Innovative energy storage technologies are rapidly gaining momentum, with novel methods promising to reshape the way we think about energy management. Among these methods, heat-based batteries have emerged as surprisingly versatile tools for energy storage, capable of supporting various industries and applications.
Take Brenmiller Energy, for example. Founded over a decade ago, this Israel-based company has primarily focused on thermal energy storage systems—specifically, heat batteries. Initially aimed at enhancing solar-thermal power plants, Brenmiller has since expanded its reach, utilizing its bGen systems to provide energy for hospitals and sectors like food and beverage processing. These systems capture excess electricity to generate heat, which can then be stored for later use, improving energy efficiency across the board.
The scale of Brenmiller's innovation is impressive. Co-founder Doron Brenmiller noted, “Throughout the years, we have evolved from producing heat batteries for specific purposes to developing systems applicable for many more.” Their technology allows for cheap, clean electricity to be converted to heat, aiming to significantly reduce reliance on costly fossil fuels.
Globally, thermal energy storage has captured the attention of investors, with companies like Brenmiller raising significant funds. To date, they've secured $100 million and have contracts valued at over $500 million lined up for deployment. The widespread adoption of these technologies aligns with the increasing need for effective solutions to store renewable energy, particularly as countries attempt to meet ambitious decarbonization goals.
But how do these heat batteries actually work? Brenmiller’s bGen systems utilize crushed rock as the energy storage medium. This rock, which can be sourced from many locations, is placed inside thermally insulated containers known as bCubes. These cubes can absorb heat from various sources, including hot air, steam, or electrical resistance heaters, and can send out this heat through the same pathways, offering tremendous flexibility for users.
With about 97% of the heat generated being extractable, efficiency is one of the key selling points for these systems. They are being implemented at diverse sites, such as beverage processing plants like Tempo, which uses Brenmiller technology to replace diesel-fired boilers with modern, sustainable energy sources. Similar projects are underway at Wolfson Medical Center, aiming to replace heavy fuel oil with more efficient electrical solutions.
Brenmiller’s offerings highlight how shifting to renewable energy sources can be economically and physically viable—especially as fossil fuel prices rise and carbon emission penalties loom. Despite challenges, the firm's systems are seeing strong adoption and embody the kind of innovation needed to accelerate energy transition.
Meanwhile, another groundbreaking project taking center stage is the geo-thermal energy storage known as GeoTES. Funded by the U.S. Department of Energy, this initiative aims to leverage abandoned oil wells for long-duration thermal energy storage—potentially storing concentrated solar heat for up to 1,000 hours! This technology, developed by PRM, utilizes parabolic trough solar collectors to absorb heat and then circulate it through underground sandstone formations, maintaining high temperatures for extended periods.
The results are nothing short of remarkable. By using this closed-loop system, PRM can effectively store energy over long durations, theoretically supplying multiple days or even weeks of power without needing any new construction, relying instead on existing geological formations. This ambitious plan marries the long-standing capabilities of geothermal technology with the solar innovations of today, allowing us to rethink energy storage and management entirely.
When discharging energy from the GeoTES systems, pressurized hot water is utilized to create steam, effectively functioning similarly to geothermal systems. This hybrid model could significantly outperform traditional concentrated solar power (CSP) plants, which usually only store heat for up to 24 hours.
With promising data from National Renewable Energy Laboratory (NREL) studies, costs associated with the GeoTES technology could be incredibly competitive, making it possible to achieve electricity costs as low as 6 cents per kilowatt-hour. Coupled with the cost of heat storage potentially dropping to 1 cent per kilowatt-hour, financial feasibility becomes more evident.
The project is set to take off near Bakersfield, California, with preparations underway to create this closed-loop energy storage system. NREL has already conducted extensive analysis to identify suitable locations, emphasizing the porous nature of the sandstone reservoirs, which are conducive for storing significant volumes of heat.
Future challenges, as pointed out by NREL lead researcher Guangdong Zhu, rely on ensuring the stored water remains at safe temperatures to prevent any detrimental effects on the geological formations. A balancing act for the future, no doubt, but one well worth considering for California’s sun-rich environment.
Innovative ideas like Brenmiller’s heat batteries and PRM's GeoTES model present exciting advancements for energy storage. The industry now not only finds ways to store energy more effectively but also exploits existing resources and structures—ensuring technologies do not just offer novel improvements, but also facilitate the necessary transitions to clean energy. This thrilling evolution promises great potential as renewables become household names, and with the right support, energy storage technologies are likely to play pivotal roles, powering our sustainable future.
