BOSTON--For clean-energy businesses, the mantra to think globally and act locally now resonates more than ever.

The advance of Republican politicians in yesterday's national elections means that state-level efforts to encourage green technologies become more important, according to speakers on a panel at the Sixth Annual Clean Energy Conference here today. The political shake-up means that national policies to cap carbon emissions and stimulate alternatives to fossil fuels are less likely to happen, they said.

"Policy via mandates is going to have serious problems in the House of Representatives and the Senate," Melanie Kenderine, the executive director of the MIT Energy Initiative, said during a panel this morning. "We are bringing leaders into the House and Senate who are serious climate deniers and I think that's very problematic."

In a ballot question California voted to keep in place a global warming bill to cap emissions and voters there elected Jerry Brown as governor, who has said he will support clean-energy industries. In Massachusetts, Deval Patrick, whose administration has backed green tech businesses, was re-elected.

But policies in other states, notably state-level renewable portfolio standards, will be challenged in places, such as Colorado, said Peter Rothstein, the president of the New England Clean Energy Council. About half of the states now have mandates that require utilities to get a percentage of their electricity from renewable sources.

Even if many state-level programs stay in place, entrepreneurs who work in green technology need to contend with a patchwork of programs, Rothstein said. What's preferred is a unified national energy policy, something other countries are doing, he said.

"The rest of the world is out-investing us," Rothstein said. "Part of the story now will be whether companies will be able to grow and have access to early markets here in the U.S. Or will they be founded by universities and start-ups and need to go elsewhere to scale"

Energy efficiency is one area where states and cities can continue to make advances, said Henrietta Davis, the vice mayor of Cambridge, Mass. The Regional Greenhouse Gas Initiative (RGGI), which puts a cap on carbon emissions from utilities, has successfully put most of that money towards energy efficiency efforts, said Rothstein.

Meanwhile, several national programs already in place may not be renewed. The ARPA-E program, which has proved popular with scientists and entrepreneurs, was funded by $400 million in the stimulus plan, but now needs to be funded as part of the budget, panelists noted.

Vincent DeVito, a partner at law firm Bowditch & Dewey, said that the change in the political picture at the national level won't have that much impact, particularly with regard to carbon emissions, given that the last Congress failed to pass a comprehensive climate and energy bill.