Memorandum submitted by Mr Peter Fraenkel,
Managing Director, Marine Current Turbines Ltd
SUMMARY
1. This memorandum consists of an introduction
to explain the interest and experience of the submitting organisation
in tidal stream (or non-barrier tidal energy) plus a brief outline
of the strategic importance of developing marine renewable energy
resources. This is followed by 10 distinct and important reasons
why we believe tidal stream technology of the kind we are developing
has excellent prospects for becoming technically, economically
and hence commercially viable, together with an explanation as
to why it has only recently become a practical option. Following
the introduction we have taken each of the issues described as
being of special interest to the Committee and provided a brief
response specific to tidal stream or non-barrier tidal energy.
INTRODUCTION
Marine Current Turbines Ltd and its involvement
in technology development
2. Marine Current Turbines Ltd (MCT) has
been set up specifically to develop and commercialise technology
for the exploitation of tidal and other marine currents. In other
words, to exploit kinetic energy of flowing water in much the
same way that wind turbines exploit the kinetic energy in the
atmosphere. We believe we are unique in our specialisation in
this field and that the technology we are developing (for which
we hold patents) has the potential to be a world leader.
3. MCT was originally founded by IT Power
Ltd (ITP), a technical consultancy company with 20 years' experience
of all aspects of renewable energy. ITP has completed a number
of pioneering projects on tidal (and river) current energy, mainly
in partnership with other organisations; these include several
projects funded by the European Commission and the DTI which will
be summarised below. Since ITP is primarily a consultancy company,
MCT was formed recently as a more appropriate vehicle to develop
commercial technology.
4. MCT has been instrumental in forming
a consortium of companies with a common interest in developing
tidal stream technology, including IT Power Ltd, Seacore Ltd.,
(a leading company in offshore engineering which has installed
the world's first offshore windfarm), Bendalls Engineering (a
manufacturer of high quality steel fabrications, primarily so
far for the petroleum and the nuclear industries), and Corus UK
Ltd (formerly British Steel). Each of these companies brings a
unique capability which will be required in the development of
the technology and all of them can benefit from the commercial
development which it is expected will result. There is also an
international dimension through part funding of the first phase
of our R&D project by the European Commission (contracted
to IT Power) which involves A Friederich Flender, the world's
leading manufacturer of wind turbine gearboxes and their associated
company Loher which builds marine electrical generators and seabed
mounted pumping equipment for the offshore oil and gas industry.
At the time of writing it seems likely that the inputs from our
German partners will be financially supported by their government
as well as by the EC.
5. The topics to be studied by the Select
Committee are especially important to us, since we have requested
financial support of the first phase of our R&D programme
from the DTI, who have received a proposal requesting approximately
£930,000 support from the UK Government towards the cost
of a £2 million initial project to install an experimental
tidal turbine off the coast of North Devon in 2002. The DTI have
in turn appointed independent consultants, Binnie, Black &
Veatch to evaluate the potential viability of the technology we
propose developing, and BBV are due to deliver a draft report
to the DTI during the course of February 2001. Moreover we believe
a measure of public state support is necessary for the technology
to receive the credibility to attract finance from the private
sector; energy systems that are not seen to be approved of by
government seem unlikely to develop any momentum.
Importance of marine renewable energy resources
in general
6. Most renewable energy technologies require
significant space, mainly because the energy resources they are
based on are diffuse. Land-based renewable energy technologies
are already facing constraints due to conflicts over land-use,
but the seas offer huge open spaces where future new energy technologies
could be deployed on a grand scale, without serious negative impact
on either the environment or on other human activities. Arguably,
unless we develop and use marine renewable energy resources we
will not be able to meet our future energy needs without continuing
to burn increasing quantities of fossil fuels simply because there
is insufficient space in areas of high population to deploy renewable
energy systems on a large enough scale to meet future energy needs.
This is the main argument for investing in these new and so far
little-developed offshore clean energy solutions. However, marine
renewable energy resources are generally more costly and difficult
to access than the land-based options, at least initially (which
is why experience with them so far is quite limited).
