Memorandum by Rear Admiral Robin Hogg
and Professor Leslie Bradbury
This submission deals specifically with "Issue
6" in the Select Committee's call for evidence. In Devon
generally, and in the South Hams in particular, planning applications
for Wind Farms have caused widespread concern, both locally by
those living in the affected areas, and more widely by all those
concerned with the peace, tranquillity and beauty of the largely
unspoilt countryside. Whilst there is general support for the
use of renewable energy, the trade-off between the effectiveness
of Wind Farms on land and their effect on the countryside has
resulted in much misunderstanding and cynicism in the public mind.
It was for this reason that I commissioned the
attached study by an aerodynamics consultant, Professor Leslie
Bradbury, to examine the overall effectiveness of two typical
Sites currently being applied for in the South Hams: one at the
New Town of Sherford and one close to a remote rural community
near Kingsbridge. His brief was to provide a balanced overview
of the contribution made by Wind Farms to national power generation.
This was to enable us to make a coherent cost-benefit analysis
of the likely utility of these proposed Wind Farm Sites, set against
their undoubted damage to the landscape and the wide enjoyment
of it by all those who live in or visit the area. His conclusions
have nation-wide relevance.
I attach Professor Bradbury's report as a contribution
to the debate but several key factors emerge that would, I hope,
inform and influence their Lordship's discussions:
Wind Turbines are inherently low
energy sources and intermittent generators of electricity. Unless
they are very large; typically with rotor diameters in excess
of 90 metres demanding overall heights of around 120 metres and
are sited in areas where there is sufficient predicted wind, they
will not be effective. These sites tend to be in elevated areas
and, by definition, highly intrusive to the landscape.
For a wind turbine to be viable it
needs to be erected in a position where there will be a "guaranteed
average minimum wind speed of a 7.5 metres/second or above".
It follows that any application to erect a Wind Farm that cannot
guarantee such average Wind Speeds should not be considered. Such
a limitation should form part of Planning Law.
The technology and economics of wind
power dictate that Wind Farms of less than 10 Turbines are not
cost-effective. Small groups of turbines make little practical
or economic sense unless forming part of a coherent industrial
or business enterprise.
Wind Farms make quite unreasonable
demands on the environment in terms of land usage, typically requiring
1,000 times the land area of a single fossil fuel generation plant
of the same generating capacity.
Major cost-drivers tend to be: gaining
access to the National Grid, the need for numerous turbines of
very large size to make the investment viable and the lack of
sensible Planning Guidance in PPS 22 and its extension.
All investment in renewable energy
involves "Trade-Offs" of one sort or another, whether
it is for the application of Nuclear, Hydro-Electric, Wave or
Wind power. Electricity generation using wind power is the only
one of these technologies that cannot, by definition, contribute
to Base Load, relying as it does on an unpredictable and unreliable
source of energy. Any wind energy contribution must, therefore,
be judged more critically for its effects on the environment when
proposals to construct wind farms on land come forward.
In submitting this short technical appraisal
for your Lordships consideration we would strongly argue that
an absolute minimum technical and planning requirement should
be imposed on all applications to erect wind farms in England
and Wales and that these limitations should form part of future
This minimum technical requirement should
Any proposed Wind Farm site on land
should have an average wind speed of at least 7. 5 metres per
No Wind Farm application should be
considered involving less than 10 turbines.
As a general rule, no Wind Turbine
should be allowed within two kilometres of an habitable building
unless linked to a coherent industrial or business enterprise.
Bearing in mind Wind Farms excessive
demand for land usage, the intermittent nature of the power generated
and the unavoidable impact on the landscape, all future planning
applications should be forced to give greater weight to environmental
"WIND FARMS"THEIR PLACE
IN THE DEMAND FOR RENEWABLE ENERGY
This note deals primarily with issue 6 in the
Committee's Call for Evidence document.
How do the external costs of renewable generation
of electricitysuch as concerns in many affected rural areas
that wind farms and extra pylons spoil areas of natural beautycompare
with those of fossil fuels and nuclear power? How should these
be measured and compared? Is the planning system striking the
right balance between all the different considerations?
