Partners Group investing €400 million in German BESS platform ‘green flexibility’

LinkedIn
Twitter
Reddit
Facebook
Email

Private equity firm Partners Group has invested in ‘green flexibility’, a BESS platform in Germany, with an initial equity commitment of €400 million (US$411 million).

With the equity commitment and complementary debt financing, green flexibility will have over €1 billion to invest in its pipeline of battery energy storage system (BESS) projects in Germany, some of which are already under construction.

The firm specialises in developing and operating large-scale BESS for stabilising the grid and reducing curtailment, and it aims to establish itself as a leading independent flexibility provider (IFP) by monetising its storage capacity through long-term contracts. It said it will benefit from growth trends in Germany, which now has 100GW of PV online and aims to more than double that by 2030.

Green flexibility was founded by CEO Christoph Ostermann. He was one of the founders of sonnen, the virtual power plant (VPP) aggregator where he spent ten years until 2021, and is also on the board of numerous Germany clean energy technology firms including solar PV manufacturer 1KOMMA5 and flexibility services provider Esforin.

This article requires Premium SubscriptionBasic (FREE) Subscription

Enjoy 12 months of exclusive analysis

Not ready to commit yet?
  • Regular insight and analysis of the industry’s biggest developments
  • In-depth interviews with the industry’s leading figures
  • Annual digital subscription to the PV Tech Power journal
  • Discounts on Solar Media’s portfolio of events, in-person and virtual

Or continue reading this article for free

Commenting on the deal, Ostermann said: “Long-term reliability, the highest safety standards, and the
best technology are critical—because the energy transition needs stability and dependability. And for this, we have assembled the most experienced team in the market.”

The firm’s commercialisation strategy appears similar to that which is conventional in the Dutch market, where BESS projects are rented out in slices to different parties to use that flexibility (explained in a recent Premium article).

Shift in profile of owner-operators in German BESS market

The announcement speaks to an evolution and maturation in the types of companies driving the deployment of large-scale BESS projects in Germany.

When Energy-Storage.news did a deep-dive into the German BESS market in 2022, the main companies that had deployed or were building large-scale BESS were legacy utilities and independent power producers (IPPs) like RWE and LEAG. A big challenge highlighted by one market source back then was simply a lack of companies investing in and building BESS.

Since then, clean energy developer-operators like Gore Street Capital, Aquila Clean Energy, Nofar Energy have entered the market while new, BESS specialists like green flexibility, Eco Stor, and Terralyr have entered the scene too. Eco Stor has been around for several years, but only recently shifted to owning its own operational projects, having mainly done engineering, procurement and construction (EPC) previously.

The German market is also evolving in numerous other ways. In a recent post on LinkedIn post, system integrator Fluence’s Lars Stephen pointed to the first GWh-scale projects soon coming online, 4-hour systems coming to market, saturating still not hitting the market and DSOs increasingly opting for BESS as four major trends for 2025.

2 December 2025
NH Collection Vittorio Veneto, Rome, Italy
Across two packed days, the Summit focused on three core themes: revenue & trading, the lifecycle of the battery, and optimisation tools. Attendees explored innovative strategies for enhancing asset performance and longevity, with a spotlight on key markets like Germany, Italy, and the UK. Stay tuned for details on the 2025 edition of the Battery Asset Management Summit Europe, where we’ll continue to chart the path forward for energy storage asset management.
24 February 2026
InterContinental London - The O2, London, UK
This isn’t just another summit – it’s our biggest and most exhilarating Summit yet! Picture this: immersive workshop spaces where ideas come to life, dedicated industry working groups igniting innovation, live podcasts sparking lively discussions, hard-hitting keynotes that will leave you inspired, and an abundance of networking opportunities that will take your connections to new heights!

Read Next

October 3, 2025
BESS provider Sungrow and power firm Engie have connected the first phase of a 400MW/800MWh project, one of the largest in Europe, to the grid in Belgium.
October 2, 2025
The TSO of Italy has completed its first MACSE auctions for energy storage, procuring 10GWh of capacity at what the NHOA CEO called ‘exceptionally competitive prices’.
October 1, 2025
Power firm VPI has signed a 700MW pipeline BESS joint venture in Germany with developer Noveria Energy, while system integrator ADS-TEC has revealed a 1GW/2GWh project.
Premium
September 30, 2025
We catch up with executives from second life specialist BESS integrator Voltfang and investor Palladio Partners to discuss their recent €250 million (US$293 million) partnership to deploy projects in Germany.
September 30, 2025
The power markets of Europe continue their shift to 15-minute settlement periods today (30 September), a reform which could increase the revenue opportunities for energy storage and other flexibility resources.

Most Popular

Email Newsletter