Chattanooga Times Free Press

Environmen­talists, dam operators, at war for years, start making peace

- BY BRAD PLUMER

WASHINGTON — The industry that operates America’s hydroelect­ric dams and several environmen­tal groups announced an unusual agreement Tuesday to work together to get more clean energy from hydropower while reducing the environmen­tal harm from dams, in a sign that the threat of climate change is spurring both sides to rethink their decadeslon­g battle over a large but contentiou­s source of renewable power.

The United States generated about 7% of its electricit­y last year from hydropower, mainly from large dams built decades ago, such as the Hoover Dam, which uses flowing water from the Colorado River to power turbines. In the Tennessee Valley, TVA operates 29 powergener­ating dams throughout the Tennessee River system, some of which date back to TVA’s creation in 1933, and a pumped-storage facility atop Racoon Mountain in Chattanoog­a. TVA derives about 10% of its power from its hydroelect­ric stations.

While those hydro facilities don’t emit planet-warming carbon dioxide, the dams themselves have often proved ecological­ly devastatin­g, choking off America’s once-wild rivers and killing fish population­s.

So, over the past 50 years, conservati­on groups have rallied to block any large new dams from being built, while proposals to upgrade older hydropower facilities or construct new water-powered energy-storage projects have often been bogged down in lengthy regulatory disputes over environmen­tal safeguards.

The new agreement signals a desire to de- escalate this long-running war.

In a joint statement, industry groups and environmen­talists said they would collaborat­e on a set of specific policy measures that could help generate more renewable electricit­y from dams already in place, while retrofitti­ng many of the nation’s 90,000 existing dams to be safer and less ecological­ly damaging.

The two sides also said they would work together to accelerate the removal of older dams that are no longer needed, in order to improve the health of rivers. More than 1,000 dams nationwide have already been torn down in recent decades.

The statement, the result of two years of quiet negotiatio­ns, was signed by the National Hydropower Associatio­n, an industry trade group, as well as environmen­tal groups including American Rivers, the World Wildlife Fund and the Union of Concerned Scientists. Another influentia­l organizati­on, The Nature Conservanc­y, listed itself as a “participan­t,” signaling that it was not prepared to sign the full statement but would stay engaged in the ongoing dialogue over hydropower policies.

Bob Irvin, president of American Rivers, which has long highlighte­d the harm dams cause to the nation’s waterways, said growing concern over global warming had caused some environmen­talists to reassess their long- standing opposition to hydropower.

“The climate crisis has become a lot more acute and we recognize that we need to generate carbon-free energy whenever and wherever we can,” Irvin said. “And we do see that hydropower has a role to play there.”

Irvin emphasized that his group would still oppose any effort to build new dams on rivers. But that still left plenty of room for compromise.

Energy experts have said that adding more hydropower could provide a useful tool in the fight against climate change. While wind turbines and solar panels are becoming more widespread, they don’t run all the time, and hydroelect­ricity can offer a backstop as utilities clean up their electrical grids.

In theory, there’s potential for the United States to get much more energy from running water. An in-depth study by the Department of Energy in 2016 found the nation could increase its hydropower capacity by 50% without building any large new dams.

Today, less than 3% of the nation’s 90,000 dams generate power. There are numerous smaller dams built for irrigation or flood control that could be retrofitte­d with turbines to produce electricit­y.

“We’re not talking about the Hoover Dams of old,” said Jose Zayas, a former Energy Department official who oversaw the study. “There have been some big technologi­cal advances that now let us produce more energy in a much more sustainabl­e way.”

Some companies are designing new turbines that allow fish to pass safely through, while others are looking at ways to reduce oxygen depletion in the water caused by dams.

One particular­ly promising approach is to build more facilities known as pumped hydro storage, an old technology that involves connecting two reservoirs of water, one at a higher altitude than the other. When there’s surplus electricit­y on the grid, those facilities use that power to pump water from the lower reservoir to the higher one. When electricit­y is needed, such as during lulls in wind or solar power, the water flows back downhill, spinning a turbine to generate electricit­y.

Although many grid operato rs a re now installing large arrays of lithium- ion batteries for that type of storage, batteries can typically only store 4- 6 hours’ worth of electricit­y. A pumped-hydro facility could potentiall­y store power for much longer periods of time, allowing utilities to juggle even more solar and wind energy.

The downside is that those massive, billiondol­lar pumped- storage facilities face steep regulatory hurdles, and can attract opposition even when they don’t require large new dams. While energy companies have proposed or applied for federal approval to build 50 gigawatts worth of pumped- storage projects — roughly 30 times the capacity of all the batteries connected to the grid today — hardly any new pumped storage has been built since 1995.

“Investors tend to be wary of these projects, because there’s a lot of regulatory risk,” said Lee Bailey, managing director of the U. S. Renewables Group, a private equity fund.

As part of the new agreement, environmen­tal groups and industry said they would collaborat­e to help expand the pumped- storage market, exploring lower impact off- river technologi­es and new policy incentives. The groups also said they would work together to make the regulatory process for upgrading and removing dams more predictabl­e.

The groups also agreed to lobby for policies to repair, or in some cases take down, the thousands of aging dams around the country that are in danger of collapse. In May, rain- swollen flooding breached two dams in central Michigan, forcing thousands of nearby residents to flee their homes.

Heavier downpours fueled by climate change are putting many dams at increased risk of failure. Experts have estimated it could cost tens of billions of dollars to repair and upgrade the 15,500 dams nationwide classified as high hazard.

Achieving many of those goals will be difficult, requiring significan­t regulatory changes at both the state and federal level, as well as major new sources of funding. Many of the nation’s dams serve a vast array of purposes, such as producing electricit­y, controllin­g floods, irrigating crops and creating reservoirs for boaters. Taking down older dams or upgrading existing ones can often be a complicate­d process that requires balancing numerous competing interests.

 ?? CONTRIBUTE­D PHOTO BY THE TENNESSEE VALLEY AUTHORITY ?? The Norris Dam in Anderson County, Tenn., was one of the first hydroelect­ric dams built by TVA in the 1930s.
CONTRIBUTE­D PHOTO BY THE TENNESSEE VALLEY AUTHORITY The Norris Dam in Anderson County, Tenn., was one of the first hydroelect­ric dams built by TVA in the 1930s.

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