We must not overlook heat storage in our efforts to increase the use of renewable energy sources.

It is now well established that to mitigate the worst effects of climate change, we need to rapidly reach net-zero carbon emissions. This means obtaining more of our energy from renewable sources and finding ways to store it for extended periods to address the intermittency of wind and solar energy.

Even though huge battery installations and green hydrogen are often considered the most promising storage solutions, alternative options are often overlooked. Renewables are typically associated with electricity, but heat is also a valuable commodity, meeting about half of the world’s total energy demand. Stored heat can also be used to generate electricity when the sun is not shining and the wind is not blowing. Therefore, we cannot overlook the potential of heat storage in our race to ramp up renewables.

In our featured article, "How Simple Technology Can Accelerate the Transition to Net Zero", we learn about a variety of emerging heat storage technologies collectively known as Thermal Energy Storage (TES). These innovations, such as heated bricks and molten salt, are remarkably simple and have the potential to be cost-effective. Early estimates suggest that these technologies could cost as little as one-fifth of the price per kilowatt-hour compared to energy storage using green hydrogen. The International Renewable Energy Agency has reported that TES offers "unique benefits."

The issue at hand is the lack of awareness and limited investment in TES. Although private investors in the US and Europe are starting to allocate significant funds to pilot projects, governments worldwide need to intensify their efforts if we are to realize the potential of TES as a relatively straightforward solution to address the intermittency challenge of renewable energy. If the cost estimates hold true, we cannot afford to overlook the potential of TES.