[M II A II R II K]

Seeing Source of Electricity in Water Pipes


May 8, 2012

By JIM DWYER

Read More: http://www.nytimes.com/2012/05/09/ny...urce.html?_r=2

The water that comes out of taps in New York City runs downhill 125 miles from the Catskill Mountains, every last drop the product of 19th-century genius and scheming that made the modern metropolis possible. Now comes a new proposition for what is arguably the world’s greatest urban water system: people are trying to figure out if, on its way to your shower, the water can also drive turbines and make electricity.

- If it works out, and there are many reasons it might not, hydroelectric power harvested from the city’s water mains could be a renewable source of carbon-free power, like solar and wind. But unlike those sources, this one would be completely predictable. Powered only by gravity, nearly a million gallons of water rushes into the city every minute. From streams dammed in the hills and mountains north of the city, the flow moves with such force that even as it branches into pipes that run down every street, it rises to a height of six stories on pure momentum. Below that, most buildings need no pumps.

- As that pressure drops, energy is released. Now the city will study whether it can capture it and turn it into electricity, under a bill sponsored by Mr. Gennaro and signed into law last week by Mayor Michael R. Bloomberg. The raw physics are seductive. Still, reality also gets a vote. No one doubts the tremendous power of that water flow, least of all the guardians of the water system in the city’s Department of Environmental Protection. But they are openly skeptical about whether there are practical uses for it. For one thing, the valves are in the middle of the streets. Electricity generated there would have to make its way to the grid, unless there was some use for it in the street.

- THE city’s water stewards have said that space is already very tight below the streets, with its honeycomb of subway tunnels, water pipes, sewage lines, electrical and fiber optic and other utility cables, transformers and assorted gizmos. “It does not seem prudent to encroach upon and deplete this valuable underground real estate for unproven benefit,” Anthony J. Fiore, a deputy commissioner, testified last year. Mr. Zammataro, 54, who grew up in the Bensonhurst neighborhood of Brooklyn, began thinking about water power after the Sept. 11 attacks, when the small wireless company he was working for downtown had to move temporarily to Times Square.

- Every drop of water that flows into New York City also flows out: unlike the clean water supply, the sewage plants require tremendous amounts of power, and some of it is coming from the methane gas released by the sewage. At least one of Mr. Gennaro’s estimates about potential power has been about 200 times too high, officials said. Still, he noted that the new study was agreed to by the mayor. It is due in 18 months. “We have a green administration, a green Council, and I want to make sure that when we leave, we have a lot of homework assignments for the next ones,” Mr. Gennaro said.

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