Calistoga Resiliency Center : Energy Vault lands $28m to deliver green hydrogen storage microgrid tackling wildfire-related blackouts

Energy Vault Holdings Inc. has closed $28 million in project financing to support the deployment of the Calistoga Resiliency Center, a landmark clean energy project that marks a major milestone in the evolution of sustainable power infrastructure in wildfire-prone regions. Positioned as the world’s first ultra-long duration hybrid microgrid integrating green hydrogen energy storage with lithium-ion battery systems, the Calistoga Resiliency Center is designed to keep the lights on in Northern California communities during high-risk Public Safety Power Shutoff (PSPS) events.

Backed by a tolling agreement with Pacific Gas and Electric Company, the project directly addresses the challenges posed by California’s intensifying wildfire seasons. The financing round includes the sale of Investment Tax Credits (ITCs) under the U.S. Inflation Reduction Act, returning capital to Energy Vault’s balance sheet and marking the first realized value from the company’s “Own & Operate” strategy for long-duration storage assets.

What makes the Calistoga Resiliency Center a first-of-its-kind microgrid?

The Calistoga Resiliency Center is a microgrid unlike any other deployed to date. It delivers approximately 293 megawatt-hours of capacity, with the ability to operate independently from the grid for up to 48 continuous hours during emergency shutoffs. Its hybrid configuration includes hydrogen fuel cells for continuous clean electricity generation, paired with Energy Vault’s B-VAULT DC battery system for instant response, voltage support, and black-start capabilities.

This solution is tailored for regions that frequently experience power disruptions due to wildfires, extreme weather, or grid congestion. The CRC, now mechanically complete and undergoing commissioning, is expected to be fully operational by the second quarter of 2025. It is capable of peaking at 8.5 megawatts of output during critical periods and is entirely zero-emission, meeting California’s Renewable Portfolio Standard requirements.

Why is green hydrogen energy storage central to this project?

At the core of the Calistoga Resiliency Center’s innovation is its use of green hydrogen energy storage, which allows it to generate electricity without carbon emissions. Green hydrogen is produced by electrolyzing water using renewable electricity, storing energy in the form of hydrogen gas that can later be converted into power using fuel cells. Unlike diesel generators, hydrogen systems offer a scalable, sustainable alternative with far lower environmental and health impacts.

Energy Vault’s integration of green hydrogen ensures that the Calistoga microgrid can not only store energy for long durations but also discharge that energy over multi-day intervals—an essential feature for events like PSPS, which can last several days. When the grid is down, the hydrogen system provides steady power generation, while the lithium-ion batteries ensure immediate availability and grid-forming capabilities.

How does VaultOS enable autonomous control of the microgrid?

To ensure seamless and secure operations, the entire Calistoga system is managed by VaultOS, Energy Vault’s technology-agnostic energy management system. VaultOS coordinates interactions between the hydrogen fuel cells, B-VAULT battery arrays, and external systems, including PG&E’s Distribution Control Center. It enables autonomous decision-making across the microgrid, managing transitions between grid-connected and islanded operations while maintaining system stability and safety.

VaultOS supports real-time energy balancing, black-start sequencing, and remote monitoring. Its flexibility and interoperability are central to Energy Vault’s broader platform strategy, which aims to deploy similar systems across multiple geographies with minimal software customization.

How does the Calistoga Resiliency Center support PG&E’s wildfire mitigation strategy?

PG&E, one of California’s largest utilities, faces mounting pressure to mitigate the risk of its infrastructure contributing to wildfires. The company’s adoption of PSPS protocols, though effective in preventing disasters, has created new challenges for customers in rural and mountainous regions like Calistoga, who often lose power for extended periods during high-wind or red-flag weather conditions.

The Calistoga Resiliency Center directly addresses this pain point. Through a tolling agreement with PG&E, the system ensures that even during a PSPS event, the local community can continue accessing critical services powered by renewable, zero-emission energy. This aligns with the broader objectives of the California Public Utilities Commission, which has called for utilities to adopt long-duration storage solutions that improve resiliency while advancing decarbonization goals.

How does this financing milestone support Energy Vault’s business strategy?

The successful $28 million financing reflects strong market validation for Energy Vault’s transition from a technology provider to a long-term asset owner. By selling the Investment Tax Credit linked to the Calistoga project, the company has recovered capital expenditure while retaining operational control of the asset. This supports the model introduced at Energy Vault’s May 2024 Investor and Analyst Day, in which the company emphasized recurring tolling revenues and asset optimization over one-time system sales.

Further reinforcing its strategy, Energy Vault has also secured binding commitments to monetize ITCs from two additional projects nearing commercial operation in Snyder, Texas. The Cross Trails and Customer R&D Center microgrids are expected to bring in more than $25 million in additional capital, further expanding the company’s footprint in energy storage infrastructure.

What role do partners like Plug Power and Chart Industries play in this project?

Energy Vault collaborated with Plug Power and Chart Industries to develop and integrate key components of the Calistoga Resiliency Center. Plug Power, a leader in hydrogen fuel cell systems, contributed to the hydrogen-to-power conversion capabilities of the microgrid, while Chart Industries supplied cryogenic and hydrogen storage infrastructure. Their involvement not only strengthened the technical foundation of the project but also lent additional credibility during investor and analyst evaluations.

A recent site tour offered stakeholders a view into the facility’s readiness and execution quality. Attendees observed the full system—including hydrogen processing units, storage tanks, and battery arrays—already in place and undergoing testing. This transparency played a critical role in securing financial commitments and laying the groundwork for replication of the model elsewhere.

How could Calistoga become a blueprint for future energy resilience?

The Calistoga Resiliency Center is being positioned as a scalable blueprint for future deployments across the western United States and other regions prone to climate-related grid disruptions. With climate change increasing the frequency and severity of wildfires, floods, and extreme temperatures, utilities are seeking decentralized, long-duration energy systems that can deliver resilience without relying on fossil fuels.

The modular nature of the Calistoga microgrid makes it well-suited for adaptation to new locations. Its integration of hydrogen and battery storage can be tailored to meet specific load profiles, regulatory conditions, and environmental risks. As regulators and utility planners assess post-2025 infrastructure targets, the CRC is expected to serve as a reference case for zero-emission microgrids that offer both technical reliability and commercial viability.

The Calistoga Resiliency Center stands at the intersection of clean energy innovation, public safety, and infrastructure modernization. By demonstrating that green hydrogen can serve as a reliable backbone for ultra-long duration storage, Energy Vault has delivered more than a technological milestone—it has created a new model for how communities can protect themselves from the growing threats of climate volatility. As the project moves toward commercial operation in 2025, its success will likely shape the next wave of clean, decentralized energy solutions in California and beyond.