Keith Daly
Wind Power: A Renewable Energy Strategy for Ireland
Abstract
The aim of this report is to investigate the use of Wind Power in Ireland. It will show the current situation in the country, the reliance on non renewable energy and how a transition to wind power can benefit the country both economically and environmentally. It will show the current level of wind power use in Ireland and highlight the potential for expansion. The report will also go in to details about future technology that is currently being developed.
Overview
Man’s harnessing of wind power is a concept that has been around for thousands of years from the days of the first sailors to windmills for milling grain and pumping water. In more recent times the potential of wind power has been realised and implemented to generate electricity. Wind Energy is the generation of electricity from the wind which powers electricity generators. Thus it is a form of energy conversion by converting kinetic energy (wind) to mechanical energy (electricity turbine).
Why Choose Wind Power
Oil prices have steadily increased since the start of the 21st century and with current political uncertainty in the Middle East and North Africa prices are likely to remain high.
[1]
Ireland is heavily reliant on oil and gas imports for its energy needs. Oil imports accounted for just over 50% of Ireland’s primary energy consumption in 2009 making it the fifth highest in the European Union. Natural Gas consumption accounted for 29% of Ireland’s primary energy needs and 93 % of that was imported. [2]
[3] Fuel Mix for Ireland
The figure above show’s Ireland’s primary energy requirement from 1990 to 2009 and it clearly shows that Ireland is heavily dependent on oil and gas. The figure shows a steady increase in consumption from 1990 but takes a sharp decline in 2008 which is probably due to people being more economically conscious as a result of the global economic crisis of recent years.[3]
Since the 1970’s there has been much excitement at the prospect of finding large oil and gas reserves off the west coast of Ireland but to date there have only been two significant finds at Kinsale, Cork in 1971 (which is relatively depleted) and at Corrib in Mayo (which has suffered production problems due to local protests about onshore refining). [4]
Ireland has also signed up to the Kyoto protocol which pledges it to limit its carbon emissions to 13% of 1990 levels by 2012.
Government Policy
From the mid 1990’s the Irish government has committed itself to reducing its carbon emissions by signing up to international policies such as the Kyoto Protocol which aims to limit Ireland’s greenhouse emissions by 13% of levels recorded in 1990. The Kyoto Protocol expires in 2012 but Ireland has agreed to abide by several European policies on carbon emissions and climate change. In 2008 Ireland agreed to an EU climate change package that aims by the year 2020 to reduce greenhouse emissions by 20% below the levels recorded in 1990. [5]
Greenhouse Gas Emissions by Source 1990 – 201
Source: Based on Environmental Protection Agency (EPA) data
The reduction in emissions has been attributed to Ireland adopting a more environmentally conscious strategy by implementing policies such as Kyoto and the EU Climate Energy Package. Ireland is also committed to environmental policies that have affected our energy consumption and the way we live our lives. There is a carbon tax of €15 per tonne which has increased to €20 per tonne when the Irish finance minister delivered the national budget in December 2010.[6]
Ireland is also committed to the implementation of renewable energy technology to supplement and hopefully replace existing non renewable energy technology to provide its electricity needs.
According to the Irish Government’s Energy Policy Framework 2007-2020 renewable energy is to account for 15% of gross electricity consumption by 2010 and by 40% in 2020. The 2020 figure was revised from 33% in the 2008 carbon budget by then minister for Energy and National Resources Eamonn Ryan.
Renewable Energy (%) Contribution to Gross Final Consumption (Directive 2009/28/EC)
From the graph it is clear that wind power generation has increased dramatically over the past decade and significantly wind power accounted for about 10% of Ireland’s electricity needs in 2010. This clearly shows that wind power generation can provide enough electricity to have a significant impact on the total power generation in Ireland. [7]
How much energy is Ireland Consuming?
According to Ireland’s electricity grid manager Eirgrid Ireland’s energy usage peaked at 5090 MW in 2010. Eirgrid also states that it’s electricity availability is at 6872MW at the time of writing this report.
[8] Eirgrid – Graph showing how electricity is consumed over the course of a year.
Technology
Wind turbines usually come in two varieties, horizontal axis and vertical axis.
Horizontal Axis Wind Turbine
The horizontal axis wind turbine(HAWT) is the most widely adopted design in use today. It is usually comprised of a two or three bladed design(though there are a few single blade designs in operation). It works when the wind blows into the rotor blades creating a lifting force that turns the blades which drives an electrical generator. The whole mechanism is positioned on top of a large tower which varies in height but is usually over 50 meters high. The turbine direction is controlled by sensors that measure the wind direction and can adjust accordingly by rotating the turbine on top of the tower into the direction of the wind. The pitch of the blades can also be adjusted to obtain the optimal angle of attack and thus become more efficient.
[9] The components of a typical HAWT Wind Turbine
Vertical Axis Wind Turbine
The Vertical Axis Wind Turbine (VAWT) is different to the HAWT in that is not dependant on wind direction. The rotor shaft is vertical and the generator and gearbox are located at the base which makes maintenance much easier. The main disadvantages of the VAWT are its low rotational speed. The fact that there is no commercially viable designs being used in large quantities means that costs are high. Many VAWT designs are being experimented with such as the Darrieus and Savonius designs.
Wind turbine design comes in three main types:
Constant Speed: This type runs at a single speed and is not very aerodynamically efficient as it will stall in high winds. This type of design is fairly old but it is relatively cheap.
Variable Speed Double Feed Induction Generator (DFIG): This type of design enable the turbine to run at variable speeds with less stress on the gearbox. This means that the design is more aerodynamically efficient and subject to less noise production. The drawback is that it costs more than a constant speed turbine.
