A revolutionary marine energy machine is to undergo an upgrade to enhance its potential to generate electricity on a commercial scale.

The wave energy converter, called Pelamis, has clocked up over 1,000 hours of operation during sea trials and while under test at EMEC, the European Marine Energy Centre, in Orkney.

The test results for the prototype have underpinned the world's first commercial order for a wave energy farm.

The £6 million order is for three 750kW Pelamis machines similar to the prototype under test at EMEC.

The machines are currently being manufactured in Scotland and will be deployed off northern Portugal later this year.

Now the company that developed the Pelamis system, Edinburgh-based Ocean Power Delivery Ltd (OPD), is to thoroughly inspect and upgrade the prototype machine before a battery of further tests are carried out at EMEC during the course of the year.

The aim is modify deployment and recovery equipment and procedures. This will make it easier and cheaper to deploy the machine at sea, increasing its attractiveness to companies developing offshore wave farms.

The planned alterations will involve Pelamis being towed to Leith in Edinburgh, where modifications will be made in a dry dock. The aim is to tow the machine from Orkney during the next few weeks, when weather conditions are suitable.

Neil Kermode, EMEC's managing director, said: "The Pelamis prototype made history as the first machine to produce offshore wave power for the National Grid.

"Our role is to help developers gain the vital at-sea experience they need as they seek to take revolutionary new technology from the embryonic stage into the commercial market place.

"So we look forward to Pelamis' return to Orkney and to helping its further development through an extensive test programme at EMEC."

The Pelamis prototype is 120 metres in length, made up of four tube sections linked by hinged joints, and lies in the water semi-submerged. 

When the machine is flexed by the movement of waves, its internal generators produce up to 750kW of electricity, sufficient to meet the annual needs of more than 500 homes.

In 2004, the prototype was towed into position at EMEC's Atlantic test site using a North Sea anchor handling tug (AHT).

Its design meant that these highly capable vessels had to be used whenever the machine needed to be moved to and from its test berth.

But high oil prices have led to a dramatic upturn in North Sea operations, driving the cost of hiring AHTs to record levels of over £60,000 a day.

Richard Yemm, OPD's managing director, said this had placed severe financial constraints on the testing of the Pelamis prototype over the past year.

As a result, the company has accelerated the development of a new remotely operated mooring attachment and detachment system, that will allow the use of smaller, cheaper vessels when the machine needs to be installed or retrieved.

The prototype will be fitted with the new system during its stay in Edinburgh, with new sub-sea components installed at the EMEC test site before trials re-commence.

The company says that once the modifications are made, Pelamis will be back on site in Orkney by Easter, allowing sufficient testing to be conducted prior to the final assembly and deployment of the production machines in Portugal.

Richard Yemm said: "It's great to be moving again - 2005 was a frustrating time for the prototype test programme.

"However, the OPD engineering team has worked overtime to deliver the new mooring system components, and we are now ready to proceed.

"We are looking forward to getting the machine back to work on the EMEC test site and to building up an extensive test profile during this year."

Link to EMEC website