Energize Weekly, April 24, 2019
Vermont’s largest utility, Green Mountain Power, has set a goal of reaching 100 percent carbon-free generation by 2025 and 100 percent renewable energy by 2030.
Green Mountain, which serves 264,000 customers or about 40 percent of the state, is already 90 percent carbon-free, getting the bulk of its electricity from hydropower and a power purchase agreement (PPA) with a New Hampshire nuclear plant. Most of the utility’s energy comes from PPAs.
The utility’s goals, set out in its integrated resource plan, call for more renewable generation, with an emphasis on distributed generation, and more storage.
“The two largest sources that supplied the bulk of our power needs—long-term PPAs from Hydro-Québec and the Vermont Yankee nuclear plant—ended and have been replaced with a more diverse mix of resources that includes more utility scale renewable power sources; a somewhat smaller long-term purchase from Hydro-Québec; a smaller long-term nuclear purchase backed by the Seabrook plant in New Hampshire; and extraordinary growth of distributed renewable generation in our service territory,” the resource plan said.
The plan puts an emphasis on continuing to develop distributed generation and upgrading the grid to better handle diverse sources of generation.
“Establishing communities of distributed energy resources that are communications-enabled to optimize the operating cost of the electrical system and the use of renewable and non-emitting generating sources,” the plan said.
In support of this goal, the plan calls for the addition of 50 megawatts (MW) to 100 MW of storage in Green Mountain’s service territory in the next 10 years.
In May 2018, Green Mountain announced a program with Tesla to provide 2,000 residential customers with home batteries for $15 a month.
In January, the Vermont Public Utility Commission approved a Green Mountain solar plus storage project with 14.4 MW of solar capacity and 6 MW of storage.
While Green Mountain is already close to the 100 percent carbon-free target thanks to the large hydropower and nuclear PPAs, it will have a ways to go to get to 100 percent renewable electricity.
The utility owns 44 small hydropower projects with a total of 103 MW of capacity, two wind farms with a total of 71 MW of capacity and 12 photovoltaic solar installations with about 25 MW of capacity. Solar makes up less than 2 percent of the generation portfolio.
Green Mountain generates just 20 percent of its own resources, which include six oil-fired plants. The remainder primarily comes from 24 long-term PPAs and six short-term PPAs.
The breakdown of electricity by source for 2017 was 49.4 percent large hydro, 6.3 percent existing Vermont hydro, 28 percent market purchases and less than 1 percent renewable.
“We are in the midst of transforming integrated resource planning into meaningful innovation planning, covering the details of distribution, procurement, asset management, and financial planning within the context of the shift toward customer-centered distributed energy resources,” the resource plan said.
