MULTI-HOUR ENERGY STORAGE: THE THERMAL ENERGY STORAGE OPTION

摘要

Energy Storage (ES) is increasingly recognized as a critically beneficial element, both for the overall electric energy grid and for individual microgrids. The value of ES grows further, as more intermittent renewable power technologies (wind and solar) are deployed. Various ES technologies can be considered, including Pumped Hydroelectric ES, Compressed Air ES, Mechanical Flywheel ES, and Electro-chemical Battery ES. The technical and economic characteristics of these technologies are presented and compared, specifically as they apply to multi-hour (rather than short duration) storage situations. Batteries, in particular, are gaining a lot of attention and increased use. However, another technology - large cool Thermal Energy Storage (TES) - often provides superior performance and economics. The characteristics of large Chilled Water (CHW) TES are reviewed and compared with those of batteries, including: 1. Status and maturity of the technology development 2. Difficulty or ease of siting and permitting 3. Project lead time 4. Round-trip energy efficiency 5. Life expectancy Actual examples of specific real-world TES installations are reviewed, including applications in various industries, e.g. aeronautical, automotive, Pharmaceuticals, printing, insurance data processing, computing facilities, and corporate R&D. Among the many industrial users are household names such as: 3M, Abbott Laboratories, ARCO, BMW. Boeing, Calpine, Chrysler, Dominion Energy, DuPont, ExxonMobil, Ford, GM, Halliburton, Honeywell, Hewlett Packard, IBM, Lockheed Martin, McDonnell Douglas, Mercedes Benz, Motorola, Northrup-Grumman, Pratt & Whitney, Raytheon, Shell, State Farm, Texaco, Texas Instruments, Toyota, UPS, and Westinghouse - many of whom have multiple installations. CHW TES is often employed, not only for daily peak electric demand management, but also for one or more secondary benefits, e.g.: 1. added resiliency via emergency back-up cooling, 2. improved load factor and economics for on-site Combined Heat & Power, 3. improved performance and economics of on-site gas turbines via Turbine Inlet Cooling, 4. reduced risk (and often reduced insurance premiums) via dual-use as a fire protection reservoir, and perhaps most notably, 5. additional installed cooling capacity at unit capital costs ($/ton) below those of conventional chiller plants.