After years in which alternative energy grew one solar roof at a time and through small wind turbines set up in a few backyards, Long Island may be on the verge of building big renewable energy projects.

The Long Island Power Authority has completed a study that found it’s possible to build the nation’s first offshore wind project and plans to proceed with a solar power project that dwarfs anything done in New York to date.

The change in approach amounts to a revolution in renewable energy as the Long Island Power Authority and advocates begin to look at solar and wind as potential sources for large projects.

“We need to move from small, incremental projects to large-scale projects,” said Gordian Raacke, executive director of Renewable Energy Long Island in East Hampton.

The think-small approach just hasn’t worked. Despite huge efforts and incentives, only 1,700 solar systems have gone up on Long Island. Fewer than 100 were set up by businesses. And LIPA isn’t the only one thinking big.

President Barack Obama targeted reducing the nation’s carbon emissions by 80 percent by 2050, giving moral and financial stimulus to alternative power.

“We’re not going to make the 80 percent [goal] one roof at a time,” Raacke said. “We need to do that, but we need to think big in terms of alternative energy.”

While President Obama beats the alternative energy drum in Washington, New York’s Gov. David A. Paterson also is making his own push for big alternative power projects statewide.

Paterson wants 45 percent of the state’s electricity to be through improved energy efficiency and renewable sources by 2015. While “improved efficiency” leaves wiggle room and much of that could be through hydro power, other alternative sources would play roles.

“We must find alternative solutions to traditional fossil fuel sources,” Paterson said in a written statement. “By taking advantage of the natural resources that New York has to offer, we will position ourselves to be the national leader in renewable and alternative energy.”

The new solar system

In the biggest sign of the changing approach to alternative energy, LIPA has selected two firms from which it will buy 50 megawatts of solar energy, enough energy to power about 6,500 homes and reduce carbon dioxide emissions by 20,000 tons a year. That project alone would provide more than three times the power residential systems generate Islandwide.

In addition to contracting for solar power, LIPA is providing rebates to businesses of up to 100 kilowatts, 10 times the previous ceiling.

“This gives our [business] customers the ability to take advantage of their larger roof space and the net metering provision,” said Michael Deering, LIPA vice president of environmental affairs. “We’ve got a number of inquiries from commercial customers. Folks are looking at it.”

And LIPA approved net metering for businesses, letting them sell unused solar power back to the grid. The increased savings makes it more desirable for companies to go solar.

Raacke said it’s too early to tell how many businesses will be enticed by net metering. “That’s just starting to become known among commercial customers,” Raacke said. “I have a feeling that will expand the solar market.”

Wind in their sales

If the new approach to big solar projects for Long Island is a change, LIPA’s also thinking big with wind, which recently seemed to be dead in the water.

The authority pulled the plug on a plan for Florida Power and Light to build a 140-megawatt wind turbine off Jones Beach. The reason in part was that the project wasn’t ambitious enough.

“It was too small, too close to shore. The cost continued to escalate with no real fixed ending,” Deering said. “While [the new project is] further out, it’s large, which gives us better economies of scale.”

LIPA is teaming with Consolidated Edison in the hope of building what could be the nation’s first offshore wind project, although there are many such projects elsewhere in the world. And it would be more than two times the size of the earlier proposal and potentially grow far beyond that.

The two already completed a study showing it’s feasible to connect 700 megawatts of wind power from 13 miles offshore in the Atlantic Ocean to the electric grid.

Law said he’s encouraged by the study, showing “a large offshore wind project can work in our service territory.”

LIPA and Con Ed are working with the New York State Energy Research and Development Authority to develop a tower to measure wind strength at the proposed location.

“A larger project means that the cost per kilowatt hour is going to be less,” Raacke said. “The Europeans are building 1,000 megawatt wind projects and bigger. The industry has evolved to bigger scale projects. The technology is there. But can we find the right site?”

Answers blowing in wind

While big projects could be good news, some say they might not benefit local alternative energy firms as much as hoped.

Marc Clejan, co-founder of Southampton GreenLogic Energy, worries big companies such as BP are getting the big solar contracts. While they could hire local installers, he’s concerned they might not.

“Given that LIPA’s ultimate mandate is to serve the people of Long Island, it seems to me that any large contract they sign should require local labor be used,” Clejan said. “Jobs are key right now, and this is not the time to be outsourcing Long Island’s jobs. “

But LIPA is careful to point out it’s not replacing its effort to boost alternative energy one solar roof at a time so much as supplementing it. It has set aside $14.4 million for renewable energy, including millions for residential, this year. And the authority approved $1.2 million in incentives for its Backyard Wind initiative to encourage homeowners, businesses, municipalities and nonprofits.

“That’s a small program,” Raacke said. “The big expansion into wind is going to be offshore. That’s going to be huge.”