Ten reasons why tidal current, (non barrier tidal)
are likely to be technically and commercially viable as an energy
resource
7. 1. Higher energy intensity than most
renewables: the energy captured per annum for each square metre
of tidal turbine rotor at the locations with sufficiently fast
currents for economic exploitation is in the order of four to
10 times more than that from a wind turbine at a good wind location
and over 30 times greater than that of a solar photovoltaic array
in a location such as the Sahara desert. Tidal turbines can therefore
be relatively small in relation to their power rating compared
with other renewable energy technologies. For example, a 1MW tidal
turbine rotor would be less than 20m in diameter whereas a typical
1MW wind turbine needs a rotor of about 60m in diameter. Small
is beautiful in this respect, as capital costs relate to size.
8. 2. Predictable energy: the energy
in tidal streams is generated by the tides, so unlike the randomly
produced energy from weather-dependent renewables such as wind,
sun or waves, our technology will deliver electricity to a timetable
predictable for years or even decades in advance; this makes the
electrical output inherently more valuable to an electricity utility
as future electricity sales can be contracted at known times when
a premium might be gained due to high demand.
9. 3. Large resource: although tidal
currents with sufficient velocity to offer the possibility of
cost-effective energy production only occur at comparatively few
locations, such as around headlands and in straits, the resource
is known to be large enough to deliver tens if not hundreds of
terrawatt-hours per annum. Several especially energetic locations
around the UK coasts are expected to have the velocity over a
large enough area to permit the installation of projects of up
to several gigawatts of installed capacity.
10. 4. Favourable load factor: tidal
turbines can achieve a higher capacity factor or load factor than
is common with wind turbines, potentially in the range 35 to 40
per cent with a conventional two-tide regime (wind turbine capacity
factors tend to be in the 25 to 35 per cent range). Hence the
energy captured per megawatt of installed capacity is likely to
be up to 50 per cent higher from a tidal turbine farm than from
a wind turbine farm, yet wind turbines are already a viable method
for power generation.
11. 5. Compactness—projects need
less sea-space than offshore wind: because the flow of tidal currents
is generally bi-directional (rather than multi-directional as
with winds) tidal turbines can be packed closely together transversely
across the flow so that the power density of a tidal turbine farm
is in the order of 50 to 100MW/km2 compared with perhaps 10 to
20MW/km2 for a wind turbine. Therefore less sea-space is needed
for a given installed capacity of tidal turbines and cable costs
for interconnecting the turbines are significantly reduced. There
are also other technical reasons why close packing of turbines
can reduce costs.
12. 6. Low visual impact allows location
close to shore: tidal current turbines can be either totally submerged
and out of sight, or (preferably) surface-piercing but with a
limited visual profile. Therefore they are likely to be acceptable
much closer to the shore than wind farms and this again can result
in significant cost savings through the shorter electrical connection
to the shore.
13. 7. Low cost and robust steel construction
based largely on conventional engineering: the tidal turbine we
are developing is based on fabricated steel, more like a ship
than an aircraft, which is a relatively low cost and robust means
of construction. Moreover, the basic principles involved are well-understood
and the systems can be built largely from components that have
already been developed for use in other contexts; for example
the rotor and drive train are not dissimilar technically from
a hydropower bulb turbine, or a large submersible pump or, for
that matter, a modern ship's thruster or "Azipod". Therefore
we believe the development risks are relatively low and reliable
technology can be demonstrated reasonably quickly. We hope and
expect that commercial projects can be initiated within three
to four years of initiating the R&D programme providing the
necessary resources materialise.
14. 8. Modular technology—turbines
can be installed on a small or on a large scale: tidal stream
turbines can be installed in small batches on a modular basis
and the lead time for installation can be relatively short (a
few months). Hence there is a lot of flexibility in the size of
possible projects (they can start small and be extended at reduced
marginal cost later) and also revenue can be realised relatively
soon after the capital investment costs are incurred, with less
risk of serious cost over-runs than for non-modular large projects.
Tidal barrages or large scale hydro are quite inflexible in this
respect, with little scope for expansion to meet increasing demand
and long lead times for construction during which large cost over-runs
can occur before a penny of revenue is generated.
15. 9. Underwater conditions are relatively
benign: although the sea appears to be a harsh environment, conditions
more than 5m below the surface are relatively calm and predictable;
there is no underwater equivalent of a hurricane. Waves decay
rapidly with depth, especially where there are strong currents.
