Managing demand on the power grid continues to grow increasingly more complex. Along with the urgent need to reduce carbon-based energy generation, consumer demand for energy is growing and shifting hourly, daily, monthly, and seasonally. New distributed energy resources are being developed and integrated at a faster rate every day and renewable generation and its variability are being brought online faster than predicted. All these factors make it more challenging for all utilities to meet demand when and where it is needed.
As more aggressive goals are set to transition the electrical system away from fossil fuels, energy storage is poised to be the economical solution to address the rapid growth and variability of distributed renewable generation. Energy storage growth is market-driven as power can be worth less than zero at times in some regions and power providers look for ways to avoid investing in costly new generation assets. But this growth is also being incentivized and regulated by federal and an increasing number of state governments.
In early 2018, the Federal Energy Regulatory Commission (FERC) created Order 841 directing Regional Transmission Organizations and Independent System Operators to remove barriers to the participation of electric storage in wholesale markets. The U.S. Department of Energy announced a $30 million project to fund long duration research projects. And as of June 2019, 15 states led by California, Massachusetts, and New York have developed energy storage policies designed to meet aggressive carbon-reduction goals by encouraging further development and integration of new energy storage technologies.
Different energy storage technologies have different capabilities. Two metrics used by the U.S. Energy Information Administration to describe energy storage are power capacity and energy capacity. Power capacity is the maximum amount of power output available at any one instant and is measured in megawatts (MW). The energy capacity is the total amount of energy that a storage system can store or discharge and is measured in megawatt hours (MWh). Energy capacity is a factor of both the amount of power and the length of time that power can be discharged. A battery system that can discharge power for 4 hours or more is referred to as long duration energy storage. A Navigant Research report explains that, "Interest in long duration energy storage is rising as the rapid growth of variable output renewables continues and issues with grid stability and efficiency become more tangible for grid operators."
One proven long duration storage technology is Thermal Energy Storage (TES) from Viking Cold Solutions. When TES is installed inside commercial and industrial frozen food storage facilities (the cold chain), not only do they increase efficiency but the energy they store can be discharged up to 13 hours per day. In the U.S. alone there are over 2,200 warehouses, 40,000 supermarkets, and 620,000 restaurants storing frozen food that require refrigeration to run nearly 24/7. This cold chain has the highest demand per cubic foot of any industrial load and is the third highest consuming category. Inside a single commercial freezer (average size 15,000 square feet) TES is able to store over 100 kW and discharge for 5 hours (nearly 600 kWh). And inside a single industrial freezer (average size 100,000 square feet) TES can store nearly 400 kW and discharge for 10 hours (nearly 3.8 MWh). One 93,000 square foot facility in California with TES stores 350-500 kW and discharges for 13 hours per day (4.5 to 6.5 MWh), six days a week.
Viking Cold's TES systems are composed of two non-mechanical components: intelligent cloud-based controls & monitoring and individually sealed cells of Phase Change Materials (PCM). The systems are quickly and easily installed in existing C&I facilities, require no additional space, last the lifetime of the freezer with zero maintenance, have no roundtrip losses, and are 100% recyclable. All this adds up to a Levelized Cost of Energy (LCOE) of less than 2 cents per kWh, much lower than traditional lithium-ion battery storage (around 19 cents per kWh).
Numerous utilities across the country including many in California and the northeast states have approved and incentivized Viking Cold TES technology. One demand management project sponsored by Eversource in Massachusetts was designed to target a four hour high demand window and installed eight systems capable of storing 1.3 megawatts with an average time from customer agreement to commissioning of 127 days.
Another utility project with San Diego Gas & Electric sponsored by the California Public Utilities Commission’s Emerging Technology Coordinating Council was located at the San Diego Food Bank and paired TES with onsite Solar PV. Results included 95% overnight grid energy reduction and a 39% annual reduction in refrigeration energy consumption.
The importance of long duration energy storage will continue to grow as more renewable generation is adopted and added to the grid and as cleaner energy options are regulated and incentivized. Viking Cold’s Thermal Energy Storage systems offer long duration storage at an incredibly low LCOE for an energy intensive sector with thousands of existing C&I facilities across the country and around the globe.