How Norway produces hydropower with a minimal carbon footprint

With hydropower and other renewables accounting for over 98 per cent of all electricity produced in Norway, the country delivers stable, affordable and low-emission energy to industries that depend on a reliable power supply. This has helped Norwegian heavy industry to operate with one of the world’s smallest carbon footprints

Hydropower is unique among renewable energy sources. It can be produced on demand, providing balancing power for intermittent wind and solar when the wind doesn’t blow and the sun doesn’t shine.

Hydropower also offers non-power-related benefits in the form of multipurpose reservoirs, improved infrastructure, increased availability of fresh water, and much more.

According to the International Energy Agency (IEA), hydropower will remain the world’s most important source of renewable energy in the foreseeable future.

Like all electricity production, hydropower can have ecological and climate impacts. Senior Research Scientist Atle Harby of SINTEF is one of the world’s leading researchers into the environmental impacts of hydropower. He explains how hydropower plants can influence nature’s own carbon cycle.

“Normally CO₂ is released when organic materials decompose. This is a step in the natural carbon cycle. However, if there is a lack of oxygen when organic material decomposes, methane is emitted, instead of CO₂. […] The risk of this happening increases somewhat in hydropower reservoirs, as the turbines draw water from the deep part of the reservoir where there may be methane. However, the risk of producing methane is higher in warmer climates and in stagnant waters.”

Norway’s topography significantly reduces this risk. Hanne Lerche Raadal is Head of Research at the Norwegian Institute for Sustainability Research (NORSUS) and has led several research projects analysing the total carbon footprint of Norwegian hydropower. According to her, methane emissions from hydroelectric plants are a relatively small problem in Norway.

She stresses that the impacts of construction and operation must also be factored in when analysing the sustainability of hydropower.

“We use tools to perform a total life cycle analysis of the power plants. We look at emissions related to everything built out of concrete and steel, as well as maintenance and replacement of turbines and the like during a 100-year lifetime – in addition to methane emissions.”

“Our results show that Norwegian hydropower plants have an average carbon footprint of 3.3 grams of CO₂-equivalents per kWh, of which emissions from impounded areas comprise between half to two-thirds of this.”

Raadal says that this is very low in an international context.

Norway’s landscape allows many hydropower plants to be built using existing lakes, reducing the need to inundate large areas or displace communities. Still, Harby says, “A hydropower plant will always involve changes to the aquatic ecosystem.”

Hydropower developers in Norway must therefore satisfy stringent environmental regulations. Compensation measures can minimise ecological footprint, and even allow the ecosystem to thrive.

“At SINTEF we have developed an environmental design concept for hydropower,” he explains. “This involves mapping which conditions will be changed by the plant and how this will affect both fish and ecosystem. With the right measures, the fish and the ecosystem can thrive, even with large-scale power production. For example, spawning gravel can be put down or fish can be led past or outside the turbines as they migrate downstream.”

Harby emphasises the need for ethical and sustainable hydropower development.

“There are always a lot of issues to be weighed with hydropower,” he notes. “Biodiversity and destruction of nature are one thing. There are also many international examples of people, often indigenous people, being forced to move. Another problem is when the electricity produced does not benefit the local population, but is rather sold for profit. And, as with all large-scale infrastructure projects, there is always the risk of corruption.”

However, he is optimistic about hydropower’s future, provided that best practice is followed.

And because hydropower can produce electricity on demand, it can also play a crucial role in integrating other renewable energy sources such as wind and solar into the global energy mix.

Explore hydropower and other energy solutions and connect directly with innovative Norwegian companies that can help to solve global renewable energy challenges.