Memorandum submitted by the Royal Society
1. The Royal Society of Edinburgh (RSE)
is pleased to respond to the Select Committee's request for comments
on wave and tidal energy. The RSE is Scotland's National Academy
of Science and Letters, comprising Fellows elected on the basis
of their distinction, from the full range of academic disciplines,
and from industry, commerce and the professions. This response
has been compiled with the assistance of a wide cross section
of Fellows and approved for distribution under delegated authority
for the Council.
2. The specific questions identified in
the call for evidence are addressed below.
Is the technology available for efficient generation
of power from waves and tides?
3. The concepts for generation from wave
and tidal resources are well-developed, but the technology is
not yet mature for either.
4. Water-based technologies have an advantage
over wind and solar in that the energy flux is an order of magnitude
higher, typically 4kW per metre squared compared with 400W, and
often much less, for wind and solar technologies. Modern load
management techniques have also substantially alleviated earlier
intermittent load fluctuating problems pertaining to both tidal
and wave power among other renewable sources. However, factors
relating to system integration still have to be considered even
now for both tidal power and wave power.
5. Wave energy converters need hydrodynamic
characteristics to enable them to operate at maximum efficiency
over the normal range of sea conditions, yet they must be robust
enough to withstand the worst storms. Despite its large potential
resource for the UK of 40-50 TWh/year (approximately 15-20 per
cent of UK electricity generation output), no economic large scale
wave energy device has yet been produced, and load management
and integration problems are still quite severe.
Will wave and tidal energy become commercially
viable in the near future, and attractive to the private sector
as a profitable investment?
6. Most likely sources of wave energy are
on the West coast of Britain, and at some considerable distance
from likely large users of electricity. Hence the total costs
for design and erection of the energy generators, and the power
transmission system must be analysed and estimated in relation
to the market, and the price which the market will pay. Too often
in the past, seemingly attractive projects have foundered because
of over-optimistic initial assumptions. The problem of grid connection
is common to all renewable sources as distribution grids tend
to be "tapered" towards their periphery, which is often
where the renewable energy is available. The intermittent nature
of the supply also puts it at a disadvantage with the New Electricity
Trading Arrangements (NETA) under which fluctuating supply attracts
7. The economic advantage of wave and tidal
power will also depend upon the relative values of imported and
exported energy and on the ability of the supply system to meet
the pumping demand. It will be difficult for either to become
commercially viable if the present economic indicators continue
to be used. However, if a new approach is taken to assess the
value of renewable resources, then viability may become possible.
Recent moves towards "green credits" are moves in the
right direction but more could be done. These new arrangements
require suppliers to provide 10 per cent of their supply from
renewable sources by 2010 or pay a penalty. However, at present
the price of electricity produced by wave and tidal stream technologies
comes in at above 5p per unit (the capped price of the renewable
electricity to be supplied in this arrangement). It will be difficult,
therefore, to see why electricity suppliers should enter into
such contracts with wave and tidal power providers, when they
can buy themselves out at 5p per unit. In addition, tidal stream
energy is not included in the Renewable obligation list of acceptable
technologies despite its potential.
What projects are currently running in the UK
and how successful have they been?
8. The main wave energy project is a shoreline
device, now called Limpet, on the Island of Islay and is run jointly
by WaveGen and Professor Whittaker from the Queen's University
Belfast. It operated sucessfully for 10 years and has now been
superseded by the Mk2 device which has been operating since November
2000 and generates 500kW. While the concept has been proven, it
is onshore and so limited in power rating and it requires specific
shoreline characteristics. A significant problem has also been
in transmitting the power to the grid, with the existing grid
line to the main land requiring significant and costly strengthening.
9. In terms of tidal stream energy, and
science is well understood but the technology requires further
development. One 300kW unit is about to be installed by Marine
Current Turbines of Lynmouth in Devon and The Engineering Business
has also demonstrated a small model device which they are seeking
to upgrade to upgrage to a demonstration stage.
Why did past projects fail?
10. Wave and Tidal Energy technologies lack
a large corporate sponsor and this lack is of critical importance.
In the past, commercial pressures have also driven some projects
too fast, with credibility being lost through embarrassing and
high profile failures.
What role should wave and tidal energy have in
the Government's renewable energy strategy? Should they be a higher
11. Wave and tidal stream devices have the
potential to be as important as onshore wind energy but the technology
needs to be demonstrated and encouraged if it is to develop.
What Research and Development is being undertaken
at present? Is national funding for R&D being well co-ordinated?
12. A few research teams have modest programmes.
For example Professor Salter at the Department of Mechanical Engineering,
University of Edinburgh is working on wave power using a modified
Swedish buoy system. However, the Edingburgh wave tank, where
this work is being undertaken, is scheduled for demolition.
13. The Department of Trade and Industry
(DTI) supports a wide range of work on renewable energy under
its New and Renewable Energy programme, managed on behalf of DTI
by the Energy Technology Support Unit (ETSU). The EPSRC also have
a Renewable and New Energy Technologies programme.
What are the environmental implications of wave
and tidal energy, particularly for marine life? How will such
devices affect shipping?
14. The environmental effects of wave power
were considered some years ago as part of a Department of Energy
programme concentrating on large 2,000mW Offshore installations
off the Outer Hebrides. A decrease in the wave energy incident
on shores and shallow inshore waters could result in changes in
the numbers and species of the local flora and fauna, and the
reduction in wave height could also lead to less replenishment
of water to splash-filled pools. They may also lead to the growth,
rather than the erosion, of beaches. Off-shore installations will
also require shore base support facilities as well as a fleet
of support vessels.
15. The onshore Islay Wave station is viewed
by many as not contributing to the local visual amenity and some
designs of air-turbine may produce unpleasant noise which could
be audible above the background of wind and waves. Offshore devices
will have less visual impact but may come into conflict with fishing
activities in terms of risk of collision and the fouling of fishing
gear on mooring systems. Offshore devices may, however, create
calm conditions lee-side which will make sailing less dangerous.
16. Tidal stream devices are judged to be
considerably less obstrusive than wind turbines and barrages and
the likely hazard to navigation will be no different from that
exhibited by current offshore installations. The impact on marine
life has yet to be assessed.
How does Britain compare with other comparable
nations in R&D in this field? What projects are currently
being undertaken abroad and how successful have they been?
17. Because Britain has one of the best
world resources of wave and tidal climate, we are well-placed
to develop this potential and the Limpet wave-power device is
one of the most advanced systems world wide.
18. There are smaller systems wave-power
devices powering buoys and remote instrumentation at sea. For
example, the Japanese TWG-3 is currently used by Trinity House
Light House Service as well as in Denmark and Japan. Blue Energy
in Canada has also developed a 25kW Darrieus vertical axis turbine.
The Portuguese have built an oscillating water-column device in
the Azores and further work on tidal stream devices is being undertaken
in Norway, Italy and China.
19. Several designs have been developed
and tested around the world and over the last 10 years and predictions
now show that from an initial generating cost of 20p/kWh in 1980,
cost will be down to 6p/kWh in 2001.
20. In responding to this inquiry the RSE
would like to draw attention to the following Royal Society of
Edinburgh responses which are of relevance to this subject: Energy
and the Environment (December 1998) and New and Renewable
Energy (May 1999). Copies of the above publications are available
from the Research Officer, Dr Marc Rands (email: [email protected]).
16 February 2001