Choose the statement that is true:
- Hydropower is by far the world’s leading source of low-carbon electricity and will be a key part of solutions to meet future energy demands without destabilizing the climate.
- Hydropower has contributed to dramatic declines in freshwater species and ecosystem services, and the projected expansion of hydropower threatens to be a leading contributor to more such losses.
- Both of the above
Unfortunately, the correct answer is “c”, which basically means there are no easy answers to questions about how the world can achieve a future with both sustainable energy and healthy rivers.
But that doesn’t mean there aren’t answers. They’re out there, but finding them is going to require innovative science, new approaches and a willingness by people with diverse interests to collaborate on solutions.
Next week, The Nature Conservancy will release a white paper that we hope will help catalyze this collaborative search for answers. In The Power of Rivers: finding balance between energy and conservation in hydropower development, we quantify what is at stake with hydropower expansion—a global total of river kilometers at risk from fragmentation and flow alteration from planned hydropower dams—and the potential for more balanced outcomes for energy development and rivers. We also take a first cut at estimating costs for funding these better outcomes to show that solutions are within reach.
First, the challenge. Working with a database that includes thousands of future dams (under construction and planned), we found that reaching hydropower development levels near the common projections for 2050 would increase fragmentation or flow impacts on more than 300,000 kilometers of rivers globally (in this report we defined rivers to include not just main-stem rivers, but also their major tributaries).
These impacts are projected to occur disproportionately in those river basins with the greatest freshwater species diversity: we found that 70 percent of all affected kilometers would be within the ecoregions in the top quartile of fish species diversity. Further, hydropower expansion will occur in many of the regions where people have the most direct dependence on rivers for their food and livelihoods.
The Mekong River basin provides a clear example of the potential impacts of hydropower development in terms of both biodiversity and ecosystem services with immense social and economic value. Using the report’s threshold for defining a river, the Mekong and its major tributaries encompass 30,000 kilometers of channels, connected into a vast network for moving water and sediment downstream—and fish, both up and downstream, on spawning migrations. Currently, 26,000 of those kilometers are unaffected by dams. Completion of all hydropower dams currently in the planning pipeline would leave just 4,200 kilometers unaffected—a decline of 84 percent. The Mekong is second only to the Amazon in terms of fish species richness (in a basin one-tenth the size), and its freshwater harvest is by far the most important in the world, producing at least three million tons of fish and other aquatic species annually (nearly 20 percent of all freshwater harvest globally) that feeds tens of millions of people.
Given the scale of resources at risk, conservationists’ instincts are to push for Laos and Cambodia to cancel most of those Mekong basin dams. But that would be a tough recommendation for us to give. In three days, the typical American uses as much electricity as a Cambodian uses for the whole year. Laos sees hydroelectric power as one of the few resources it can export for foreign revenue to grow its economy. Americans don’t have to look too deep into our past to find a time when we dammed our own organic machine for producing fish—the Columbia River—in the name of economic development, a transformation lauded by Woody Guthrie as “turning our darkness to dawn.” (Granted, hydropower, economic growth, distribution of benefits and corruption weave a tangled web in many countries, but the strong correlation between nations’ levels of water infrastructure development and per capita income is not a coincidence). Conservationists based in more economically developed countries can’t ignore our own history of intense dam development and past willingness to trade fish-producing rivers for electron-producing rivers.
There are no easy answers. But drawing on the full history of dam development in the United States—from its initial expansion to recent attempts to find better balance—and new science, we can point to better answers.
The Power of Rivers highlights some of them. In this paper, we discuss the potential for “Hydropower by Design” to identify spatial configurations of dams that can reach an energy objective while minimizing impacts on other rivers values.
Hydropower by Design was inspired in part by the re-design of a basin in the United States—the Penobscot River (Maine). There, the Penobscot Indian Nation and conservation organizations, including the Conservancy, purchased three hydropower dams and removed two of them (the third will be bypassed). As a result, the extent of river habitat available to migratory fish—including Atlantic salmon, American shad and shortnose sturgeon—will increase dramatically. Meanwhile, capacity and operational changes at the dams that remain are projected to maintain historic levels of energy generation from the Penobscot basin.
The Penobscot provides a clear lesson: similar levels of energy can be generated from alternative arrangements of dams, and those alternatives can differ dramatically in their environmental and social performance.
The Penobscot provides an intriguing example for already-developed systems looking to re-balance energy with other river values. For regions undergoing new expansion of hydropower, the Penobscot’s example is sweetened by foresight: think at the system-scale and get it right the first time; don’t wait for a century of losses before re-engineering—and paying for—a more balanced solution.