The largest source of renewable energy in the world is hydropower that accounts for about half of all renewable energy production. The sustainability of this conventional power source is increasingly being called into question as more is learned about the ongoing detrimental effects of dams. Yet, more dams continue to be built, especially in the developing world.

Research at Michigan State University (MSU) has revealed that the environment, and people around the world, may benefit more from in-stream turbines than dams.

In a paper just published in Nature Sustainability, an interdisciplinary MSU team including Suyog Chaudhari, a Ph.D. student in civil and environmental engineering (CEE) and his adviser, CEE Associate Professor Yadu Pokhrel, studied the feasibility of energy generation by using in-stream turbines instead of building large dams. The title of the paper is, “In-stream turbines for rethinking hydropower development in the Amazon basin.”

Chaudhari said hydropower is expected to continue to dominate the renewable energy sector despite the growing environmental concerns around the world.

“Traditionally, the hydropower industry has focused on using large dams that impound water to maximize energy generation at a given location. More than 50,000 large dams have been built globally. They have been crucial in providing the needed energy in many regions,” Chaudhari said.

“In many cases, however, the negative effects of large dams are adding up,” Pokhrel explained. “They include the displacement of local communities, loss of fertile land, degradation of biodiversity, blockage to fish migration, and dramatic alteration of the hydrologic landscape both in the upstream and downstream of the dams. In some cases, dams even modify local climate and impact many other connected systems.”

In the U.S. and Europe, where dams were aggressively built during the 20th century, there are now more dams being removed than new dams built because of their detrimental effects, he said.

“Rising energy demands in developing nations have, however, led to a major upsurge in dam building,” Pokhrel continued. “Construction initiatives are highly controversial because of the lack of transparency on the planning and decision process, and negative socio-environmental costs that often surpass energy benefits.”

A strong example is the rapid boom in dam construction in the Amazon River Basin in South America. Some large dams are being built and hundreds of others are planned, with many proposed in exceptionally biodiverse sites and regions that are home to indigenous communities.

“There are fears that these dams, if constructed, may completely disrupt the natural environment, cause massive deforestation, displace indigenous communities, and threaten local livelihoods,” Pokhrel said. “Another critical issue is that most of the generated power is used for economic gains, with no concern over whether the local communities have access to electricity.”

Chaudhari said the research team explored the use of a disruptive technology for producing energy without building large dams.

“The technology uses in-stream turbines that can be placed on river channels and do not significantly alter the natural flow systems.”

The study chose the Brazilian portion of the Amazon River Basin to assess whether in-stream turbines could generate the same portion of the energy that a massive dam like the Belo Monte Dam in the Xingu River of the Amazon River system could generate.

“We used a new-generation hydrological model and a novel approach to estimate energy generation capacity of in-stream turbines over large river systems,” Chaudhari explained. “We found that about two-thirds of the energy planned to be generated within the Amazon River Basin could be produced by using these in-stream turbines.

“In fact, in five selected locations where large dams are planned to be built in the near future, we found that the entirety of energy could be generated by using in-stream turbines. More importantly, we also found that energy generation from in-stream turbines could be even cheaper than from large dams, partly because of far less social and environmental costs associated with in-stream turbines.”

Pokhrel noted that in-stream turbines have received significant attention in recent years. The U.S. Department of Energy is making huge investments to explore the feasibility of large-scale deployment of in-stream turbines in U.S. and elsewhere.

“Our study is the first to demonstrate such feasibility over large scales and has important implications for the future of hydropower. While our study took the Amazon River as a case example, the approach is valid for any other place,” Pokhrel added.

Original Article: MSU-led research makes sustainability case for in-stream turbines

More from: Michigan State University