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Harnessing renewable energy is a crucial step in building sustainable communities, and as climate change accelerates, finding carbon-free energy sources that are affordable, reliable, and can handle changes in policy, extreme weather events, and rising demand is more important than ever. One often-overlooked solution? Our rivers.
Small hydroelectric turbines (“Small Hydro”), like the ones designed by Belgian company Turbulent featured by the World Economic Forum, offer a clean, continuous, and local supply of energy to river communities. And rivers are still an untapped resource through the lens of Small Hydro — there are more than 2.5 million miles of rivers in the United States alone.
Here is some quick math to show the potential impact of Small Hydro:
- A 30 kW turbine, running 24/7/365 (or 8,760 hours per year) with 90% uptime, will produce ~236,520 kWh annually.
- If communities installed one turbine every 10th mile on available rivers (~250,000 turbines), they would produce ~59 billion kWh annually.
- To put this in perspective, households in the US consume on average about 10,500 kWh annually, so these turbines would be able to power over 5.6 million homes!
And with two-thirds of the world’s population living within two miles of a river, Small Hydro presents an enormous opportunity to create lasting impacts in the availability and production of clean energy around the globe.
Small Hydro, Big Impact
Traditional hydroelectric power (“Big Hydro”) comes from structures like the Hoover Dam, which for decades has provided huge amounts of reliable, renewable energy to the western United States. But, while effective at generating power, dams like these also have huge costs. They disrupt ecosystems, displace communities, and are generally on the decline: “most favorable dam sites have already been taken” and fewer than 3% still produce electricity.
Unlike Big Hydro though, Small Hydro works with existing river flows, capturing kinetic energy without disrupting ecosystems. Turbines can be installed directly alongside rivers (see image below), allowing them to flow freely, which is ideal because it preserves habitats for fish and other wildlife while generating clean power with minimal infrastructure and maintenance. Furthermore, single, slow moving blade designs allow fish to swim through unharmed. Studies have also shown that fewer blades increase turbine survival rates. As a result, these installations maintain biodiversity and the landscape, creating a win-win situation for communities and the environment in a simple, elegant electricity solution.
Cutting Our Losses
Complementing our rivers is only one of Small Hydro’s virtues; another is that it is local. Locally-sourced power is important because it brings energy generation and consumption closer together, which has some large financial and technical benefits.
Long-distance energy transmission, on transmission lines that crisscross mountains and highways, leads to substantial energy losses — some power never makes it to its destination. The U.S. Energy Information Administration estimates that transmission losses account for about 5% of all electricity generated nationwide. And these losses can climb even higher in remote areas, where energy has to travel farther to reach end-users.
The financial picture also results in losses: generators lose unrecoverable costs or potential sales, and customers pay healthy surcharges for transmission infrastructure. One estimate shows high voltage direct current transmission costing $3.9 million per mile! Small Hydro avoids this by powering adjacent communities directly, delivering electricity straight to a community’s distribution system, thereby reducing electrical and financial losses.
Moreover, for communities accustomed to weather-related power outages, Small Hydro offers a more resilient option. Unlike centralized grids, which are vulnerable to system-wide failures, microgrids allow communities to maintain life-saving power even if the main grid goes down, which becomes increasingly compelling as natural disasters continue to worsen.
The River Always Flows
Localized power adds resilience to communities, but the fact that rivers flow constantly — rain or shine, day or night — amplifies that advantage. Other renewables are less consistent: wind turbines only work when the wind blows, solar panels only work when the sun shines. But the continuous flow of rivers can generate power 24 hours a day every day, solving the renewables intermittency problem. Small Hydro can also help flatten the duck curve by providing continual power at peak hours when solar generation is less productive.
Constant river power could also fortify remote and rural communities by ensuring energy availability for their electric cooperatives, which serve over 42 million people. Co-ops electrify areas where traditional power sources are limited, expensive, or unreliable, and where “alway-available energy is key to keeping the lights on.” And river turbines can be daisy-chained together to increase power output from kilowatts to megawatts depending on a community’s needs. As a primary or backup energy source, Small Hydro could help bring down electricity costs, add round-the-clock renewables to cooperative energy mixes, and provide much needed energy resilience and security to these underserved areas.
Challenges Remain
Small Hydro is a promising clean energy source, but there will still be challenges to deploying it widely and at-scale. Obviously, Small Hydro will not be viable on every river or in every community — feasibility will be dependent on the river’s or community’s particulars. And even though some environmental studies have taken place, more analysis needs to be done to understand its full impacts on river ecosystems and the human communities that rely on them. Next, the bulk transmission system may have its problems, but distribution systems are also far from perfect. Interconnecting hundreds of small projects to local electric grids presents an enormous issue, not to mention the permitting hurdles that must also take place before projects can come online.
But the largest obstacle to Small Hydro may be people. NIMBYism, a term for opposition to general development, and competing uses for rivers like recreation, utilities, and even aesthetics could cause enough opposition to prevent projects from moving forward. Renewables developers know all too well that completing a project is easier with a supportive community rather than one opposed.
Go With the Flow
No technology is perfect, and there are nuances to consider, but as urban and rural communities alike seek reliable and renewable energy options, the advantages of Small Hydro become clear. These microgrids leverage existing resources and are well-suited to the geographical realities of millions of people who live near rivers. Rather than relying on long-distance transmission and centralized grids, communities can produce energy locally, minimizing losses, cost, and environmental impact. And the urgency of climate change further highlights the need for decentralized energy solutions, especially in areas where large-scale renewables are impractical due to space or economic constraints.
As policymakers, utility providers, and community leaders weigh their choices, they should look to rivers as reliable, sustainable resources for clean energy, especially near population centers. Small Hydro presents a clean energy opportunity that is simultaneously environmentally friendly, local and resilient, cost-effective and constant, to say nothing of its decarbonization benefits, which have been contemplated elsewhere. Solving climate change and delivering clean, affordable, and reliable energy to the world will doubtlessly require an “all of the above” approach, and Small Hydro, working in concert with our rivers, definitely has a part to play.
Author Bio: Colin Welch is a renewables developer at Duke Energy with a long-seated interest in sustainability, and in 2024, he became a National Fellow with the Clean Energy Leadership Institute. A self-proclaimed environmentalist, who spends a lot of time thinking about energy and the environment, Colin holds an MBA with a concentration in energy and sustainability from Carnegie Mellon University’s Tepper School of Business and a bachelor of science in environmental science from the University of Virginia. He currently lives with his fiance in the three river city of Pittsburgh, Pennsylvania.
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