One of the biggest challenges for the renewable energy industry is that solar energy isn’t available at night, wind stops blowing periodically and other sources can also be intermittent. While lithium-ion battery installations are racing to keep up with demand, other technologies that provide better storage may soon supplant them. 

Energy Storage is Growing

With solar being the fastest-growing source of new energy in the U.S. and other renewables also increasing rapidly, enabling storage of that energy from the time it is produced to when it is used is essential. Fortunately, storage is growing quickly too. Utility-scale battery storage capacity in the U.S. increased significantly during the last three years, according to the US Energy Information Administration (EIA), with an annual average growth rate of 70 percent. The U.S. power system had operational battery storage capacity of 43.6 gigawatts (GW) by the end of 2025 and increased by another 8.3 GW during the first six months of 2026. 

Solar and storage accounted for 91 percent of generating capacity added in the first quarter of 2026, the Solar Energy Industries Association (SEIA) found, and nearly 50 percent of new residential solar systems were paired with batteries during that period.

While utility-scale storage projects are understandably the largest systems, Utility Dive found that all three segments - utility-scale, residential and commercial/community/industrial - set records during the first quarter. Tax policy and demand for storage located together with energy generation are key drivers for installation, especially since there are still tax credits for utility-scale energy storage. 

That increase in storage is bolstered by growth in the manufacturing of batteries and other storage solutions in the U.S. Having domestic battery production reduces supply chain risks, helps push renewable energy usage and creates jobs. Policies to increase domestic manufacturing have helped create a surge in energy storage manufacturing.  

Pumped Hydroelectric and Lithium-Ion Dominate 

The most commonly used storage method in the U.S. is still pumped hydroelectric storage. It works by pumping water into an elevated reservoir when excess electricity is available and releasing it through turbines to generate electricity when needed. 

Lithium-ion batteries are currently the next most widely deployed grid-scale storage technology. Their high energy density, high efficiency, modularity and rapidly declining costs enable utilities to use them to balance short-term fluctuations, provide backup power and integrate renewable energy. The market is also shifting toward larger lithium-ion battery sizes that deliver higher energy density per container, making it cheaper than legacy equipment. 

Innovations Change Storage

While lithium-ion batteries have many benefits, they also use critical minerals, have a significant risk of fires and are limited to a finite number of charging cycles. Many alternative battery technologies, on the other hand, have fewer risks, can be used far longer and can be recycled at the end of their life. 

There are a multitude of alternative battery solutions, and many have gone from research projects to commercial deployment. While alternative storage technologies such as sodium-ion, flow batteries and iron-air systems are gaining traction, there are other solutions as well. A survey of the various technologies shows what may come next and perhaps even replace lithium-ion.

One of the most promising alternatives is sodium-ion batteries, which have graduated from research labs to real-world installations. They use sodium in the cathode, can retain over 90 percent capacity at sub-zero temperatures and have a lower risk of fires. Although they are slightly more expensive per kilowatt hour than lithium-ion batteries today, costs are coming down and could drop to parity or lower before long. 

Flow batteries are also evolving rapidly. They are rechargeable batteries that use two chemical solutions (electrolytes) to store energy, PV Magazine explained, with the electrolytes stored in external tanks. Flow batteries are notable for their scalability and long-duration energy storage capabilities, Battery Council International explained, and the unique design which separates energy storage from power generation provides flexibility and durability. Flow batteries also have long lifecycles and can be safer than some other battery chemistries because they are less likely to overheat.

A lot of work is also going into hydrogen storage, especially since it can be used as fuel for aviation and shipping. Renewable energy can be converted into hydrogen for longer term storage via electrolysis, and it can be converted back into electricity when needed. Hydrogen can also be transported in liquid ammonia form.

Although compressed air energy storage (CAES) is not as common yet, there are plenty of projects underway. CAES stores energy by compressing air into large underground caverns or tanks when electricity supply is plentiful. When electricity is needed, the compressed air expands through turbines to generate power. 

Thermal energy storage systems store energy in the form of heat or cold, often using materials such as molten salts or phase-change materials, and converting them to produce electricity when needed. Molten salt storage can harness solar energy to heat a reservoir of potassium and sodium nitrate to a temperature above 500 degrees Celsius, for instance, and this temperature can be maintained for 10 hours after the sun has set. It is gaining attention because of the ability to provide long-duration storage and to integrate with existing thermal power plants.

Other longer-duration storage technologies that extend the usefulness of stored energy beyond four hours include liquid sulfur and iron-based chemistry, New Energy Today added.

Despite the momentum behind lithium-ion batteries, the risks and limitations are more widely recognized now and alternatives are clearly needed. Many of these new energy storage technologies promise lower costs, increased safety and greater sustainability by reducing reliance on critical minerals such as cobalt and nickel. Sodium-ion seems to have an inside track to become fully competitive with lithium-ion in the near future, and hydrogen offers good potential for the transport industry.