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Getting a power boost from ordinary H2O

The MWRA’s latest energy initiative is to harness electricity from pressure that builds on water flowing from its reservoirs

By Erin Ailworth
Globe Staff / January 3, 2011

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It’s literally an energy drink. In the near future, if you live in Greater Boston, the water you pull from the kitchen tap will have helped to generate enough electricity to power nearly 110 homes a year.

The Massachusetts Water Resources Authority, which supplies approximately 200 million gallons of water a day to about 50 communities around Boston, recently installed a device to harness energy from pressurized water that’s piped into the authority’s storage facility in Weston.

The device incorporates a hydraulic turbine and hydroelectric generator, and is one of several methods the authority is using to convert water, wind, and sunlight into power, in order to offset its own electricity consumption and save nearly $2 million annually, said Frederick Laskey, executive director of the water agency.

“It basically helps get us off the roller coaster of utility bills,’’ he said, adding that the authority consumes about $47 million worth of electricity a year. “The more we can self-generate, the less vulnerable we are to the peaks and valleys of the [energy commodities] market.’’

The authority amplified efforts to create its own energy following a 2007 executive order from Governor Deval Patrick asking the state’s agencies to lead “by example,’’ and get at least 15 percent of their annual electricity from renewable sources by 2012. The agencies were also asked to reduce their overall energy consumption by 20 percent in the same time frame.

So far, the water authority is using two wind turbines, two solar panel installations, several other hydroelectric generators, and a system that converts methane to steam. The electricity that is ultimately produced helps to power the delivery system that pulls water from the Quabbin and Wachusett reservoirs.

Gravity sends that water, which becomes pressurized as it travels, via aqueducts to a treatment plant in Marlborough, then east to a network of tanks, including the Loring Road facility, that depressurize and store the drinkable water before it is distributed to communities.

At Loring Road, the potable water will move through the new hydroelectric device, which will release the gravity-fed pressure from the water and convert it to energy for later use.

Federal stimulus funds and a $138,559 grant from the quasi-public agency Massachusetts Technology Collaborative are helping pay for the $1.8 million project. Laskey said the agency expects the generator to collect an average 1.2 million kilowatt- hours of electricity a year — or enough to power nearly 110 homes. That will save the agency an estimated $150,000 a year once the turbine and generator are up and running — hopefully, sometime this month, Laskey added.

Ian Bowles, former state energy secretary and former authority chairman, said the MWRA’s energy efforts are “pretty impressive’’ considering that it is one of the largest power consumers in the area.

“They’re the right place to pioneer this,’’ Bowles said.

The hydroelectric project has been certified by the Low Impact Hydropower Institute, a nonprofit group in Maine that scrutinizes water-generating electricity systems to ensure that they don’t harm the environment.

“They’re sort of getting double use out of the system,’’ said institute executive director Fred Ayer. “Not only do they deliver water to the thirsty citizens of Boston, they make electricity.’’

However, US Fish & Wildlife Service biologist Melissa Grader, said that while she supports the water authority’s use of the hydroelectric generator, she and her colleagues think the institute’s praise of the project is premature.

“We really think it should have some field testing and be under operation first,’’ she said. “We’d prefer to have it in operation for six months before having it certified.’’

Seth Kaplan, an environmental advocate with the nonprofit Conservation Law Foundation, said he sees both potential and challenge from the water authority’s new hydroelectric turbine.

“The bottom line is, if you can make it work, capturing these incidental bits of energy that we generate by moving water from one place to another is a wonderful thing,’’ Kaplan said, but “anytime we are trying to harness energy from the water, we need to do it carefully.’’

Erin Ailworth can be reached at eailworth@globe.com.

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