What Fullmark Energy does

Fullmark Energy is a Chicago-based independent power producer (IPP) that develops, finances, builds, owns, and operates standalone grid-scale battery energy storage system (BESS) projects across the United States. Founded in 2018 and originally incubated within Hecate Energy as Hecate Grid, the company was launched as a joint venture with InfraRed Capital Partners — an international infrastructure asset manager with approximately $13B in equity capital under management — and rebranded to Fullmark Energy in May 2025 to reflect its evolution into a fully integrated storage developer-owner-operator. Its operational Redwood Projects portfolio totals 125MW/290MWh across four lithium iron phosphate (LFP) facilities in Southern California (Johanna ESS, Desert-Carris, Ortega, and San Jacinto), with the 65MW/130MWh San Jacinto facility reaching commercial operations in November 2025 and completing the portfolio. The company maintains a 4GW development pipeline spanning California, Texas, and the Mid-Atlantic region.

The company's core technology stack centers on lithium iron phosphate (LFP) battery chemistry for grid-scale storage, complemented by the proprietary Medea dispatch platform, which provides minute-by-minute optimization of energy storage assets across the portfolio and is paired with TWAICE battery analytics for predictive monitoring. Operations are supported by a 10-year long-term service agreement with Mitsubishi Power Americas on the Johanna facility and participation in the CAISO market, where projects earn revenue through energy arbitrage, frequency regulation, and resource adequacy capacity.

Fullmark's revenue model is multi-stream. Operating revenue is generated by selling grid services into CAISO and via direct offtake to utilities and community choice aggregators, including Southern California Edison, Clean Power Alliance, and the City of Banning Municipal Electric Utility. The company also monetizes Investment Tax Credits via transfers enabled by the Inflation Reduction Act — completing a $46M ITC transfer for the Redwood Projects portfolio in November 2025 — and secures project-level debt facilities, including a $100M consolidated term loan and letter of credit facility (January 2023) and a $125M Letter of Credit facility with MUFG (August 2024). The go-to-market is enterprise field sales targeting utilities, electric cooperatives, public power entities, and institutional investors, with no standardized public pricing. The company is privately held and headquartered at 600 W Fulton St, Suite 510, Chicago, Illinois.

Name

Fullmark Energy

Legal name

Hecate Grid LLC

Website

https://fullmarkenergy.com

Company type

Private

Founded year

2018

Operating status

Operating

Headcount range

11–50 employees

Short description

Fullmark Energy is a Chicago-based independent power producer that develops, owns, and operates standalone grid-scale battery energy storage systems. The company serves utilities, electric cooperatives, and community choice aggregators, with 125MW operational capacity and a 4GW development pipeline.

Ownership category

akta.pro rank

Product category

Grid-Scale Battery Energy Storage

NAICS

Electric Power Generation (22111), Electric Power Generation, Transmission and Distribution (2211), Electric Power Transmission, Control, and Distribution (22112)

SIC

Electric Services (4911), Cogeneration Services & Small Power Producers (4991)

akta.pro primary industry

Utility-Scale BESS Project Development & Ownership (IPP/Developer) (EUAFAAAA)

akta.pro secondary industries

BESS Operations, Maintenance & Asset Performance Management (APM) (EUAFAAAG), BESS Market Participation & Trading Services (Ancillary/Capacity/Arbitrage) (EUAFAAAL), Energy Storage (BESS) Monitoring, Control & Optimization (EUADAPAG), BESS Financing, Insurance & Contracting (Tax Equity, PPA/Tolling, Warranties) (EUAFAAAI)

Keywords

• Battery energy storage
• Grid-scale storage
• Independent power producer
• Utility-scale batteries
• Energy storage development

