Many industrial processes operate around the clock and therefore require constant heating. By carefully controlling heat transfer, Rondo’s system can recharge quickly, taking advantage of short periods when electricity is cheap because renewable sources are available. The startup’s thermal batteries will likely require about four hours of charging to be able to continuously provide heat, day or night.
One of the main challenges for heat storage technologies will be building enough systems to meet the huge energy demands of heavy industry. Sector uses ‘monstrous’ amount of heat, says Rebecca Dell, senior director of industry at ClimateWorks. Of all the energy used each year in industry, about three-quarters is in the form of heat, whereas today only one-quarter is electricity. Process heat is approximately 20% of total global energy demand.
Fossil fuels have been the obvious and most economical way to power these massive industrial processes, but wind and solar energy prices have fallen by more than 90% in recent decades. Dell says this has opened the door for electricity to play a bigger role in the industry.
“We’re at that beautiful moment where we can stop burning stuff for our warmth And cheaper,” says O’Donnell.
There are a few other potential options for using cheap renewables in industry. Some installations could be adjusted to use electricity directly, instead of high heat. Companies are working on electrochemical processes for making cement and steelfor example, although replacing all existing factory infrastructure can take decades. Using electricity to produce hydrogenwhich can then be burned to generate electricity, is another potential route, although in many cases it is still cost prohibitive and inefficient.
Any effort to meet the massive demand for heat from industry will require a dramatic expansion of electricity generation. A standard cement plant uses about 250 megawatts of energy, mostly in the form of heat, all the time, Dell says. That’s about 250,000 people in electricity, so electrifying a large industrial facility will mean adding electricity demand equivalent to that of a small town.
One brick at a time
Rondo is not alone in its quest to deploy thermal batteries in industry. Antora Energy, based in California, also builds heat storage systems, using carbon. “It’s super simple, they’re literally just solid blocks,” says co-founder and COO Justin Briggs.
Instead of using a separate heating element (like Rondo’s “toaster coil”) to turn electricity into heat, Antora’s system will use carbon blocks as the resistive heating element, so they generate and store heat. This could reduce cost and complexity, says Briggs. But the choice will also mean that the system must be carefully sealed, as graphite and other forms of carbon can degrade at high temperatures in air.