IN BRIEF

Ocean wave energy is mostly derived from a transfer of wind energy to the surface of the ocean. Due to the diffe-rence of properties in the energy car-rier media (water), wave energy is less intermittent and more predictable than other renewable technologies such as wind, although forecasting techniques need improvement.

Oceans represent a huge, predictable resource for renewable energy. The main forms of ocean energy are waves, tides, marine currents, salinity gradient and temperature gradient. Wave and tidal energy are currently the most mature technologies.

Wave energy is mostly derived from a transfer of wind energy to the surface of the ocean. The energy is measured in terms of kilowatts per metre of wave front (kW/m) and can be converted to electricity in a number of ways.

THE TECHNOLOGY

Capturing energy from waves is com-plex and very location specific. In gene-ral, there are three main types of wave energy systems:

Shoreline devices, either fixed to or embedded in the shoreline, do not require deep-water moorings or long underwater electricity cables and are easier to install and maintain. Their disadvantage is the less powerful wave resource available.

Near-shore devices are deployed at moderate water depths (20-25m), at distances of up to 500m from the shore. With many of the advantages of shore-line devices, they exploit higher power wave resources. They include several point absorber systems.

Offshore devices use the more powerful wave resources available in water more than 25m deep. More recent designs for

offshore devices concentrate on small, modular devices, yielding high power output when deployed in arrays.

Many devices and designs are currently being studied and/or developed. Up to 50 types of wave energy converters have been designed, but less than 20% are at the full-scale prototype stage. The main technologies used for wave energy extraction are:

Ocean Wave Energy

SETIS – Ocean Wave Energy | page 1

NATIONAL TARGETS FOR OCEAN ENERGY IN EUROPE

United Kingdom2.0 GWin 2020

Ireland0.5 GWin 2020

Denmark0.5 GWin 2020

France0.8 GWin 2020

Spain (Basque)0.1 GWin 2010Portugal

0.3 GWin 2020

Spain (Canary isl.)0.5 GWin 2015

Source: European Ocean Energy Association

• aterminatorplacedperpendiculartothe main direction of the wave;

• anoscillatingwatercolumnwhichgenerates electricity from the wave heave pressure effect in a shaft;

• apoint-absorberwhichisafloatingstructure that absorbs energy from all directions through its movement at or near the water surface;

• anattenuator,similartoaterminatorbut oriented parallel to the direction of the waves;

• overtoppingdevices,afloatingreser-voir, partially submerged, in which a head of water is created and further used to run hydro turbines.

Rated power capacity for a single system ranges from 70 kW to a few MWs. Several units can be assembled to create a wave energy farm. Average load factors for

wave power installations could reach 3500 to 4000 full load hours per year.

Ongoing researchMedium-scale wave power demonstra-tion facilities are currently being erec-ted or planned. European companies are active in shoreline, near-shore and offshore based devices. The Pelamis Wave Energy Converter – an attenuator technology for offshore wave power – developed by Ocean Power Delivery is at an advanced stage of development. A 750 kW size unit is already in operation in Scotland.

Overall, nine wave energy systems, with different technologies developed by European stakeholders, are being tested under real sea conditions.

Development zones, including testing facilities and grid infrastructure, are also being established in Ireland, the UK, Portugal, Finland and Italy.

THE INDUSTRY

As wave energy production grows, it is creating a new industry, which could also provide opportunities for spin-offs for other offshore activities such as ship building.

Currently, the most advanced type of shoreline device is the oscillating water column (OWC). The Pico plant, a 400 kW rated shoreline OWC equipped with a Wells turbine was constructed in 1995-99. Based on this, a ‘wave energy breakwater’ is being built in the Douro estuary in Portugal, mainly financed by the EDP group.

Another wave energy system that can be integrated into a breakwater is the Seawave Slot-Cone Generator (SSG). The SSG can give the breakwater an added value through the sale of electricity, as well as being combined with fresh water production.

SETIS – Ocean Wave Energy | page 2

Oceans cover 75% of the world’s surface – one of the largest renew-able energy sources available. Ocean Energy (OE) involves the generation of electricity from waves, tides, currents, the salinity gradient and the thermal gradient of the sea.

Ocean energy could contribute to energy security and reduce green-house gas emissions, while ocean energy technology could enhance the competitiveness of European industries.

Estimates set the global theoretical energy production potential of OE at over 100 000 TWh/year. For compari-

son, global electricity consumption is currently around 16 000 TWh/year.

The global wave energy resource exploitable with today’s technology is estimated to be in the order of 1 400 TWh/year. Conversion of wave resources into energy could supply a substantial part of the electricity demand of several countries in Europe, such as Ireland, UK, Denmark, Portugal and Spain. Due to the variety of forms in which the ocean stores and supplies energy, there are a large number of concepts for wave energy conversion.

Various wave energy systems have been deployed at sea in several

countries and these technologies are making the transition from research to demonstration to market pene-tration. Though wave energy is not yet competitive with more mature technologies such as wind, in the medium term it will contribute sig-nificantly to energy markets close to the sea.

In the longer term, wave energy could become a much more impor-tant part of the world’s energy port-folio. The best resources are found between 40-60° latitude, which takes in most of the European Atlantic coast, where the available resource is 30-70 kW/m with peaks to 100 kW/m.

