Factsheet 7: Small-scale wind for businesses
Energy efficiency should be a priority for all businesses trying to reduce their environmental impacts
and energy costs. Making efficiency improvements should be a continuous process of review and
action. For more information on taking a strategic approach to energy efficiency see link. Before
installing a small-scale wind system it is important to undertake energy efficiency measures. The
energy hierarchy provides a good guide as to how energy use can be most effectively reduced:
Priority 1: Reduce the need for energy
Priority 2: Use energy more efficiently
Priority 3: Use low carbon and renewable energy
Background
Wind turbines come in a variety of sizes and designs, all converting wind energy into electricity.
Most systems are ‘grid-connected’; they are connected to the existing building’s wiring and the
electricity generated is used on-site with any surplus being exported. Where grid connection is not
possible, off-grid systems (which use batteries to store the electricity until it is required) can be
utilised.
Wind turbines produce the greatest power when placed at sites with a good wind resource.
However, wind turbines have visual impacts and may not be considered appropriate in many
locations. Therefore, where environmental impacts can be satisfactorily addressed, the location of a
wind turbine may have to be a compromise between wind speed and its impact on its surroundings.
The energy generated by a wind turbine varies exponentially with wind speed; a suitable resource is
essential to ensure that a reasonable level of generation from the system is obtained. Wind speed is
dependent on location and generally increases with height above ground. For the best energy yield
and therefore return on investment, wind turbines should be located at sites with a good wind
resource. Wind speed data can be obtained from the Department of Energy and Climate Change
wind database. Wind speed varies with local conditions; any buildings or trees adjacent to a wind
turbine will cause turbulence and reduce wind speed. Whilst it is possible to mount wind turbines on
buildings, the increased turbulence and reduction in wind speed can reduce generation depending
upon the type of wind turbine design chosen. Before installing a wind turbine it is a very good idea
to measure wind speed for a period of around a year to establish the average wind speed at the
site.
With a grid-connected system, any electricity generated but not used at the site is exported to the
grid; therefore the system can be sized according to planning considerations (and capital available)
rather than the energy demand of the site. Where all of the electricity generated by the turbine can
be used on-site, expensive imported energy can be offset. Such situations will provide the most
attractive financial scenario, particularly where energy demand is greatest in winter. When used for
off-grid installations, and where appropriate to the setting, turbines are well suited for use in
conjunction with solar PV panels to provide reliable all year round electricity.
Most wind turbines are ‘horizontal axis’ machines, i.e. the blades rotate around a horizontal axle.
Vertical axis turbines are designed to perform well in turbulent areas (such as urban sites). Typical
turbine sizes are: 7m total height (1m blade radius and a tower height of 6m) for a 1kW system and
15m total height (3m blade radius on a tower height of 12m) for a 5kW system.
Practical considerations
Turbines are usually mounted on a metal tower secured by concrete foundations. Vehicle access to
the installation site is usually required to enable installation. The land area used by the turbine is
Whilst reasonable steps have been taken to ensure that the information contained within this publication is correct, the authors, the Peak
District National Park Authority, its agents, contractors and sub-contractors give no warranty and make no representation as to its
accuracy or suitability and accept no liability for any errors or omissions or for any loss or damage arising from the use of or reliance on
the information.
August 2010
small and the area around it can retain its existing use. As a cable must be installed between the
turbine and connection point, turbines should be located close to electrical connection points so that
cabling costs and electrical losses can be minimised. Large systems require connection to a three
phase supply and if the system is larger than 16A / phase (around 10kW), permission must be
sought from the local Distribution Network Operator prior to connection. Turbines should not be
located across the path of microwave telecommunications systems (the presence of which may be
indicated by local radio-masts).
Wind turbines last around 20 years and require occasional inspection and maintenance. In the case
of the larger 5kW turbine the maintenance would comprise an annual service costing several
hundred pounds and major parts such as bearings may need replacing after five to ten years.
Financial considerations
The electricity generated at a site is dependent on the turbine rating and design as well as the wind
resource. Therefore, it is important to choose the best turbine for a particular wind regime to
maximise output. The figures below show expected generation from 1kW and 5kW turbines
installed at a rural site with no local obstructions and a wind speed of 5m/s at 10m above ground
level. The value of electricity has been calculated assuming that all electricity is used on-site, thus
offsetting imports at a rate of 10p/kWh. In addition to electricity bill savings, eligible systems
installed under the Micro-generation Certification Scheme can benefit from financial incentives from
the Feed In Tariff as described below.
Typical costs and savings from a small wind turbine:
Turbine
size
(kW)
Cost
(£)
Output
(kWh per
year)
Value of generated
electricity
(£ saved per year)
Feed In
Tariff (£ paid
per year)
Carbon
saving
(tonnes/year)
1
£4,000
1,200
£120
£400
0.6
5
£25,000
8,800
£880
£2,300
4
Environmental impact and planning considerations
The natural beauty of the National Park is considered highly sensitive to wind turbine development.
Please contact the National Park Authority to discuss the environmental impact of a project and
planning issues at the earliest opportunity and certainly before submitting a planning application.
Early consultation with stakeholders can be invaluable in understanding how a system can be
located to minimise its impact and whether a wind turbine of a particular size is likely to be
considered suitable at a particular location.
Turbines should be located to minimise their visual impact on the surrounding area, e.g. they should
be located to avoid standing out on the skyline and located to make use of natural cover and local
topography. Consideration should be given to impact on neighbouring land uses and buildings. In
Britain, turbines are normally painted white or grey so that they blend in with the sky (which is
typically light grey). If the turbine will be only viewed against trees or hills the turbine could be
coloured green, brown or black to help minimise impact. Planning applications will typically need to
be supported by studies specified by the planning authority at the scoping stage. Studies may
include: visual assessments, noise studies, and ecological surveys, e.g. birds and bats studies.
Archaeological reports may also be necessary in areas where ground-works could disturb
archaeological remains. More detail of the likely planning considerations within the National Park
can be found in the Supplementary Planning Guidance for Energy: Renewables and Conservation.
Whilst reasonable steps have been taken to ensure that the information contained within this publication is correct, the authors, the Peak
District National Park Authority, its agents, contractors and sub-contractors give no warranty and make no representation as to its
accuracy or suitability and accept no liability for any errors or omissions or for any loss or damage arising from the use of or reliance on
the information.
August 2010