Headquarters

HQ city

Chicago

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

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

Revenue model

1. Grid Services Revenue: Revenue generated from participation in CAISO market providing critical grid services including energy arbitrage, frequency regulation, and resource adequacy capacity. The company sells electricity and grid services to utilities and grid operators.
2. Investment Tax Credit (ITC) Transfer: Monetization of Investment Tax Credits through transfer transactions to buyers in the industrial sector, enabled by the Inflation Reduction Act. Fullmark transferred $46M in ITC for the Redwood Projects portfolio.
3. Project Financing: Fullmark Energy secured financing through various debt facilities including a $100M consolidated term loan and letter of credit facility (January 2023) for Redwood Projects, and a $125M LC facility with MUFG for interconnection and offtake security.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels3 records

Core offering

Fullmark Energy is an independent power producer that develops, finances, builds, owns, and operates standalone, utility-scale battery energy storage system (BESS) projects across the United States. It monetizes these assets by providing wholesale grid services—including energy arbitrage, frequency regulation, and resource adequacy capacity—through direct offtake agreements with utilities and community choice aggregators, and by participating in the CAISO market, using its proprietary Medea Dispatch Platform for minute-by-minute optimization.

Product overview

Fullmark Energy is an independent power producer focused exclusively on developing, building, owning, and operating grid-scale battery energy storage system (BESS) projects. The company offers a portfolio of operational energy storage assets including the Johanna ESS (20MW/80MWh), Desert-Carris (20MW/40MWh), Ortega (20MW/40MWh), and San Jacinto (65MW/130MWh) projects, collectively known as the Redwood Projects portfolio totaling 125MW/290MWh. Operations are managed through the company's proprietary Medea dispatch platform for minute-by-minute optimization. The company has a 4GW development pipeline across multiple U.S. markets including California, Texas, and the Mid-Atlantic region, with planned projects including the 80MW Chiquito facility in California, 500MW Ramsey facility, and 250MW East Valley project in Texas. Projects participate in CAISO market providing grid services including energy arbitrage, frequency regulation, and resource adequacy.

Differentiator

Problem solved

Functional benefit

Products and services

• Johanna Energy Storage System (ESS) A 20MW/80MWh grid-connected, standalone energy storage facility in Santa Ana, California. Designed to reduce grid congestion by enabling utilities and community choice aggregators to save excess power from renewable generation for up to four hours, allowing clean energy to be deployed at peak times.
• Desert-Carris Energy Storage Project A 20MW/40MWh standalone battery energy storage facility located in Palm Springs, California, operating in the CAISO wholesale power market. Provides grid services including energy arbitrage, frequency regulation, and resource adequacy capacity to Southern California Edison's distribution system.
• Ortega Energy Storage Project A 20MW/40MWh standalone battery energy storage project located in Lake Elsinore, California. Provides energy arbitrage, frequency regulation, and resource adequacy in the CAISO market, with a sensitive design approach meeting landowner and California Department of Fish & Wildlife wetland conservation standards.
• San Jacinto Energy Storage Project A 65MW/130MWh standalone battery energy storage facility in Banning, California, and the final asset in the Redwood Projects portfolio. Serves the City of Banning Municipal Electric Utility and provides grid services through CAISO market participation.
• Redwood Projects Portfolio A strategic collection of four standalone battery energy storage facilities totaling 125MW/290MWh across Southern California, including Johanna ESS (20MW/80MWh), Desert-Carris (20MW/40MWh), Ortega (20MW/40MWh), and San Jacinto (65MW/130MWh). The portfolio approach reduces single points of failure through geographic distribution and strengthens revenue profiles through diversified offtake agreements.
• Medea Dispatch Platform Fullmark Energy's proprietary dispatch optimization platform used for minute-by-minute optimization of energy storage operations across the company's project portfolio. Enables long-term asset management, performance optimization, CAISO market participation, and safe, reliable operations of utility-scale BESS assets.

Quantifiable outcome

• 125MW/290MWh operational capacity across 4 facilities in Southern California
• +3 more outcomes

Named customers3 records

Segments5 records

Ideal customer profiles3 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

AI capability1 record

Feature2 records

Partnerships

Six partnerships are on record, tiered partner, historical/parent, core and key customer.

