thermal battery power clean industrial heat

Over the past 12 weeks, California startups Rondo Energy It is said to be the world’s largest thermal battery in operation. Rondo’s system converts cheap renewable electricity into heat that can be released on demand into industrial processes.

This differs from most next-generation energy storage strategies, which provide power to the grid in the absence of sun or wind. Instead, Rondo’s system aims to help decarbonize emissions-heavy sectors like steel manufacturing and cement.

The system works like a toaster crossed with a blast furnace. The electricity from solar arrays heats iron wires, similar to a toaster oven. These heat hundreds of tons of refractory bricks to temperatures up to 1,500 degrees Celsius. After charging for four to six hours a day, the heat can be released as air or steam, without combustion or emissions.

To discharge the heat, a circulating air blower is turned on, which pushes air up through the brick stack and heats it to more than 1,000 degrees Celsius before releasing it through the outlet. The heat delivery rate can be controlled by adjusting the air flow. The battery may discharge steam instead of heat by injecting water into the enclosed chamber before leaving the battery through an outlet through which hot air passes.

The real challenge in thermal energy storage is not the storage of heat; It is able to charge faster and then provide consistent heat at the same temperature, it says John O’DonnellChief Innovation Officer of Rondo Energy. The structure of the Rondo’s heat battery, which O’Donnell describes as “a 3D checkerboard of brick and open chambers”, keeps temperatures consistent and enables fast charging. “We can turn the charging circuit on and off as fast as you can turn your toaster on and off,” says O’Donnell. “So we can be agile.”

In Rondo’s first project, its 100-megawatt-hour battery is supplying heat to an advanced oil recovery facility operated by Holmes Western Oil Corporation in Kern County, California. The battery, which is the size of a small office building, is powered by an off-grid, 20-MW solar array built for the purpose. It converts clean electricity into heat, and then generates steam that is injected into oil wells, heating the oil so it becomes thinner and flows more easily, increasing production.

Holmes Western Oil had previously accomplished this with a gas-fired boiler. Cutting it would save Holmes just under 13,000 tonnes of CO₂ According to Rondeau, annual emissions would be lower as well as costs. “This oil field uses the second largest share of industrial heat in the state,” says O’Donnell.

Rondo’s decision to deploy its first commercial-scale, emission-reducing batteries for fossil fuel extraction sparked some controversy.

Thermal batteries for clean industrial heating

Several other companies are developing thermal batteries with industrial heating applications. Entora Energy Creates modular carbon-block heat batteries that can reach temperatures of more than 1,500 degrees Celsius and are being deployed at pilot industrial sites. Energynest is conducting initial commercial installation of its concrete-based thermal modules, and is partnering with Siemens Energy to expand across Europe. Calectraultra-high-temperature systems are in the pilot stage, and EarthN Energy launched its modular low-temperature heat batteries in July.

These companies focus on the summer as it is the center of production of main products like steel, cement, food and chemicals. Many of these manufacturing processes run continuously and maintain high temperatures for many weeks or months 72°C to pasteurize milk For more than 1,000 degrees Celsius steel making Or cement.

Fossil fuels have long been the cheapest, most efficient way to generate heat consistently; Nothing burns as slowly and hotly as coal or natural gas. Their energy density, reliability, and low cost have made them difficult to replace. However, industrial heat is accounted for about 18 percent greenhouse gas emissions and more than 20 percent of global energy consumption. So innovators aiming to decarbonize these industrial sectors have their work cut out for them.

But solar energy is getting cheaper. In 2024, California’s solar fields you generated Almost as much electricity as its gas plants. “Because of what the wind and solar industry has done, we now have intermittent grid prices that are cheaper than fuel in many places in the world,” says O’Donnell. Some places produce so much clean electricity that the grid can’t absorb it, causing electricity prices to go negative. For a few hours a day.

How can thermal batteries scale?

Thermal batteries that supply heat face many challenges. To scale up, industrial customers must buy in bulk during times of the day when renewable electricity is cheapest, which requires dynamic real-time pricing. Many states allow only industrial customers to purchase electricity at fixed daily rates. “We are really keen to see the regulatory framework modernised,” says O’Donnell.

The price of natural gas also plays a role. It is relatively cheap in the United States due to shale gas produced by fracking, but if its price increases due to exports or other factors, batteries like Rondo could become a cheap source of heat. This is already the case in European countries like Germany, where natural gas price It has skyrocketed in the last three and a half years.

Also, heat batteries can be difficult to integrate into existing industrial infrastructure. Not every facility has space for an office building-sized battery and a dedicated solar array. The high upfront cost of batteries and the fact that they are still a largely unproven technology will make some prospective customers reluctant to try them.

Nonetheless, heat batteries like Rondo are a promising solution for decarbonizing the industrial sector. “The thermal storage market is fully capable of accelerating to make a meaningful impact,” says Blaine Collison, Executive Director of . Renewable Thermal CollaborativeAn alliance that focuses on decarbonizing thermal energy. “When I look at some of the fundamental characteristics of the technology – relatively simple materials, ability to take renewable electricity, modularity – I see scale.”