What Moakley Courthouse's Old-School Cooling System Could Teach Us About Energy Storage

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Sixty-five IceBank Energy Storage tanks in the basement of the Moakley Courthouse in Boston. (Jesse Costa/WBUR)
Sixty-five IceBank Energy Storage tanks in the basement of the Moakley Courthouse in Boston. (Jesse Costa/WBUR)

Massachusetts is hot on the trail of the holy grail. The holy grail of renewable energy that is.

The state has launched a $10 million energy storage competition. It's seeking demonstration projects to help utilities overcome the biggest drawback to generating electricity from the wind and sun. They only produce power some of the time.

"Storage is the key technology to help us to really use renewables when the sun isn't shining, when the wind isn't blowing," says Matthew Beaton, the state's secretary of energy and environmental affairs. "We can still rely on those electrons that were generated from those resources. This is one of the most exciting areas because there are so many different forms of storage that are out there. Storage is going to be incredibly important."

There are exotic energy storage technologies being developed in the state. One is based on the chemistry of rhubarb, another uses molten glass. We'll be exploring these and other storage technologies in an occasional series of Bostonomix stories, but today, I take a look at a big battery already in use in Boston that is not on the cutting edge, but is definitely very cool.

Deep Below The Courthouse

A high pitched hum comes from pumps and boilers in the basement of the Moakley Courthouse in Boston's Innovation District, but in the seldom seen sub-basement below, things are a lot quieter — and a lot cooler.

"Yeah, it's cold in here," says Paul Valenta, head of marketing and sales for CALMAC Manufacturing. "We're storing energy right?"

He stands in front of neat rows of giant, gray plastic cylinders. They're frigid to the touch.

"They're big, dumb tanks that do what they're told," he says.

And what CALMAC's dumb, thermal storage tanks do is cool the Moakley Courthouse in a very smart, energy efficient way.

Large pipes filled with glycol antifreeze connect the tanks to a chiller machine — basically a refrigerator — then smaller tubes, filled with the chilled antifreeze, circulate inside the tanks.

"And those tubes are surrounded by water, and that water freezes solid."

This process turns the 65 tanks, each filled with 1,500 gallons of water, into giant ice cubes, and turns the Moakley Courthouse sub-basement into a farm of frozen batteries that can be charged when energy is cheap and harvested when cooling is needed.

"And the idea behind the product is — in most parts of the country — energy is half price at night, and so with our system you create your air conditioning at night, store it in the form of ice and then use it the next day to offset chiller operation using electricity," Valenta explains.

He calls thermal storage the low-hanging fruit of energy demand because buildings account for two- thirds of our use of electricity — and the largest share of that is for cooling. With electricity rates in Boston among the highest in the nation, payback for the CALMAC storage system was quick.

"I think it was an extra one and a half million dollars back in 1996 when the project bid," Valenta tells me. "So it cost a million and a half, and the savings were going to be about a million and a half a year. That's a big number."

The tanks, which are filled with 1,500 gallons of water, turn into giant ice cubes over night to keep the building cool during the day. (Jesse Costa/WBUR)
The tanks, which are filled with 1,500 gallons of water, turn into giant ice cubes over night to keep the building cool during the day. (Jesse Costa/WBUR)

'People Don't Know About This'

Over the past 35 years, CALMAC has installed its ice storage system in 4,000 buildings in 50 countries.

Outside of the Moakley Courthouse in the Seaport, 20 new buildings are going up — stores, condos, commercial space.

You'd think buying some big, dumb tanks to save big energy bucks would be a no brainer, but you'd be wrong. The Moakley sub-basement ice storage system is out of sight and seemingly the minds of developers.

"Even when we go around talking to some consultants in the area, we talk about the courthouse project they say, 'Oh, that system hasn't worked for years, they don't even use it anymore, it's been pulled out,' " Valenta says.

Bill Johnson, chief engineer at the courthouse, agrees.

"People don't know about this," he says. "Very few people know about this. The people who work here know about it, that's about it.

"The tenants who are here, they want their office the right temperature. They don't care how we have to do. So we need to provide air conditioning. It's just not something they know about. They're not concerned with it. They just want the end result," Johnson says.

And in a typical commercial building people want it cheap, which explains why a simple energy storage system like CALMAC's hasn't caught on like wildfire.

It's a matter of literally passing the buck. In real estate circles, it's called: the triple net lease.

"Building owners don't necessarily have to create the lowest cost power for their tenants because they're passing those costs through," said Travis Sheehan, a senior infrastructure adviser with the Boston Redevelopment Authority.

Sheehan says real estate developers have no incentive to install more expensive energy storage systems because their first concern is reducing their upfront construction costs to make their rents as attractive as possible.

"The flip side to that means standard boilers, standard chillers, standard electrical connections," Sheehan says.

Federal buildings can afford the higher, upfront costs for ice energy storage, because the owner/occupants — taxpayers — are patient. The system pays off in the long run.

"It's tanks, it's tubing, it doesn't break, it doesn't move, you don't have to grease bearings," Johnson, the courthouse's chief engineer, says. "You don't have to do anything to it. Whenever we can save money here, we all save."

The tanks create energy at night, store it in the form of ice, then use it the next day to offset air conditioning costs. (Jesse Costa/WBUR)
The tanks create energy at night, store it in the form of ice, then use it the next day to offset air conditioning costs. (Jesse Costa/WBUR)

'Real Opportunity' For Change

Ice storage is simple, unlike other exotic energy storage technologies under development in the state.

"And it is nerdy, it's hard to do, but that's what makes it exciting," says Judith Judson, commissioner of the Massachusetts Department of Energy Resources.

She's leading the state's energy storage effort. Massachusetts just became the third state in the nation to pass energy storage legislation.

"There's a real opportunity to really change the way we utilize our electric grid infrastructure by adding energy storage," she said.

If by year's end, commissioner Judson determines grid scale storage is viable, cost effective and needed, mandatory storage targets will be set and electric companies in the state will have to start complying by 2020.

"We're really looking at becoming a national leader in this area and taking advantage of the potential this technology has, but we haven't seen it take off to the level we want," she says.

The United States has more than enough electric generating capacity. If we could just even out our consumption, using a variety of batteries to store energy from renewable sources, U.S. Energy Secretary Ernest Moniz predicts the nation could be completely free of fossil fuel power plants by mid-century.

It would be revolutionary — something to celebrate. And Valenta, of CALMAC, agrees: The sub-basement of the Moakley Courthouse, where the company's giant energy ice storage system stands, would make a great place to party.

"We could have a giant cocktail party here," he says, laughing. "Let's go! Real big one, absolutely."

This segment aired on August 19, 2016.

Bruce Gellerman Senior Reporter
Bruce Gellerman was a journalist and senior correspondent, frequently covering science, business, technology and the environment.



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