The present scheme whereby landowners can approach
power companies to install wind turbines on their land is creating
anarchy in the development of wind power in rural areas and, for
that matter, elsewhere. It is resulting in large numbers of planning
application disputes which are causing aggravation and costs to
rural communities and, at the same time, encourages applications
that would, in any case, make a negligible contribution to the
nation's "renewables" power targets. The origin of this
problem is vagueness in planning guidelines (like Planning Policy
Statement 22 and its extension) and the fact that the Renewables
Obligation Certificates make it attractive for power companies
to install even relatively small numbers of turbines on sites
that from a technical standpoint are not suitable in terms of
the wind characteristics. In the long term, this could add significantly
to the cost (as much as £10 billion) and the number of turbines
(up to 50% more) necessary to meet the "renewables"
targets. This problem is discussed in this submission and it is
suggested that the planning guidelines and the overall planning
process need modification to avoid these problems.
Some comments will be made about the relative
environmental impact of fossil and nuclear power stations compared
with wind turbines and it will be argued that the planning system
is not striking the right balance at all and that more precise
criteria need to be met before planning applications should even
1. BASIC DATA
Electrical power production in the
UK in 2006 was 44,000 megawatts.
A typical coal or gas power station
has a rated output of around 1,000 megawatts.
The submission mainly uses a 90-metre
diameter wind turbine that has a so-called rated output of 2 megawatts
as an example of a design that is likely to be most common for
on-shore developments in the future. These stand about 120 to
140 metres from base to rotor tip. In the context of wind turbines,
"rated" output does not mean deliverable power as it
does with a conventional power station. Deliverable power is about
a third of this and is a function of the hub mean wind speed as
will be shown below.
The area occupied by a 2 megawatt
rated turbine is taken to be 0.16 square kilometres (ie a square
of 0.4 x 0.4 kilometres).
The cost of installing wind turbines
is taken to be £1 million per rated megawatt for wind farm
installations (say, 10 turbines or more) and £1.25 million
for installations of one or two turbines.
2. OUTPUT POWER
It is important to put numbers to our argument
and so to set the scene, figure 1 contains calculations of the
output of three wind turbines over a range of mean wind speeds
from 5 to 10 metres per second. They are based on commercial designs.
The first is a 52 metre diameter rotor that has a so-called rated
output of 850 kilowatts. This unit is rather typical of the early
units on wind farms in Cornwall and elsewhere. The actual power
output from these turbines is very low at around several hundred
kilowatts and they have made a negligible contribution to the
"renewables" target and so should not be considered
in any future planning applications. The other two turbines are
more typical of recent designs with rotor diameters of 90 metres
and 126 metres giving rated outputs of 2 megawatts and 5 megawatts
respectively. The larger is a massive structure and probably suited
only to off-shore developments. Thus, we are going to use the
90 metre 2 megawatts design in our submission as it will almost
certainly be typical of the bulk of the on-shore units to be installed
in the future around the UK.
3. THE IMPACT
If we take 20% of the UK's electricity output
for 2006 as an ambitious and long term guide target for wind power
(ie 8,800 megawatts) then table 1 shows the impact of mean speed
on (i) the number of turbines necessary to meet this target, (ii)
the area they will occupy in square kilometres (iii) the overall
cost and (iv) the cost per kilowatt-hour of the electricity produced.
Also shown for the cost data is the influence of installing wind
turbines in farms of, say, 10 or more as against installing them
in small clusters of 1 to 3.
