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
• Wave energy offers a large potential resources to be exploited
• 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
• 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
•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
2015
4%
2020
6%
2025
10%
2030
15%
Total wave energy devices production (TWh)
13
20
33
50
Total wave energy devices production (MWh)
13 333 333
20 000 000
33 333 333
50 000 000
0,3
0,32
0,34
0,35
4 000 000
6 400 000
11 333 333
17 500 000
Total devices power (MW) 4000 h use
Power per device (MW)
1 000
0,2
1 600
0,22
2 833
0,25
4 375
0,3
Number of dev ices required
5 000
7 273
11 333
14 583
50
100
200
300
5 000
7 273
11 333
14 583
Load factor
Recoverable annual energy (MWh)
Km of coast estimated for wave power devices
Estimated Capex - 1m £ per dev ice