FlexGen Valuation, Funding & Investors

FlexGen is valued at $754M as of July 2022.

Last FlexGen valuation

$754M

Series C · Jul 2022

Last FlexGen funding round

$100M

Series C · Jul 2022

Cumulative funding FlexGen raised

$276M

across 3 funding rounds

Key investors in FlexGen

FlexGen Overview

About FlexGen

FlexGen is a Durham-headquartered energy storage firm founded in 2009, specializing in HybridOS software and digital controls for utility-scale battery systems. The platform manages fleets from single sites to hundreds, with lifecycle services ensuring system reliability and performance.


Founded

2009

HQ

United StatesDurham, NC

Status

Privately held

Customer focus

B2B

Revenue model

Subscription, Services

Valuation

$754M (Jul 2022)

FlexGen Valuation

FlexGen is currently valued at $754M, based on its Series C in July 2022.

The $100M round was led by Vitol.

FlexGen valuation by funding round

FlexGen valuation by funding round
DateStageValuation
Jul 2022Series C$754M

FlexGen Funding History

FlexGen has raised a total of $276M across 3 funding rounds.

FlexGen's first fundraising round was a $26M Series A in August 2015. The most recent completed round was a $100M Series C in July 2022.

FlexGen funding rounds

FlexGen funding rounds
DateStageInvestorsRaisedValuationDeal Summary
Jul 2022Series CVitol (lead)$100M$754MFlexGen Power Systems is a Durham, North Carolina-based company providing integration services and software technology for battery energy storage systems (BESS), serving utilities, independent power producers (IPPs), and cooperatives with cost-effective, safe, and manageable energy storage solutions to address renewables intermittency and grid stability. On July 19, 2022, FlexGen closed a $100 million Series C funding round anchored by Vitol, the world's largest independent energy trader, in partnership with existing investors including those from its prior $150 million Series B led by Apollo Global Management in 2021. The investment supports execution of FlexGen's large pipeline of large-scale BESS projects across multiple regions and international expansion leveraging Vitol's global footprint, with Vitol also providing optimization services to FlexGen's customers. Vitol, which reported $279 billion in revenues in 2021 and invests in renewable energy assets, views FlexGen as a leader in energy storage solutions essential for carbon reduction targets. CEO Kelcy Pegler emphasized the round's role in powering continued growth and solidifying FlexGen's position in the market. The funding aligns with surging interest in energy storage, as evidenced by peer Powin Energy's $135 million raise shortly before and broader sector funding reaching $17 billion in H1 2022 per Mercom reports. Subsequent funding includes a $75 million line of credit in January 2025, bringing total raised to over $361 million across seven rounds from investors like J.P. Morgan, Caterpillar Ventures, Altira Group, and GE Ventures.
Aug 2021Series BApollo Global Management (lead); Altira Group$150M-FlexGen Power Systems is a leading provider of integration services and software technology for energy storage solutions, supporting deployments of more than 1.2 GWh of systems for utility, microgrid, and commercial & industrial customers in the US and globally since its founding in 2009. The company's HybridOS platform includes energy management applications such as DigitalTwin, FlexPack, SiteController, FleetManager, PowerCloud, and FlexBidr. In late August 2021, funds managed by affiliates of Apollo Global Management announced a $150 million equity commitment to FlexGen, made in partnership with existing investors including Denver-based VC firm Altira Group and the founding investment group led by Jerry Miller and Mark Dreyfus. Other prior investors include Caterpillar Ventures and GE Ventures. Apollo led the round, extending support for FlexGen's energy storage capabilities amid the clean energy transition. FlexGen's CEO Kelcy Pegler stated the financing would accelerate growth and establish bankability for energy storage investments. Apollo highlighted tremendous opportunities in the sector as grids increasingly rely on renewables, positioning FlexGen's expertise favorably. This followed a $100 million Series C round in July 2021 where Altira participated via its Technology Fund VI and a special purpose vehicle. The investment aligns with Apollo's track record in clean energy, including stakes in US Wind, TOPS, AS Graanul Invest, and SPAC deals with Fisker, Sunlight Financial, and Allego. Altira, founded in 1996, has invested over $1 billion in over 60 energy tech companies. Citi acted as financial advisor to FlexGen, with DLA Piper as legal counsel; Vinson & Elkins represented Apollo.
Aug 2015Series AAltira Group (lead); GVenture Technology; Caterpillar Ventures$26M-FlexGen Power Systems is a Houston-based company specializing in hybrid energy storage software and systems that improve performance and reduce costs for energy storage technologies in utility, consumer, industrial power systems, oilfield applications, and power generation markets. The technology enables economic integration of energy storage with power generation assets and has been deployed globally with the U.S. military and in oil and gas operations. In 2015, Altira Group led a $25.5 million Series A financing round, with participation from GE Ventures and Caterpillar Ventures, to accelerate deployment into oilfield and power generation markets worldwide. Altira Group, a Denver-based venture capital firm focused on technology-advantaged oilfield service companies, highlighted FlexGen's proven technology, large markets, and quality management as aligning with their investment strategy through Fund VI, which partners with U.S. super-independent oil and gas companies. These partners provide resources and serve as customers to accelerate portfolio growth. The round built on FlexGen's field-tested solutions offering immediate cost savings, improved operating performance, and reliability for oil and gas partners. FlexGen has since grown significantly, participating in later rounds including a $150 million development capital raise in August 2021 from Altira Group and Apollo Global Management, and a $100 million Series C in July 2022 led by Vitol with Altira participation. By 2022, FlexGen had installed over 3 GWh of energy storage systems across the U.S. for utility, microgrid, and commercial customers. In August 2025, FlexGen acquired key assets and IP from Powin, supporting over 25 GWh across 200 projects in 10 countries, solidifying its leadership in grid-scale energy storage with HybridOS software and lifecycle services.

