FlexGen was founded in 2009 and is headquartered in Durham, North Carolina. FlexGen enables utility scale battery storage while expediting grid reliability and sustainability. Their HybridOS digital control system is preconfigured before being installed on every project, ensuring utilities have intelligent, optmized control of their battery fleets.

Since its founding, FlexGen has installed over 6 GWh of energy storage systems across the U.S. for utilities, electric cooperatives, and C&I customers.

On July 2022, FlexGen announced the close of a $100 million Series C Investment round. The investment is anchored by Vitol. This investment further positions FlexGen as one of the leaders in energy storage integration, and will support the execution of its pipeline of projects.

FlexGen delivers utility-scale storage projects integrated with traditional and renewable power generation globally. Their clients and partners include developers, utilities, government agencies and industrial companies across the globe. They provide a variety of solutions:

• Energy Management System (EMS), to control energy storage assets
• Battery Energy Storage Systems (BESS), fully integrated Battery, Power Electronics and EMS
• EPC Solutions, FlexGen designs, procures, constructs and integrates the BESS project
• Development Services, FlexGen performs use case analysis and ESS sizing and configuration
• Operational Services, FlexGen can provide the HybridOS software, remote support, operational support and preventative maintenance

In this way FlexGen works as an integrator in the utility-sale energy storage space, providing hardware, software and development of energy storage solutions.

The software is core to the solution they provide, FlexGen HybridOS is an energy management system with digital controls that is designed to dispatch renewable and conventional power generation with energy storage systems to provide intelligent control of clean energy. Their latest version of their software was released in 2023, the HybridOS 11,for utility, power generation, and industrial customers.

FlexGen also provides LifeCycle Services after commissioning, providing the tools and services needed to maintain the asset’s performance. With this solution FlexGen enables:

• Monitoring: 24/7 monitoring to view and chart site performance data, notifying if anything requires attention.
• Support: FlexGen's remote support and 24/7 Remote Operations Center operations team at disposition.
• Maintenance: FlexGen's maintenance professionals keep storage assets performing at their peak.

On December 2024, FlexGen has signed a joint development agreement (JDA) with Eos Energy Enterprises to develop and commercialise a fully integrated BESS solution using Eos’ zinc batteries and Flexgen’s EMS. This solution will combine Eos’ Z3 zinc-based long duration energy storage (LDES) systems, a US inverter and transformer package, with FlexGen’s HybridOS EMS.

FlexGen offers a service based pricing structure. They work directly with IPPs, Developers and Utilities to help drive down overall project costs and increase project returns. They apply their technical and battery supply chain expertise to enable project owners to procure direct from OEM's. This enables project owners to remove all unnecessary margin stack that would otherwise exist in typical EPC procurements.

FlexGen's HybridOS Energy Management System has been developed over the past 10 years. FlexGen’s proprietary storage database includes 9 years of operating data and performance metrics on over 20 different types of energy storage.

It is FlexGen's combination of proven EMS software and business model that sets them apart from other solutions. Among these differences:

• FlexGen is hardware agnostic, working with multiple vendors to provide optimal solutions per project.
• Integrating hardware and software, they meet full range of operational and commercial demands across the li-ion value chain.
• Have active market participation
• Enables EPC margin de-stacking and lower client investment costs
• Customized and flexible procurement

Primary applications are standalone storage, utility-scale solar + storage, gas peaker + storage, C&I, and industrial microgrids.

The FlexGen HybridOS can control various power system assets including:

• Energy Storage Systems (ESS) FlexGen HybridOS is capable of managing any commercially available battery energy storage system (ESS). These systems primarily use lithium-ion battery based energy storage, and are capable of delivering rated power for a duration of 20 minutes to 4 hours. The ESS will consist of a controller that coordinates the power converter system (PCS) with the battery management system (BMS) to provide the single high-level interface to FlexGen HybridOS. These ESS will normally provide direct command functions for active and reactive power and may include other service modes that can be utilized by FlexGen HybridOS either on grid or off.

• Solar PV Systems These solar PV systems include string or central type solar inverters coupled with appropriately sized PV panel fields. The solar inverter itself typically provides the control interface to FlexGen HybridOS and automatically manages solar-specific functionality such as maximum power point tracking (MPPT). Other functions, such as tracking axis adjustment or meteorological data collection may be performed by other autonomous controllers and associated with a given solar system within FlexGen HybridOS.

• Feeders (Utility and Asset-specific) Within FlexGen HybridOS, a feeder includes a power meter and/or protective relay and may optionally represent a circuit breaker with the appropriate protective relay associated. When only a power meter is present, the feeder is used to monitor the power flow in the branch as an input to other functions or metrics. When a protective relay and circuit breaker is associated, the feeder may represent a true utility feed, aggregate downstream load or a bus tie between generation and/or loads. Relay functions such as dead-bus checks, synchro checks, reverse power disconnect, under/over voltage and frequency disconnects and others are handled by the protective relay, and HybridOS makes use of open/close permissives to sequence the energization or de-energization of a site.