The solar-plus-ice concept was unveiled at a gathering in San Diego this week of leaders from the energy storage industry, which is riding a wave of investment and growth tied to advances in big batteries, electric vehicles and smart-grid technology.
California continues to commission quick-start natural gas power plants to back up solar and wind power, while policymakers hold out hope for breakthroughs in energy storage.
Enter the oddball machine called Ice Bear that doesn’t replace the air conditioner, but helps it run more efficiently by using cheap electricity to freeze a 450-gallon tank of water at night.
Copper tubing snakes through the ice block and — on sweltering afternoons — provides coolant to evaporator coils in existing, nearby rooftop air conditioners.
That allows commercial buildings to shut down air conditioning compressors for up to six hours at a time, often when grid electricity is most expensive, explained Mike Hopkins, CEO of Glendale-based Ice Energy.
The company manufactures Ice Bears and has distributed them in bundles across dozens or even hundreds of commercial rooftops on behalf of utilities in California.
Ice cooling dates back at least to ancient Rome. And early movie houses used caches of ice to cool the air before modern refrigeration took over and relegated ice machines to obscurity — and fictional fantasy like the ammonia-based ice machine in “The Mosquito Coast.”
In recent decades, big businesses have turned to a variety of ice machines to save on electricity bills by shifting energy use for cooling away from premium power prices that coincide with daytime air conditioning demands.
Hopkins and his colleagues are taking the concept one step further by offering rooftop solar energy side-by-side with ice-based energy storage, through a partnership with NRG Energy.
Neither technology is new, but the plan puts the companies just ahead of high-tech efforts by the likes of Tesla Motors and SolarCity to engineer and produce commercial and household battery packs that can store solar power for use after dark or during blackouts.
“There is tremendous value in having a great new energy source (solar) and being able to watch how that performs and having a bunch of ice” to store energy, Hopkins said.
America’s embrace of air conditioning has propelled an over-expansion of the power grid in the eyes of Mark MacCracken, CEO of CALMAC, which manufactures large silo-shaped ice coolers for businesses, school districts and houses of worship.
He estimates that air conditioning compressors, not including fans, now account for 35 percent to 40 percent of peak, daytime power demands. Thermal energy storage — namely ice — can spread out those demands around the clock, eliminating the need for wires and power plants.
Municipal utilities — from Redding to Anaheim — have paid to deploy Ice Bears on commercial rooftops to drive down afternoon power demands and avoid more costly traditional investments in substations and air-polluting power plants.
The biggest order yet — that would deploy some 1,400 Ice Bears — was placed by Southern California Edison last November. The power contract, awaiting approval by the California Public Utilities Commission, would offset 26 megawatts of power demands — with each megawatt representing the electricity needs of up to 400 homes. Edison and Ice Energy declined to disclose terms of the contract.
The technology, and its ability to address critical power needs, won out in head-to-head competition with batteries, solar and traditional natural gas power plants, explained Jesse Bryce, Edison’s manager for contract origination.
“We’re technology agnostic,” Bryce said. “We’re going to look at the needs of our customers to ensure reliability at lowest cost. If they can pair thermal (ice) storage with solar and it meets the needs of our customers at the lowest price, we’re interested.”
How exactly solar and ice storage fit together will be up to the buyer.
Hopkins said electricity from the solar panels might be used to power air conditioners at mid-day when sunlight and heat are both intense.
The Ice Bear might take over cooling duties for a few hours early in the morning, and then again toward sunset in the lingering heat.
“The beauty of the ice storage is you just do it whenever you want,” he said.
Ice Energy is planning for a household version of the Ice Bear as California moves residential utility customers to time-based pricing. That could make it worthwhile for homes to freeze ice at night and save on air conditioning by day.
The “Ice Cub” might qualify for California clean energy incentives too, Hopkins said.
©2015 The San Diego Union-Tribune Distributed by Tribune Content Agency, LLC.
