Pelamis Wave Power Limited, based in Scotland, manufacturers 750 kW wave generators, pictured here during a test deployment. Their first commercial plant, located off the coast of Portugal, just opened, ushering in a new era of wave power. (Source: Pelamis Wave Power Limited)
The PWEC generators undergo construction at a dock in Portugal. (Source: Pelamis Wave Power Limited)
The finished generators are now active, providing 2.25 MW of power to Portugal, at a modest price tag of $13.1M USD. (Source: Pelamis Wave Power Limited)
New "sea snake" wave plant will carry a price tag of around $13.1M USD and will generate 2.25 MW
With the rush of alternative energy interest, initial enthusiasm has been directed largely towards wind and solar power, while other more exotic forms were left unnoticed. All of that is starting to change though, with alternative alternative energy finally being looked at in depth. Google has taken the lead in exploring non-conventional energy sources, championing geothermal power and tidal power.
And now another piece of major good news for non-mainstream alternative energy. The world's first wave power plant opened this week, off the coast of Portugal. The new plant cost only $13.1M USD to deploy, but will offer a capacity of around 2.25 MW. This already beats current solar offerings, for example its over twice as efficient as the Oregon Road project which is creating 104 kW for $1.3M USD.
The most promising part about the new plant is that its potential is largely untapped. While solar has seen years of refinement, interest in wave power is just picking up. This should help it be a competitive alternative to nuclear power in the near future, allowing for a variety of options.
The heart of the new plant is Pelamis Wave Energy Converters (PWEC). Designed by Pelamis Wave Power Limited, a Scottish engineering firm, these converters sit three milles off the coast of Agucadoura in north Portugal and provide power 24-7. Each converter has a modest output of 750 kW, and together three compose the 2.25 MW plant.
A second phase of the plant, contingent upon its success, is planned, which will expand the plant with 25 additional reactors, bringing the capacity to 21 MW. This would be enough energy to power 15,000 homes. The project is a joint venture between a Babcock and Brown Ltd., a global specialist asset manager, Energias de Portugal (EDP),Portuguese energy group EFACEC, and Pelamis Wave Power Limited.
The new generators were named after the sea snake Pelamis. They measure 3.5 m in diameter and are 140 m long. They float partiall submerged on the ocean's surface. Babcock and Brown's Anthony Kennaway explains the operation of the PWEC stating, "Effectively what you have is four long sections making up one machine. Between those sections are three small generating motors. The four sections are all joined by hydraulic rams. As the waves run through the machine it pushes the rams in and out. The action of the rams going to-and-fro pushes hydraulic fluid into a high pressure reservoir. That high pressure reservoir then releases the fluid at a steady rate through a generating motor."
Much of the project's costs are not in the generators themselves, but in the undersea cable, which links the generators' output to a substation on shore, which then converts it into usable electricity and puts it on Portugal's grid.
Like solar cells, wave power is reliant on the weather. However, it should be a steadier power source, producing power even at night. Over a year, its expected to average around 20-40 percent of its peak capacity. According to the plant owners, once the 25 additional generators are in place, a savings of 60,000 tons of CO2 yearly will be gained. British scientists say that wide adoption of wave power could save 1-2 billion tons of CO2 yearly.
Ian Fells, emeritus professor of energy conversion at Newcastle University, UK says the new project is exciting, but he warns of one possible pitfall. He states, "It's extraordinarily difficult to design a machine that will cope with the extreme violence of waves. Some wave machines are under the surface all the time -- but they are not as well developed as yet. Pelamis lies in the surface and it remains to be seen how successful it will be. It's extraordinarily difficult to design a machine that will cope with the extreme violence of waves. Some wave machines are under the surface all the time -- but they are not as well developed as yet. Pelamis lies in the surface and it remains to be seen how successful it will be."
While affordable, challenges to wave power remain. As Professor Fells raises, there's the issue of longevity and survival in extreme storms. As the technology is very new, there's few reliable estimates on how long the best-designed wave generators could operate. Further, it would take over 6,500 of the generators to equal the output of one nuclear power plant. This would yield a cost of $21B USD, which does not compare favorably with construction cost of equivalent output modern nuclear plants, which typically run around $6 to $8B USD.
Still, as the tech is developed more, capacities should increase, endurance improve, and costs drop. The future is looking bright for wave power.
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