Skwid setback as protoype sinks

Japanese marine contractor Modec has postponed plans to start testing its Skwid hybrid wind/tidal offshore energy concept after a key component sank to the bottom of Japan’s Inland Sea.

The Tokyo-based company had been planning to start testing the Skwid off the coast of Saga prefecture, on the southern Japanese island of Kyushu, from late last week.

However, the prototype’s marine turbine component sank on 12 October off the northern coast of Kyushu while being towed by barge from Kagawa prefecture, on the adjacent island of Shikoku.

The demonstration scheme was expected to take about a year.

Modec is not yet sure if the turbine is recoverable but hopes to resume the trial in January or February next year.

It is now unclear whether Modec will be able to start selling electricity from the Skwid to regional utility Kyushu Electric Power in 2014, as initially planned. And it is still uncertain whether the concept will qualify for Japan's wind feed-in tariff (FIT).

The FIT rate for onshore and offshore projects is ¥23.1 ($0.232) per kWh over 20 years.

The Skwid concept pairs a three-bladed vertical-axis wind turbine (VAWT) with a Savonius ocean-current turbine. Its split-cylinder, bucket-shaped current turbine powers the wind turbine, while keeping the device upright at sea.

Modec’s first renewable energy design is calculated to have an output capacity of 500kW in winds of 13 metres per second (m/s) rising toward 1MW in velocities of 16m/s.

The 24-metre-diameter Darrieus VAWT is designed to capture twice as much energy as a similar onshore turbine.

Modec decided to test the hybrid offshore energy prototype off the coast of Karatsu, Saga, because of the area’s strong currents and reliable wind conditions.

The area is also appealing because the company wants to lease the Skwid to local fishing co-operatives.

The company has said that in the future, the concept could be used to provide electricity to remote islands.