As a result the tidal turbine technology we are developing needs
to be designed to survive extreme loadings that are much closer
to the design conditions than for wind or wave energy devices.
Hence the degree of overdesign needed to withstand rare extreme
conditions is relatively small, as is risk of damage from storms.
Reduced extreme loads lead to greater cost-effectiveness. Common
concerns about corrosion protection and marine growth can be readily
countered using techniques such as cathodic protection developed
from experience with offshore oil and gas development; however
steel structures installed in the North Sea during the Second
World War still stand 60 years later even without cathodic protection.
There is no reason why the supporting structure for tidal steam
turbines should not have a life of half a century or more, much
like the civil works for a hydro plant.
16. 10. Tidal turbines are expected
to have a minimal environmental impact: they can generate electricity
for decades without pollution. The rotors need to rotate a low
speeds (to avoid cavitation) and therefore pose no real threat
to fish or marine mammals; a ship's propeller typically rotates
at 10 times the speed of our turbine rotors, and moreover the
turbine stays in one place but ships move, often at faster speeds
than marine fauna.
17. The combination of these advantages
ought to indicate a technology that could offer some of the least
costly electricity possible from any source, least costly in terms
of both cash and environmental damage. Detailed analysis of the
likely costs of the technology leads us to believe these benefits
can be realised within a relatively limited time frame and from
a relatively low cost R&D programme using already known engineering
techniques.
A frequently asked question is, "why, if
this is such a good idea, has it not been done before?"
18. Answer—as soon as any engineer
starts to evaluate the technical requirements for installing a
tidal turbine in the sea, a number of seemingly daunting problems
arise. The main problems are firstly how to hold a turbine rotor
securely enough that it cannot be swept away; for example the
thrust on the rotor of a 1MW tidal turbine rotor running at full
power is in the order of 100 tonnes force, which of course poses
a significant structural or mooring problem. Secondly how, if
you need to carry out work on the system, can you do this underwater
with fast moving currents? Slack tide is a matter of minutes,
and conditions at energetic locations are the underwater equivalent
of a storm swept mountain top, so it is virtually impossible for
divers or ROVs to function effectively. However the breakthrough
that makes the technology we are developing feasible is the result
of a relatively recent technical breakthrough, the possibility
of installing steel piles (large steel tubes) in holes in the
seabed drilled from a jackup barge. A jackup barge can raise itself
on legs like a table to provide a steady platform above the sea
from which all the installation work can be completed. Moreover
the patented turbine concept we are developing is mounted on a
pile in such a way that it can be raised above the surface of
the sea for maintenance or repair. In other words, we have found
a relatively low cost structure with the integrity to support
a large turbine or turbines with solid reliability for many decades
and the entire system can be installed, serviced and replaced
without any need for underwater operations; everything is done
from either a jackup barge or surface work boats. Without this
approach we do not think the exploitation of tidal currents would
be a practical proposition.
19. It is worth noting that the most cost-effective
solution for installing offshore wind turbines is also on mono-piles
for much the same reasons.
ISSUES STATED
TO BE
OF SPECIAL
INTEREST FOR
THE COMMITTEE
Technological viability. Is the technology available
for efficient generation of power from waves and tides?
20. The concept of using tidal currents
as an energy resource has not been seriously taken up until relatively
recently (the 1980s and 90s). Only limited resources have been
available so far to permit experimentation and research (the European
Commission has been the largest donor by far, but even the EC
has only funded about half a dozen projects in this field). As
a result, most of the work so far has been either theoretical
or else small scale experimentation. "Full-size" pilot
projects are now needed to take the technology forward as the
main uncertainties relate to implementation, operation, cost and
reliability.
21. The concept we are developing has reached
the stage where it is ready for a "full-scale" pilot
project, and it is hoped to install a 300kW demonstrator and test
bed off the coast of Devon in 2002. The EC has part funded this
work and a design has been developed and costed, a site has been
identified and surveyed and permissions have been requested from
all the relevant authorities. The indications are that the necessary
permissions will be granted. The industrial partners have pledged
to contribute a significant financial component and an application
has been made to the DTI for the necessary top-up finance to carry
this phase of a planned R&D programme to a successful conclusion
by 2004. The DTI has responded reasonably positively by appointing
Binnie, Black and Veatch as independent consultants to confirm
or disprove the claimed viability of the technology for commercial
development. B, B & V are due to submit a draft report to
the DTI during February 2001.
