Battery storage systems covering a range of durations are needed to avoid intermittency in a 100% renewable electric grid
By Mukesh Chatter, Alsym Energy
To achieve net-zero carbon emissions by 2050 and deploy renewable energy en masse, we must employ diverse battery storage system types. Not only will various battery chemistries be needed to circumvent supply chain constraints, promote safety, and scale production to meet demand, but battery storage options of different discharge durations will be needed to cover supply gaps present in an all-renewable power grid.
While short-term energy storage provides critical services such as stabilizing the grid and shifting daily energy supply to times when it’s needed most, long-duration energy storage (LDES) technologies can provide power for an extended period, ranging from several hours to days. This capability is important as it allows the power grid to respond to outages and provide system flexibility. It also enables resiliency to the entire energy system, which will experience more stress as electrification accelerates and the production of e-fuels such as hydrogen, methanol, and ammonia scales up.
Without LDES technologies, gaps in supply and frequent outages will prevent the US from fully realizing the potential of a sustainable and decarbonized energy future. Supply stability is a prerequisite for electrification and solar and wind energy adoption, and short- and long-duration energy storage systems together have the potential to be the solution if they can be scaled up to the level needed.
Growth and Challenges of LDES
According to the International Energy Agency (IEA), the amount of renewable capacity added throughout 2021 to 2026 will be approximately 50% higher than from 2015 to 2020. With clean energy generation ramping up, the challenges facing the scale-up of LDES technologies need to be addressed. Many LDES systems are still in the initial stages of expansion, but innovations in thermal, electrochemical, mechanical, and chemical storage have started to accelerate.
To get through the valley of technological barriers, significant investment in R&D is required to enhance effectiveness and dependability. With increased funding, developers can explore new methods to improve the efficiency of LDES systems (some currently have round-trip efficiencies of 40% or lower), making them better at cost-effectively storing and releasing energy to benefit the power grid and bringing down lifetime system costs.
“The amount of innovation in the battery space is so high that it is hard to see any of the existing incumbent technologies in their current form having dominant market share in 7-10 years. But I do think that the automotive industry will price out the utility-scale industry in lithium-ion, so you will see a rapid shift away from lithium-ion in the utility sector towards other chemistries, which is happening as we speak.”
— JIGAR SHAH, DIRECTOR, LOAN PROGRAMS OFFICE, UNITED STATES DEPARTMENT OF ENERGY, MARCH 2023
It’s worth noting that lithium-ion batteries, commonly used in electric vehicles (EVs) and widely commercially available, are not cost-effective for LDES purposes. Lithium-ion systems can technically provide power for multiple days, but the cost to build multi-day systems at scale would be prohibitive. This is why many utilities and project owners with access to cheap land are looking to lower-energy, less-efficient technologies that offer lower long-term costs.
Infrastructure is also needed to ramp up LDES technologies, including developing new manufacturing facilities and supply chains to support the production of LDES components at scale. Developing a robust supply chain for these materials is crucial to scaling up LDES production and reducing costs.
There are also policy and regulatory needs. Governments and utilities must incentivize the deployment of LDES systems by offering subsidies, tax credits, and other financial incentives. Regulatory frameworks are required to ensure fair compensation for LDES operators and encourage investment in these systems over piecemeal li-ion systems. With the cumulative services they provide, there must be policies to promote the integration of LDES into the grid, such as mandates for utilities to procure a certain amount of energy storage capacity from these types of storage. While the Inflation Reduction Act incentivizes storage projects in the US, there are no requirements for storing any amount of energy. Compare this to China, where 23 provinces now require a minimum 10% renewable-storage pairing ratio to scale up investments in energy storage.
Lastly, LDES technologies require collaboration between stakeholders. Researchers, policymakers, utilities, and private sector companies must collaborate to drive innovation and deployment. Crosscutting can also help identify areas where LDES technologies could have the most significant impact, such as improving grid reliability, integrating more renewable energy sources, and reducing greenhouse gas emissions.
LDES in Action
Several LDES projects are already deployed and proving their case. Pumped storage hydropower (PSH) is one of the most commercially mature types of mechanical long-duration storage on the market; today, there are 43 PSH plants in operation in the US, and they account for the bulk of all utility-scale energy storage (both short and long duration).
Many governments worldwide have implemented strategies and proposals to support the growth of renewable energy and LDES technologies. The Long-Duration Storage Shot is part of the U.S. Department of Energy’s broader Energy Storage Grand Challenge, which aims to accelerate the development and deployment of energy storage technologies. The Long-Duration Storage Shot specifically targets LDES technologies to reduce the cost of grid-scale energy storage by 90% for systems that deliver 10+ hours of duration within the decade. The initiative will fund various projects, including researching new materials and chemistries, developing new manufacturing processes, and deploying large-scale LDES projects.
As the world transitions to solar, wind, hydroelectric, geothermal, and other renewable energy sources, LDES technologies are critical to providing stable and dependable power. Scaling up LDES technologies demands supportive policies, research and development investment, new manufacturing facilities and supply chains, and alternative battery technologies that can improve performance and cost-effectiveness while maintaining safety. To address the climate crisis, industry leaders must continue to pursue innovative and diverse solutions to meet the growing demand for renewable energy storage.
About the Author
Mukesh Chatter is the CEO of Alsym Energy, a technology company developing a low-cost, high-performance rechargeable battery chemistry that is free of lithium and cobalt.
