Prototype power

The oceans' waves and tides are becoming an increasingly popular green energy source, and there are many new ideas for devices to harness their power.

Yet none of these devices will see commercial success without a successful working prototype — the key that will open the door to government backing from the £42m Marine Renewables Deployment Fund, further private capital and eventual commercialisation.

For example, Scottish company

successful 2004 test of its technology that uses the motion of ocean surface waves to create electricity paved the way for the world's first commercial wave farm. That farm, at Portugal's Aguçadora Wave Park, was successfully opened in September.

Dublin-based

, the first company to deploy a tidal energy prototype at the

(EMEC) in the Orkney Islands in 2006, has also seen the benefits of a successful prototype. The company is now simultaneously developing three commercial projects in Canada, France and the Channel Islands.

While this progress from prototypes towards commercial devices is encouraging, there are many other devices that never make that end stage because expectations from investors are too high.