• TWAICEpartnerTechnology or Integration · 7 November 2025Battery analytics partner mentioned as stakeholder participant in San Jacinto ribbon-cutting ceremony. TWAICE provides predictive analytics and optimization software for battery energy storage systems.
• Active Engineering ServicespartnerImplementation/ SI/ Consulting Partner · 20 August 2025Engineering services firm providing erosion control and stormwater pollution prevention plan (SWPPP) services across multiple Fullmark Energy projects. Led by Robert Rineer, PE, Director of Operations and Principal Engineer.
• Hecate Energyhistorical/parentStrategic or Co-development Partner · 18 June 2024Fullmark Energy was originally incubated within Hecate Energy, a leading renewable energy developer. The company rebranded from Hecate Grid to Fullmark Energy in May 2025. Previously operated as a joint venture between Hecate Energy and InfraRed Capital Partners.
• Mitsubishi Power AmericascoreTechnology or Integration · 30 September 2021Technology provider for Johanna ESS facility with a 10-year long-term service agreement to service the battery energy storage system. Mitsubishi Power Americas provides specialized, turn-key battery systems and ongoing maintenance support.
• Southern California Edisonkey customerOthers · 30 September 2021Major California utility and preferred resource pilot program participant. Edison International subsidiary has signed contracts to utilize energy from Johanna ESS batteries and participated in project ribbon-cutting ceremony.
• Clean Power Alliancekey customerOthers · 30 September 2021Community choice aggregator serving customers with renewable energy, partnering with Fullmark Energy on Johanna ESS to fill the missing piece of the clean energy puzzle: storage.

Scale indicators9 records

Recent moves7 records

Expansion highlights5 records

Direct peers

• esVolta: Standalone battery energy storage developer/operator with operational assets in California and other Western U.S. markets. Comparable pure-play BESS IPP that was acquired by BP, illustrating the M&A potential for Fullmark.
• Jupiter Power: Independent power producer focused exclusively on utility-scale standalone battery energy storage in U.S. markets. Direct comparable as a pure-play BESS IPP with operational capacity in multiple ISOs and similar financing structures.
• GlidePath Power Solutions: Developer and operator of standalone battery energy storage projects; CEO Chris McKissack led GlidePath for a decade before joining Fullmark. Direct strategic comparable with overlapping technology and customer base.
• Plus Power: Pure-play standalone BESS developer and operator with operational projects across multiple U.S. states including California. Closely comparable as a utility-scale battery storage-only IPP competing in the same CAISO and ERCOT markets.

Broad incumbents

• Tesla Energy (Megapack): Vertically integrated BESS manufacturer and project developer using LFP chemistry. Competes in the same utility-scale standalone storage market with proprietary hardware and software stack.
• Fluence Energy: Global energy storage technology provider and IPP offering both integrated hardware/software solutions and own-developer projects. Broader incumbent serving similar utility customers with overlapping storage offerings.
• Clearway Energy: Publicly traded yieldco with utility-scale renewable and battery storage operating portfolio. Comparable utility-scale IPP model with similar long-term offtake structures and grid services revenue.
• AES Clean Energy: Large-scale renewable and storage IPP with multi-GW battery storage portfolio in California and other U.S. markets. Broader incumbent with similar utility offtake customers and CAISO exposure.

Emerging players

• Stem Inc: AI-driven clean energy storage and software provider combining software optimization with behind-the-meter and front-of-meter storage assets. Adjacent in technology (optimization) and storage, but commercially more focused on C&I behind-the-meter.

Others

• Hecate Energy: Original incubator of Fullmark (formerly Hecate Grid). Solar and storage developer with overlapping management history, EPC ecosystem relationships, and U.S. renewable project development expertise.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights7 records

Customer concentration

Revenue estimate

Valuation estimate

Number of profiles

Profiles6 records

Funding overview

Funding rounds

Investors

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 Fullmark Energy