INFLUENCE OF MEAN WIND SPEED ON TURBINE NUMBERS
AND THE OPERATING COSTS OF WIND POWER
|Total power (megawatts)
||Life of turbine (years)
||Cost per turbine (10+ windfarm) (£M)
||Cost per turbine (1 to 3 units) (£M)
|Mean wind speed (metres/sec)||Mean power per turbine (kilowatts)
||Area covered (square kilometres)
||Cost (£ billions) for high number wind farms (10+)
||Cost (£ billions) for small number installations (1 to 3)
||Pence per kilowatt- hour for high number wind farms (10+)
||Pence per kilowatt-hour for small number installations (1 to 3)
Because there are no quantitative planning guidelines on
the wind speed of sites, many on-shore planning applications are
made where the mean wind speed is 7 metres/second or less. As
can be seen from the table, this sets a bad precedent because
it will lead to far more turbines than are necessary if only sites
with wind speeds greater than, say, 7.5 metres per second were
considered as suitable. The consequences of this are that the
wind power contribution to our overall power needs will be far
more intrusive than it need be and at a far higher cost. As an
illustration, if we take the extreme cases in the table of 6.5
metres per second and 8.5 metres per second, the extra costs are
of the order of £10 billion for 50% more turbines. In addition,
many of the rural sites being considered would contain only small
numbers of turbines and this contributes further to the cost increment.
From an examination of the wind map of the UK, there is no shortage
of good sites both on-shore and off-shore but a more pro-active
planning process is needed to ensure that they are used sensibly.
Relying on the randomness of landowners striking contractual relationships
with power companies is not the way to do it.
With some particular exceptions referred to later, planning
permission should not be considered for on-shore wind turbines
unless the wind characteristics of the site meet some minimum
standard. The suggestion is that this should be set at a minimum
of 7.5 metres per second at the turbine hub height. In addition
to this (also with some specific exceptions), planning permission
for sites of less than, say, 10 or 20 turbines should not be considered.
By virtue of their scale, these larger sites should therefore
be reasonably remote from residential areas.
Many do not appreciate that the requirement from "renewables"
is not only that they produce "green" energy but they
also have to produce electrical energy on an industrial scale.
This is not going to be achieved by random small-scale developments
but by properly sited large-scale wind farm developments. This
is self-evident in off-shore developments but it applies equally
well butwith more difficultyto on-shore developments
too. In this context, it should be noted that according to the
latest British Wind Energy Association database, there are now
a total of 2,032 wind turbines installed in the UK (both on-shore
and off-shore). The rated output of these is given as 2,545
megawatts. If we assume a power factor of a third, this gives
a real output of about 850 megawattsstill less than one
conventional power station! Even this comparatively small
contribution to the nation's power has caused an inordinate number
of planning disputes and, unless the planning guidelines are modified,
the whole development of wind power will become mired in a continuation
of this process.
5. COMMENT ON
One of the Catch-22 aspects of wind power is that areas like
cliffs, hilltops and elevated terrain generally will have the
most suitable wind characteristics and these are often areas of
the greatest natural beauty and the most visible sites from afar.
However, whilst the visual impact of wind turbines is a subjective
issue, most would acknowledge that they are not too intrusive
when viewed from a distance compared to, say, electricity pylons
and other tall structures that litter the countryside. On the
other hand, because of their great height and the dynamic effect
of the rotors, their near-impact can be very invasive and can
seriously detract from the attractiveness of, say, a rural village
6. EXCEPTIONS TO
There are many industrial sites and estates on which small
numbers of quite large turbines have been erected. These are mostly
privately sponsored by the company or companies on these sites.
Good examples of this are Avonmouth Docks (3 x 82 metre 2 megawatt
turbines) and McQuains Oven Chips, Whittlesey (3 x 90 metre 3
megawatt turbines). Even when they are not particularly wind sites,
these types of developments should not be discouraged because
(a) they create no environmental or aesthetic problems, (b) they
are invariably close to points of connection to the grid and so
are comparatively less expensive than similar developments in
rural areas and (c) they enhance the "green" credentials
of the developers.
7. CONSEQUENCES OF
If the above guidelines were incorporated formally into planning
guidelines, it would at a stroke remove most of the contentious
planning disputes such as characterise those proposals in rural
areas and also those low-wind sites such as fenland areas. It
would stop planning applications being made on small farm land
plots adjacent to rural villages and it would concentrate efforts
on those sites that offered a real contribution to our industrial
power requirements as opposed to the almost token-like contribution
that is a feature of many of the existing developments.
