Balancing the Energy Grid

The ability of concrete to store heat could make it an important energy storage solution, helping to balance electricity grids by flexibly using renewable energy at times of peak generation.

Thermal mass is the ability of heavyweight building materials, such as concrete, to store energy, which is later released. In summer this avoids overheating in buildings and keeps temperatures comfortable by both absorbing energy from the air and providing cool radiative surfaces. In winter, the thermal mass can absorb heat gains during the day and reradiate them in the evening. 

Thermal mass is used to improve the energy efficiency of buildings and provide a stable indoor temperature. A further – previously untapped – benefit is to use the thermal storage capacity offered by the structure to provide flexibility in energy grids, thereby facilitating the uptake of renewable energy.

One of the challenges of renewable energy is the mismatch between when this energy is generated and when it is needed. In order to make the most of the energy generated by renewables, such as wind and solar, flexibility is needed in the electricity grid. Heavyweight buildings can provide this flexibility by allowing consumer demand to be shifted in time through structural thermal energy storage.

One form this can take is known as active demand response (ADR), where smart controls and energy storage help balance the electricity grid. Here, the structural thermal energy storage capacity of a heavyweight building has huge potential, as this requires no additional investment costs, unlike other storage systems. By actively preheating or precooling a building during off-peak times (such as early in the morning), energy is absorbed and stored within the fabric of a building, then released over the course of the next few hours.

This offers several benefits. For the environment, higher use of renewable energy reduces the use of fossil fuels, reducing CO2 emissions. It reduces energy bills for consumers, as energy is used during off-peak times, when electricity prices are lower. Finally, for energy grids, it lowers peak demand, reducing the need for additional investment in power generation capacity.

Further reading and sources
Passive Cooling Utilising Thermal Mass

Header photo by Paul Mocan on Unsplash