A 60kW tidal turbine has started delivering power off the coast of Maine.
Built by Ocean Renewable Power Company (ORPC), the Beta Power System is the largest ocean energy generator installed in US - although it is dwarfed by the 1MW machine unveiled by Atlantis Resources in Scotland last week.
"Performance test results show that the turbine generator unit's electrical output meets or exceeds expectations for the full range of current velocities encountered," said ORPC.
The firm will use data obtained from the Beta Power System, which is a temporary installation, to fine tune the design of its commercial TidGen tidal generator, planned for installation in the same area next year.
TidGen will be connected to the grid and "will generate up to 250 kW in a six knot water current", said ORPC.
The turbine is a cross-flow design, constructed from composite materials to avoid corrosion.
Although the Atlantis turbine is different hydrodynamically - it is more like a windmill - both turbines use direct drive from turbine to generator to avoid having a gearbox, and both use permanent magnet generators.
