In 2022, the fuel combustion that powers the world’s industries emitted over 6.5 million metric tons of carbon dioxide: more than any prior year, and more than any other sector besides transport and power generation. Despite global pledges to cut emissions, this figure has continued to creep steadily higher. We rely on the products produced by industry— steel, chemicals, paper, glass— but we also cannot live with the current status quo. To limit warming to 1.5 °C, industries need access to realistic solutions that can speed up decarbonization now as well as in the future.
Part of the challenge of decarbonizing industry lies in the need for high temperatures, not all of which can be covered by electricity. Processes such as firing blast furnaces to make steel, melting glass, and synthesizing ammonia require high-temperature fuels, which generate both greenhouse gases and waste heat as they burn. Green hydrogen is seen as a carbon-free alternative, capable of generating high temperatures for process heat without CO2 emissions and replacing the ingredients necessary for processes in steelmaking and the chemical sector. However, manufacturers and governments should be wary about viewing hydrogen as a silver bullet.
Currently, almost all hydrogen produced worldwide is “gray,” meaning it uses natural gas to power the electrolysis process— in turn cancelling out its own climate benefits. Meanwhile, “green” hydrogen, produced using renewables, likely needs a decade or more before it reaches the economies of scale needed to be viable on the market. But climate change will not wait for a decade— its impacts are happening now. For decarbonization efforts to be effective, a pluralistic approach is needed: more tools in the toolbox, less sitting and waiting for a single solution to reach maturity.
Luckily, there are pathways available. The U.S. Department of Energy outlines four key technological pillars for industrial decarbonization: Energy efficiency, industrial electrification, low-carbon fuels & feedstocks, and carbon capture. None of these pillars alone are sufficient for full decarbonization, but when combined, they complement each other’s strengths and compensate for gaps. While low-carbon fuels and carbon capture are still in the early stages of development, technologies for energy efficiency optimization and electrification are further along, meaning their deployment is needed today while the window for impactful emissions reduction is still open.
One such example is thermal energy storage. As the name implies, this technology stores energy in the form of heat with output temperatures up to 1300 °C, making it highly suitable for industrial applications. As an input energy source, thermal energy storage systems can use both excess heat from industrial processes and renewable power generation, which is converted into heat and stored. Thermal storage therefore meets two industrial decarbonization pillars simultaneously: Energy efficiency through the utilization of waste heat, and better integration of renewables through the conversion of green power into usable process heat.
Thermal energy storage is positioned to become a necessary component of a holistic industrial decarbonization strategy. While not a new concept, new developments in the last decade make it a fit solution for high-temperature processes. Industrial heat storages are already being deployed across several industries, including steel, ceramics, paper, and food processing. This broad interest does not only stem from thermal storage’s decarbonization advantages, but also from its usability.
Unlike hydrogen, which requires installing new infrastructure such as a pipeline system to supply the fuel, thermal energy storage can be implemented into existing operations with only a connection to the grid. If waste heat is utilized, the system can even be decoupled from any infrastructure other than the user’s. As many industries invest in their own large-scale PV and wind power plants, they are curtailing a large portion of their electricity or feeding it back to the grid. With thermal energy storage, this cheap energy can be used to decarbonize process heat flexibly. And most importantly, it is already price-comparable with the use of existing natural gas-powered equipment, making it realistic from a business perspective.
The challenge of industrial decarbonization is too complex to be addressed by a single technology— but in this crowded landscape, thermal energy storage stands out for its viability today. Given the urgency of addressing climate change, this aspect is crucial: It ensures that industries can meet their emission reduction targets and maintain operational efficiency and economic viability now, buying much-needed time for a complete industrial decarbonization.
Andrew Emil, CCO, Kraftblock: Andrew Emil is an executive with 15+ years of expertise spearheading decarbonization and the deployment of climate technologies at leading conglomerates such as Cummins, MAN/H-TEC, and Linde. By driving sustainable energy and optimizing industrial processes, his leadership has advanced corporate sustainability goals and contributed to the global green transition.
