A new EDF study published this week in Environmental Science and Technology shows that hydropower — the leading renewable energy technology projected to grow rapidly — is not always as good for the climate as broadly assumed. Moreover, continuing to assume that it is could mean that projects meant to reduce greenhouse emissions will unintentionally increase them instead.
Motivated by pervasive misconceptions of the climate impacts of hydropower, we assessed the warming impacts over time of sustained greenhouse gas emissions estimated from nearly 1,500 existing hydropower plants around the globe. We also looked at the implications of future hydropower development.
If minimizing climate impacts are not a priority in the design, construction and geographic placement of new hydropower facilities, we could end up generating electricity that yields more warming — especially in the near-term — than fossil fuels.
How hydropower can be worse for the climate than fossil fuels
Hydropower is produced when water stored behind a dam is released, using the power of gravity to spin turbines, which generate electricity. There is no fossil fuel burning or smokestacks involved. Which is why, on average, electricity from a hydropower facility has a smaller carbon footprint per unit of energy than electricity generated from fossil fuels.