Communities around the world have obstructed and redirected water sources for centuries in order to prevent flooding and provide reliable sources of drinking water and crop irrigation. Efforts to harness water’s force and convert it into hydropower first surfaced in China around 200 BC.
After decades of invention and refinement, turbine-powered hydroelectricity debuted in England in 1878 and was introduced in the US four years later. It now generates about 16% of the world’s electricity, producing nearly three times the kilowatts resulting from wind power and about six times the energy produced by solar installations.
Still, while hydropower is broadly considered a renewable energy source, it has long stoked conflict with environmentalists, dimming enthusiasm for its benefits.
Hydropower’s Environmental Impact
Hydropower is largely generated by dams or pass-through structures placed on rivers or smaller water flows. The United States has more than 90,000 dams of various sizes, and the International Commission on Large Dams reports that there are nearly 59,000 large dams worldwide.
The International Energy Agency (IEA) projects that hydro-generated electricity will increase more than 9% worldwide over the next five years, boosted by new large projects in Asia and South America. In the longer term, the IEA sees hydropower generation expanding 25% over the next 10 years and another 20% between 2030 and 2040.
Although hydropower does not consume fossil fuels and operates at relatively low costs, it is not necessarily “green.” As it staunches a river’s natural flow, a large dam creates reservoirs that can wash out homes and the landscape. It can also alter the river’s temperature, silt levels, and ability to support vegetation, fish, and other dependent creatures.
Some also question the total environmental impact of hydropower. One researcher concluded that greenhouse gas emissions from a newly formed reservoir can approach those from coal power plants, notably within the first 10 years of the dam’s existence.
A Complex Investment in Sustainable Infrastructure
Despite these reservations, hydropower is slated to remain an important part of a renewable-fueled future. The IEA anticipates solar and wind will not achieve similar generation levels until the 2030s.
In recognition of the pressing need to tackle climate change, environmentalists and industry advocates in the US recently agreed to a unified focus on rehabilitating and retrofitting existing dams as well as removing those that no longer provide value. Paving the way for this agreement, environmentalists acknowledged the technology’s renewable potential while industry representatives acknowledged environmental considerations.
Congress has also pushed for streamlined regulatory and licensing processes, especially for smaller projects. Such developments have raised the potential for investment in decentralized initiatives in particular. Still, only a quarter of the nation’s current hydropower capacity is privately held; this means that public-private opportunities in developing nations may offer a higher degree of access.
Ultimately, the International Finance Corporation (IFC) explains that hydropower investing is complex due to its high up-front costs, regulatory and site-specific risks, and long-term nature. Yet given its long-standing effectiveness, the IFC nonetheless sees further hydro-development as “very important, especially in developing countries.”