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Technology with roots going back to the Bronze Age may offer a fast and inexpensive solution to help achieve the United Nations climate goal of net zero emissions by 2050, according to recent Stanford-led research in PNAS Nexus.

The technology involves assembling heat-absorbing bricks in an insulated container, where they can store heat generated by solar or wind power for later use at the temperatures required for industrial processes. The heat can then be released when needed by passing air through channels in the stacks of “firebricks,” thus allowing cement, steel, glass, and paper factories to run on renewable energy even when wind and sunshine are unavailable.

These systems, which several companies have recently begun to commercialize for industrial heat storage, are a form of thermal energy storage. The bricks are made from the same materials as the insulating bricks that lined primitive kilns and iron-making furnaces thousands of years ago. To optimize for heat storage instead of insulation, the materials are combined in different amounts.

Batteries can store electricity from renewable sources and provide electricity to generate heat on demand. “The difference between firebrick storage and battery storage is that the firebricks store heat rather than electricity and are one-tenth the cost of batteries,” said lead study author Mark Z. Jacobson, a professor of civil and environmental engineering in the Stanford Doerr School of Sustainability and School of Engineering. “The materials are much simpler too. They are basically just the components of dirt.”

Many industries require high-temperature heat for manufacturing. Temperatures in factories need to reach at least 1,300 degrees Celsius (nearly 2,400 degrees Fahrenheit) to produce cement, and 1,000 C (about 1,800 F) or hotter for glass, iron, and steelmaking. Today, about 17% of all carbon dioxide emissions worldwide stem from burning fossil fuels to produce heat for industrial processes according to Jacobson and co-author Daniel Sambor’s calculations. Generating industrial heat from renewable sources could all but eliminate these emissions.

“By storing energy in the form closest to its end use you reduce inefficiencies in energy conversion,” said Sambor a postdoctoral scholar in civil and environmental engineering. “It’s often said in our field that ‘if you want hot showers store hot water; if you want cold drinks store ice’; so this study can be summarized as ‘if you need heat for industry store it in firebricks.’”

The researchers set out to examine the impact of using firebricks to store most industrial process heat in 149 countries in a hypothetical future where each country has transitioned to wind geothermal hydropower and solar for all energy purposes. The 149 countries are responsible for 99.75% of global carbon dioxide emissions from fossil fuels. “Ours is the first study to examine a large-scale transition of renewable energy with firebricks as part of the solution,” Jacobson said. “We found that firebricks enable a faster and lower-cost transition to renewables; that helps everyone in terms of health climate jobs; energy security.”

The team used computer models to compare costs land needs health impacts; emissions involved in two scenarios for a hypothetical future where 149 countries by 2050 are using renewables for all energy purposes: In one scenario firebricks provide 90% of industrial process heat; In another there’s zero adoption of firebricks or other forms thermal energy storage industrial processes: In no-firebrick scenario researchers assumed heats industrial processes would come instead electric furnaces heaters boilers; pumps batteries used stores electricity technologies:

Researchers found scenario with firebricks could cut capital costs $1:27 trillion across countries compared no-firebrick reducing demand grid need capacity batteries:

Solutions accelerating transition clean connected human health previous research shown air pollution burning causes millions early deaths each year: “Every bit combustion fuels we replace reduces pollution” Jacobson said: “And because limited amount money transition high speed lower cost overall system faster implement it.”

Jacobson spent career understanding pollution problems developing plans solve focus relatively new inspired desire identify effective solutions adopted quickly:

“Imagine propose expensive difficult method transitioning renewable electricity – few takers save money compared previous method implemented rapidly” he said: “What excites me impact very large whereas lot technologies looked marginal impacts substantial benefit low cost multiple angles helping reduce mortality making easier world clean renewables.”

Jacobson senior fellow Stanford Woods Institute Environment Precourt Institute Energy:

Sambor funded Engineer Research Development Center:

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