MONTPELIER -- Vermont has agreed to work with other states to bring large amounts of Canadian hydroelectric power to the region to meet growing energy needs. Environmentalists say that prospect could harm ratepayers and the environment.

Vermont partnered with five other New England states and Canada last year to share the cost of the transmission infrastructure needed to carry hydroelectric power from Canada. The additional power would help states meet their renewable energy goals and fill in for other power stations soon to go offline, such as Vermont Yankee.

The regional energy plan does not detail the impacts the proposal might have on ratepayers and the environment in Vermont. The plan includes a sweeping build-out of natural gas and electric transmission infrastructure, according to Sandra Levine, a senior attorney at the Conservation Law Foundation.

CLF this week filed a public records request to the state for all documents related to transmission build-outs, natural gas pipeline capacity and hydropower imports from Canada. The requests were sent to the other states as well.

The Department of Public Service said new transmission projects to bring hydropower to the region would drive down the cost of electricity by competing with natural gas - which is used in other states as a source of electricity during peak demand periods.

"Under no circumstances would we support a project where the benefits did not outweigh the costs," Commissioner Chris Recchia said Friday.

The law foundation filed its request to find out the details of the energy plan - including which private-sector developers are involved.

"The Governors' regional energy plan appears to be the product of backroom deal-making rather than sound public policy informed by open dialogue," said Seth Kaplan, vice president of policy and climate advocacy at CLF, in a statement this week.

Vermont has made progress on building out a distributed electricity portfolio - largely through its net metering program, which allows residents and business to generate their own electricity. Sourcing new power from Canada is not designed to replace the state's growing small-scale energy industry, Recchia said.

An estimated $5.4 billion will be invested in the region's transmission infrastructure over the next four years, according to a recent ISO New England report.

Through the partnership, Vermont will be able to share its distributed generation model - which has saved the state $400 million in the past several years - with other states, reducing the need for some new transmission projects in the long term, according to the department.

"To the extent that we can get the states to reduce those transmission projects, we save a lot of money," Recchia said.

Nonetheless, developers have their eyes on transmission corridors to bring hydroelectric power to the region - one proposal would carry a high voltage power cable under Lake Champlain and beyond; another would pass across Maine; and the controversial Northern Pass would clear a path through New Hampshire's northern forests to bring power to Massachusetts.

One developer, Transmission Developers Inc., or TDI New England, has plans to run a 150-mile cable from Canada to southern Vermont. The New England Clean Power Link, as it's called, needs state and federal approval.

Electric vehicles

The regional leaders also looked at expanding electric vehicle infrastructure, including the 138-mile Vermont-Quebec Electric Vehicle Charging Corridor, a news release stated last year.

The governors have agreed to put 3.3 million zero-emissions vehicles on the road by 2025. The chair of Vermont's Climate Cabinet has made electric vehicles - and the infrastructure demands that come with them - a top priority in the years ahead.

"Almost half of our emissions in Vermont come from transportation," Secretary of the Agency of Natural Resources Deb Markowitz said Thursday. "So it's a top priority in my agency as to how do we help create the right environment to make electric vehicles the right choice for Vermont families."

She is working on building out a "green corridor" that would first connect Burlington to Montreal (and later down to Boston, Mass., and as far as New York City). Critical to this plan is setting up universal signage and adequate electric vehicle charging stations at homes, businesses, and along the corridor, she said. Already, about 50 percent of Vermont communities have at least one electric vehicle, she said.