Big companies using thermal storage to meet carbon rules.

Bloomberg: “Clustered deep beneath the trading floors of Goldman Sachs Group Inc.’s Manhattan headquarters are 92 tanks with enough ice for 3.4 million margaritas.”
“Goldman runs chilled anti-freeze through pipes connected to the 11-ton vessels during summer nights — when power costs less — to freeze the water. That ice is used the next day in its air-conditioning system, when high-demand electricity comes with a surcharge.
Proponents of so-called thermal storage systems such as Goldman’s, which have roots in the New England ice houses of the 18th century, are pushing to expand its use. And they see it as a way to help utilities comply with future carbon rules as well as to store power from rooftop solar panels or wind farmswhose output often surges when demand is low.
….Getting thermal storage to take off has been a slog, though, as building owners don’t want to invest in power savings that will accrue to their tenants, and utilities exempt most customers, especially residential ones, from pricing based on peak demand periods. Without those pricing cues, government tax breaks or subsidies may be needed to boost the use of ice tanks, said Jim Lazar, a utility consultant in Olympia, Washington, who wrote a report on integrating more renewables in the electric grid.
….Water is a cheaper and easier way to store a chunk of that energy, Lazar said. In addition to ice tanks, home water heaters can be tweaked to fire up when electricity is in ready supply, he said.
Buildings are a big part of any energy equation: They account for two-thirds of U.S. electricity demand. A quarter of the energy used by commercial buildings — the largest share — is for cooling.
In the basement of Goldman’s New York City headquarters, the nation’s largest thermal storage system makes 1.7 million pounds of ice every night. A single storage tank contains about as much cooling capacity as 400 bedroom-sized air-conditioning units. The tightly packed units, which are part of the building’s 25 million to 30 million gallons of annual water consumption, sweat like beer cans on a hot day, as a maze of overhead piping connects them to a system that reaches skyward to six rooftop cooling towers.
….The 43-story building, which opened in 2009 and houses about 8,000 employees, is 30 percent more efficient than a typical office.
Goldman estimates that it saves about $50,000 monthly on its summer power bills.
Goldman uses the “ice storage system to arbitrage difference between on- and off-peak electricity prices,” said MacCracken, who has been selling the systems since the 1980s. “In energy conservation, everybody focuses on kilowatts, but they don’t focus on peak demand.”