Ice-cold energy storage
2 May 2014
A very cool technology for energy storage is ice, which in warm climates can optimise cooling supplies. While electricity demand is low, water is frozen and stored in an insulated tank onsite. During periods of higher demand, the ice is used to cool water or other refrigerants in a building’s air-conditioning system, offsetting the need for electricity.
An estimated 1 gigawatt of ice storage is deployed in the United States to cut peak energy consumption in warmer areas of the nation, while many countries in Asia increasingly use ice storage.
China has deployed hundreds of ice storage projects since the 1990s. Shanghai’s China Pavilion uses a combination of heat pumps and ice storage to provide approximately 160 days of cooling a year. In Beijing, ice storage has saved almost USD 1.4 million a year in electricity costs for the International Financial Centre building, while China Petrochemical Corporation’s research and office building has offset more than one-third of its peak electricity demand by using ice storage.
In Japan, Tokyo Denki University’s Tokyo Sanyo Campus has used both ice and liquid water tanks for energy storage since 2012. Funded by the Ministry of Land, Infrastructure, Transport and Tourism, the project employs 400 cubic metre (m3) ice storage tanks tied to 690 m3 water storage tanks for freezing water with cheaper off-peak electricity; the ice is subsequently melted to meet cooling requirements. While the project’s primary objective is to lower campus CO2 emissions associated with energy consumption, it also aims to increase energy efficiency and cut peak demand.
This article by Melissa C. Lott, lead author of the Technology Roadmap: Energy Storage, originally appeared in IEA Energy: The Journal of the International Energy Agency. Through the end of 2014, the IEA regularly produced IEA Energy, but analysis and views contained in the journal are those of individual IEA analysts and not necessarily those of the IEA Secretariat or IEA member countries, and are not to be construed as advice on any specific issue or situation. Click here to read issues of IEA Energy.