Pelamis, World’s First Commercial Wave Energy Project, Agucadoura , Portugal

The world's first commercial wave energy project is now delivering 2.25MW off the north Portugal coast. Ocean Power Delivery (OPD) has supplied the first three Pelamis P-750 "advanced wave energy conversion technology" machines, with another 28 machines being planned along the Portugal coast within a year. They will generate 22.5MW for state-run power company Energias de Portugal.

The order for the initial phase is worth €8.2m, funded by a Portuguese consortium led by Enersis. The project brings power ashore at Agucadoura, and will supply 1,500 homes using the national state run electricity grid system. When complete, the project should meet the average electricity demand of more than 15,000 Portuguese households. It should also displace above 60,000 carbon dioxide emissions tons per year.

The Pelamis has a similar output to a modern wind turbine. Future 'wave farm' projects are likely to consist of multiple interlinked machines connected to the shore by a single subsea cable. A typical 30MW installation would occupy a square kilometre of ocean.

"SALTER’S DUCK" PIONEERS WAVE ENERGY RESEARCH

Wave energy research was pioneered by "Salter’s Duck", developed by Professor Stephen Salter of the University of Edinburgh. With an efficiency of around 90%, the duck moves up and down with the waves. It is still a laboratory prototype, and was put on hold because of technical issues and a lack of support by the UK government. It did, however, lead to the development of the Pelamis.

The Pelamis is cylindrical, with four main tube segments linked by hinged joints. Each segment measures 120m long and 3.5m wide, and weighs 750 tons when fully ballasted. The machine operates semi-submerged, extracting power from the wave-induced motion of the hinged joints. This power is resisted by hydraulic rams, which pump high-pressure oil through smoothing accumulators to hydraulic motors. Each module contains a complete electro-hydraulic power generation system, with a single seabed cable linking several devices to the shore.

The machine is held in position by a mooring system combining floats and weights that prevent the mooring cables from becoming taut. This maintains enough restraint to keep the Pelamis positioned but allows the machine to swing head on to oncoming waves. The Pelamis is ideally moored in waters around 50–60m deep (often 5–10km from the shore). This gives access to large swell waves but avoids the costs of a longer submarine cable. 

The first full-scale pre-production Pelamis prototype was tested at the European Marine Energy Centre in Orkney. The design was independently verified by WS Atkins according to (DNV) offshore codes and standards.

The modules for Portugal were originally fabricated in Stonehaven by Ross Deeptech, an experienced offshore fabricator. After installation of the electro-hydraulic power take-off systems was complete, the modules were transported to Lewis. There, they joined the main tube segments made by Camcal, a specialist in large cylindrical structures. The component parts were shipped in March 2006 to the Port of Peniche for final assembly, commissioning and installation at a site 5km off the coast of northern Portugal, near Póvoa de Varzim.

PREMIUM PRICE FOR WAVE POWER IN PORTUGAL

Wave power is perhaps Portugal’s most promising form of renewable energy. Large, powerful waves come in from the Atlantic over a long coastline. Estimates predict that wave power could make up to 30% of the country's gross domestic product by 2050. Wave also has the potential to become one of the lowest cost forms of electricity generation, with opening costs now around half those of wind energy and a quarter those of solar PV.

The Portuguese government has established a feeder market that pays a premium for wave-generated electricity. This is the approach that led Denmark and Germany to kick-start the wind industry, which now has a turnover of over €12bn/year and employs 60,000 people worldwide. The worldwide market for wave power is estimated at £500bn.

The EU-funded Agucadoura project was begun in 2003, and is the result of over 20 years of research at Lisbon's Superior Technical Institute. The project was funded by a consortium headed by Portuguese renewable energy company Enersis. Enersis’ controlling shareholder is Endesa, a Spanish multinational that holds over 60% of the company’s shares.

NEW INVESTMENT FOR OPD

Ocean Power Delivery Ltd is based in Edinburgh (Scotland), and was formed in January 1998. In June 2006, it raised over £13m of investment from a consortium of new and existing investors led by SAM Private Equity. The finance is funding the expansion of the business, meeting existing and anticipated orders, and accelerating the next generation machine.

OPD was the first to generate electricity into the grid from commercial-scale offshore wave energy. The company employs 60 staff and is working to secure projects in the UK, with Scottish Power and Amec in Scotland and Ocean Prospect in the South West of England. It is also pursuing project sales in Western Europe, North America, Africa, Asia and Australasia.