Wind Power: Integrating Wind Turbine Generators (WTG’s) with Energy Storage

Abstract

The current storage concepts are ready for deployment. Storage needs to be implemented in particular for Wind Energy, not just here in the US but in all developing countries. The biggest impact is probably the flexibility of operation. Economic dispatch to meet market needs, absorb excess capacity or large load swings with compression are powerful market tools. It is possible to improve energy management and obtain better value from bulk power purchase and sales, reduce risks and vulnerabilities from fuel price shocks. In particular, volatility in the US will always be a factor, long term projections show that natural gas prices will continue to rise with increased demand which cannot readily be met from new sources other than LNG imports. The trend of increased harvesting of wind energy will put further stress on the grid reliability. This is already manifested in Europe where a far greater percentage of its generating base is committed to the variances of wind power production. Most importantly, Bulk Energy Storage will "buffer" utilities from the lack of spinning reserve and load following capability, a result of many independent Wind Generating Farms installed in the last 5 years and substantial planned capacity. It will remove concerns about power quality and new threats to reliability. CAES as a generating asset has capacity value, as if it were a thermal asset, fully dispatchable, and a low emissions profile. Using liquid air as an energy storage medium could be a potential solution to being able to locate storage for wind energy closer to load centers. This concept is proposed by Expansion Energy LLC. The Cryogenic tanks store liquid air are at relatively low pressure, which when required can be pumped at 42 bar to suit the prime mover, the liquid air is preheated and vaporized with the GT exhaust to feed an expander generating unit. Like many innovative concepts, ideas such as this will need further development ad investigation for wind integration.