Form Energy Form Energy is out to make long-term storage of renewable energy, like solar and wind, commercially feasible with an innovative take on an old technology: iron-air batteries. Form aims to produce iron-air batteries on a large scale and integrate them into our electric grid, to provide long-term storage for energy generated from renewable sources. Iron-air batteries work by taking advantage of the rusting process of iron. They aren’t a new technology, but they have yet to be commercialized. When an iron-air battery discharges, iron metal combines with oxygen, forming iron oxide (rust) and releasing electrons. This flow of electrons provides energy in the form of electricity. On the flip side, when excess electricity is available—for example, from a wind turbine or a solar panel—that electricity drives the reverse chemical reaction, charging the battery. Rust is converted back into iron metal, releasing oxygen. Key indicators Headquarters: Somerville, Massachusetts, USA Notable fact: Form has five founders, including MIT Professor Yet-Ming Chiang and Mateo Jaramillo, formerly of Tesla. It’s the result of two separate companies merging when the founders realized they had the same vision for long-term energy storage. Potential for impact Form has demonstrated that iron-air batteries can be built at one-tenth the cost of lithium-ion batteries, largely because the primary materials used to make them are cheap and abundant. That low cost could make it feasible for utilities to use the batteries for long-duration scenarios, storing energy for up to 100 hours. Storage is a pivotal issue in the adoption of renewable energy. Consumers need to access energy at all times, and their usage fluctuates throughout the day. But renewable energy sources like solar produce energy only at certain times, like when the sun is out. Lithium-ion batteries—which dominate the battery market—aren’t a great solution since they are expensive, have less storage capacity, and may have a shorter lifespan than iron-air batteries. Today, fossil fuels are often burned to compensate for gaps in production, exacerbating climate change. If enough iron-air batteries are storing energy for these moments, the grid could move away from fossil fuels. Caveats Form was featured on the 2023 edition of this list and has made steady progress: The company finished its new factory in West Virginia earlier this year, but it hasn’t started producing batteries to ship to customers just yet. Form is now running production trials at the factory. So although Form has significant orders from utility companies around the US, it has yet to fulfill any and deploy its batteries commercially. Related Story