For peat’s sake: Hydroelectric dams ‘worse than coal plants’
Huge areas are flooded behind new dams, and it can create a very big greenhouse gas problem
Squatting on the spongy soil of a Canadian peat bog, this climate scientist’s work is given added urgency by the fact that hydroelectric dams can emit as many greenhouse gases as coal plants.
By laying a small cone-shaped device to “measure the breathing” of the bog in Quebec province, Michelle Garneau, a university researcher and a member of the UN’s Intergovernmental Panel on Climate Change (IPCC), is collecting the first data on areas flooded to build the new Romaine hydroelectric dams in a bid to assess the project’s impact on the region.
While renewable hydroelectricity is considered to be one of the cleanest sources of energy on the planet, there is no proven model for calculating the greenhouse gas emissions released by flooding huge areas behind new dams.
With construction of four new dams on the Romaine River in northern Quebec nearly complete, researchers saw an opportunity to try new techniques to measure its carbon footprint.
The team led by Garneau zeroed in on a swamp a stone’s throw from the raging river in the wilds of Canada’s boreal forest, an area accessible only by helicopter. After landing, she takes several boxes out of the belly of the aircraft and places them next to some solar panels and a portable weather station that she and her students installed over this summer.
The devices are expected to produce sample data within two years. “Every 20 minutes, the cone will capture and measure the breathing of the soil,” she explains, placing a transparent device that resembles a handbell on the lichen, as wild geese honk and cackle overhead. She takes a few steps further on the unstable ground and places a box that connects to sensors already sunk into the ground.
“This automated device to measure the photosynthetic activity records the CO2 and methane emissions every three minutes, for hours,” the researcher says. Carbon dioxide (CO2) and methane emissions are the main sources of global warming.
Another team is measuring CO2 emissions from artificial lakes created by flooding lands behind dams, for eventual comparison.
More research needed
About one-third of the world’s land area is covered by forests, which act as sinks for greenhouse gases. Canada’s vast boreal forest has trapped more than 300 billion tons of CO2, according to the Washington-based Natural Resources Defense Council.
However, 10% to 13% of Canada’s boreal forest is covered by peatlands (wetlands with high levels of organic matter) and very little is known about them, says Garneau, research chair on peat ecosystems and climate change at the University of Quebec in Montreal (UQAM).
Her work is supported by the province’s utility Hydro-Quebec, whose dams – once the four additional hydropower plants on the Romaine River are turned on in 2019 – will supply 90% of Quebec’s power needs. The data collected in this study should “serve the IPCC and the advancement of science in general” by helping to better peg the carbon footprint of flooded wilderness, Garneau said.
The information is crucial with several new big hydroelectric projects due to come online in the coming years, including in Canada, the Democratic Republic of Congo, Ethiopia, Laos, Tajikistan and Zimbabwe.
“We’re creating artificial reservoirs around the world, but (greenhouse gas) emissions from hydroelectricity are not well accounted for,” said Paul del Giorgio, a biologist at UQAM. “There are some dams in tropical zones that emit as many greenhouse gases as coal plants,” due to the accelerated decomposition of drowned organic materials, said the Argentinian researcher.
Del Giorgio and his students complement Garneau’s research by taking water samples from flooded lands behind dams that are analysed in a field laboratory set up in Havre-Saint-Pierre’s town hall. Both datasets will be plugged into a complex set of equations to determine the volume of greenhouse gas emissions from dams.
The first results of their work are expected in 2019 and are highly anticipated by climate scientists worldwide, says Garneau.
The IPCC desperately needs “to have better models, for better predicting climate change”.