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Water Authority Bans Some Geothermal Systems Citing Threat to Aquifer

Thu, 11/12/2020 - 09:10

On Tuesday, in its second virtual meeting in a week, the East Hampton Town Board discussed several environmental matters.

Ty Fuller, Suffolk County Water Authority's director of Strategy Initiatives, issued a warning about the impact of geothermal heating and cooling systems on public water.

Geothermal energy, the heat inside the earth, is captured via utility-scale power plants, or, at the residential level, ground-source heat pumps that heat and cool houses. In the latter, heat is transferred by pumping water or a refrigerant through a loop of vertical or horizontal pipes buried just below ground level, where the temperature is constant. During the winter, the liquid absorbs warmth from the earth and it is pumped to the structure above. The liquid cools following the heat transfer and is pumped back underground, repeating the process. In warm weather, the process runs in reverse.

There are closed-loop and open-loop geothermal systems; the former recirculates the same water throughout the system, while the latter constantly discharges and refreshes the water running through it. An estimated 4,000 to 5,000 geothermal systems are in use on Long Island, 70 percent of them open-loop systems. It is not known how many of them use public water.

Geothermal systems are a cleaner, energy-efficient alternative to fossil fuel-based technology, and can offer large reductions in heating and cooling costs. But the water authority voted unanimously in July to no longer approve applications for water service that use open-loop HVAC (heating, ventilation, and air-conditioning) systems, based on a recommendation from the Long Island Commission for Aquifer Protection, which is charged with assessing threats to the Island's sole-source aquifer that provides drinking water. The ban also prohibits existing customers with open-loop systems using a private well from ever switching to S.C.W.A. water. The commission has urged Suffolk's municipal governments to adopt their own geothermal codes.

This, Mr. Fuller told the board, is due to such systems' impact on the groundwater supply. Chiefly, they require a lot of water. A typical 2,000-square-foot house requires about 15 gallons per minute, or more than 21,000 gallons per day of continuous water usage, he said. But houses greater than 10,000 square feet can have systems that use in excess of 50 gallons per minute, or 72,000 gallons per day.

"The issue that we find is that on the East End, some homeowners don't use their own supply well, due to they're close to the coast," he said, "and these supply wells could be impacted by seawater, which could corrode the system." It's cheaper to connect to the public water supply, which, he said, is "not something geothermal systems were envisioned to do."

Water usage capacity is already limited on the East End, Mr. Fuller said, "and you're talking homes in East Hampton, Southampton, that are larger. They use a lot more water, and now it's creating this unnecessary burden on the water supply. While you offset electrical load, you've increased the load on water supply; you have just changed the impact from one utility to another."

Overpumping the aquifer in coastal areas can have irreversible water-quality impacts such as saltwater intrusion or "upconing," the rising of saline water into the freshwater zone in an aquifer. The impact is "catastrophic," Mr. Fuller said. "To keep up with demand, we have to construct more wells," drawing more water from the aquifer, which can strain it and result in saltwater intrusion.

Mr. Fuller said that the town's building and planning departments could document and track new geothermal systems, which could help curb their use and "ensure there are no surprises for us."

Supervisor Peter Van Scoyoc said the board had received draft legislation from the commission and would discuss potential legislation.

Also at Tuesday's meeting, the board discussed draft legislation that would ban commercial landscapers' use of gas and diesel-powered leaf blowers from May 20 to Sept. 20, and restrict their use during the remainder of the year. Similar laws took effect this year in East Hampton Village and Southampton Village.

Hundreds of residents, Mr. Van Scoyoc said, have offered the opinion that such leaf blowers "have become way too pervasive and have destroyed the quality of life" throughout the town. Encouraging "green" landscaping practices, including the use of quieter, emission-free electric leaf blowers, would reduce air and noise pollution, he said.

The supervisor would be able to waive restrictions in the aftermath of a severe storm, or, on a case-by-case basis, in special circumstances such as an abandoned or neglected property.

The legislation follows a recommendation from the town's energy sustainability advisory committee. Lena Tabori, the committee's chairwoman, called in to the meeting to emphasize gas and diesel-powered leaf blowers' impact on health and the environment, and not just noise. "Noise and toxic pollution for the <I>user<P> of the equipment is a critical aspect," she said, "not to mention constantly getting gas spillage under all circumstances, affecting the aquifer."

She asked that the board reconsider exemptions to residential property owners. "We have to transition to electric on every level we can," she said. "I think the homeowner has to get with the program along with everybody else."

The draft legislation will be circulated to the chief of police and the director of code enforcement for comment as to how enforcement would be accomplished.

The board also heard from Lauren Steinberg of the Natural Resources Department, discussing an updated policy to further the transition of the town's fleet to electric vehicles. The new policy would require that any new light-duty vehicle, purchased or leased, be fully electric, producing no tailpipe emissions. Where a battery-powered electric vehicle is not available, department heads would be authorized to select a plug-in hybrid electric vehicle. If that type were unavailable, a non-plug-in hybrid could be chosen. (Plug-in hybrid electric vehicles typically have a larger and more powerful battery than non-plug-in hybrid vehicles.)

The town would purchase electric medium and heavy-duty vehicles as they become available, Ms. Steinberg said. The town will also continue to install electric vehicle-charging stations, focusing on locations where they can best be used by its fleet.


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