Champaign, Illinois startup Cache Energy is receiving financial and technical support from Chicago’s Evergreen Climate Innovations to advance its ultra-long duration energy storage technology. In addition to gaining ground in multi-day energy storage, the founder says this innovation could help to advance global energy equity.

“Lithium-ion batteries do a great job of storing energy for five or six hours. But we really need a solution that can store energy for longer duration – multiple-day storage,” said Arpit Dwivedi, Cache Energy founder. “That’s exactly where we fall in.”

Dwivedi says he always had a passion for entrepreneurship and for energy while growing up in India. He came to America specifically to study energy at the University of Illinois Urbana-Champaign and earn a Ph.D.

“It gave me some time to think about what is the most impactful solution, what is that missing piece, and really developing a solution which could enable access to clean energy for everyone, everywhere,” he said. 

Cache Energy develops energy storage technologies from a nontoxic, abundant mineral oxide material and strives for a positive impact on people’s lives.

“Energy lies at the root cause of all socioeconomic problems that the world faces,” Dwivedi said.

“Sun and wind don’t differentiate between people; it is for everybody and is for free. If you just learn to store it, we can ensure that the world has a level playing field and people have access to cheap and clean energy.”

These founding principles are one reason Cache caught Evergreen’s attention.

“Cache’s solution of energizing material that can be easily transported without losing charge has a significant impact on energy access and equity,” said Erik Birkerts, CEO of Evergreen Climate Innovations. “Such flexibility means that critical energy storage can be deployed where it is needed most, such as in underserved communities.” 

It’s all in the materials

Another of Cache Energy’s key goals is to get its innovation as close as possible to the energy density of fossil fuels without the negative consequences. The team knew that fossil fuels are just chemicals that produce energy during a chemical reaction – burning – and they set out to identify other chemical reactions that have similar energy output without releasing greenhouse gases.

“In a way, it is like we are transcending the concept of energy storage and fuel and combining them together,” Dwivedi said.

“So we actually call our solution ‘long-duration energy storage in a solid fuel,’ and we call it ‘future fuel.’” 

The technology uses a thermo-chemical energy storage process based on a cheap mineral oxide material found nearly everywhere in the world that can be stored at room temperature without special containment. It reacts with steam to produce energy with zero greenhouse gas emissions. The system can perform multiple energy storage and release cycles from the same material, just like conventional batteries, Dwivedi said. The intellectual property protections cover both the material and reactor innovations, he said.

The material has the potential to store energy for months with almost no loss, according to Dwivedi. It can be easily transported and stored by using existing coal industry infrastructure. In fact, the technology can be retrofitted onto coal power plant boilers, Dwivedi said. And users can leverage existing employees’ skill sets instead of resorting to extensive training or layoffs. This eliminates “one of the biggest challenges in shifting to clean energy,” which is figuring out “what happens to the skilled labor that we have had for decades at coal plants,” Dwivedi said.

The material eliminates the fire and corrosion hazards with competing systems, such as lithium-ion battery fire dangers. Dwivedi says this makes it suitable for a variety of industrial applications, and in the future for residential or commercial heating and utility-scale solar farms. 

As the innovation scales, the price comes down. Dwivedi says that every doubling in size so far has reduced costs by 20%.

What’s next

Cache Energy has built a system and aims to scale it up to 100-300 kW in the next six months or so. They will then partner with customers to pilot test it. Currently, they’re exploring potential industrial and water treatment plant partnerships. 

“It seems like it has a lot of features, but ultimately, inherently, it is just us trying to mimic what fossil fuels did best while trying to do away with what they did not do best,” Dwivedi said.