Grid-Scale U.S. storage capacity could reach 125GW by 2050, or even as much as 680GW, according to research from NREL. Almost all today, under 25GW, comes from pumped hydro which has probably reached its limit so the future is batteries. Growth depends on commercial viability, so the research led by NREL has modelled what services storage can supply, the main three being firm capacity, energy time-shifting and operating reserves. The sets of scenarios modelled constrain each of the three to see what happens. The results show that allowing storage to provide firm capacity will accelerate future deployment the most. Operating reserves, on the hand, have limited market potential and do not drive the deployment of storage. The conclusion is to be flexible, allow all three rather than focus on one, but prioritise for optimal deployment and cost reduction. Cost and performance assumptions were used for storage, wind, solar PV, and natural gas to determine the key drivers. That led to yet more evidence that more solar – variable by nature – allows shorter-duration batteries (the cheapest kind) to be a competitive source of peaking capacity.

With declining technology costs and increasing renewable deployment, energy storage is poised to be a valuable resource on future power grids—but what is the total market potential for storage technologies, and what are the key drivers of cost-optimal deployment?

In the latest report from the Storage Futures Study (SFS), Economic Potential of Diurnal Storage in the U.S. Power Sector, NREL analysts Will Frazier, Wesley Cole, Paul Denholm, Scott Machen, and Nate Blair, describe significant market potential for utility-scale diurnal storage (up to 12 hours) in the U.S. power system through 2050. They found storage adds the most value to the grid and deployment increases when the power system allows storage to simultaneously provide multiple grid services and when there is greater solar photovoltaic (PV) penetration.

“We find significant market potential for diurnal energy storage across a variety of modelled scenarios, mostly occurring by 2030,” said Will Frazier, National Renewable Energy Laboratory (NREL) analyst and lead author of the report. “To realise cost-optimal storage deployment, the power system will need to allow storage to provide capacity and energy time-shifting grid services.”

The SFS—led by NREL and supported by the U.S. Department of Energy’s (DOE’s) Energy Storage Grand Challenge—is a multiyear research project to explore how advancing energy storage technologies could impact the deployment of utility-scale storage and adoption of distributed storage, including impacts to future power system infrastructure investment and operations.

Scenarios: multiple vs. limited services

For this work, researchers added new capabilities to NREL’s Regional Energy Deployment System (ReEDS) capacity expansion model to accurately represent the value of diurnal battery energy storage when it is allowed to provide grid services—an inherently complex modelling challenge. Cost and performance metrics focus on Li-ion batteries because the technology has more market maturity than other emerging technologies. Because the value of storage depends greatly on timing, ReEDS simulated system operations every hour.

NREL researchers used ReEDS to model two sets of scenarios—one that allows storage to provide multiple grid services and one that restricts the services that storage can provide. All the scenarios use different cost and performance assumptions for storage, wind, solar PV, and natural gas to determine the key drivers of energy storage deployment.

125GW by 2050. Or maybe 680GW?

Across all scenarios in the study, utility-scale diurnal energy storage deployment grows significantly through 2050, totalling over 125 gigawatts of installed capacity in the modest cost and performance assumptions—a more than five-fold increase from today’s total. Depending on cost and other variables, deployment could total as much as 680 gigawatts by 2050.

“These are game-changing numbers,” Frazier said. “Today we have 23 gigawatts of storage capacity, all of which is pumped-hydro.”

Initially, the new storage deployment is mostly shorter duration (up to 4 hours) and then progresses to longer durations (up to 12 hours) as deployment increases, mostly because longer-duration storage is currently more expensive. In 2030, annual deployment of battery storage ranges from 1 to 30 gigawatts across the scenarios. By 2050, annual deployment ranges from 7 to 77 gigawatts.

System flexibility key to storage deployment

To understand what could drive future grid-scale storage deployment, NREL modelled the techno-economic potential of storage when it is allowed to independently provide three grid services: capacity, energy time-shifting, and operating reserves.

NREL found not allowing storage to provide firm capacity impacts future deployment the most, although not allowing firm capacity or energy time-shifting services can also substantially decrease potential deployment. Operating reserves, on the hand, do not drive the deployment of storage within the study because they find limited overall market potential for this service.

Storage and solar symbiosis

Multiple NREL studies have pointed to the symbiotic nature of solar and storage, and this study reinforces that relationship. More PV generation makes peak demand periods shorter and decreases how much energy capacity is needed from storage—thereby increasing the value of storage capacity and effectively decreasing the cost of storage by allowing shorter-duration batteries to be a competitive source of peaking capacity. NREL found over time the value of energy storage in providing peaking capacity increases as load grows and existing generators retire.

Solar PV generation also has a strong relationship with time-shifting services. More PV generation creates more volatile energy price profiles, increasing the potential of storage energy time-shifting. Like peaking capacity, the value of energy time-shifting grows over time with increased PV penetration.

Next Up in the Storage Futures Study

The SFS will continue to explore topics from the foundational report that outlines a visionary framework for the possible evolution of the stationary energy storage industry—and the power system as a whole.

The next report in the series will assess customer adoption potential of distributed diurnal storage for several future scenarios. The study will also include the larger impacts of storage deployment on power system evolution and operations.

Visit the Storage Futures Study page for more information about the broader study, and learn more about NREL’s energy analysis research.

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This article is published with permission from the National Renewable Energy Laboratory