Tidewater: Long-duration storage for coastal grids

Tidewater makes iron-air battery systems for grid operators along the Norwegian and North Sea coast, where offshore wind output can swing sharply from one day to the next. Each installation stores energy for up to 100 hours, long enough to carry a regional grid through a calm spell, and uses materials that are cheap and widely available.

Ingrid and Erik had spent a decade in the Norwegian energy sector before starting the company. We invested in the seed round in 2016, when Tidewater was eleven people and a test cell in a borrowed workshop. Clara joined the board that year and helped recruit its first head of manufacturing.

The company listed on Oslo Børs in 2024 with 1.4 gigawatt-hours of storage under contract across Norway, Denmark and Scotland. We remain one of its larger shareholders.