Flower begins Hamburg's 100 MW battery storage build

Flower has started construction of a 100 MW / 400 MWh battery energy storage system in Hamburg, a project the company says will be the city’s largest battery storage facility. The groundbreaking ceremony took place in Bergedorf on September 9, with regional political and business representatives attending. The project is expected to become operational by the end of 2028.

The four-hour battery system is designed to help stabilize the electricity grid, support more efficient use of renewable energy, and better integrate peaks in wind and solar generation into the energy system. According to the source article, it is also, to the best of current knowledge, the largest BESS located within a major German city.

John Diklev, founder and CEO of Flower, said the start of construction marks a significant step for both the company and the wider energy system in Germany.

"We are thrilled and honored to begin construction on this next chapter for Hamburg’s and Germany’s energy system. I’m grateful for the support of Bergedorf district, Hamburger Energienetze, ENGIE, Hamburg Invest, and all our other key partners in bringing this project from idea to construction", said John Diklev, founder and CEO of Flower.

The project is part of Hamburg’s broader path toward climate neutrality by 2040, as described in the source material. Katharina Fegebank, Second Mayor of Hamburg and Senator for Environment, Climate, Energy and Agriculture, linked the development to the city’s energy transition goals.

"We want to continue driving the energy transition forward in leaps and bounds and become independent of fossil fuel imports. To do this, we need smart solutions and companies that boldly invest in green, future-oriented energy sources", said Katharina Fegebank, Second Mayor of Hamburg and Senator for Environment, Climate, Energy and Agriculture.

"Battery energy storage systems will be a key technology and are currently experiencing a massive global boom. The fact that Flower is taking advantage of Hamburg’s location benefits sends a clear signal to the business community: We are leading the way in Hamburg with a forward-looking energy policy."

Hamburg Invest supported Flower in identifying a site and through the stages leading up to construction, according to the source article. Dr Rolf Strittmatter, Managing Director of Hamburg Invest, said the development also adds to Bergedorf’s role as an innovation location.

"With the start of construction by Flower, Bergedorf is further strengthening its position as a hub for innovation. It demonstrates how international investment and economic development can help drive the location forward", he said.

ENGIE, described as Flower’s long-term project partner, is backing the project through a Flexibility Purchase Agreement (FPA), also referred to as a virtual tolling agreement. Once the battery system is operational, ENGIE will support commercialization of the asset in the German energy market.

"This groundbreaking marks an important step for scalable flexibility infrastructure in Germany. Projects and partnerships like this can help address the four priorities that matter most for industry: energy prices, security of supply, decarbonization, and competitiveness", said Tobias Heyen, Head of Origination Germany at ENGIE.

The Hamburg project is Flower’s largest internally developed BESS project to date. In Germany, the company is developing several other large-scale BESS projects ranging from 6 MW to 100 MW, and its first German assets are set to be commissioned in early 2027. Its publicly announced German BESS portfolio currently totals more than 300 MW.

Outside Germany, the company said it owns four operational BESS sites in Sweden with a combined capacity of 63 MW, while three additional internally developed projects totaling 70 MW are set to become operational by the end of 2026. Flower is also developing large-scale battery projects in the Netherlands, France and Belgium.

Read the source