22. Given that the proposed project just
outlined goes ahead, a second phase will follow a year later to
develop and install a twin rotor commercial prototype. This will
be installed by 2003-04. A third phase is also planned to be the
first tidal turbine "farm", consisting of at least four
twin rotor turbines capable of delivering in the order of 3 to
5MW between them and it is planned for 2004-05. This third phase
will be partially self financing from revenue from the sale of
electricity. The development of commercial tidal turbine projects
will follow immediately thereafter in 2005-06. Marine Current
Turbines Ltd's business plan envisages the possibility of installing
in the order of 300MW worth of turbines by 2010, so the technology
could make a significant contribution to the Government's target
for 10 per cent renewable energy generation by that year.
Commercial viability. Will wave and tidal energy
become commercially viable in the near future and attractive to
the private sector as a profitable investment?
23. We have completed detailed technical
and economic analysis and believe the concept we have under development
has the potential to generate electricity within five years for
less than 4p/kWh, providing reasonably large projects (minimum
size 20 to 30MW) are carried out (to share the fixed overheads
between sufficient turbines). We believe that in the longer term,
thanks to the high energy intensity of tidal currents, generating
costs of less than 3p/kWh can be achieved. Therefore this is one
of the few large scale renewable energy concepts capable of competing
directly with fossil fuel on a generating cost basis.
Present (and recent) projects. What projects are
currently running in the UK and how successful have they been?
Why did past projects fail?
24. There are as yet no commercial projects
as the technology for large scale power generation from marine
currents is still at an early stage of development. However, there
are a number of relevant R&D activities known to be current.
These include . . .
Present UK based projects
25. "The commercial prospects for tidal
stream power", 2000-01, study led by Binnie, Black &
Veatch (with IT Power and Marine Current Turbines Ltd) funded
by the DTI, to review viability of performance and cost models
for tidal turbine under development by Marine Current Turbines
Ltd.
26. "Optcurrent"—Optimising
the performance of Tidal Current Turbines—EC Joule Programme
project JO3-CT98-0205, 1998-2001: This project is led by Prof.
Ian Bryden, Robert Gordon University, Aberdeen in partnership
with IT Power, University College, Cork (Ireland) and Thetis (Italy).
The main goal of this project is the development of a methodology
for optimum matching, both technical and economic, of tidal current
turbines to given local flow conditions. This involves development
of techniques involving 3D modelling of marine current flows and
of taking spot readings at sea to feed into the models.
27. "Seaflow"—World's First
Pilot project for the exploitation of marine currents at a commercial
scale—EC Joule Programme Project JOR3-CT98-0202, 1998-2002:
this is intended as the first phase of the R&D programme planned
by Marine Current Turbines Ltd. This project was launched in September
1998. It involves the development of what is expected to be the
world's first "commercial scale" marine current turbine,
a system rated at 300kW to be installed on a mono-pile, socketed
into the seabed in SW UK coastal waters. The target date for commissioning
the system is summer 2002. Marine Current Turbines Ltd was formed
to take on the commercial development of the technology.
28. Engineering Business "Active Water
Column Generator": The Engineering Business (a UK company)
has invented a new scheme for extracting energy from tidal streams.
This patented scheme is called the Active Water Column Generator
(AWCG). This development work was partially funded by a DTI Smart
Award. The device converts continuous flow into an oscillating
action. It is claimed the results are encouraging and that developments
leading to a large scale demonstrator are under way.
29. "Potential for using marine currents
in the Philippines": Marine Current Turbines Ltd has a "Climate
Change Challenge Fund" award from the FCO to study the potential
for using tidal currents in the Philippines, working in partnership
with the Philippines Department of Energy. The indications are
that the Philippines and other island nations in the Pacific Rim
have large current kinetic energy resources and they also have
major problems in finding viable on-shore renewable energy resources
capable of meeting more than a fraction of their future energy
needs. Hence there is considerable interest in this project.
