should be a goal to minimize the amount of carbon dioxide and methane emitted per unit of energy generated," Cole notes.
To truly tease apart the emissions generated by hydroelectricity, the authors also call for a study that assesses a site's carbon budget before and after reservoir construction. Pre- and post flooding analysis would clarify the net carbon impact of hydroelectric reservoirs.
Other contributors to the paper included Drs. Lars J. Tranvik, Yves T. Prairie, David Bastviken, Vera L. M. Huszar, Paul del Giorgio, and Fábio Roland.
The work was supported by grants from FURNAS Centrais Elétricas and from the Swedish Foundation for International Cooperation in Research and Higher Education (STINT).
The Cary Institute of Ecosystem Studies is a private, not-for-profit environmental research and education organization in Millbrook, N.Y. For more than twenty-five years, Cary Institute scientists have been investigating the complex interactions that govern the natural world. Their objective findings lead to more effective policy decisions and increased environmental literacy. Focal areas include air and water pollution, climate change, invasive species, and the ecological dimensions of infectious disease. Learn more at www.caryinstitute.org
Lori M. Quillen | EurekAlert!
Algorithm provides early warning system for tracking groundwater contamination
14.08.2018 | DOE/Lawrence Berkeley National Laboratory
Artificial Glaciers in Response to Climate Change?
10.08.2018 | Universität Heidelberg
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur
What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...
The quality of materials often depends on the manufacturing process. In casting and welding, for example, the rate at which melts solidify and the resulting microstructure of the alloy is important. With metallic foams as well, it depends on exactly how the foaming process takes place. To understand these processes fully requires fast sensing capability. The fastest 3D tomographic images to date have now been achieved at the BESSY II X-ray source operated by the Helmholtz-Zentrum Berlin.
Dr. Francisco Garcia-Moreno and his team have designed a turntable that rotates ultra-stably about its axis at a constant rotational speed. This really depends...
08.08.2018 | Event News
27.07.2018 | Event News
25.07.2018 | Event News
14.08.2018 | Information Technology
14.08.2018 | Life Sciences
14.08.2018 | Life Sciences