Germany | Residential Battery Storage Pioneer Sonnen Files for Insolvency

October 22, 2026-

German residential battery storage manufacturer sonnen GmbH has filed for insolvency, marking a major development in Europe’s home energy storage market. The company confirmed the filing after informing approximately 400 employees at its headquarters in Wildpoldsried, Bavaria, according to German business daily Handelsblatt.

The insolvency comes around two months after Shell sold sonnen to Tiven, an investment vehicle associated with investor Gert Purkert. The company had faced prolonged financial pressure, with revenue falling sharply in 2024 despite previous efforts to reduce costs and improve profitability.

According to Handelsblatt, sonnen’s revenue declined from €443 million in 2023 to €198.9 million in 2024. Its earnings before interest, taxes, depreciation and amortization (EBITDA) stood at a loss of €188.7 million in 2024. Cost-cutting measures reportedly reduced the EBITDA loss to €52.2 million in 2025, but the company remained financially challenged.

Despite the insolvency filing, existing business operations and customer service are expected to continue for more than 150,000 customers. However, several subsidiaries may be wound down or enter insolvency proceedings under self-administration, while the group’s international operations face restructuring.

The case highlights the financial challenges facing established European residential storage manufacturers amid intensifying competition, pricing pressure and the growing presence of Asian suppliers. It also underscores the difficulty of translating strong demand for home battery storage into sustainable profitability.

The future structure of sonnen’s European operations and the continuity of services for existing customers remain key issues to watch as the restructuring proceeds.