Photon Vault

What Photon Vault does

Photon Vault Inc. is a California-based, privately held energy storage startup founded in 2019 that has developed a grid-scale thermal energy storage system for the 4–100 hour long-duration storage market. The system stores heat energy in a custom-engineered composite material bank, sourced from solar thermal power or industrial waste heat, and discharges by converting the temperature gradient into a pressure gradient that drives a standard generator — functionally described by the company as "running a refrigerator backwards." The two proprietary elements are the heat generation process and the composite storage media, both of which are patented (with additional patents pending); every other component, including the generator and solar heat collector, is off-the-shelf.

The company's commercial target is utility and grid operators seeking a cheaper, cleaner, and safer alternative to lithium-ion batteries for multi-hour to multi-day storage, with industrial waste heat recovery as a secondary use case. The system claims durability advantages (no cycle-to-cycle degradation) and economic advantages (outputs more electricity than it pulls from the grid, per company materials), supported by a partner ecosystem that includes Oncor, Quanta Services, Fluor, Southwest Research Institute, and Ascend Analytics. Photon Vault has not disclosed pricing and is not yet commercial; its own careers page states the company is "preparing to build our first full-scale system."

The business is pre-revenue with 1–10 employees, founder-led by CEO Kent McCormick (PhD Physics, UC Berkeley; previously co-founded Lattice Engines, acquired by Dun & Bradstreet in 2019). Financial backers include Conifer Infrastructure Partners, New Leaf Genesis Fund, Houston Angel Network, Wilson Sonsini, and rpv global. In 2025 the company proposed a 24/7 Renewable Power Purchase Agreement in California as its first commercial market entry.

Name

Photon Vault

Legal name

Photon Vault Inc.

Website

https://photonvault.com

Company type

Private

Founded year

2019

Operating status

Operating

Headcount range

1–10 employees

Short description

Photon Vault is a California-based thermal energy storage startup developing a grid-scale system that stores heat in a proprietary composite material and converts it to electricity via standard generators, targeting the 4–100 hour long-duration storage market for utility and industrial customers.

Ownership category

akta.pro rank

Headquarters

HQ city

San Ramon

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Technology or R&D, Supply Chain, Infrastructure, Personnel, Marketing or Sales

Distribution channels1 record

Marketing channels3 records

Core offering

Photon Vault provides grid-scale thermal energy storage systems that bank heat in a proprietary custom-engineered composite material and convert the resulting temperature gradient into a pressure gradient that drives a standard generator. The system ingests heat from solar thermal power or industrial waste heat and targets the 4–100 hour duration storage market, competing with lithium-ion batteries for renewable integration applications. The offering combines a patented storage media, a patented heat generation process, and an off-the-shelf solar collector and generator assembly.

Product overview

Photon Vault Inc. offers a single unified product: the Photon Vault™ thermal energy storage system. This grid-scale solution consists of three main components that work together as an integrated system — a proprietary thermal energy storage media (custom-engineered composite material), a solar heat collector for harvesting thermal energy, and a conversion mechanism that transforms temperature gradients into electricity via a standard generator. The system is designed specifically for the 4-100 hour duration energy storage market, positioning it as an alternative to lithium-ion batteries for longer-duration applications where the company claims it is cheaper, cleaner, and safer.

Differentiator

Problem solved

Functional benefit

Products and services

• Photon Vault™ Thermal Energy Storage System

Quantifiable outcome

• Outputs more electricity than it pulls from the grid

Segments2 records

Ideal customer profiles2 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature3 records

Partnerships

Nine partnerships are on record, tiered minor and core.

• CyntergyminorStrategic or Co-development PartnerPartner listed on the Investors and Partners page. Cyntergy appears to be an energy consulting or technology firm.
• OncorcoreStrategic or Co-development PartnerPartner listed on the Investors and Partners page. Oncor is a major Texas electricity transmission and distribution utility.
• Quanta ServicescoreStrategic or Co-development PartnerPartner listed on the Investors and Partners page. Quanta Services is a leading provider of infrastructure services for the energy industry.
• WintonminorStrategic or Co-development PartnerPartner listed on the Investors and Partners page. Winton is a research-based investment and trading firm.
• Foundry Solutions & DesignminorImplementation/ SI/ Consulting PartnerPartner listed on the Investors and Partners page. Foundry Solutions & Design appears to be an engineering and design consultancy.
• io consultingminorImplementation/ SI/ Consulting PartnerPartner listed on the Investors and Partners page. io consulting is an infrastructure and operations consulting firm.
• New Mexico Clean Energy Resilience and Growth ClusterminorStrategic or Co-development PartnerPartner listed on the Investors and Partners page. A regional clean energy cluster initiative in New Mexico.
• FluorcoreStrategic or Co-development PartnerPartner listed on the Investors and Partners page. Fluor is a major global engineering, procurement, and construction company.
• Clean Tech OpenminorGTM or Marketing PartnerPartner listed on the Investors and Partners page. Clean Tech Open is a clean technology accelerator and competition organization.

Recent moves6 records

Expansion highlights5 records

Direct peers

• Form Energy: Form Energy develops iron-air battery systems specifically targeting 100+ hour grid storage, competing head-to-head with Photon Vault for utility long-duration storage procurement.
• Energy Vault: Energy Vault offers gravity- and hybrid-based long-duration energy storage systems for utility-scale deployments. It competes directly with Photon Vault for the 4-100 hour duration storage customer base and project pipeline.
• Brenmiller Energy: Brenmiller Energy produces thermal energy storage systems based on crushed rock and other solid media for industrial and utility customers, closely matching Photon Vault's solid-media thermal storage approach.
• Antora Energy: Antora Energy builds grid-scale thermal energy storage using solid carbon blocks charged by renewable electricity and discharged as heat and electricity. It is the most directly comparable competitor to Photon Vault, addressing the same long-duration thermal storage market for utility and industrial customers.
• Malta Inc. Malta builds pumped heat thermal energy storage systems using molten salt and antifreeze-like fluids. It competes directly with Photon Vault in long-duration thermal storage for grid applications.
• Kraftblock: Kraftblock manufactures a high-temperature recycled steel slag thermal storage medium for industrial and grid-scale applications, directly comparable to Photon Vault's proprietary solid composite media.
• Highview Power: Highview Power develops liquid air energy storage (LAES) plants for grid-scale long-duration storage. It targets the same utility long-duration storage market as Photon Vault, albeit with a different storage medium.

Broad incumbents

• Fluence Energy: Fluence is a leading global provider of grid-scale energy storage software and hardware solutions. As a broad incumbent, it competes with Photon Vault for utility storage procurement and project pipelines.
• Tesla Energy (Megapack): Tesla's Megapack business is the dominant incumbent in grid-scale battery storage. While it focuses on lithium-ion 4-hour systems, its scale and customer relationships set the competitive benchmark Photon Vault must meet.

Emerging players

• BrightSource Energy: BrightSource develops concentrated solar power (CSP) and thermal storage systems for utility-scale solar generation. It overlaps with Photon Vault's solar-thermal charging pathway and thermal storage medium.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat3 records

Key risks6 records

Key highlights7 records

Customer concentration

Revenue estimate

Valuation estimate

Number of profiles

Profiles11 records

Funding overview

Funding rounds1 record

Investors1 record

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Photon Vault