Energy storage is important for electrification of transportation and for high renewable energy utilization, but there is still considerable debate about how much storage capacity should be developed and on the roles and impact of a large amount of battery storage and a large number of electric vehicles. This paper aims to answer some critical questions for energy storage and electric vehicles, including how much capacity and what kind of technologies. Energy storage is important for electrification of transportation and for high renewable energy utilization, but there is still considerable debate about how much storage capacity should be developed and on the roles and impact of a large amount of battery storage and a large number of electric vehicles. This paper aims to answer some critical questions for energy storage and electric vehicles, including how much capacity and what kind of technologies should be developed, what are the roles of short-term storage and long-duration storage, what is the relationship between energy storage and electrification of transportation, and what impact will energy storage have on materials manufacturing and supply chain. Accelerating the deployment of electric vehicles and battery production has the potential to provide terawatt-hour scale storage capability for renewable energy to meet the majority of the electricity need in the United States. However, it is critical to greatly increase the cycle life and reduce the cost of the materials and technologies. Long-lasting lithium-ion batteries, next generation high-energy and low-cost lithium batteries are discussed. Many other battery chemistries are also briefly compared, but 100 % renewable utilization requires breakthroughs in both grid operation and technologies for long-duration storage. New concepts like dual use technologies should be developed.••Renewable energyEnergy storageBatteryElectric vehiclesThe importance of batteries for energy storage and electric vehicles (EVs) has been widely recognized and discussed in the literature. Many different technologies have been investigated,,. The EV market has grown significantly in the last 10 years. In comparison, currently only a very small fraction of the potential energy storage market has been captured,. There is still a large debate regarding the roles of different technologies and how they can be deployed, and what will be the research priorities for the community. For example, the estimated amount of energy storage need varies widely. Some analysis suggests that a few terawatt-hours (TWh) of storage capacity is needed, but seasonal variation requires long-duration storage of up to more than a month. The long-duration needs will significantly increase both the storage capacity needed and the cost of storage. The United States (US) Department of Energy (DOE) Energy Storage Grand Challenge sets a goal of $0.05/kWh for long energy storage, which is 3–10 times lower than what most of the state-of-the-art technologies available today can offer. There have been intense discussions of alternate technologies for long-duration storage, including new battery chemistries and hydrogen storage, but all these technologies have significant challenges, including difficulties in production, transportation and storage. Lithium-ion (Li-ion) batteries are considered the prime candidate for both EVs and energy storage technologies, but the limi. Renewable energy is fundamentally different from traditional sources and requires a paradigm shift from a centralized, top-down infrastructure to a distributed, variable infrastructure (Fig. 2). Renewable energy is highly variable and unpredictable. The generation is usually small and distributed over large areas. The generation is also location-constrained and weather-dependent. In addition, renewable generation is non-synchronous in nature. With an increasing level of renewable penetration, electric grid operation will need to address many issues, including ensuring power quality, providing adequate transmission and distribution capability, maintaining the stability of the system, and maintaining real-time balance of power supply and demand.Energy storage is considered the most effective approach to addressing the variable nature of renewable energy., Energy storage can provide a wide range of services, including improving stability and reliability, improving flexibility to manage renewables technology integration, improving grid resilience, economic efficiency, and deferring infrastructure upgrades.The key question is how much storage capacity is needed and at what cost, and how to achieve the capacity. The amount of energy storage needed has been extensively investigated and the estimate covers a wide range. Earlier studies. The above discussion suggests that developing and deploying an exceptional amount of storage capacity to meet both short-term and long-term requirements is difficult and costly today. However, there has been plenty of research and analysis to separate the different needs for storage. In the real world, system fluctuations can be substantially reduced by integarting different resources (Fig. 5). Fig. 5a shows how three hypothetical sources added together can significantly reduce the deficit (yellow region). Typically, solar power reached its peak at mid-day while wind power did the opposite. Similarly, the fluctuations can be significantly reduced if the generation from different regions can be aggregated (Fig. 5b and 5c). The power spectrum densities are an indicator of the fluctuation. Fig. 5c shows that integrating the wind generation of five regions in the US produces the least fluctuation. Fig. 5d shows that generation from all the generators in a particular region is always smoother than generation from an individual plant, judging by the ratio for fast to slow ramping. Other studies from other regions also suggest that mixed solar and wind can significantly reduce the fluctuation, and thus the needed storage. The viability of solar and wind generations usually decrease exponentially with distance, with a characteristic correlation length of 200–500 km in North America (Figs. 5d–5f).These.
