Full power

MEDWAY - The three oil-fueled power-generating units at the Exelon West Medway generating station currently don’t get a lot of use - and they aren’t meant to.

According to Tammy Sanford, a manager of project development, each of the three units, which have been running on oil for 45 years, currently run an average of just under 100 hours per year, capable of generating 117 megawatts of energy when necessary.

On Friday, when temperatures crept into the 80s, the jet-engined-powered units were silent, as they only operate when power is in high demand. The units are only started when prompted by ISO New England, an independent, not-for-profit corporation that ensures the continuous flow of electricity across New England at a competitive price.

The last time they ran was three weeks ago, according to a plant operator.

The station is known as a peaking plant, which generates power mainly during the hot summer months and the very cold winter months.

But due to several large power plants scheduled to retire, including the massive 1,500-megawatt, coal-fired Brayton Point plant in Somerset and renewable energy sources coming online, there is now a need for backup power sources during peak use.

“There have been plenty of assets retired recently in New England,” Sanford said during a tour on Friday. “We’ve got to do something to fill the gap.”

In order to do so, Exelon is proposing two new state-of-the-art, highly efficient generating units capable of producing 195 megawatts of energy to power 200,000 homes. The units will be dual fueled, meaning they can run on natural gas or ultra-low sulfur diesel fuel.

The permits sought will allow each of the new units to operate a maximum of 60 percent of the available hours in a year – 5,256 hours, including a maximum of 1,440 hours while running on oil.

The units, Sanford said, are fast-starting, meaning they can be “off the grid – cold, and within 10 minutes, can have full power.”

“That’s an incredible benefit,” Sanford said. “The technology we’re proposing is the most efficient simple-cycle technology on the market.”

In addition, the units have the lowest greenhouse gas emission rates “for any single-cycle peaker in its class,” due in part to state-of-the-art emission controls, including water injection, which requires an average of 90,000 gallons of water per day and up to 190,000 gallons.

At a state Energy Facilities Siting Board public hearing in Medway earlier this month, several residents spoke about their concerns with the project, including the sight of 160-foot stacks and a 50-foot sound wall, and the amount of water to be used.

Medway has had its own problems with water – in December, the town was finally able to locate a large leak that was costing the town about 400,000 gallons of water per day – over a third of the town’s produced water.

But with the town exceeding its permitted water use from the state Department of Environmental Protection, Exelon lent a helping hand – the company, needing water for their planned expansion, paid $40,000 for a consultant to help find the water, said Exelon spokesman Kevin Thornton.

Exelon and town officials have begun discussions on a payment in lieu of taxes agreement and a host community agreement, the latter of which Town Administrator Michael Boynton said would serve to “protect the town’s best interest in both the financial and environmental concerns.”

According to Thornton, Exelon, already a major taxpayer in town, will become the largest taxpayer after the expansion.

And, according to Sanford, the company is also proposing several mitigating measures, including the proposal to not run the new units on oil during the ozone season from May 1 to Sept. 30 - “when air quality is not the best."

Proposed to help shield the sound and sight of the new generating units will be a 50-foot wall, but the stacks will tower over the wall at 160 feet, more than double the size of the current stacks.

According to Sanford, residents will have the opportunity to provide input at least three more times along the permitting process – a filing with the state department of Energy and Environmental Affairs, an air permit filing with the state Department of Environmental Protection and a site plan review with the town’s Planning and Economic Development Board, which will be filed later this summer.

“The bottom line – we want to hear what people think,” she said. “If residents are concerned about noise or a landscape buffer – if we can incorporate something into the design, we would prefer to do that than to have some sort of adversarial relationship with the town and community.”

Zachary Comeau can be reached at 508-634-7556 and zcomeau@wickedlocal.com. Follow him on Twitter @ZComeau_MDN.