Last week, when electricity demand hit a near all time high in New England, the operator of the regional electric grid ordered the Lowell, Vt. wind project to cut its power output.
The move baffles the utility and wind developers. They question why a renewable energy project was scaled back when polluting power plants everywhere in the region were told to run full blast.
As the heat wave peaked last Friday, electricity demand in New England soared to almost 28,000 megawatts as people cranked up their air conditioners and fans to keep cool.
So ISO-New England, which manages the regional transmission grid, asked customers to voluntarily curb their power use. ISO also asked almost all generators in New England to pump electrons on to the grid to meet demand.
But it issued a contrary order to Green Mountain Power. The utility was told to cut power output from its 21 turbine wind project in Lowell. GMP spokeswoman Dorothy Schnure said utility executives were perplexed by the order since ISO also wanted GMP to put its rarely used fossil-fuel generators on line.
“Last week, the ISO actually was telling people to use less power at the same time that it was telling us to turn on our diesel fuel units and limiting what we could generate at our wind plant,” she said.
Schnure said the utility was asked to curtail output from the Lowell project by 15 to 30 megawatts. Lowell has a maximum capacity of 63 megawatts. She said GMP asked ISO New England for a reason for the cut-back order, but has not been given one.
ISO spokeswoman Marcia Blomberg said she can’t comment on its orders to particular generators. She said ISO also administers the wholesale electricity market and does not want to do anything to affect that market. Blomberg said that in general ISO tells utilities to cut power in order to protect the grid from getting overloaded.
“When the output from any resource jeopardizes reliability, curtailment may be necessary, really regardless of the amount of demand on the regional system as a whole,” she said.
In a report released in June, ISO said the transmission grid is not robust in the rural areas where New England wind projects have been built. ISO said the network in these areas was built to handle the local load, not for large power projects.
But David Blittersdorf, a wind energy developer, said last week’s cutbacks on Lowell don’t make sense since the demand for electricity was high both region-wide and in the Northeast Kingdom.
“The idea behind the curtailment on Lowell is that they have this system problem and a weak grid. But if your load’s right there, that doesn’t matter,” he said. “You want to supply it with the generation that’s right there. It’s not going hundreds of miles away, which a weak grid would have a problem with. So I consider what they’re doing really bizarre.”
Blittersdorf is a principal owner of the 10 megawatt Georgia Mountain wind project in northwestern Vermont. He said it was producing 8 megawatts last Friday, supplying carbon-free electricity to the grid just when it was needed most. He said Lowell could have contributed as well.
“They had coal plants going; they got everything going. They were running peaking oil units, some of the most costly, polluting things to do, and then they’re curtailing some wind? It’s kind of crazy,” he said.
GMP is installing a device near the Lowell project called a synchronous condenser that should resolve most of the grid reliability issues. Spokeswoman Schnure says the utility wants to work with ISO New England to avoid future cutbacks.