Green Mountain Power Company to Upgrade Otter Creek Dams

By Jerrica Davy

Green Mountain Power (GMP), an electricity provider to three-quarters of Vermont residents, has recently been approved by federal energy regulators to upgrade its three hydro-electric dams along Otter Creek, in the towns of Proctor, New Haven and Weybridge. The project is expected to cost about $19 million, and is to be completed by 2016.

Though these plans have been in the making for years, GMP’s new license, provided by the federal government, has given the company the official go-ahead. The license allows the company to generate electricity from the dam for the next 40 years.

“These improvements will significantly expand those hydro units by more than 50 percent, providing more energy for our customers and replacing market purchases,” said GMP President and CEO Mary Powell.

The dams currently provide 14.4 megawatts of renewable power, but with the improvements they will be able to generate up to 22.8 megawatts, enough electricity to power 9,200 homes annually.

According to the U.S. Energy Information Administration, Vermont already has the lowest energy costs in New England, but the upgrade is expected to further lower these costs to Green Mountain Power subscribers. Vermont residents have already benefitted from the Kingdom Community Wind project, which began generating electricity in 2012.

Green Mountain Power purchased the dams from the Vermont Marble Power Division of Omya Inc. in 2010. The hydro-electric dams originally provided energy to regional marble mills in the early 20th century and, despite their age, have continued to produce energy with little maintenance.

“We have plants that are over 100 years old and producing extremely low-cost energy,” GMP Vice President Steve Costello said.

Maintenance and repairs are key parts to increasing the efficiency of these dams. According to Costello, the dam’s previous owners were not as focused on power generation. “In some cases, the turbines were not operating,” Costello said. Improving existing turbines will create more energy without changing water levels, an important proviso should the dams coexist with the surrounding ecosystem.

The project has not been free of controversy. Dams in Vermont have rendered fish migration next to impossible for the past two centuries, and environmentalists have raised concerns about dams degrading water quality and causing algae blooms, which are common problems associated with hydroelectric power. Though hydroelectric power stations are the largest producer of renewable power in the United States, these environmental concerns have led to the removal of over 1,000 dams in the U.S.

Issues of flooding have also arisen in other dams that Green Mountain Power utilizes for power, including its Waterbury dam in northern Vermont. The town of Waterbury was devastated by flooding during Tropical Storm Irene in 2011, and state officials have recently proposed to maintain summertime water levels instead of draining the reservoir during the winter, increasing the risk of flooding in the spring. Maintaining water levels would help hydropower production, but at the risk of fish and other organisms downstream.

With those factors in mind, Green Mountain Power’s license includes the maintenance of environmental conditions surrounding the dam, with particular emphasis on upholding the state’s water quality standards. Green Mountain Power also plans on keeping a continuous minimum flow, which helps prevent water stagnation and maintains overall water quality. In addition, they plan on implementing easier upstream access for fish, hoping to correct an issue centuries in the making.

“The improvements will not only produce more clean energy, they will improve habitats on Otter Creek and dramatically improve the look of the sites,” Costello said.

The Vermont Agency of Natural Resources supports the project, and has certified its environmental responsibility.