Ocean Wave Energy
IN BRIEF
Ocean wave energy is mostly derived
from a transfer of wind energy to the
surface of the ocean. Due to the difference of properties in the energy carrier 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.
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 shoreline 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:
NATIONAL TARGETS FOR OCEAN ENERGY IN EUROPE
United Kingdom
2.0 GW
in 2020
Ireland
0.5 GW
in 2020
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.
Denmark
0.5 GW
in 2020
THE TECHNOLOGY
Capturing energy from waves is complex and very location specific. In general, 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.
France
0.8 GW
in 2020
Portugal
0.3 GW
in 2020
Spain (Basque)
0.1 GW
in 2010
Spain (Canary isl.)
0.5 GW
in 2015
Source: European Ocean Energy Association
SETIS – Ocean Wave Energy | page 1
AT A GLANCE
Oceans cover 75% of the world’s
surface – one of the largest renewable 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 greenhouse 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
• a terminator placed perpendicular to
the main direction of the wave;
wave power installations could reach
3500 to 4000 full load hours per year.
• an oscillating water column which
generates electricity from the wave
heave pressure effect in a shaft;
• an attenuator, similar to a terminator
but oriented parallel to the direction
of the waves;
Ongoing research
Medium-scale wave power demonstration facilities are currently being erected 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.
• overtopping devices, a floating reservoir, partially submerged, in which a
head of water is created and further
used to run hydro turbines.
Overall, nine wave energy systems, with
different technologies developed by
European stakeholders, are being tested
under real sea conditions.
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
Development zones, including testing
facilities and grid infrastructure, are also
being established in Ireland, the UK,
Portugal, Finland and Italy.
• a point-absorber which is a floating
structure that absorbs energy from
all directions through its movement
at or near the water surface;
countries and these technologies are
making the transition from research
to demonstration to market penetration. Though wave energy is not
yet competitive with more mature
technologies such as wind, in the
medium term it will contribute significantly to energy markets close
to the sea.
In the longer term, wave energy
could become a much more important part of the world’s energy portfolio. 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.
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
JOB CREATION PER MW OF OCEAN ENERGY
INSTALLED CAPACITY BY 2050
Numbers of jobs/MW
The AquaBuOY system is an example
of a currently-working offshore wave
energy device. It is a freely floating
heaving point absorber system that
reacts against a submersed tube, filled
with water. Another example is the Wave
Dragon, using a wave reflector to focus
the wave towards a ramp and fill a higherlevel reservoir.
Barriers
The main barrier to wave energy expansion 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 development. For an installation located at
100 km from the shore, the grid component 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 electricity 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 administrative 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 industry (ships, platform equipments) have
to be used.
Equally, there is a need for specific engineering capacities. Technology learning
is slow and expensive, and most of the
know-how is from the offshore industry. 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.
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
SETIS – Ocean Wave Energy | page 3
Finally, when it comes to deployment,
coastal management is key to regulating
potential conflicts over the use of coastal space with other maritime activities.
Needs
The technologies in their current form
entail significant financial risk and infrastructure investment. Public intervention
is needed to share the risks between
private and public stakeholders. The
first generation of wave energy capacity needs to be installed to acquire
experience on performance and maintenance, and attract investors. Therefore,
the design and implementation of support measures based on feed-in tariffs
and capital investment incentives are
crucial, as well as standards, dedicated
reference testing centres, and developing 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 stakeholders.
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, significant investments will have to be made.
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:
INSTALLED CAPACITY
Europe’s economic and technical electricity production potential from ocean
wave energy is around 150-240 TWh per
year. In terms of resources, the Atlantic
SETIS section on ocean wave power
http://setis.ec.europa.eu/technologies/
Ocean-wave-energy
European Ocean Energy Association
http://www.eu-oea.com
FACT FILE
Cost
The cost of wave power is very site
and technology specific. The cost of
current prototypes are of the order
of 6 450 to 13 500 €/kW, while initial
capital investment costs of first production units are estimated to be of
the order of 2 500 to 7000 €/kW.
The predicted electricity generating
costs from wave energy converters
have shown a significant improvement 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 Emissions
If the maximum potential is realised,
wave energy could potentially avoid
between 15 Mt/year CO2 and 25 Mt/
year CO2, with respect to the baseline. The corresponding maximum
cumulative avoided CO2 emission
for the period 2010 to 2030 would
be up to 275 Mt CO2.
Security of Supply
Wave 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 avoiding 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.
SETIS – Ocean Wave Energy | page 4