Recent UK Based Projects (Post 1990)
30. UK Tidal Stream Review, 1992-03: desk
study led by Engineering and Power Development Consultants with
Binnie & Partners, Sir Robert McAlpine & Sons, and IT
Power. Report published by ETSU and the DTI as T/05/00155, 1993.
This was the first officially supported attempt to evaluate a
national tidal current resource. This desk study confirmed that
there is a large tidal current energy resource, capable theoretically
of meeting some 19 per cent of present total UK electricity demand,
but not economically under the cautious costing assumptions applied
at that time. The most favourable results estimated that there
could be a resource of about 20TWh/yr in UK waters capable of
being exploited at a cost of up to 10p/kWh at a discount rate
of 8 per cent. The technology hypothesised consisted of axial
flow rotors mounted on gravity foundations on the seabed.
31. Axial Flow tidal turbine "Proof
of Concept" project—by Scottish Nuclear, IT Power and
NEL (formerly the National Engineering Laboratory): in 1993-04,
a consortium consisting of IT Power, Scottish Nuclear and NEL
developed an axial flow 3.5m diameter rotor suspended below a
floating catamaran pontoon. It successfully developed some 15kW
in 2.25m/s current velocity at Loch Linnhe, Scotland in 1994 and
although quite small, it remains the largest marine current turbine
so far demonstrated. It successfully met its limited objectives
and highlighted problems with mooring floating tidal current turbines.
32. The Exploitation of Tidal/Marine Currents—EC
Joule Programme—JOU2-CT94-0355—1994-06: technical
study carried out by IT Power and Tecnomare (UK). DGXII of the
EU supported a technical and a resource assessment of marine current
energy in Europe. The technical study (completed in 1996) examined
relevant technology from related areas (wind, hydropower, maritime,
and offshore) and found that electricity cost from tidal current
turbines is specially sensitive to the size of machine, economic
parameters (lifetime, discount rate), O&M costs, and the load
factor obtainable at a particular site. It estimated electricity
unit costs for "First Generation systems" at around
0.05 EU/kWh (3.5p/kWh) for a 3m/s rated current under favourable
circumstances (ie with a high load factors).
33. Feasibility Study of Tidal Current Power
Generation for Coastal Waters: Orkney and Shetland—ICIT—1995:
The Regional and Urban Energy Programme, DGXVII of the EU financed
a feasibility study on supplying Orkney and Shetland with electricity
from tidal stream turbines. Island communities, which frequently
have higher than normal conventional energy costs, may offer an
attractive initial market for electricity from tidal streams.
This programme was co-ordinated by Dr Ian Bryden, then of the
international Centre for Island Technology at Stromness and IT
Power worked on hypothesising the turbine technology. Actual on-site
current measurements were used for the first time in conjunction
with a 3D computer model to produce detailed tidal stream characteristics
for two sites. Consideration of a cluster of eight turbines of
20m diameter mounted on steel mono-piles gave a predicted electricity
cost of approximately 6p/kWh.
Renewables strategy. What role should wave and
tidal energy have in the Government's renewable energy strategy?
Should they be a higher priority?
34. It is already accepted in many quarters
that the post-Kyoto target of meeting 10 per cent of the nation's
energy needs from renewables is unlikely to be feasible if we
rely solely on onshore renewables, due to conflicts over land
use. As a result, offshore wind is now widely considered to be
an essential component to achieve the government's target, mainly
because that seems the only way wind energy can be exploited on
a sufficiently large scale. It has also turned out to be less
costly and less difficult than originally projected. However,
the marine renewables, tidal currents and waves, are more intense
than wind as a resource and therefore potentially more cost-effective;
they are just less well understood or developed. Moreover, some
of the problems of developing the new marine renewables are generic,
for example installation techniques and interconnection of systems
with each other and the grid, so work in one area could benefit
others.
35. A generic problem with all the offshore
renewables is that they cannot readily be tested on a reduced
scale (there is a minimum size of equipment that can be installed
in the sea and survive offshore conditions) and they will also
need to be deployed in large numbers for commercial viability,
due to the high fixed overheads involved in connecting them to
the grid and for the mobilisation and development of the installation
process.
