Using the water flowing through our city water pipes isn’t a brand-new idea — in fact, it was just last year that the City of Portland, Ore., signed a deal with Lucid Energy to create in-pipe power projects designed to support power for EV charging stations, among other things. It is, however, till a relatively nascent concept in terms of implementation, which is why it’s nice to see Rentricity, a relatively new start up, throwing its hat in the ring.
While the Lucid In-Pipe Power System is, essentially, a way to install small hydropower directly into a city’s water mains, Rentricity’s system relies on exploiting the points in the municipal water supply where pipes feature a flow of 1-1.5 million gallons per day (MGD) and a 30-35 pounds per square inch (PSI) pressure differential.
Such differentials can arise at a number of points within the city water systems, due to the fact that — in order to ensure that water doesn’t burst city pipes — water managers make sure to cut that pressure at a number of different points throughout the system. These pressures typically range from something like 150 PSI (when the water drops from reservoirs down to receiving stations), to less than a quarter of that. Rentricity works on the idea that, rather than wasting all that energy, we should put it to work in powering our cities.
According to Fast Company, Rentricity has already putting its pressure-harvesting turbine technology to work in a 62 kilowatt (KW) system at a water plant in Keene, New Hampshire, which is believed to be the first energy-neutral water treatment plant in the world powered by its own water supply. Rentricity has another couple such projects in the works in Pennsylvania, and a bigger 350 KW system set to launch in California in September of this year.
The company is also working with New York’s Department of Environmental Protection to investigate the potentials for generating electricity at three of New York City’s 14 wastewater treatment plants. This seems like a timely idea, given the fact that the Big Apple has made headlines more than once over the last year for adding renewable energy projects to its portfolio — among them, a RFP for a sizable renewable energy installation slated for the capped Fresh Kills landfill on Staten Island, and a series of ten solar installations on City-owned buildings, bringing its total solar generating capacity to total solar generating capacity to 648 kilowatts.
Up to 1.6 billion gallons of water flows through New York City’s pipes every day, so you can imagine the potential for (free! green!) energy just waiting to be tapped.