8. VISUAL IMPACT
The overall impact on the environment of different forms
of power generation is a complex issue but we are here just concerned
with the basic visual impact in terms of the land area occupied
by the different power sources.
The site of a typical 1,000 megawatt nuclear power station
occupies around 0.5 to 0.7 square kilometres (123 to 173 acres)
whereas a gas turbine power station with a similar output occupies
0.2 to 0.25 square kilometres (50 to 60 acres).
In the case of nuclear power stations, they are invariably
sited adjacent to the seashore because of the need for large amounts
of cooling water. These sites can be selected so that their overall
visual impact is very small. The visual imprint of gas turbine
power stations is even smaller and, because cooling water is not
required, they can be sited even quite close to urban developments
without making a noticeable impact. A simple screen of trees will
almost entirely disguise their presence.
To generate 1,000 megawatts of wind power on shore using
a 2-megawatt rated turbine will require between 1,250 and 1,500
turbines and they will occupy about 200 to 240 square kilometres
(50,000 to 60,000 acres). Thus, there is about a 1,000:1 difference
in the land usage and, unlike a fossil fuel or nuclear power station,
this number of turbines would be visually very self-evident.
It should be stressed that there are many hidden environmental
effects from conventional power stations beyond their straightforward
visual impact whereas the environmental influence of wind farms
is almost entirely related to their visual impact. Nonetheless,
as the basic sum shows, this is not trivial and it is yet one
further factor making off-shore wind farms a more attractive option
than on-shore ones.
9. LOCAL EXAMPLES
For background, Devon uses an average power of about 655
megawatts. Until recently, the county had no significant conventional
power stations but, from late 2008, a new Centrica gas turbine
power station just north of Plymouth is due to come on line giving
an output of 878 megawatts.
The South Hams area of Devon is a particularly attractive
and rural part of the county. As yet, it is free of any wind farms
but there are two proposals currently in place which, if approved,
would set a very bad precedent for the future.
9.1 Sherford new town
Sherford is a new town of 5,500 homes to be built east of
Plymouth and to the eco-town specification. The plan includes
provision for just two wind turbines rated at 2 megawatts that
will stand in a parkland area within about 500 metres of the easternmost
edge of the town. From base to tip, they would be about 120 metres
in height. Based on the best wind speed data available, these
two turbines would have a combined average power output of about
1.2 megawatts. No estimates of the overall power requirements
of the town are to be found in the planning applications but a
reasonable estimate is that it will lie in the range 6 to 8 megawatts.
The inclusion of the turbines in the plan seems to be driven by
concepts of local sustainability but, in the matter of electrical
power, this is not sensibly achievable with wind turbines. The
proposed town lies about one kilometre from the new gas turbine
power station mentioned above.
9.2 East Allington, near Kingsbridge
There is a hotly disputed proposal for three turbines to
be erected on farmland in an area of attractive rolling countryside
adjacent to three villages. It is an elevated and fairly windy
site and the three proposed turbines would have a combined output
of between 1.3 and 1.6 megawatts. Their base to tip height would
be around 100 metres. This example would set an extremely bad
precedent for the whole of South Devon. Once again, the power
output would make an entirely negligible contribution to the county's
power needs (let alone the country's) and yet it will impact on
the ambience of the three villages in an entirely deleterious
On page 8 of PPS22, there is the following paragraph:
"(vi) Small-scale projects can provide a limited
but valuable contribution to overall outputs of renewable energy
and to meeting energy needs both locally and nationally. Planning
authorities should not therefore reject planning applications
simply because the level of output is small".
This is typical of the vagueness of the planning guidelines
and it is leading to some frankly absurd planning applications
that totally fail to address the real problem of providing industrial
scales of power from "renewable" sources. The guidelines
need to be rewritten to reflect that the "renewables"
target represents a major engineering undertaking in which there
is little place for ad hoc small-scale developments.
16 June 2008