Cambridge project taps excess steam to heat buildings

Borrows from Edison concept

Steam is produced by gas-fired boilers at Veolia’s Kendall Station.
David L. Ryan/Globe Staff
Steam is produced by gas-fired boilers at Veolia’s Kendall Station.

CAMBRIDGE — After three years and $112 million, the French company Veolia has put in place a key piece of what is one of the largest systems in the United States to generate electricity and recycle steam to heat nearby buildings and businesses.

That component is a steel pipe, more than 1 mile long, that runs across Edwin Land Boulevard in Cambridge, turns left on Cambridge Parkway, and crosses the Charles River into Boston, carrying steam produced by Kendall Station, a natural-gas-fired power plant in Kendall Square. It is part of a 30-mile network of pipe running beneath Cambridge and Boston serving 240 customers, including 14 of Boston’s high-rises, several well-known Cambridge biotechnology companies, and many of the area’s major hospitals.

Veolia’s system revives a model of energy production and distribution pioneered by Thomas Edison, the inventor of the electric light bulb. In district energy systems, power plants are located close to the customers, providing the opportunity to reuse the exhaust that is the byproduct of generating electricity. The process of capturing excess exhaust and using it to make steam to heat buildings or power the chillers used in air conditioning is called combined heat and power.


District energy and combined heat and power are gaining renewed interest as concerns about climate change grow.

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Reusing the steam for heating and cooling eliminates the need to burn more oil, natural gas, and other fossil fuels that produce greenhouse gases, such as carbon dioxide, blamed for accelerating climate change.

Vignesh Gowrishankar, a staff scientist at the environmental advocacy group Natural Resources Defense Council, said a natural-gas-fired power plant at best gets about 60 percent of the energy from the fuel it burns.

Reusing the steam produced in that process means as much as 80 percent of the fuel’s energy can be captured.

“[It’s a] pretty effective energy-efficiency technology,” he said.


Veolia’s system generates enough electricity to supply the equivalent of roughly 170,000 homes and enough steam to heat 40 million square feet — roughly the space that 223 Walmart Supercenters would occupy. The company estimates that recycling steam through its network will cut carbon dioxide emissions by 475,000 tons, the equivalent of taking 80,000 cars off the road.

“We use the energy instead of throwing it away,” said Bill DiCroce, chief operating officer of Veolia Energy.

Veolia sells electricity to NStar and steam to businesses and institutions in both Cambridge and Boston. Since 2007, Veolia — which has 220,000 employees in 48 countries and annual revenues of $31 billion — has invested nearly $170 million to build out its steam transmission network in Boston and Cambridge, as well as a separate steam system serving the Longwood Medical Area. The company would not disclose its revenue from those operations.

The 30 miles of pipe beneath Boston and Cambridge also draw from two facilities in the Back Bay and Chinatown, which make only steam. The more-than-60-year-old Kendall Station, however, is now the network’s main source.

“It has basically become the heart of our system,” DiCroce said. “We heat the city with it.”


Veolia began planning the Kendall Station project in 2011, although it did not complete the purchase of the plant from NRG Energy of Princeton, N.J., and Houston until February. The project, which included upgrading the plant’s boilers and reconfiguring the complex of several buildings, has been the company’s single biggest investment here.

‘[The Kendall Station] has basically become the heart of our system. We heat the city with it.’

Inside one building, a silvery natural gas turbine built by General Electric produces 2,000-degree exhaust — the temperature of molten lava. That exhaust is cooled with water from the Charles River to produce steam.

The steam leaves the plant through two main outlets: a pipe crossing the Longfellow Bridge, as well the recent addition running along the Charles and across the Lechmere Viaduct. The new pipeline began delivering steam in December, doubling the amount that Veolia can send into Boston.

Walking through Kendall Station recently, DiCroce gestured to his right, where the biotechnology company Genzyme’s glass-walled building stretched toward the sky.

“You can see we’re kind of surrounded by biotech Cambridge,” he said. “They’re all served by our district energy network.”

Robert Thornton, president of the International District Energy Association, said he sees Veolia’s project as part of a larger renaissance for the industry, which operates more than 700 district energy systems in the United States. Edison, he said, helped launch the industry in the late nineteenth century, when he created the first large-scale combined heat and power system.

District energy remained popular for decades, but fell out of use when utilities began building power plants in remote areas, far from customers.

But now, as cities and businesses try to become more energy-efficient and environmentally responsible, Thornton said, many are reconsidering district energy as “common-sense, reliable, resilient, and an important infrastructure asset for cities.”

Erin Ailworth can be reached at Follow her on Twitter @ailworth.