Hydropower brings environmental benefits and biodiversity costs

Researchers based in Norway have created a new way to describe how much land is needed to generate electricity from hydropower. This way, policymakers and business owners will have easy access to the information they need to weigh the benefits of hydropower production against the environmental costs.

Study co-author Martin Dorber is a PhD candidate at the Norwegian University of Science and Technology.

“Some hydropower reservoirs may look natural at first,” said Dorber. “However, they are human influenced and if land has been flooded for their creation, this may impact terrestrial ecosystems.”

These kinds of renewable energy solutions have now become critically needed for climate mitigation, yet hydropower projects can place a major strain on the lands that they occupy.

The Intergovernmental Panel on Climate Change (IPCC) reported that governments and industry need to factor the long-term consequences of hydropower into current and future projects in order to accurately identify the environmental trade-offs that will result from its expansion.

The research team discovered that they had the perfect resource for gauging the environmental effects of hydropower production – an analysis tool called Life Cycle Assessment (LCA).

This tool provides researchers with a way to examine all of the environmental impacts of a product or process during its entire life cycle, essentially calculating the total environmental cost of something.

The researchers realized that there is not enough information available to allow LCA to assess certain impacts from hydropower, such as its influence on water quality and biodiversity, so they focused their study solely on the issue of land use and land use change.

“Land use and land use change is a key issue, as it is one of the biggest drivers of biodiversity loss, because it leads to loss and degradation of habitat for many species,” said Dorber.

The research team set out to conduct a life cycle inventory by determining how much land is used to produce one kilowatt hour of electricity. The study was focused on creating a life cycle inventory specifically for Norway, where more than 95 percent of all domestic power production comes from hydropower.

The researchers used satellite imagery to estimate the original size of the lakes that were used to create over a thousand hydropower reservoirs in Norway.

Ultimately, they were only able to calculate land occupation by 184 reservoirs. Collectively, these reservoirs provided 20 percent of the total average annual hydropower electricity produced in Norway between 1981 and 2010.

“By dividing the inundated land area with the annual electricity production of each hydropower reservoir, we calculated site-specific net land occupation values for the Life Cycle Inventory,” said Dorber.

“While it’s beyond the scope of this work, our approach is a crucial step towards quantifying impacts of hydropower electricity production on biodiversity for Life Cycle Analysis.”

The study is published in the journal Environmental Science and Technology.

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By Chrissy Sexton, Earth.com Staff Writer

Image Credit: Ånund Killingtveit/NTNU