Swiss firm seeks backers for world's first solar submarine

We have had solar-powered buildings, cars and even planes, but now a Swiss energy company has unveiled plans for the world's first solar-powered submarine.

BKW is seeking $10m (£6.5m) investment to press ahead with its Goldfish project to develop a small submarine that would be powered from a floating solar array.

The company has a good track record with innovative solar projects having previously developed the world's largest solar-powered ship on Lake Biel and the world's largest stadium-integrated solar power station in Bern.

The company said the planned submarine could carry up to 24 tourists on underwater sightseeing tours on Lake Thun in Switzerland.

BKW envisages the vessel linking to a floating solar charging station with five solar generators, each with at least 40 square metres of solar panels. The floating array would then be fitted with a GPS tracking system so that the submarine knows where to return to for recharging.

"The energy that is produced by the solar power station should be sufficient for the dives of the submarine, and should also guarantee the safe operation of the platform itself," said project leader Matthias Zellweger.

The company predicts that after charging, the submarine could dive up to 300 metres below the surface and travel at a speed of five knots underwater.

While there is unlikely to be a large market for small solar-powered submarines BKW is confident that the floating arrays could be adapted to provide the basis of a solar recharging network for boats and barges. The company predicts that by installing the floating arrays at busy ports and canal hubs emissions from boats and other vessesls using inland waterways could be slashed.