Wave Power Potential

An energy Scenario for the UK NBS-M016 Contempory Issues in Climate Change and Energy

Wave Power: overview

• Sun makes wind and wind makes waves > Waves are third hand solar energy • Waves generated by wind passing over the surface of the sea – direct correlation between the power of the wind and the power of the wave • Wave height determined by – wind speed, duration the wind has been blowing, depth and topography of the seafloor • Energy output (wave power) determined by – wave height, wave speed, wavelength, and water density • The energy provided most often used in – electricity generation, water desalination, and water pumps

Wave Power: history

A bit of history

… – First concepts 200 years ago, but viable schemes only in the 1970’ – Increased interest for RE, and specifically for wage energy, after the energy crisis in 1973, but insufficient money allocated to bring projects to maturity – 80’ because of oil price fall, wave energy funding reduced significantly – 90’ growing awareness of the potential of generating energy from waves  Relatively new renewable technology in comparison to other RE • 15-20 years behind technology wind  Long process to develop this type of energy but economics of current technologies are potentially attractive

Wave energy technology (1)

• Wave devices characterized by: – Locations: •Shoreline: tethered in intermediate depths •Nearshore: fixed to the seabed in shallow water •Offshore: more difficult to construct and maintain than shoreline but greatest potential as waves in deep water have greater energy content – Method used to capture the energy (fixed, tethered, floating devices): 1- Buoy moored to the seabed 2- Oscillating Water Column (OWC): can be fixed to the seabed or installed on the shoreline; simple and robust 3- Floating device for offshore: use motion of waves; leading technology currently

Wave energy technology (2)

Pelamis WEC: leading wave power technology

• 4 semi submerged cylindrical sections facing nose on towards the incoming waves and which flex and bend as waves pass > this motion is used to generate electricity • world’s first commercial wave farm to generate electricity in Portugal opened in 2008:  3 Pelamis machines with capacity of 2.25 MW (750 kW per snake); cost of 8.5 m € to deploy; project suspended in 2009 • in Scotland: plan to install the world’s largest wage farm : 3MW capacity; 4 Pelamis machines; costs 4 £m Source: Pelamis Wave Power 2009 http://www.pelamiswave.com/content.p

hp?id=161  Many devices and new technologies in emergence  But they are not technically at the industrial production stage > just pilot projects and prototypes  Wave energy is currently in the early stage of commercialisation and it is not yet a widely employed commercial technology

Worldwide potential of wave energy

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Wave energy offers a large potential resources to be exploited

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Total worldwide wave power estimated at 2TW (or 17 500TWh/year) - about double current world electricity production - and between 1-10 TW in deep water

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Only 500 GW captured with current technology

Annual average wave power density (in kW per m): any area with yearly averages of over 15kW per m has the potential to generate wave energy at competitive prices Best wave energy sites around the world are – USA, – North & South America, – Western Europe, – Japan, – South Africa, – Australia – and New Zealand http://www.tridentenergy.co.uk/images/world_map.gif

UK potential of wave energy

UK has a good wave climate – Well situated: surrounded by water + good position for wind on West Atlantic Coast (smaller waves on East Coast) (Lewis 42kW/m - Cromer 5kW/m) –Waves arriving on the Atlantic Coast (1000 km) have an average power of 40kW/m – Total annual average wave power in UK West Coast •

around 30 GW (260 TWh/year) at the shoreline

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about 80 GW (700TWh/year) in deep water

– Technical potential of offshore wave energy resource •

about 7-10 GW per year (61-87 TWh/year) depending on water depth

– Practical potential much smaller because of • Operational and economic constraints • Practical and technical constraints  Potential of wave energy is huge  The extent to which this will prove practical to harness will depend upon the successful development of both near shore and deep water technologies

Wave energy: constraints and advantages

Constraints

: – Most turbines require a constant, powerful flow > waves are irregular in both direction and power – Storms damages and corrosive power of saltwater – Devices still complicated at mechanic level and engineering difficulties – Maintenance of devices expensive – Problem of lose during conversion from mechanical energy to electricity

Advantages

: – Wave energy is environmentally friendly (low noise, low visual impact, no impact for fish like tidal energy) > commercial and political attractiveness – Wave power provides the highest kW intensity per m2 – Wave available 4000 hours per year (more than wind)

Wave power: assumptions

• Today contribution of wage energy is very small but it will become significant in the long term: 15% in 2030 with a total wave energy devices production 50TWh • Because of the huge potential, further investment in R&D (150 m£) will be done to improve design, construction techniques, technological development, and performance • This will help to decrease the cost of wave energy (today 0,08 € kWh) and to improve the load factor • Costs of producing wave power devices will be reduced by half with R&D and economy of scale • Power of Atlantic waves is about 40kW per meter exposed coastline; UK has about 1000km of Atlantic coastline and around 60 M population  1/60 m per person > incoming power 16 kWh per day per person  If 300 km is used for wave power and wave devices are 50% efficient at turning wave power into electricity  we will have 2,7 kWh per day per person

Wave power: potential by 2030

% of energy usage supplied by wave energy Total wave energy devices production (TWh) Total wave energy devices production (MWh) Load factor Recoverable annual energy (MWh) Total devices power (MW) 4000 h use Power per device (MW)

Number of devices required

Km of coast estimated for wave power devices

Estimated Capex - 1m £ per device 2015

4% 13 13 333 333 0,3 4 000 000 1 000 0,2

5 000

50

5 000 2020

6% 20 20 000 000 0,32 6 400 000 1 600 0,22

7 273

100

7 273 2025

10% 33 33 333 333 0,34 11 333 333 2 833 0,25

11 333

200

11 333 2030

15% 50 50 000 000 0,35 17 500 000 4 375 0,3

14 583

300

14 583