Across NEK, North Country: Grid operators put limit on wind power use

Wind power projects are facing limits that even the staunchest supporters can't control.

The operators of the New England grid are restricting the amount of electricity being accepted from the three operating wind projects in the Northeast Kingdom and the North Country of New Hampshire.

And there's no indication that the restrictions, called curtailments, will end anytime soon.

Curtailments to balance electricity production with demand are common, according to ISO-New England, the grid operator.

But it's the extent of the curtailments that caught some by surprise and has Vermont Electric Cooperative questioning whether any intermittent wind or solar project will be allowed to produce as much electricity as it could.

That's why the VEC board of directors wants a moratorium on new wind and solar projects in Vermont.

VEC is asking the Legislature to back off demands that utilities buy even more renewable and intermittent power until curtailments and other problems are studied.

"These curtailment issues are a surprise to us," said Dave Hallquist, CEO of VEC.

He testified before the Vermont Senate Natural Resources and Energy Committee this week, which is considering a wind project moratorium. He said the different wind projects are reacting to the curtailments.

Granite Reliable?

ISO-New England only accepted about half of the electricity that could be produced last year by Granite Reliable Power wind project in Coos County, N.H., Hallquist said.

As a result, the majority owner doesn't want to pay its full amount for 2012 to the county.

Granite Reliable Power operators say that the curtailments limited the electricity it was allowed to produce and the money the owners made.

The county and the companies are now fighting over that.

Sheffield Limits

The First Wind Project at Sheffield did not sell as much electricity as expected in 2012, said spokesman John Lamontagne.

Hallquist said that the production was 23 percent of capacity, down from the expected 32 percent for its 16 wind turbines. Wind project capacity is usually in the 32-35 percent range.

Lamontagne said the lower than expected generation was due to a number of factors, "including higher than expected utility curtailment, higher bat curtailment and below average wind speeds throughout the year."

First Wind has to reduce operations to protect bats.

"Wind generation in 2012 was below predicted wind averages based on multiple years of on-site wind measurements and testing. These reductions were partially offset by higher than expected turbine availability.

"First Wind expects that the generation projections will be on target over the life of the project," Lamontagne said.

Hallquist said VEC has estimated that curtailments caused half of the reduction in the electricity production at First Wind.

Low For Lowell

Curtailments also affect the 21 wind turbines at Kingdom Community Wind in Lowell, which has a maximum capacity of 63 megawatts.

Green Mountain Power officials said ISO-New England limited the Lowell project to 15 megawatts earlier this week.

Then the amount was increased to 30 megawatts, GMP spokesman Robert Dostis told Vermont Public Radio. Dostis said that Lowell could have produced 45 megawatts because of the winds.

At the same time, GMP has reduced turbine operation to study noise.

Dorothy Schnure with GMP said the turbines have to be shut down every four to eight hours for 20 minutes each time to take noise measurements. And, as a new plant, there is start-up maintenance issues that require the turbines to go off line.

Before the end of the year, GMP will install what's called a synchronous condenser which will smooth the flow of electricity into the grid, at a cost of $10.5 million. That, Hallquist and Schnure said, will prompt the grid operators to allow more electricity from Lowell.

"We think that can resolve most of this," Schnure said, calling the limits on generation a temporary issue.

The condenser will help, Hallquist said. "But we're not sure if it's going to entirely fix the problem."

Grid Limits

ISO-New England operators rely on curtailment of all types of power plants to balance production versus demand, spokesman Marcia Blomberg said this week.

"Our job one is dispatching power into the system on a minute-by-minute basis," Blomberg said.

"It has to be kept in balance," with the supply being generated to meet the demand.

The problem with electricity is that there isn't a way to store it for future demand, she said.

So energy plants are directed to cut back on the amount put into the grid when the demand is less.

The ISO-New England grid, said Hallquist, like others, was built on what's called spinning resources -- power plants that produce on demand consistently - including nuclear and fossil fuel plants, especially natural gas.

ISO-New England has operating protocols that determine whether wind projects can get on the grid or not and by how much. The same would be true for a large solar farm, he said.

Utility specialists knew that intermittent energy sources should expect to be curtailed, because big wind projects elsewhere in the country, like Texas and the Pacific Northwest have been curtailed by grid operators to smooth out power flow, Hallquist said.

They just didn't expect so much curtailment last year, he said.

ISO-New England may curtail resources when the energy production in one area exceeds the transmission system capability, Blomberg said.

"Sometimes these generation adjustments are preventative measures required to avoid overloading the transmission system following the loss of a resource or transmission line.

"Also, in some instances, newer resources may have interconnected to areas of the system that have limited transmission capability -- if the transmission lines are full, for instance, the resource will not be able to get all their power out," Blomberg said.

That's what Hallquist wants studied before more big renewable projects are planned or go online.

As for Lowell, the utility-owned wind project is still the lowest priced renewable energy available for both GMP and VEC, even with the expensive condenser, Hallquist and Schnure said.

VEC has enough renewable energy contracts to meet legislative requirements, Hallquist said.

But he said VEC wants the Legislature to stop requiring more until grid limits, health concerns and other problems with wind and solar are considered.

Staff Writer Amy Ash Nixon contributed to this story.

Special thanks to the Caledonian Record for granting us permission to post this article.