Who has invested in FlexGen?

5 investors have backed FlexGen across its funding rounds, including Altira Group, Apollo Global Management, Caterpillar Ventures, Vitol and GVenture Technology.

Lead investors include Vitol, Apollo Global Management and Altira Group.


FlexGen Investors

Investors in FlexGen by funding rounds participated
InvestorHQRoundsRoleFirst check
Altira GroupUnited StatesDenver, CO2LeadAug 2015
Apollo Global ManagementUnited StatesNew York City, NY1LeadAug 2021
GVenture TechnologyUnited StatesNew York City, NY1ParticipantAug 2015

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Benchmark 350K+ Funding Rounds and Disclosed VC Valuation Multiples

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Acquisitions by FlexGen

FlexGen has acquired 1 company to date.

Last acquisition by FlexGen was on April 1st 2026. FlexGen acquired Clean Energy Services for undisclosed valuation.


Latest Acquisitions by FlexGen

Clean Energy Services
Description
Clean Energy Services provides operations and maintenance for the renewable energy sector.
HQ CountryUnited States
HQ City
Houston, TX
Deal Date1 Apr 2026
Valuationundisclosed
EV/Revenue
EV/EBITDA

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FlexGen Competitors

FlexGen competitors include listed companies like ZUKEN and GuoChuang Software, and private ones like 24M Technologies, Rescale, Tractian and Zhejiang Hechuan Technology.

Public and private companies comparable to FlexGen
CompanyHQStatusRevenueEBITDAValuationRevenue Multiple
24M TechnologiesUnited StatesUnited StatesPrivate--$1.3B-
RescaleUnited StatesSan Francisco, CAPrivate--$750M-
TractianUnited StatesUnited StatesPrivate--$720M-
Zhejiang Hechuan TechnologyChinaQuzhouPrivate$149M-$812M5.4x
ZUKENJapanJapanPublicly listed$277M$51M$679M1.7x
GuoChuang SoftwareChinaChinaPublicly listed$220M($17M)$960M-

FlexGen Public Comps

FlexGen is still privately-owned, but its public comps include Breton Technology, Energy Vault, Hyliion, Shenzhen Sunwin, ZUKEN, PSI Software, ADS-TEC Energy, Shenzhen Tianyuan Dic, WIP Terminal and Enovix.

Last FYEV/RevenueEV/EBITDA
RevenueEBITDALast FYLTM2027ELast FYLTM2027E
Breton Technology$116M($37M)7.1x4.7x(22.1x)(68.3x)
Energy Vault$204M($83M)4.6x3.6x(11.4x)(46.2x)
Hyliion$3M($60M)192.1x60.8x(11.2x)(13.9x)
Shenzhen Sunwin$20M($147M)37.7x-(5.0x)-
ZUKEN$277M$51M1.6x1.7x8.9x-
PSI Software$329M($7M)2.6x2.5x(127.4x)51.0x
ADS-TEC Energy$36M($3M)23.2x26.7x(278.0x)-
Shenzhen Tianyuan Dic$1.4B$42M0.9x-28.6x-

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Common questions about FlexGen

When was FlexGen founded?FlexGen was founded in 2009.
Where is FlexGen headquartered?FlexGen is headquartered in Durham, NC, United States.
Is FlexGen publicly listed?No, FlexGen is a private, VC-backed company.
What is FlexGen's valuation?FlexGen was last valued at $754M in its Series C in July 2022.
How much funding has FlexGen raised?FlexGen has raised $276M across 3 funding rounds.
What was FlexGen's last funding round?FlexGen's last funding round was a $100M Series C in July 2022, led by Vitol.
Who are FlexGen's investors?FlexGen's investors include Altira Group, Apollo Global Management, GVenture Technology, Caterpillar Ventures and Vitol.
Which companies are comparable to FlexGen?Companies comparable to FlexGen include 24M Technologies, Rescale, Tractian, Zhejiang Hechuan Technology, ZUKEN and GuoChuang Software.
How many companies has FlexGen acquired?FlexGen has acquired 1 company, including Clean Energy Services.

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