AT A GLANCE

The AquaBuOY system is an example of a currently-working offshore wave energydevice. It is a freely floatingheaving point absorber system that reacts against a submersed tube, filled with water. Another example is the Wave Dragon,usingawavereflectortofocusthe wave towards a ramp and fill a higher-level reservoir.

Barriers The main barrier to wave energy expan-sion is that it is not cost-competitive. This is due to the marine environment and the technology still being in the early stages of development.

Appropriate grid infrastructure and connections will be important for deve-lopment. For an installation located at 100 km from the shore, the grid com-ponent can represent up to one third of the cost. Grid connections to onshore grids can also be problematic, as in some cases the grid cannot absorb the elec-tricity from wave energy production.

High licensing and authorisation costs and complex procedures are barriers. It can take up to two years to obtain a permit, at a cost of up to one million euro. Procedures are long due to a lack of dedicated or experienced adminis-trative structures.

Maintenance and construction costs are also high, especially in the start-up phase. There is currently little experience in maintenance of offshore facilities and costly infrastructures from the oil indus-try (ships, platform equipments) have to be used.

Equally, there is a need for specific engi-neering capacities. Technology learning is slow and expensive, and most of the know-how is from the offshore indus-try. The lack of expertise can result in

over-sizing of equipment and increased investment cost.

The full development and operating costs are beyond the capacities of smaller com-

panies (SMEs). Large industries are already involved, in particular some utilities, but there is a need for long term strategic development and deployment planning to secure industrial investments.

SETIS – Ocean Wave Energy | page 3

European policy-makers are facing a challenging strategy – a balancing act of

combating climate change and securing the energy supply, while ensuring global cost

competitiveness. The ocean can become a major element of this strategy: ocean energy.

Europe has the oldest maritime industry, vast ocean energy resources and it is a pioneer in

ocean energy technologies. It is well positioned to lead the world in harvesting ocean energy.

European Ocean Energy Association

JOB CREATION PER MW OF OCEAN ENERGYINSTALLED CAPACITY BY 2050

Num

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s/M

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Finally, when it comes to deployment, coastal management is key to regulating potentialconflictsovertheuseofcoas-tal space with other maritime activities.

Needs The technologies in their current form entail significant financial risk and infras-tructure investment. Public intervention is needed to share the risks between private and public stakeholders. The first generation of wave energy capa-city needs to be installed to acquire experience on performance and main-tenance, and attract investors. Therefore, the design and implementation of sup-port measures based on feed-in tariffs and capital investment incentives are crucial, as well as standards, dedicated reference testing centres, and deve-loping specific engineering capacities.

The expert wave energy community needs to train a new generation of

scientists and attract people from other sectors such as offshore wind energy to transfer know-how.

The wave ocean energy community also needs to acquire a sufficient critical size. This requires information exchange and coordination efforts among the stake-holders.

With expansion of ocean wave energy, the requirements for grids will become acute. In many cases, there is no grid available in the nearby onshore areas for connections. On the Atlantic arch, signi-ficant investments will have to be made.

INSTALLED CAPACITY

Europe’s economic and technical elec-tricity production potential from ocean wave energy is around 150-240 TWh per year. In terms of resources, the Atlantic

arc from Scotland to Portugal is the most favourable area.

Taking baseline assumptions, SETIS forecasts that the installed capacity of wave energy will reach 0.9 GW in 2020 and 1.7 GW in 2030.

Taking assumptions of the maximum potential for wave energy, forecasts predict capacity in the EU-27 of up to 10 GW by 2020 and 16 GW by 2030. This would generate 0.8% and 1.1% of the EU-27 electricity consumption projected for 2020 and 2030 respectively.

For further information:

SETIS section on ocean wave powerhttp://setis.ec.europa.eu/technologies/Ocean-wave-energyEuropean Ocean Energy Associationhttp://www.eu-oea.com

SETIS – Ocean Wave Energy | page 4

CostThe cost of wave power is very site and technology specific. The cost of current prototypes are of the order of 6450 to 13500 €/kW, while initial capital investment costs of first pro-duction units are estimated to be of the order of 2500 to 7000 €/kW.

The predicted electricity generating costs from wave energy converters have shown a significant improve-ment in the last 20 years, reaching an average price below 10 euro cents per kWh. Compared to the average

electricity price in the EU, which is approx. 4 euro cents per kWh, the electricity price produced from waves is still high, but is forecast to decrease. Carbon Dioxide EmissionsIf the maximum potential is realised, wave energy could potentially avoid between 15 Mt/year CO

2 and 25 Mt/

year CO2, with respect to the base-

line. The corresponding maximum cumulative avoided CO

2 emission

for the period 2010 to 2030 would be up to 275 Mt CO

2.

Security of SupplyWave energy technologies can replace fossil fuel-based power plants in the peak to medium scale baseload ~ 3 000 hrs to 4 000 hrs. Achieving the maximum potential for wave energy could lead to avoid-ing up to 5 Mtoe of fossil fuel use in 2020 and 10 Mtoe in 2030, with a maximum cumulative fossil fuel avoidance of 80 Mtoe, for the period 2010 to 2030. These figures do not account for the possible needs for fossil-fuel based power back-up to firm wave power capacities.

FACT FILE