Google Invests in Zinc Battery Tech for 24/7 Clean Energy

Google is advancing its goal of achieving 24/7 carbon-free energy by investing in a significant clean-energy project in West Virginia, which will integrate cutting-edge zinc battery technology for long-duration energy storage. The project, named Mammoth Solar, is situated on a 500-acre section of a former coal mine that was abandoned 20 years ago. This initiative represents a crucial step in the evolution of renewable energy, moving beyond the limitations of earlier storage solutions.

The Mammoth Solar project involves a total investment of $350 million and is a collaboration between MN8 Energy, which will build and operate the plant, and Google, which will purchase the energy generated. A key feature of this development is its reliance on zinc batteries, an emerging long-duration energy storage technology capable of holding electricity for up to 10 hours. This capability is essential for ensuring a consistent supply of renewable energy, even when solar or wind resources are not actively producing power.

Jon Yoder, president and CEO of MN8 Energy, highlighted the historical challenges in renewable energy storage. He explained that a decade ago, most solar and wind projects lacked integrated battery systems due to the absence of economically viable storage solutions for periods when the sun wasn't shining or the wind wasn't blowing. Subsequently, lithium-ion batteries became feasible for short-term storage, typically for about four hours, which helped manage peak demand in the evenings. However, these batteries proved too expensive for bridging longer gaps in energy supply.

To address this, MN8 Energy and Google explored new options for long-term storage that could complement existing lithium-ion systems. Yoder stated that they evaluated "dozens of different combinations of technologies" to assess their functionality against their cost. The zinc battery technology, manufactured by Eos, emerged as a promising solution. Yoder cited the batteries' relatively high round-trip efficiency, meaning a significant portion of the stored energy can be retrieved. Furthermore, Eos batteries utilize sustainable materials, specifically zinc and bromine, which are Earth-abundant, and contribute to a more resilient supply chain compared to traditional battery chemistries. The company also noted that these zinc batteries do not pose a fire risk, adding another layer of safety and viability to the project.