In the quest for proven, clean, sustainable forms of energy, we have looked to the sky to harness wind; we have looked to the seas and the rivers to harness water; we even looked to space to harness the sun. Billions upon billions of collective dollars, yen, and euros have flowed into finding the next great source of renewable energy. The latest and greatest energy ideas scream at us from every television, bus, and magazine article, proclaiming dominance in a crowded field. One proven energy technology, however, has remained conspicuously missing, yet is essential to enable the proliferation of the better-known renewable technologies. It also happens to be one of the most simple, proven, and cost-saving technologies available.
Thermal energy storage (TES) has been quietly and effectively providing reliably lower energy costs for over 30 years. Like a giant cell phone battery, TES systems store and dispatch electric energy (in the form of chilled water) in large cooling systems of large commercial and industrial buildings, university campuses, and airports located throughout the world. Similar energy storage systems such as pumped hydro, compressed air, and flywheels (to name a few) can store and dispatch electrons in a similar manner, yet TES is lower in first cost and life cycle costs.
TES tanks work in conjunction with a chilled water district cooling system. A tank can be “charged up” with chilled water during off-peak hours (usually at night), and discharged during peak hours (usually during the daytime). It reduces peak energy demand (depending on the amount of usage) by 10%-40%, and can reduce energy usage by 5%-30%. Also, by shifting the electric load from daytime to nighttime, energy source emissions are thus dramatically reduced. For those areas that suffer from dreaded “rolling blackouts,” TES greatly improves grid reliability, which would only improve as the technology advances.
Recent higher price differences between on-peak and off-peak power are changing the way consumers look at energy storage solutions. Bulk storage technologies enable energy cost arbitrage where utilities essentially buy low-cost, off-peak power for use during high-cost peak periods. Solar and wind energy proponents should embrace the ability of storage technologies by storing wind and solar energy produced during off-peak periods. Since wind levels are intermittent and usually are greater at night, (i.e., off-peak hours), this can reverse a glaring inefficiency with wind technology by harnessing its maximum output. Similarly, solar power is intermittent, and storage technologies allow this nearly limitless renewable energy source to be stored and dispatched onto the electric grid—benefitting users many miles from the source.
Adding more renewable energy sources without adding TES makes little sense. For example, the state of Texas has already experienced nighttime conditions where the wind power available exceeded the marginal requirement for electricity within the Electric Reliability Council of Texas (ERCOT) electric grid. This resulted in the spot energy market trading power at nighttime for zero, and negative dollars per kilowatt-hour—essentially paying spot market rate payers to consume energy during these periods of high wind and low energy use. Aggressive renewable power requirements in states like California will only further exaggerate the discrepancies between when the power is created, and when it is actually needed.
So where is the legislative love for TES? While the technology lacks a serious presence on Capitol Hill, federal, state and local governments have begun to discover the cost-savings of its use. TES actually has unique potential to be a major piece of any future legislative or regulatory energy policy: a proven, non-partisan, cost-saving, renewable and clean, special interest-free technology that creates construction jobs. If the federal government continues to pursue other forms of renewable energies to build a lasting national infrastructure, it needs to do so in a responsible manner that can cut long term costs and increase reliability and efficiency. TES is about as close to a political no-brainer as it gets.
Justin Kintz is a former George W. Bush Administration appointee to the U.S. Department of the Interior, and current Manager of Special Projects at the Sudden Cardiac Arrest Association in Washington D.C.