Technology Overviews

Iron–air batteries promise affordable, multi-day energy storage for the grid by harnessing abundant, eco-friendly iron, but face challenges with efficiency and material durability at scale. Ongoing innovations in materials and system design aim to unlock their potential as a safe, sustainable solution for firming renewables and boosting grid resilience.

Sodium-Cooled Fast Reactors promise a leap in nuclear sustainability by maximizing fuel use and minimizing waste, thanks to their innovative use of liquid sodium coolant and closed fuel cycles. Despite their potential for safer, more efficient power, SFRs face hurdles from high costs and engineering challenges, but global efforts in Russia, India, and China are pushing the technology toward commercial reality.

From ancient kilns to cutting-edge grid-scale solutions, Thermal Energy Storage systems are revolutionizing industrial decarbonization and renewable energy integration with high-temperature, low-cost, and modular technologies that surpass conventional batteries. As innovations drive material sustainability and system flexibility, overcoming technical and market barriers will be key to unlocking TES’s full potential for deep decarbonization and grid resilience.

Closed-loop geothermal systems (CLGSs) are revolutionizing geothermal energy by using sealed wellbores to extract subsurface heat without fracking, water consumption, or seismic risk, as demonstrated by GreenFire Energy and Eavor Technologies. While CLGSs offer vast global potential and reliable performance, their widespread adoption for electricity generation hinges on significant reductions in drilling costs, making district heating their most promising near-term application.

Compressed Air Energy Storage has transformed from basic mechanical applications to cutting-edge systems like adiabatic and isothermal CAES, which boost efficiency and eliminate fossil fuel use by capturing and reusing compression heat. Despite innovations in storage architecture and media, CAES must overcome high costs, geological constraints, and regulatory hurdles to realize its potential as a scalable, zero-emission solution for long-duration energy storage.

Amine-based post-combustion CO2 capture, long dominated by monoethanolamine, is evolving with advanced mixed amine blends and process innovations that cut energy use and costs. However, persistent challenges with solvent degradation, corrosion, and energy penalties continue to drive research for more robust, efficient, and scalable carbon capture solutions.

High-Temperature Gas-cooled Reactors (HTGRs) have advanced over 75 years, offering robust safety, high efficiency, and unique industrial applications thanks to innovations like TRISO fuel and helium coolant. While recent international projects highlight their transformative potential for clean energy and decarbonization, HTGRs must still overcome challenges in fuel supply, regulation, and waste management to achieve widespread deployment.

Enhanced Geothermal Systems are revolutionizing clean energy by unlocking heat from deep, hot rocks using advanced drilling and reservoir engineering, making geothermal power possible in regions previously out of reach. Despite their promise for scalable, reliable energy, EGS must overcome high costs, technical challenges, and environmental concerns to achieve widespread adoption.