As LIPA and PSEG award contracts for large solar arrays across Long Island, limitations on the grid are beginning to challenge the utilities' ability to accept green energy sources.

The problem is already playing out in Calverton, where two large solar arrays could max out the total amount of energy a Long Island Power Authority grid facility in that East End community can handle.

Under the current structure, each of LIPA's more than 180 substations can only handle about 10 megawatts of power from additional energy sources. Substations are critical outposts of LIPA's grid, converting high-voltage energy from power sources to the lower voltages required by homes and businesses.

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Many of the larger LIPA solar projects approved by the authority's trustees earlier this year could push substations to the limits of their capacities, a factor that could in the future limit home and small-business solar arrays at a time of unprecedented growth in that market, utility officials and experts said. One recently approved project for the Tallgrass golf course in Shoreham is for 24 megawatts. It's across the street from a 9.5-megawatt array.

The capacity issue was considered important enough that the Suffolk Planning Commission, as part of its recent guidelines for town codes, recommended a high-tech solution be built into bidding papers for commercial-scale projects so that they don't gobble up all the capacity at the expense of smaller ones, including home systems.

"You don't want residential solar to get crowded out because they are near a utility-scale array," said David Calone, chairman of the Suffolk Planning Commission and a former LIPA trustee.

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He said while it's "generally a good thing to have larger-scale solar" from a public policy perspective, the commission realized that "if there's too much of it in a given area, then residents won't have the opportunity to put solar on their own roofs."

Companies affected

For now, the capacity issue is primarily affecting companies that want to develop large arrays, not home systems. In some cases, developers that have already been awarded LIPA contracts to produce solar have been left with the prospect of either paying for expensive infrastructure upgrades or walking away from their projects.

Nearly half the projects planned for a 100-megawatt LIPA feed-in tariff solar program have been abandoned, Newsday has reported.

"It's a huge problem," said Marie Zere, president of Zere Real Estate Services, a Ronkonkoma commercial real estate broker who has worked on solar-farm real estate deals. Already, she said, commercial solar developers who sought projects in Calverton have had to pull them because of substation capacity issues.

"There are many other people who have tried to get into the area, only to find that it is at capacity," she said.

A PSEG Long Island official acknowledged the substation at Calverton is reaching its limit for new generation. But he said the utility has ways of mitigating that. He noted that thus far, the utility "has never turned away" a residential rooftop customer from installing solar because substations are reaching their limitation.

Smart inverters

One way to deal with the problem is by using devices called smart inverters, which would automatically reduce the amount of power accepted onto the grid from the large solar arrays. Suffolk's Planning Commission advised the use of smart inverters for commercial installations greater than 5 megawatts.

State regulators are watching the situation closely. Widely distributed solar and other renewables are a big part of the state's Reforming the Energy Vision initiative, which seeks green energy and market solutions to grid problems that have long been solved by adding costly new power plants and power lines. Just last week, the new state energy plan called for 50 percent of the state's energy needs to come from renewables by 2030.

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"Fitting renewables onto a grid that was built to move power from big power plants to customers is a challenge, no doubt, but the technology is available to make it work," said Julia Bovey, director of the Department of Public Service on Long Island. "The alternative is to spend billions of ratepayer dollars to build more old-fashioned power plants and wires, something Long Islanders have said they don't want and can't afford."

The PSEG official said while it was "possible" that "someday we have so much solar we can't take anymore," he stressed the grid now has "plenty of capacity."

More projects coming

But more green-energy projects are coming, and could stretch capacity. In addition to two commercial feed-in tariff solar programs for a total of 150 megawatts and a separate LIPA bid request for 120 megawatts of solar power, PSEG is preparing to go out to bid with another 160-megawatt renewable energy plan.

Some local solar installers see LIPA's addition of lots of utility-scale solar projects from out-of-state developers as a David and Goliath issue, one in which the utility maintains control of the grid and ratepayer dollars over individual homeowners. Many residential solar power systems can cut power costs drastically, some down to zero. That means less revenue is coming into LIPA's coffers.

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"Why should a developer from outside the region be able to suck up all the capacity in one area?" said Mike Bailis, vice president of SUNation, an Oakdale-based solar installer. "It's not right. They have to share the wealth a little."

Gordian Raacke, executive director of Renewable Energy Long Island, a green-energy advocate, said the move to renewables is so important, with climate concerns so critical, that the utility should do whatever it takes to accommodate both resident and large-scale solar.

"I don't think the utilities should be pitting large-scale solar against residential rooftop solar," he said. "We need both. It's just a matter of upgrading infrastructure."