Slick Energy Storage Trick Deploys 21st Century Firebricks

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The industrial carbon footprint has been a tough nut for renewable energy fans to crack, partly because of the ultra-high heat required for boilers and other equipment. Wind turbines and solar panels alone are not up to the job. An energy storage intermediary is required, but lithium-ion batteries are not up to the task, either. So, innovators are turning to a millennia-old technology in the form of firebricks. Yes, bricks.

A Super-Hot Thermal Energy Storage System For Industrial Decarbonization

The idea of a hot brick is simple enough, says anyone who has walked barefoot on hot sand. For industrial decarbonization the challenge is to transfer energy in and out of a solid substance efficiently and economically, on a cost-competitive basis with conventional fossil energy systems. Solid things also tend to crack and fall apart when subjected to intense cycles of heating and cooling, so engineering a suitable, durable material is another hurdle (see more hot brick background here).

The latest news in the brick-based thermal energy storage field comes from the Boston startup Electrified Thermal Solutions. The company’s Joule Hive Thermal Battery was initially developed at MIT and received a development assist from ARPA-E, the high-risk, high-reward funding branch of the US Department of Energy, back in 2021.

In March, the Energy Department included Electrified Thermal in an industrial decarbonization funding round covering 33 projects across the US. The Electrified Thermal project was slated to receive up to $35.2 million in partnership with ISP Chemicals and the Tennessee Valley Authority towards the replacement of natural gas boilers at a chemical plant in Kentucky, resulting in a cut of almost 70% in greenhouse gas emissions related to steam generation.

On August 5, Electrified thermal also reported that it received “Technology-to-Market Plus Up” extension funding ARPA-E after making it up the innovative technology readiness ladder to Level 6, out of a maximum of 9 levels. NASA initially developed the Technology Readiness Level scale to assess the relevance and maturity of new technologies for space applications. It has since been adapted for energy technologies.

Next Steps For Brick-Based Thermal Energy Storage

Technology Readiness Level 6 is a giant step up from Level 1, which involves the observation of basic principles. By Level 6, innovators need to demonstrate that their prototype functions as expected in a working environment. In the August 5 announcement, ETS demonstrated that its “E-Brick” system can reach 1,700°C (3,092°Fahrenheit) for industrial processes, with energy delivery accomplished by blowing air across the surface of the bricks.

ETS is anticipating that an award of $5 million from the Energy Department’s Industrial Efficiency and Decarbonization Office and the $35 million from the Office of Clean Energy Demonstrations will enable it to leapfrog up to Technology Readiness Level 8 in the coming, year.

“In demonstrating that ETS’ E-Brick circuits can generate the required temperatures directly from electricity while durably and continuously cycling between low and high temperatures is a key milestone to commercialization and achieves the vision jointly set out by ETS and ARPA-E,” the company emphasized in August, adding that its “zero carbon, cost-competitive, on-demand, flame-temperature industrial heat” is hot enough to replace fossil energy used in steel making as well as cement, glass, and chemicals among other industries.

“Industrial heat processes are responsible for approximately 20% of global greenhouse gas emissions,” ETS emphasizes, much of which is attributed to burning natural gas.

Let The Private Sector Pile-On Begin

ARPA-E was established by an act of Congress in the waning years of the Bush administration. The aim is to step up in support of energy-related innovations in the national interest when private sector investment dollars are unavailable or insufficient, so it’s big news when investors finally do sit up and take notice.

Earlier today, Electrified Thermal announced that just such a thing has happened. The company raised $19 million to help kickstart its energy storage solution into commercial development, supported by a group of A-list industrial stakeholders and clean tech investors. Holcim MAQER Ventures, Vale Ventures, TechEnergy Ventures, EDP Ventures, Tupras Ventures, GVP Climate Clean Energy Ventures, Starlight Ventures, Mass Ventures, and Clean Energy Venture Group all played a role.

“Electrified Thermal stands out for their pragmatic approach to solving industry’s most pressing challenge – efficiently and economically decarbonizing industrial heat – with the added benefits of seamlessly integrating into existing infrastructure and unlocking a market opportunity of ca. $100 billion,” remarked GVP Climate co-founder and CIO Brett Olsher.

Better Thermal Energy Storage For High Heat

As for what, exactly, is this super-hot energy storage E-brick made out of, Electrified Thermal describes the material as a sort of amped-up firebrick. Firebricks are a dense form of ceramics commonly used in kilns, furnaces, and other applications where the ability to withstand high heat is required.

ARPA-E adds a bit more detail, describing the technology as FIRES, short for Firebrick Resistance-heated Energy Storage. “FIRES is based on a novel joule-heated system built from electrically conductive ceramics designed at MIT,” the office explains.

Last month, Zach Winn of MIT News took a deeper dive into the technology and its inventor, Daniel Stack (SM ’17, PhD ’21). “Since coming to MIT in 2014, Stack has worked to develop thermal batteries that use electricity to heat up a conductive version of ceramic firebricks, which have been used as heat stores and insulators for centuries,” Winn noted.

Brick-based energy storage systems typically deploy electric resistance heaters. They are suitable for processes requiring lower heat, but the high-heat processes targeted by Electrified Thermal require a more durable solution. Working with his advisor and Principal Research Scientist Charles Forsberg at MIT, Stack formulated a new firebrick composition that eliminates the need for conventional electrical systems. “Electrified Thermal’s bricks are 98 percent similar to existing firebricks and are produced using the same processes, allowing existing manufacturers to make them inexpensively,” Winn observed.

“A promising material for these firebricks is silicon carbide, which is already produced at massive scales for uses such as sandpaper,” MIT News noted back in 2017. I’ve reached out to Electrified Thermal for an update on that, so stay tuned for more information.

Another big question, of course, is who’s gonna pay for all this. In a 2019 paper published in the journal Applied Energy, Stack, Forsberg, and colleague Daniel Curtis described the FIRES thermal energy storage system as “an affordable path to decarbonization.” With a cost estimated at about $10.00 per kilowatt-hour, the system is “substantially less expensive than batteries.”

“Northwestern Iowa market analysis shows payback within 2 years and economic profitability,” the authors added.

With the leg up from both public and private sector partners, Electrified Thermal has big plans for commercial development. The aim is to deploy enough thermal energy storage to up to 2 gigawatts’ worth of thermal power capacity by 2030 — just in time to create another headache for ExxonMobil and other natural gas stakeholders.

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Image (cropped): Boston startup re-invents millennia-old firebricks for 21st century renewable energy storage and industrial decarbonization (courtesy of Electrified Thermal Solutions).