RUMFORD – The Androscoggin River’s heavy springtime flow cascades down falls at the side of a brick hydroelectric plant not far from the middle of this western Maine papermaking city.

The view from below is more than scenic. You might say it’s electrifying, considering the dam’s output accounts for much of the power running the lights 50 miles away in the Capitol, in transportation garages, prisons and other state-owned buildings across Maine.

And while the water roars through the falls, Maine is quietly assuming a nation-leading role as the only state in which 100 percent of the electricity used in state-owned buildings comes from renewable sources. Those green, nonfossil power sources also include wind, solar and geothermal power, and power from municipal waste generators.

“Our state government purchases of renewable energy are indicative of our willingness to take direct actions to reduce global warming,” said David Littell, commissioner of the state Department of Environmental Protection.

Maine is one of about a dozen states that have set goals for use of green energy in their buildings, said Sue Gouchoe of the Solar Center at North Carolina State University, whose database tracks such policies and trends across the country.

But Gouchoe said no other state has a goal of 100 percent renewable power in their buildings – let alone achieves that level.

Most other states with green power purchasing requirements for state buildings set minimums of anywhere from 3 to 20 percent, according to an energy researcher for the National Conference of State Legislatures.

Next to Maine’s, Connecticut’s standard is the highest, with goals of 20 percent renewable-energy purchases in 2010 rising to 50 percent in 2020 and 100 percent in 2050, said Glen Andersen of the NCSL.

No state or other power purchaser can purchase electrons that have literally been generated by any particular source – renewable or not. All power generation sites – green, fossil fuel-based and otherwise – pour their energy into a grid, through which power from a mix of sources is distributed.

But with global warming a growing concern, many power purchasers from state governments to individual homeowners stipulate that the equivalent of the power they use is generated from renewable sources. Besides financially bolstering green energy, it offsets greenhouse gas emissions.

In Maine and some other states, homeowners can opt for all-green purchases when they choose energy suppliers. A Maine law already requires all competitive electricity providers to get 30 percent of their power from renewable sources.

To get its government to 100 percent, the state purchased renewable energy credits for 50,000 megawatt hours of power generated by the Rumford Falls hydro station, which is owned by Brookfield Power of Quebec.

The renewable energy credit purchase displaces about 20,000 tons of carbon dioxide emissions per year, the equivalent of taking about 2,400 cars off the road, said Chip Gavin, director of the state Bureau of General Services, which buys the electricity for state-owned facilities.

Gavin explained the purchase during a legislative committee hearing on a bill that sought to require all state-owned and state-leased buildings to get 100 percent of their power from renewable sources by 2010.

During the March hearing, Gavin told the State and Local Government Committee that green power already accounted for all of their electric power in state buildings. As for leased space, electricity purchases are made by the landlord, so that provision of the bill was cut out.

Maine gets high praise for what it’s accomplished from the Natural Resources Defense Council, which keeps a close eye on global warming issues nationally.

“Maine is not only ahead of the problem, it is also ahead of the game,” said Dale Bryk, a senior attorney in the council’s air and energy program. “Investment and adoption of renewable energy technologies will serve to strengthen the state economy and give them a leg up on other states in the future.”