Download Offshore Wind Factfile - Centre for Alternative Technology

Offshore Wind Factfile
Key points
 Huge potential to produce electricity for the UK
 The amount of electricity produced over the year can be roughly predicted but day to day
production can only be predicted at fairly short notice
 More electricity is produced in the winter, when more electricity is required
Background information – how does it work?
 Wind is moving air caused by the uneven heating of the Earth's surface by the sun. When air is
warmed, for example by land warmed by the sun, it expands and rises, and heavier, cooler air
rushes in to take its place, creating wind.
 Offshore wind turbines are placed in the sea. In shallower waters, up to around 80 metres in
depth, wind turbines are fixed to the seabed. Most current offshore wind farms are of this type.
North Hoyle Windfarm near
Rhyl, North Wales
Generates enough electricity for
50,000 homes
It is also possible to have floating wind turbines in much deeper waters. Floating turbines have already
been built and tested, and a floating-turbine wind farm is planned in Scotland.
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 Offshore wind turbines usually generate more electricity than land-based turbines due to their
larger size and higher wind speeds at sea. A typical turbine at sea has a rotor diameter of over
100m long with a rated output of 5 MW. Designs up to 8 MW are now available. [2,3,4].
Current use in world and UK
World
 The use of wind power is expanding rapidly around the world.
 The installed capacity (the amount built and producing energy) reached nearly 300 gigawatts
(GW) in 2012 and wind power provided 2% of the world’s electricity [5].
 However, the vast majority of this was from onshore wind, with only 5 GW of offshore by 2012.
Most offshore wind is installed off northern Europe, but China also has working offshore wind
farms and both China and the United States have ambitious future plans for offshore wind [6].
Britain
 Britain is currently the world’s largest user of offshore wind.
 By the end of 2012, the UK had 3 GW of offshore wind installed capacity.
This provided 2% of the UK’s electricity [7]. The figure is now over 3.6 GW and over a thousand offshore
wind turbines.
 It is expected there will be around 8 GW of installed capacity by 2016 and around 18 GW installed
by 2020, by which point offshore wind will supply about 20% of the UK’s electricity annually [8].
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Climate change and impact on nature
Climate Change
Wind turbines do not emit any greenhouse gases when generating electricity.
There are some greenhouse gases from the
 manufacture,
 installation,
 maintenance and
 disposal of turbines
and their supporting infrastructure.
Lifecycle assessments of offshore wind energy suggest emissions of about
11 grams of CO2 or equivalent greenhouse gas per kilowatt-hour (gCO2e/kWh) [9].
Other Environmental Impacts
The visual impact is usually less for offshore wind turbines than onshore turbines, although some
offshore wind farms are clearly visible from the coastline.
Local environmental impacts include
 The process of fixing the turbines to the sea bed has an impact on local habitats on the seabed
but once the base has been there for a while it can help create habitat, as sea creatures attach
themselves and make their homes on and around objects on the seabed.
 Large windfarms can upset birds’ breeding grounds and the migration routes they follow. In
Britain these areas are avoided when planning windfarms.
A UK government report recommended a coastal buffer zone of 12 nautical miles, within which major
wind farm development would not normally occur, to minimise environmental impacts [10].
Risks
 Wind power is a low risk technology. Whilst there is some risk in the manufacture and installation
of turbines, this is low.
 Since wind turbines produce no air pollution in operation and only a relatively small amount in
production, the negative impacts on human health are minimal.
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 Some studies conclude that wind power causes very few deaths per unit of energy produced
compared with fossil fuel energy sources [11,12,13].
Cost now and in the future
 It is estimated that new offshore wind farms, constructed now, could produce electricity at a cost
of about
12-13 pence per kWh.
 This cost could fall to around 10-11 pence/kWh by 2030.
 In future, if carbon taxes are implemented, electricity from offshore wind will be cheaper than that
from coal and close to that from gas [14,15].
If wind farms (or other sources whose output varies up and down uncontrollably), supply a high
proportion of our electricity, it will be necessary to manage the electricity system rather differently. This
might add up to 1 pence per kWh of the variable electricity [15].
World and UK resource
Wind power is a renewable resource – it will not run out.
World
 The global resource for wind power is very large.
 The technical potential for offshore wind has been estimated at 130 exajoules per year (37,000
TWh/year) at depths less than 50 m.
 This is over one and half times greater than current global electricity production. If deeper waters
are considered the potential could be many hundreds of exajoules per year [16].
Britain
 The UK resource for wind is very good, as we get some of strongest winds in Europe, both
onshore and offshore [17].
 It is estimated that offshore wind in the UK could provide around 400 TWh/year from wind
turbines fixed in the seabed.
 This is more than our current total electricity consumption.
 Floating wind turbines in deeper waters could potentially provide even more - up to 1,500 TWh,
which is almost as much as our total current final energy use [2,18].
Wales
The Welsh Government has a target to increase the offshore wind capacity of Wales to 6 GW by 2016
(Department of Energy and Climate Change, 2014b). The map of current, approved and planned
offshore wind farms can be zoomed in on Wales/to your local area: http://www.renewables-map.co.uk/
Gwynt y Môr has an installed capacity of 576 MW, using Siemens 3.6MW turbines and generators. It is
capable of generating enough energy to meet the average annual energy needs of around 400,000
homes [21].
