The trend to decarbonize is transforming the U.S. power grid. The grid increasingly depends less upon fossil fuels and more upon distributed energy resources or technologies such as solar photovoltaic and offshore wind alongside new energy efficiency, demand response, energy storage and other customer-based technologies[i].
Thermal energy storage technology is a key enabler of this transition because of the flexibility it provides to building operators. It is widely viewed as a key way to reduce carbon emissions as more wind and solar, come online: by allowing renewable energy to be available when it is needed the most. The solution stores excess renewable energy for later use and discharges the stored energy when renewable energy is not available.
This trend is evident in the Northeast United States (U.S.) where power grid is undergoing a rapid modernization to decarbonize the electric supply through beneficial electrification. With the fuel mix changing, transmission grid operators in New York and New England – New York Independent System Operator (ISO) and ISO New England, respectively – have looked to all forms of energy storage, from batteries to thermal energy storage are energy storage resources to improve grid operations and reach clean energy goals[ii].
However, new data suggests that thermal energy storage does more than accommodate renewables: it can also lower greenhouse gas (GHG) emissions across the Northeast by storing[iii] less expensive, lower emission energy overnight and make that energy available during peak daytime periods when emissions are higher. With thermal energy storage, buildings and campuses can swap out high-GHG on-peak power with much less carbon-intensive electricity at night[iv]
New York: Achieving Clean Energy Goals
New York’s Clean Energy Standard (CES), the most comprehensive and ambitious clean energy goal in the state's history, represents one of the drivers behind the state’s decarbonization[v].
Previously, in New York, the downstate region’s fuel mix contained some of the Eastern Seaboard’s dirtiest, most carbon-emitting plants:[vi] Implementation of distributed energy resources has helped enable New York to transform to cleaner energy while maintaining grid reliability. The New York grid is now powered mainly by clean hydro and nuclear with the state’s “peaker” power plants turned off at night.
At night, those peaker plants are off, and the grid is powered mainly by clean hydro and nuclear. The thermal energy storage tanks then discharge – using stored energy to offset chiller consumption – during the heat of the day, when statewide demand is highest, and peaking units must be called to contribute. Therefore, thermal energy storage enables the NY grid to cut back its use of the dirtiest, most smog-producing peaking plants in the state.