Engineering giant Siemens and Swedish floating wind power start-up SeaTwirl have signed a collaboration deal expected to take the latter’s innovative turbine-plus-storage concept “a big and important step” toward a commercial-scale unit being in the water by 2020.

The “long-term cooperation” will be focused on the technical dimensions of SeaTwirl’s semisubmersible design, which features vertical, angled rotor blades set around a hollow, ring-shaped ‘torus’ that functions as part of a seawater-fed energy storage system.