36. Therefore there needs to be a strategy
to demonstrate tidal stream and wave energy on a realistic scale
for large scale replication as rapidly as possible. This is primarily
to get the experience necessary to understand the practical problems,
and how they might be overcome and to give the technologies the
credibility and reduce the perceived risk so as to attract the
private sector investment needed to take them to commercial reality.
This might be seen as a form of public private partnership, with
the state helping to incentivise the private sector to invest
in technology that is essential to solve the huge problem of providing
clean energy in the future for the benefit for all.
37. Tidal currents can almost certainly
be taken forward to commercial development within a relatively
short period (around five years), due to being largely based on
well understood engineering principles, and through using already
available engineering techniques and components. Wave energy,
on the other hand, may take longer to mature due to the much harsher
extreme conditions that the systems need to withstand and also
due to the lack of clarity as to which form of technology is likely
to succeed first.
38. Both the Marine Foresight panel report
"Energies from the Sea—Towards 2020" (April 1999)
and the House of Lords Select Committee on the European Communities
report "Electricity from Renewables" (June 1999) advocated
that the Government should support R&D on tidal stream technology,
but until now there has been no DTI policy on whether or not "tidal
stream" should be part of its programme. The recently commissioned
study by Binnie, Black & Veatch (see above) is the first significant
commitment to looking at tidal stream for the DTI since the 1992
Tidal Stream Review (also referred to earlier). It is certainly
to be hoped that following the B B & V report, the government
will include tidal stream as an integral and important part of
its renewable energy programme, with a view to seeing it making
a significant contribution (more than 100MW) to the national electricity
supply by 2010, something which will almost certainly be achievable
given suitable financial and political support.
39. To achieve this aim, there is a need
for a well structured R&D programme that will require significant
government funding to kick it off, but which, once under way should
increasingly attract private sector finance. Public finance should
no doubt be provided on a competitive basis and any form of technology
that gains support might have a phased development plan with pre-defined
"milestones" to be reached before further funding can
be forthcoming. However, the Government needs to share the risk
with the private sector participants, especially at the early
stages, as even the most promising ideas can run into unforeseen
problems that take a bit more time and expense to solve. No novel
method of energy generation has ever been effectively pioneered
without some government support and it would be unreasonable to
expect an infant industry to develop purely as a result of "market
forces", especially in an area of technology that is so highly
dependent on legislative arrangements (eg NETA).
40. Since one of the main reasons for advocating
the development of tidal stream technology is that it is a potentially
low cost power source, the necessary R&D programme's costs
can also be reasonably modest. Marine Current Turbines Ltd has
a planned programme to develop commercial technology which will
probably require a total investment in R&D of no more than
about £15 to £20 million, some of which can be debt
financed from electricity sales revenue, which is a small amount
of investment to develop an entirely new energy technology with
potential for much larger scale development.
Research and Development. What Research and Development
is being undertaken at present? How much funding is available,
and how easy is it for innovative ideas to gain support? Is national
funding for R&D being well co-ordinated? What sort of peer-review
processes are undertaken?
41. The present and recent tidal stream
R&D projects in the UK were summarised earlier. Virtually
all of them have been either funded in whole or in part by the
European Commission, often with the partners providing matching
funds from internal resources. This area of technology has not
so far been supported by the UK government as part of the DTI's
renewable energy programme, although EPSRC has invited universities
and research institutions in the UK to submit proposals for research
in the area of tidal stream following the favourable recommendations
in 1999 from the "Foresight" initiative. As a result
a number of small research projects have started recently in several
UK universities, although unfortunately it is believed the last
call from EPSRC failed to generate any new projects in this field,
despite several proposals having been submitted.
42. The situation has improved recently
in that it is understood (from informal discussions) that the
DTI does not rule out support for tidal stream R&D in its
recent call for proposals for renewable energy R&D. Also other
bodies such as the Industry Technology Facilitator (ITF), a not
for profit organisation based in Aberdeen and owned by 16 oil
and gas operating companies, has recently invited proposals for
R&D on topics including tidal stream energy, although any
projects resulting from this need to be aimed at meeting oil industry
needs.
Environmental aspects. What are the environmental
implications of wave and tidal energy, particularly for marine
life? How will such devices affect shipping?
