Macquarie Asset Management and Infrastructure Funds Target BESS Platforms in Europe

Enel, RWE and Iberdrola rank among the first major European energy groups to invest in battery storage, known as BESS (Battery Energy Storage Systems), over a decade ago. These utilities mobilized their corporate balance sheets and internal capabilities — engineering, project construction, electricity market trading and asset management — to develop and operate the first generation of such projects. Their motivations at that time were strategic and technical in nature rather than commercial, according to sector analyses.

Battery storage becomes an asset class for private institutional capital

This pioneering presence of major utilities enabled battery storage to establish itself as an asset class accessible to private institutional capital. Infrastructure funds are now acquiring or creating large-scale BESS development platforms equipped with advanced market optimization capabilities. By leveraging nimble operators focused on optimization, these financial sponsors are accelerating the institutionalization of the sector and its expansion in still-fragmented markets.

Sponsors typically acquire stakes in developer platforms to access their project portfolios. They then provide construction financing or "brown-to-green" financing — aimed at converting existing assets or sites toward low-carbon uses — to develop the portfolio assets. This combined approach enables access to project pipelines while financing their large-scale development.

Macquarie Asset Management acquires Island Green Power in the United Kingdom

The acquisition of Island Green Power by Macquarie Asset Management, completed in May 2025, is a representative example of this trend. Island Green Power is a British developer of solar and BESS projects. This transaction illustrates the strategy through which large-scale infrastructure funds are acquiring developer platforms to accelerate their battery storage expansion in the United Kingdom.

The European BESS market, characterized by its fragmentation, is attracting institutional capital seeking platforms that offer optimization and market engagement capabilities. Infrastructure funds are no longer limiting themselves to financing individual projects but are targeting integrated platforms combining development, construction and operation. The pioneering investments by Enel, RWE and Iberdrola thus laid the groundwork for a market that institutional financial actors are now helping to structure on a broader scale.