Hydropower is supposed to be "clean," as it doesn't rely on the burning of fossil fuels. But this form of renewable energy is controversial for several reasons.
From displacing human settlements to inundating biodiverse landscapes, the construction of dams and hydropower facilities presents numerous environmental and social problems. Yet hydropower is a source of renewable energy - and if done with proper planning, can truly be green.
While the Brazilian government praises hydropower as a motor for economic development, local people fear environmental and social impacts. A new dam project on the Tapajos river was recently stopped, people there are preparing to cope with future projects. (Report: Zoe Sullivan) Reporting for this story was supported by the environmental news site Mongabay.com
Brazil's indigenous Munduruku people are fighting against the development of hydroelectric dams on the Tapajós River, a major tributary of the Amazon. The hydropower, supposedly a green form of energy, would destroy forests - and could even increase greenhouse gas emissions.
Slovenia is a country of high mountains and fast flowing rivers; ideal for generating renewable electricity from hydropower. But environmentalists say too many dams are being planned, and that environmental laws are being broken. Kerry Skyring reports on the campaign to stop the Mokrice dam on the Sava river.