Waves are beautiful to look at, but analysing the energy they contain can be very complex.
Wind in the Mediterranean has been known to whip up waves as high as 10 metres off the Algerian coast and in the Aegean Sea. Such extreme conditions pose challenges of vibration and wind sheer for offshore energy installations. Mediterranean winds are often strong and turbulent while waves are dense and of a high frequency although widely spread.
Wave energy in the Mediterranean is still in its infancy and discussions are ongoing. Malta’s national renewable energy action plan hesitated to declare any sort of target as long as sufficient data on the potential of the resource is lacking.
Up until recently only a single wave height study had been done by consultants Scott Wilson. Many more parameters have to be looked at before arriving at any idea of feasibility.
Wave energy technology has been a long time coming, often overshadowed by other forms of renewable energy. It was even suppressed by the fossil fuels and nuclear power industries in the 1980s, according to UK parliamentary records.
At a seminar hosted by the Malta Council of Science and Technology, the inventor of a type of wave energy converter, Foerd Ames, gave a brief history of how waves have been used for power in different ways, stretching over the past 300 years.
The first known patent for reaping power from ocean waves dates back to 1799. In 1910, a house on the coastal cliffs of Bordeaux, France, was powered by means of an air-driven turbine pumped by a water column rising with every wave up a vertical borehole on a seaside cliff.
Research on powering navigational buoy lights with wave energy in the 1940s led to a proposal to extract power from angular motion in the joints of an articulated raft.
The first wave energy converter, a prototype built with huge Atlantic waves in mind, came under fire from surfers who were afraid it might steal their surf after taking the power from the wave.
When the price of fossil fuel shot up during the oil crisis of 1973, interest in further development of wave energy spiralled, although attempts to suddenly crank the technology of those times up to a larger scale may have been too much, too soon.
The inventor of the converter, Stephen Salter, admitted that the 2,000-megawatt wave energy power station commissioned by the British government was ahead of its time:
“It’s a bit like somebody saying in 1905 that they had a really good idea for a huge aircraft like the Airbus A380 when people didn’t believe that biplanes would fly.”
Estimated costs for production of electricity from the converter known as Salter’s Duck looked low enough, but before it could be tested at sea the funding ran out.
At the time, competition for energy funding grants was high, especially from the nuclear industry. It has been alleged that Britain’s wave energy programme was shut down in 1982 after a secret meeting between the panel awarding energy grants and members of the nuclear and fossil fuels industries.
The wave programme manager who had openly predicted that Salter’s Duck, if properly funded and developed, could become economically viable, was excluded from the meeting. Wave energy pioneer Salter claims: “They basically killed the project because it was going to threaten the expansion of the nuclear industry”.
Research and development on how to convert wave power into electricity has since picked up again, spurred by climate change concerns. At an international conference on water technology this year, a plan for desalinating seawater for the city of Cairo, Egypt, with wave power was put forward.
The wave powered desalination module, a Salter’s Duck add-on, bobs up and down, pressurising the atmosphere inside, which lowers the boiling point of water. Heating this water will then turn it to steam, ridding it of salt. It then condenses the steam into drinkable water and sends it to shore.
Increasingly the focus is on adapting designs to meet specific conditions of different sites. Collecting all the data needed before an area can be identified as feasible for wave energy installations is a challenging enterprise.
A research and development project by the name of Marine Renewable Integrated Application (Marina) Platform (www.waveplam.eu) is now looking at how to exploit both wind and wave power on a single deepwater production platform, maximising output while reducing losses. Final results of the project are expected by 2014.
The project highlights the potential for deepwater offshore renewable energy parks and looks at whether they can be competitive. Offshore wind/wave parks of this type are envisaged to have a capacity of over 1,000 megawatts.
Malta is considered a promising location: “It looks feasible but needs careful design,” said Prof. George Kallos from the University of Athens, Greece. He spoke of creating synergies between the two technologies to lower costs and help them become economically viable. The university is currently engaged in mapping the resource in an atlas showing all the different types of available energy.
Dr Cedric Caruana from the University of Malta’s Department of Industrial Electrical Power Conversion noted that delivering the energy to points of use could prove difficult when conversion takes place in harsh conditions at sea. Using the energy to make hydrogen fuel on site might be an alternative although every time energy is converted to another form there are more losses.
Questions remain about whether the national grid is ready to take on such forms of energy without laying cables to the mainland to stabilise it. Interconnection with the European grid looks problematic due to the depth of the Malta-Sicily trench.
At a glance, promoters claim that slower and more predictable downtime compared to wind energy could make wave energy easier to integrate with an existing power grid system.
How to exploit wave energy in a way that will not harm the environment was dealt with by Bjorn Welander of Vigourtech Ltd. The lifecycle and decommissioning phase of wave farms was also looked at.
Vigourtech Ltd is assisting Malta Intelligent Energy Management Agency and the University of Malta in an EU-Med programme proposal assessing feasibility of wave energy exploitation in the Mediterranean.
So far, several entities, including Seabased, Dexawave and Ocean Wave Energy Company have been associated with wave energy possibilities in Malta.
A European Intelligent Energy report has found that, despite Europe’s perception of itself as a world leader in favouring renewable energy policies, “European politics have reacted far later than ideal on the increasingly obvious need for alternative, sustainable energy supplies.”
During the workshops held at the end of the seminar participants debated permitting hurdles, legislation, financing and servicing of wave energy farms.