Rhyl Flats wind farm, which has a power rating of 90 MW, is situated 5 km off the coast of North Wales,
between Abergele and Rhos-on-Sea and provides enough electricity to power 61,000 homes.
North Hoyle, a 60 MW wind farm, also located off the coast of North Wales, can power 50,000 homes.
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[20]
Link to article about case study of Rhyl Flats: http://www.rwe.com/web/cms/en/310584/rweinnogy/sites/wind-offshore/in-operation/rhyl-flats/summary/
Video about the installation of Rhyl Flats wind farm http://www.youtube.com/watch?v=DWfbvEAcLmQ
Reliability/flexibility




Wind power is an intermittent source of energy, which means that the amount produced varies up
and down in an uncontrollable way as the wind speed varies.
The wind over the seas surrounding the UK are stronger than those over land [17].
However, there are still times when the wind speeds in UK waters are quite low.
The average amount of energy produced over the year can be predicted but in the short term,
output can only be predicted accurately over a matter of days, so careful planning is necessary to
provide energy when people need it.
References
[1] EIA (2013). Wind Explained. United States Energy Information Administration.
http://www.eia.gov/energyexplained/index.cfm?page=wind_home [accessed 21/1/2014].
[2] CAT (2013). Zero Carbon Britain: Re-thinking the Future. Centre for Alternative Technology.
http://zerocarbonbritain.org/ [accessed 22/1/2014].
[3] EESI (2010). Fact sheet: Offshore Wind Energy. Environmental and Energy Study Institute.
http://www.eesi.org/files/offshore_wind_101310.pdf [accessed 22/1/2014].
[4] BBC (2013). Floating Statoil wind farm planned off coast of Peterhead. BBC News.
http://www.bbc.co.uk/news/uk-scotland-north-east-orkney-shetland-25086288 [accessed 22/1/2014].
[5] BP (2013). BP Statistical Review of World Energy June 2013. BP. http://www.bp.com/en/global/corporate/aboutbp/energy-economics/statistical-review-of-world-energy-2013.html [accessed 8/1/2014].
[6] GWEC (undated). Global Offshore. Global Wind Energy Council. http://www.gwec.net/global-figures/globaloffshore/ [accessed 22/1/2014].
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[7] DECC (2013). Statistics at DECC. Department for Energy and Climate Change.
https://www.gov.uk/government/organisations/department-of-energy-climate-change/about/statistics [accessed
8/1/2014].
[8] Renewable UK (undated). Wind Energy. Renewable UK. http://www.renewableuk.com/en/renewableenergy/wind-energy/index.cfm [accessed 21/1/2014].
[9] OpenEI (undated). LCA Harmonization. OpenEI. http://en.openei.org/apps/LCA/ [accessed 17/1/2014].
[10] DECC (2009). UK Offshore Energy Strategic Environmental Assessment (OESEA): Environmental Report.
Department for Energy and Climate Change. https://www.gov.uk/government/publications/uk-offshore-energystrategic-environmental-assessment-oesea-environmental-report [accessed 22/1/2014].
[11] Starfelt, N. and Wikdahl, C (undated). Economic Analysis of Various Options of Electricity Generation - Taking
into Account Health and Environmental Effects. http://manhaz.cyf.gov.pl/manhaz/strona_konferencja_EAE2001/15%20-%20Polenp~1.pdf [accessed 14/1/2014].
[12] Unnamed (undated). Deaths per TWh for all energy sources. http://nextbigfuture.com/2008/03/deaths-per-twhfor-all-energy-sources.html [accessed 14/1/2014].
[13] Mackay, D. (2013). Sustainable Energy – without the hot air. http://www.withouthotair.com/ [accessed
20/1/2014].
[14] CCC (2010). The Fourth Carbon Budget – reducing emissions through the 2020s. The Committee on Climate
Change. http://www.theccc.org.uk/publication/the-fourth-carbon-budget-reducing-emissions-through-the-2020s-2/
[accessed 9/1/2014].
[15] DECC (2012). Electricity Generation Costs. Department for Energy and Climate Change.
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/65713/6883-electricity-generationcosts.pdf [accessed 9/1/2014].
[16] IPCC (2011). IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation.
Intergovernmental Panel on Climate Change. http://srren.ipcc-wg3.de/report/ [accessed 21/1/2014].
[17] Wind Atlas (2011). European Wind Atlas. The World of Wind Atlases – Wind Atlases of the World.
http://www.windatlas.dk/europe/About.html [accessed 22/1/2014].
[18] CCC (2011). The Renewable Energy Review. The Committee on Climate Change.
http://www.theccc.org.uk/publication/the-renewable-energy-review/ [accessed 9/1/2014].
[19] Elexon (undated). Neta - Electricity summary page. Elexon. http://www.bmreports.com/bsp/bsp_home.htm
[accessed 8/1/2014].
[20] Map of installed and approved large scale wind sites
http://www.assemblywales.org/Research%20Documents/Renewable%20Energy%20in%20Wales%20in%20figures
%20-%20Research%20paper-12082013-248986/13-059-English.pdf
Map of current renewable energy installations, can be zoomed in on Wales: http://www.renewables-map.co.uk/
[21] http://www.rwe.com/web/cms/en/1202906/rwe-innogy/sites/wind-offshore/in-operation/gwynt-y-mr/
http://learning.cat.org.uk/ http://learning.cat.org.uk/en/resources
– background information for Energy Trumps cards. Full resource available as free download at
http://learning.cat.org.uk/en/resources
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