Cache Energy’s Enigmatic White Pellets May Be Key to Ending Coal and Natural Gas Dependency

The cost of installing wind and solar power has plummeted, occasionally leading to an excess of energy that leaves utilities at a loss about its management. There have been instances where utilities compensate other energy producers to reduce their output.

Consequently, there’s a vigorous effort among experts to devise cost-effective energy storage solutions, aiming to make renewable sources reliable round-the-clock and economically competitive against fossil fuels.

Cache Energy is entering the scene with an innovative strategy. Eschewing conventional methods of storing energy in heat form, such as using sand or custom bricks, Cache opts for chemical storage. It employs pellets made from lime, which is obtained from limestone. The company’s founder and CEO, Arpit Dwivedi, refers to this method as creating “coal without the downsides.”

Dwivedi explained to TechCrunch that this low-cost, solid substance can generate heat and utilize infrastructure similar to that used for fossil fuels.

According to Dwivedi, these pellets could be accumulated in heaps or silos, conveyed through belts, and shipped in railcars. He emphasizes that simply encasing them—potentially even with merely a tarp—suffices to preserve their energy indefinitely.

Cache has remained under the radar until its recent unveiling to TechCrunch by Dwivedi, who embarked on the venture in 2021 during his PhD tenure at the University of Illinois, showing off a technology intended to supplant fossil fuels in heating sectors.

The initial material, calcium hydroxide, is chosen for its wide availability and versatile applications, from paper production to food processing. To counter its powdery nature, suitable for the company’s needs, Cache developed a technique to consolidate the material, resulting in durable pellets of optimal size for the energy storage and release reactions. Dwivedi highlighted the meticulous efforts in refining the pellet size.

Heating the pellets drives off water, transforming them into calcium oxide, or quicklime—the “charged” state. Rehydrating them reverses the transformation, liberating heat with an impressive efficiency of around 95%, according to Dwivedi.

The heat generated by Cache’s pellets can reach up to 550 degrees Celsius, sufficient for the majority of industrial tasks and heating buildings. The ambition extends to developing a variant capable of achieving 900 degrees Celsius, expanding their potential market. The firm’s recent $8.5 million seed financing will fuel further development, with contributions from varied investors and a plan to undertake a Series A funding round.

With the aim to keep device and material costs low, leveraging standard components, Cache’s solution is notably economical, with production prices ranging between 20 to 40 cents per kilowatt-hour.

Cache’s success depends notably on electricity pricing. In regions where renewable energy is widespread and inexpensive, such as Texas or Arizona, the pellets could offer an economical method to store energy. The vision is to see these pellets charged in renewable-abundant areas and utilized nationwide, akin to traditional fuel deliveries, but with a significant reduction in carbon emissions, marking a step forward in eliminating the reliance on fossil fuels for heat.