Wave Energy
Overview
Global Highlights
What’s Happening in BC?
What Does it Cost?
Environmental Matters
Technical Matters
Price, Policy and Political Matters
Can I Use it at Home?
Links
Overview
Waves contain large amounts of energy, particularly large
waves and ocean swell. Wave energy is in reality a stored
and concentrated form of solar energy, with the wind as the
intermediary.
Wave energy research was pursued intensively during the
1970’s and early 80’s, especially in Britain. Interest in
it was then revived in the mid 90’s as one of the options
to reduce fossil fuel dependency and address global warming.
During these last 30 years a large number of devices such
as the nodding duck, the Osprey, tethered buoys, bottom standing
oscillating water columns, over-spilling systems, floating
bags, articulated rafts, submerged pressure chambers, and
many others have been tried with varying degrees of success.
However, wave technology is now slowly maturing, and the
day of commercial viability is approaching.
There are two basic types of wave technology: fixed onshore
and floating offshore. Up to very recently most of the research
and development has been focused on fixed devices onshore
or in shallow waters. Now, however, there is increasing interest
in the much greater offshore resource with a variety of floating
devices being developed.
The greatest wave energy resource is in the mid-latitudes,
between 40 and 60 degrees N & S. This is where winds
blow most consistently, while in more tropical areas there
are often long periods of calm weather in between severe
storms.
Global Highlights
- The World Energy Council has estimated the global wave
energy potential to be 2,000 GW. (New Scientist, Sept.20,
2003)
- The economically recoverable wave energy resource for
the UK has been estimated by the Ocean Power Delivery Company
to be 87 TWhrs/year.
- A 500 kW fixed device called the Limpet has been operating
on the island of Islay off the coast of Scotland since
November 2000. It was built and installed by Wavegen, and
was the first commercial-scale grid-connected wave energy
device installed anywhere. Its output is being sold to
the local utility for 5.95 pence/kWhr. (Environmental Science & Technology,
No.3, 2001)
- In February 2004 ocean testing began of the 750 kW Pelamis,
also called the Sea Snake, which is the first deep-water
grid-connected wave power generator in the world. It is
120m long, 3.5m wide and weighs 750 tonnes. It is built
and operated by the Ocean Power Delivery Company of the
UK.
What’s Happening in BC
In 2001, the Green Energy Study of BC, Phase 1, was completed
for BC Hydro. It stated that 8.25 GW of wave power is incident
on western Vancouver Island, and Winter Harbour and Ucluelet
were identified as suitable sites for installations, each
with a potential of 200 MW. The study estimated that by 2009/10,
Vancouver Island could have 75 MW of installed wave capacity,
generating 156 GWhrs/year, and by 2019/20 there could be
225 MW generating 468 GWhrs/year. All of it would be at less
than 7 cents/kWhr.
In June of 2001, BC Hydro announced a 20 MW Vancouver Island
Green Energy Demonstration Program, of which wave energy
was to be a part. About a year later Ocean Power Delivery
of the UK and Energetech of Australia were selected to develop
demonstration projects of 2 MW each. However, in April 2003,
BC Hydro pulled out of these projects, saying that the success
of their more recent Call for Private Green Power Proposals
eliminated the need for BC Hydro to be involved in funding
demonstration projects.
What Does It Cost?
According to the World Energy Council, costs are currently
in the 12-16 CAN cents/kWhr range, but within 3-5 years they
can be expected to come down to the 5-7 cents range.
Energy from the Limpet is sold by Wavegen for 5.95 pence/kWhr
(14cents/kWhr).
BC Hydro’s Green Energy Study for BC, Phase 1, estimated
the future price of wave energy to be in the 4-9 cents/kWhr
range.
When we look at these costs and compare them to conventional
technologies, it should be kept in mind that electricity
from fossil fuels will only get more expensive in the future
as supplies dwindles, and also that fossil fuel energy does
not include the cost of externalities such as pollution and
greenhouse gas emissions.
Environmental Matters
Fixed wave energy devices can disturb shoreline ecosystems,
and siting must be done with careful attention to sensitive
areas. On the other hand, these fixed devices tend to be
located on exposed rocky sites rather than in more sensitive
estuarine areas.
Offshore floating devices can be navigational hazards and
must have adequate lighting and radar warning equipment.
Technical Matters
The size of the global wave energy resource has been mapped,
but it is important to notice that the values given (40-70
kW/linear metre for good sites) are for deep-water locations.
As you get closer to shore, breaking waves and friction along
the rising seabed reduce the energy to about a third. This
is why even companies such as Wavegen, which has until now
focused only on fixed onshore devices, recognizes that the
long term future of bulk wave energy generation lies in using
the offshore resource rather than the onshore. (Tom Heath,
Wavegen website, and New Scientist, Sept.23, 2000)
Ocean Power Delivery of the UK, with its Pelamis Sea Snake,
is a leader in offshore technology, and its vision is one
of large wave farms where each square km can generate 30
MW.
Price, Policy & Political Matters
The history of the development of wave energy technology
clearly shows that government support is necessary. When
such support abruptly stopped, as in the UK in 1982, technological
advances also stopped, or at least slowed down dramatically,
only to pick up again once public support was reinstated.
BC was on the cusp of developing experience and expertise
in wave energy in 2001, until BC Hydro abandoned their program,
at which time all wave activity stopped. Unless some support
is reinstated, little wave development will occur here until
the technology is developed further in other countries. Then
we will have once again missed a chance of participating
in the development of an emerging new industry, and all its
attendant economic benefits.
Can I Do at Home?
Some of the older devices are quite small in scale, but
most are not available commercially. You would also need
a foreshore lease.
Links
General:
Credits
Written by Bo Martin for the BC Sustainable Energy Association.
Text updated July 22, 2004
Links updated September 14, 2007
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