“Green steam” from underground pipe networks could be a promising source of process heat for the world’s major cities, National Geographic reported earlier this month.
“Widely used but rarely mentioned in conversations about how cities can slash climate-warming greenhouse gases while sustaining growth, district energy is attracting new interest,” the magazine notes. “The United States alone has more than 700 of these subterranean systems, some dating back to the 1880s.”
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“These legacy urban networks that were built back in the day by the utilities have become, fundamentally, portals for sustainable energy,” says Bill DiCroce of Paris-based Veolia, a company that runs a dozen district energy networks in North American cities like Baltimore, Montreal, Philadelphia, and Cambridge, MA.
In Cambridge, Veolia invested US$112 million to capture waste heat from the Kendall Street gas plant that was previously vented into the Charles River. Now, the heat is piped to Boston, where the company says it has eliminated 475,000 tons of greenhouse gas emissions.
District energy “is a lot cheaper than it is for me to actually have to maintain a piece of equipment that would heat enough water or steam to keep these buildings going,” said Faneuil Hall Marketplace Operations Manager Chris Sherman.
Last year, the UN Environment Programme reported on 45 “champion cities”, including Oslo and Tokyo, that had used district energy to cut primary energy demand 30-50%. Copenhagen uses recycled waste heat to save the equivalent of 1.4 million barrels of oil per year. Rob Thornton, president and CEO of the International District Energy Association, points to “some resurgence, investment, and renewal in the district energy industry in the last 10, 15 years,” including “dramatic investment” in the Middle East. h/t to EcoWatch  for pointing us to this story)