Concrete, one of the most extensively utilised building materials globally, is now being explored for innovative energy storage applications. Researchers are leveraging concrete’s beneficial properties like high heat capacity, availability, and structural strength to develop sustainable solutions to store energy. This creative use of such a common material promises to accelerate the transition to renewable energy.
Concrete Foundations as Supercapacitors
Scientists at MIT have developed a supercapacitor concrete by incorporating carbon-rich materials like charcoal powder into the cement mixture. This electrified concrete can store energy electrochemically and discharge it rapidly to power homes or charge EVs. Calculations show a standard concrete foundation could store 10 kWh of electricity – enough to power an average UK household for one day. With further engineering, supercapacitor concrete could be integrated into buildings to store solar energy and stabilise grids.
Capturing Thermal Energy in Concrete
Another technique uses concrete as a thermal battery to store energy as heat. Norwegian company EnergyNest uses resistive elements to heat up concrete blocks during periods of excess electricity. A 40 ft container of their thermal concrete can store 3 MWh of energy. The conserved thermal energy is later utilised for power generation or heating purposes. With concrete’s high heat capacity and slow heat release, these thermal storage systems can capture large amounts of energy. Successful projects in Europe and the Middle East showcase the potential.
Elevating Concrete for Gravity Energy Storage
A third approach utilises gravity energy storage. Concrete blocks weighing up to 35 metric tonnes are lifted using excess electricity to store energy as gravitational potential energy. Lowering the blocks through generators converts the potential energy back to electricity when required. Startups like EnergyVault and Gravitricity are pioneering this method to develop grid-scale solutions with capacities up to 80 MWh. Gravity storage provides long duration storage capabilities.
An Accessible, Efficient Technology
Concrete-based energy storage techniques are scalable, cost-effective and utilise widely available materials. Integration into buildings and infrastructure is straightforward. With further innovations to enhance storage capacity and 70-85% roundtrip efficiency, concrete promises to become a sustainable, efficient storage medium to enable the worldwide transition to renewable energy.