43. An obvious worry is whether marine fauna
are at risk from impact with the revolving rotor blades of a tidal
stream turbine. The conclusion was that the environmental impact
including risk of injury to wildlife is likely to be very low.
It should be noted that a tidal turbine rotor is limited to a
rotor blade tip velocity of no more than around 15m/s (ie approx.
30 knots) to avoid loss of efficiency due to cavitation, and most
sea creatures found in areas of high currents can swim at similar
velocities. In contrast, the average ship propeller rotates 10
times faster than a tidal stream turbine and moreover is a much
greater threat since the vessel it is attached to may be moving
at a much faster speed than fish or marine mammals, whereas the
tidal turbine is of course fixed in one spot.
44. An environmental impact study was completed
in connection with the project "Feasibility Study of Tidal
Current Power Generation for Coastal Waters: Orkney and Shetland—ICIT—1995"
referred to earlier, because clearly there is special concern
in those islands to avoid causing any harm to marine mammals such
as seals. This study found that the risk from tidal turbines to
the environment is likely to be minimal (and of course the benefits
from avoided atmospheric pollution if the technology "takes
off" will be large).
45. Tidal stream turbines will pose an obstacle
for shipping, although most of the best high energy locations
with fast currents are usually close to a rocky shore, and are
not in areas that are used as shipping lanes. All the resource
studies so far carried out have assumed that only areas outside
regular shipping lanes can be used for tidal stream energy systems.
The turbines will of course be clearly marked on marine charts
and will carry the gamut of necessary navigation aids including
lights, radar reflectors and foghorns. Arguably they may serve
to assist navigation in the same way that navigation buoys do,
by being more identifiable to mariners than unmarked and often
hazardous natural features nearby. It is likely that large tidal
stream projects will need to be part of a shipping and fisheries
exclusion zone. However, the sea has an enormous area and even
the largest marine current projects will need to use only a small
part of the space available.
46. There could also be a conflict with
fishing, although it is not normal to fish at locations with peak
currents of several knots for obvious reasons.
47. In the last analysis, no energy technology
can be completely lacking in environmental impact, but tidal steam
technology looks likely to offer less negative environmental impact
than most.
International comparisons. 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?"
48. We believe the UK has a technical lead
in the field of tidal stream technology, together with interested
industrial partners capable of extending the lead and developing
a unique British capability of supplying the world with tidal
turbine technology (probably with German participation).
49. Given the necessary government backing
to allow a rapid and effective R&D programme to go ahead,
then there seems no reason why the UK might not gain a major new
industry within 10 years, with considerable export potential,
for hardware, licensed production and services. This could be
achieved as part of the solution to the problem of meeting our
clean energy needs through simultaneously developing projects
to use the technology in our home market.
50. All the projects relating to water current
energy conversion carried out abroad have also been small scale
experiments or desk studies. Countries with the most technically
credible activities completed so far are the Netherlands, Japan,
Australia and Russia where small turbines have been successfully
built and tested and demonstrated (these were all only a few kW
in rated power). All of these, with the exception of the Japanese
project, involved mounting turbines under floating rafts, which
at present would be difficult to scale up to a level to feed power
to the grid due to unresolved difficulties in mooring a large
enough raft. The Japanese (a university research team rather than
a commercial entity), installed a small turbine on the sea bed
and it ran successfully for about nine months. A Canadian company
has taken a concept tested extensively with Canadian government
support during the 1980s and is pushing the idea strongly with
a view to raising large sums of money, which involves building
what they call a "tidal fence", a wall in the sea with
turbines in it. For various technical reasons we do not believe
this is a serious competitive threat (it looks unlikely to be
cost-effective) other than in terms of possibly attracting finance
away from work we believe to have better chances of commercial
success.
51. We are quite certain that the extraction
of energy from marine and tidal currents will soon be a viable
method of energy generation. Potential competitors are beginning
to see the possibilities too. We have various advantages which
could soon be lost unless we can press ahead at a good pace with
the necessary R&D programme. Britain has so far largely failed
to gain a significant market share in any renewable energy technologies;
here we have a new chance to develop an important new technology
with high commercial potential providing it can get the support
it needs soon.
February 2001
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