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Scarborough first town hall to get 'tri-gen' energy system

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Posted: Wednesday, April 3, 2013 1:00 pm | Updated: 1:27 pm, Wed Apr 3, 2013.

SCARBOROUGH – Thanks to a $216,400 grant from Efficiency Maine, Scarborough will soon have the first town office in Maine heated and cooled from electricity produced on-site using a “tri-generation” system.

Also known as CCHP, for combined cooling, heat, and power, the $516,000 tri-generation system will be built on the west side of the town office, where natural gas will drive a turbine to produce electricity. The heat that would otherwise leach off the generator into the air will then be captured by the system and sent to boilers for heat in the winter or to an “absorption chiller” for air conditioning in the summer. To meet the heating and cooling needs of the 25,000-square-foot building, the generators will necessarily make more electricity than the town office can actually use, leaving excess power it can pump back onto the Central Maine Power grid or to the nearby high school.

Eventually, said Town Councilor Judy Roy, liaison to the energy committee, which put more than a year into researching the project, it could even lead to construction of a new firehouse – as a replacement for the outdated Oak Hill station – that could take advantage of the new system.

“I think with this you could now see that happen within the next five or six years,” said Roy, noting that the town owns the two residential buildings on Route 1 immediately to the west of the town office, and is in negotiations to buy the third.

The tri-gen plant won’t be big enough to also serve a fire station, but it can be expanded and Town Manager Tom Hall said he expects to recoup the investment on the initial phase of construction in less than 40 months out of savings over what is now paid in utility outlays.

“Our model and analysis is based on the town office building only and that return on investment from savings is attractive in and of itself,” said Hall. “If you factor into that locating a new building of similar size right next to us, which wouldn’t need the mechanical systems that would otherwise be required, then you’re looking at really big savings.”

The Efficiency Maine grant is part of $3.2 million the independent trust recently awarded through its competitive program for large energy consumers. That program reimburses up to 50 percent of construction costs for energy-saving systems, in amounts ranging form $100,000 to $500,000. However, even at that, Scarborough is one of the smallest awardees, and certainly one of the smaller tri-gen systems.

“They were competing against paper companies, hospitals and wastewater treatment plants,” said Ian Burnes, program manager of strategic initiatives for Efficiency Maine. “One of the reasons Efficiency Maine chose to fund this project is because of the strong commitment to both planning and execution Scarborough has shown. They’ve clearly put a lot of thought into this and it shows from their application.

“Tri-generation is a very successful technology. Eastern Maine Medical Center has had a large unit running for a number of years,” said Burnes, “But where we’re seeing the cutting edge in Scarborough is that this is a smaller plant than we’ve seen in other places and that comes from some of the technological advances in equipment.

“Ten years ago this was something that was available only to much larger projects,” said Burnes. “I wouldn’t say Scarborough is the first in the state to produce their own energy – I’m sure there are town offices elsewhere equipped with solar panels – but they certainly are the first to use tri-generation as an energy model.”

According to Burnes, normal systems that produce electricity using natural gas are only 35-50 percent efficient, in terms of the heat rate – defined as the fuel a generator must burn, measured in British Thermal Units, to push one kilowatt-hour of electricity onto a transmission line.

What’s more, said Burnes, about 8 percent of that electricity fades away as it travels over power lines.

“Now, if you look at the stacks in, say, Westbrook, you can see huge amounts of steam just pouring up into the atmosphere,” said Burnes. “But a tri-generation system can be 75-80 percent efficient because it captures and uses all of that excess energy for cooling, as well as heating. And, it’s all done on site.”

Scarborough got notice of the Efficiency Maine grant March 20. Hall said the tri-generation project will be bid out later this spring once a contract is signed between the town and Efficiency Maine.

During the yearlong investigation by the energy committee, Paul Aubrey, owner of Scarborough-based Self-Gen Inc., pitched a deal in which he would install a tri-gen system free of charge in return for a 10-year contract to operate it. Under that system, similar to the one between South Portland and ReVision Energy that recently put solar panels atop the city’s Planning and Development Office, the town would buy back the heat and electricity produced on site.

It would then get reimbursed for half the difference between its current bills and what the tri-gen system costs to run, while Aubrey’s investors would get the other half.

“Maine is 20 years behind the times on this, and this model is perfect for Maine because we have seven months of heating need,” said Aubrey last year, when the town was still kicking tires.

By producing its own electricity on site, Aubrey said, Scarborough could cut its carbon footprint – the amount of greenhouse gas it contributes to the environment – by 25 percent. Even better, the Public Utilities Commission will allow up 10 net meters per system, he added, holding out the vision of an even larger network designed to serve the entire municipal campus, including not only town hall and an as-yet-hypothetical fire station, but the high school, middle school and public library.

The new Wentworth Intermediate School, now under construction, will use geothermal heating.

Although Hall called Aubrey’s proposal “an exciting option” last year during energy committee deliberations, he now says he “is inclined” to have the town pay for construction up front and get all the savings. He does hope, however, to find a vendor through the bid process that can maintain as well as build the system.

“I’m not expecting our custodial staff to be responsible for that,” he said.

Money for the town’s share of the project has been included in Hall’s capital improvement projects plan for future borrowing, now before the town finance committee. Hall said he expects the project to survive the annual budgeting process, and for good reason.

“If I were a betting man, I would suggest commodity prices are not likely to go down,” he said. “The more energy we can make ourselves, the better.”

Efficiency Maine was founded in 2002 and funded primarily through the “system benefit charge” included in electricity rates, as well as the Regional Greenhouse Gas Initiative. In 2009, the Efficiency Maine Trust was established under a nine-member board of directors to oversee all energy efficiency programs in the state not related to transportation. According to the trust, every dollar it spent from 2010 to 2011 generated $2.58 in “lifetime economic benefits.”

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