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




Key Data


Pelamis Wave Power's Agucadoura Wave Farm is the world's first commercial wave energy project located five kilometre off the Agucadoura coast in Portugal. The farm started delivering 2.25MW produced by three Pelamis generators in September 2008.

Pelamis Wave Power, earlier known as Ocean Power Delivery (OPD) supplied the first three Pelamis P-750 "advanced wave energy conversion technology" machines. Another 28 machines were planned as a part of phase 2 to generate 22.5MW for state-run power company Energias de Portugal.

The first three generators, however, had to be towed back to the port after four months of commissioning because of technical problems. The global financial crunch of 2008 made financing of the re-installation of the generators even more difficult. The wave farm has since then been shut down.

The order for the initial phase was worth €8.2m, funded by a Portuguese consortium led by Enersis. The project was expected to bring power ashore at Agucadoura, and provide electricity to 1,500 homes using the national state run electricity grid system. On completion of both the phases, the project was expected to meet the average electricity demand of more than 15,000 Portuguese households and displace above 60,000 carbon dioxide emissions tons per year.

Technology

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.

"Each module contains a complete electro-hydraulic power generation system, with a single seabed cable linking several devices to the shore. "

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.

Portugal power market

"On completion of both the phases, the project was expected to meet the average electricity demand of more than 15,000 Portuguese households."

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 started 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.

A total of 31 Pelamis wave machines are planned for the Portugal coast within the year.
Ocean Power Delivery has supplied the first three Pelamis P-750 wave machines to Energias de Portugal.
Joint test rig for the Pelamis “advanced wave energy conversion technology”.
Plan view of a typical wave farm configuration
Test rig for the original “Salter’s Duck”, developed by Professor Stephen Salter of the University of Edinburgh. (image from University of Edinburgh).
One-seventh scale prototype of Pelamis at sea off Edinburgh.
Prediction of Pelamis' power response surface in unit amplitude regular waves against frequency and wave heading.