Ice 'batteries' can store clean energy
Distributed energy storage across the electricity grid will help us take better advantage of renewable but intermittent power sources like wind, and thermal energy storage — making ice at night to provide cooling during the day — has a role to play.
Under the energy storage bill passed in California last week, the California Public Utilities Commission will have to determine what targets, if any, utility companies should meet in terms of viable, cost-effective energy storage systems. Each utility’s renewable energy procurement plan will need to address how energy storage can be used to reduce the demand for electricity during peak periods. One part of this will involve looking at how thermal storage can provide permanent load-shifting to help meet air-conditioning needs.
HVAC — heating, ventilating and air-conditioning — is the largest contributor to peak energy demand. Because electricity for air-conditioning can be easily shifted, thermal energy storage is becoming a more popular air-conditioning choice for high-performance commercial properties.
Lowering the peak demand electricity consumption of buildings is critical to integrating renewable energies. In buildings, you can make a lot of ice at night and then, during the day, use that ice to cool the building so it doesn’t need those electrons during the day. You’ve essentially shifted energy usage of a major portion of the building from day to night. Nighttime electricity is less expensive, more efficient to generate and less polluting. And it happens to correspond with when wind is mainly blowing.
Over the next two years, as utilities discuss targets and a plan to store energy, businesses, schools and hospitals across the US will be taking control of their electricity use by storing thermal energy in their own buildings. Being smarter about how we generate and store our energy in buildings and on the grid will allow us to lower our dependence on fossil fuels while providing more reliable and efficient sources of energy to repower our nation.
Editor’s note: This was a guest commentary by Mark MacCracken, CEO of CALMAC Manufacturing Corporation, the largest manufacturer of thermal energy storage equipment in the world. CALMAC’s IceBank energy storage system has been installed by such users as Credit Suisse, Morgan Stanley, the Bank of America Tower and Rockefeller Center.
