Introduction

NREL indicates that energy storage systems will play an important role in the U.S. electricity system between now and 2050, offering opportunities to replace fossil fuels with low-cost renewable energy and to balance electricity supply and demand across the Country.

The system's ability to store excess capacity from solar and wind facilities means it can contribute to the energy mix when it is most needed, even under the most conservative scenarios of variable renewable energy deployment, the study notes.

Researchers at the National Renewable Energy Laboratory (NREL) modeled a series of scenarios for U.S. energy storage deployment by 2050, including reference cases, low-cost batteries, low-cost solar power, high-cost natural gas power, and zero-carbon scenarios.
Even in the reference case, the installed capacity of energy storage systems operating on the US grid will rise from about 23GW currently installed to 213GW by 2050 -- the vast majority of storage capacity today comes from pumped storage facilities, despite the rapid growth and market share of lithium-ion battery storage systems. This figure rose to 384GW/1,792GWh in the low-cost battery scenario and to 932GW/6,097GWh in the zero-carbon scenario.

The multiple applications where energy storage systems can provide services, from ancillary grid services to energy arbitrage and capacity services, all play a role, but energy arbitrage and capacity value is really starting to emerge as the grid moves towards higher renewable energy penetration.

National Renewable Energy Laboratory

Energy storage systems as a peak-capacity asset (storing energy generated when renewables are cheap and plentiful and then exporting it to the grid during periods of peak demand) are a particularly valuable application and will become increasingly valuable in the future.
It is also important to note that increased deployment of energy storage may reduce the start-up and frequency of fossil fuel generators, avoiding or reducing the adverse public health effects that may result from the operation of coal-fired power plants, especially for those living near those plants.
Modeling energy storage utilization per hour of the day. Energy storage system adoption follows changes in peak electricity demand, including as solar generation becomes more or less
In fact, energy storage systems can improve the efficiency of almost any generation asset: increasing the utilization of solar and wind power facilities, which produce energy at low marginal cost.
The researchers found that the synergies between battery storage systems and solar facilities are more consistent than those between battery storage systems and wind power, because solar power is more predictable. Wind power facilities can run for longer or shorter periods of time than needed, making it harder to integrate wind power.

The researchers acknowledge that modeling power systems and considering deploying more energy storage systems and renewable energy deployments is a complex business, as is balancing the grid with these resources, but it is entirely feasible.

Opinions 

Jennie Jorgenson, principal investigator at the National Renewable Energy Laboratory (NREL), said, "Once again, we have found that future power systems with large amounts of energy storage capacity can successfully achieve all-weather load balancing. Most importantly, we found that power systems with high levels of energy storage operate more efficiently by storing renewable energy instead of fossil fuel electricity."
The study focused on deploying day-night or multi-day storage systems with durations of up to 12 hours, and while its research team says further research into the role of systems that keep discharging for longer periods of time could be more beneficial, the relationship between storage systems and transmission infrastructure is complex and needs to be further validated.
As peak-capacity assets, the primary demand for energy storage systems will remain consistent throughout the year, but an energy storage system with a continuous discharge time of about 10 hours will be most valuable when the grid bears its peak demand. The value of fossil fuel power plants is growing as they are decommissioned.
The report by the National Renewable Energy Laboratory (NREL) includes using its capacity planning model for the power sector, called Regional Energy Deployment System (ReEDS), and combining it with PLEXOS, an energy market simulation and forecasting software. ReEDS are publicly available to help model and analyze the community.