Return's Pooled Battery Portfolio Anchors First Centrica Energy Partnership in Germany

Amsterdam-based battery storage developer Return has structured its first formal agreement with Centrica Energy around a portfolio model that avoids tying contracted capacity to any single installation, the two companies confirmed on September 21, 2026. The long-term Virtual Tolling deal covers 100 MW and 400 MWh of battery storage flexibility drawn from Return's network of physical assets across Germany.

How the Virtual Flexibility Portfolio Works

At the centre of the arrangement is what Return calls its Virtual Flexibility Portfolio, a structure that aggregates capacity from multiple Return-owned battery energy storage systems operating across Germany. Rather than committing Centrica Energy to the output of one dedicated battery project, the agreement gives the company access to pooled capacity spread across a wider set of physical assets. Both parties describe this design as providing greater diversification and resilience.

The contracted 400 MWh remains underpinned by physical battery infrastructure, but the ability to draw from across the portfolio means performance is not dependent on any single site. Sjoerd Bazen, Managing Director at Return, said the structure was built specifically to enable this kind of flexibility at scale.

"This agreement demonstrates how our Virtual Flexibility Portfolio can provide an offtaker with access to flexibility across a broader portfolio of physical assets rather than relying on one dedicated battery," he said. "That foundation allows Centrica to click in additional flex capacity as required."

Complementary Roles for Each Partner

The two companies have divided responsibilities along lines each describes as playing to distinct strengths. Return retains ownership and operational management of the underlying battery assets. Centrica Energy takes on the role of commercialising the flexibility through its multi-market optimisation service, participating across wholesale markets and ancillary services in Germany.

Cassim Mangerah, Managing Director of Centrica Energy, pointed to the resilience advantages of accessing 400 MWh spread across a portfolio rather than concentrated at one location. "Flexibility is what makes a renewable-led system work, and this innovative agreement with Return helps bring more of it to the German market," he said. "Scaling it in Europe's largest power market is part of how we energise a greener, fairer future."

Germany's Growing Demand for Fast-Responding Storage

The agreement is framed against the context of Germany's expanding renewable energy base, which is intensifying the need for resources capable of responding quickly to imbalances between generation and consumption.

Battery storage is positioned to help the system absorb larger volumes of wind and solar power by bridging the gap between when electricity is produced and when it is needed. The Virtual Tolling structure is intended to provide a scalable mechanism for meeting that need.

As Return continues to develop its German portfolio, the agreement allows additional capacity to be incorporated without requiring a separate contract for each new project, giving Centrica Energy a path to grow its access as the underlying asset base expands.

Return's Recent Flurry of European Partnerships

The Centrica deal arrives during a concentrated period of announcement activity for Return. One week earlier, on September 14, 2026, the company disclosed an expansion of its existing flexible battery storage partnership with ENGIE in Germany to 400 MW.

On the same date, Return confirmed it had reached financial close on what it described as Spain's largest standalone battery storage portfolio. Prior to those announcements, Return and Vattenfall signed a long-term agreement on August 31, 2026, tied to the Sirius project reaching financial close.

In July 2026, Return and ENGIE had signed a ten-year agreement directed at accelerating battery storage development in Spain. The Centrica Energy partnership represents the first time the two companies have entered a formal agreement. Both have indicated the Virtual Tolling structure is designed to grow alongside Return's German asset portfolio, with the capacity accessible to Centrica able to increase as new projects are added to the network.