Direct Drive (DD): this design involves having no gearbox and a variable speed generator. This design is very expensive.[10]
[11] Example of a VAWT Wind Turbine
[12] Example of a HAWT Wind Turbine
How much power can a wind turbine generate
[13] Wind Power Curve for a typical 1.8MW wind turbine
The graph above is a typical representation of a 1.8Mw turbine. As you can see energy starts to get generated at about 4m/s and the automatic safety shutdown happens at about 25m/s. The amount of power increases by the third power when the speed increases. That means that when the wind speed doubles the power generated increases by 8 times.
According to Albert Betz in 1919 the departing wind speed passing through a turbine is one third of the speed of that entering the turbine meaning that the power that is extracted is 16/27 of the potential power or 59%. [34]
How do we get power
Wind Energy is calculated using by using the formula:
E = 0.5 * m * v^2
= 0.5 *ρ* A *t* v^2
= 0.5 * ρ* A * t * v^3
Where:
A = the area the wind is covering
M= Mass of the wind (A * V * T * )
V = wind speed
T = 1 second
ρ = Density of the wind
Note: The power of wind per unit area per second is calculated as
The density of air is about 1.3 kg per m^3 [34]
So how do we harness this energy and convert it to power? The most common approach is to use wind turbines.
Example: Say we had a wind turbine with rotor diameter of 70 meters with the wind blowing at speed of 15 m/s. How much energy can we generate in 1 hour?
Solution:
M (Mass) = Area * Length * Density = 270129600kg
Area(m^2) = π x 35^2 = 3848m^2 (Radius (35) = Diameter (70) / 2
Length = 15 (m/s) = 15 x 60 x 60 = 54000m
Density = 1.3kg/m3
Energy generated is: 0.5 * 270129600 * 15^2 = 30.3 GJ
Assuming that the turbine is turning at 40% efficiency then: 0.4 * 30.3GJ = 12.12GJ
And converting to MWh: 12.12 / 3600 = 3.36 MWh
[34]
Storage
Due to the unpredictable nature of wind and variation in electricity demand from consumers the issue of energy storage appears e.g. what will we do with electricity being generated in the middle of the night when demand is low?
Eirgrid reading of energy consumption on 01/12/2011
[8]
The graph above represents the power consumption of Ireland on 01/12/2011 based on Eirgrid’s readings. Obviously this graph will vary based on the time of year but power consumption will still remain low in the early hours of the morning. So how can we store the excess energy?
Some of the approaches are:
Pumped Hydro Storage: This is where water is pumped into a reservoir and then released when required to drive a turbine. This option is currently in operation at Turlough Hill in County Wicklow.
Compressed air energy storage: This is where aid is compressed into a subterranean cave and then released when required to drive a gas turbine. The Kinsale gas field is being explored as such a location.[14]
Rechargeable Batteries: These can be charged up and discharged when required.
Hydrogen Storage: The excess electricity can be used to extract hydrogen from water which can then be used in fuel cells.
Onshore Vs Offshore Power Generation in Ireland
The argument of whether to place wind turbines onshore or offshore is still a contentious issue. So I will briefly examine both approaches.
The graph below shows the European wind atlas which illustrates that Ireland has a great untapped potential in wind energy.
[15] European Wind Atlas
Onshore
According to the Irish Wind Energy Association, “Irelands total capacity is 2010.25MW generated from 169 wind farms in 27 counties” and 1985.05MW of this is onshore based [16]. The advantages of onshore wind farms are that they are easily accessible for installation and maintenance. They are also not subject to the same elemental forces as offshore wind turbines. They are also cheaper to install than offshore turbines.
The disadvantages of onshore turbines are that they require a lot of planning and are subject to restrictions. They are subject to protests from residents and conservationists who claim that they spoil the scenery, harm birds, interfere with radio and communications and are quite noisy. This makes the list of potential sites quite small.
The best sites for onshore wind turbines in Ireland are Mayo, Donegal, Galway and Wicklow according to the Sustainable Energy Authority of Ireland and their Wind Atlas.[17]
SEAI Wind Atlas - Onshore Wind Resources
The current state of onshore wind farm distribution in Ireland would seem to show in the graphic below that greater development is needed in some counties such as Mayo, Galway and Wicklow as these counties are not maximising their potential for generating power. Although these counties have the potential to generate a lot of power they are restricted by planning regulations, protests from people and lack of investment.[18]
Irish Wind Energy Association - Installed Capacity by County
Offshore Wind
Ireland has the advantage of having some of the strongest offshore winds in the EU but to date there is only one offshore wind farm in the country located at the Arklow Banks in County Wicklow and this facility only generates 25MW of power.
The advantages of offshore power are that they not subject to the same planning restrictions as onshore facilities. They are out of sight so they don’t spoil the scenery for people, noise pollution is not a factor and interference with communication and birds is reduced significantly. There is the potential to install bigger turbines which would not be feasible for onshore sites. There are 5MW offshore turbines in place around the world and 10MW turbines being developed. This means that offshore wind turbines have the potential to generate more power than their onshore counterparts.[19]
The disadvantages of offshore turbines are that they cost more to install than onshore turbines due to the need to construct a seabed foundation and run a power cable from the turbine back to the shore. Another disadvantage is that maintenance costs are much higher due to the corrosive nature of the sea and the remote location of the turbine.
There are currently five offshore sites being developed in Ireland including the ongoing work on the Arklow Banks. These sites when complete will have the ability to generate over 2600MW of electricity.[20]
Another potential problem with offshore wind turbines are that they are currently only being installed in shallow water which limits the amount of power that can be generated. The map below shows the sites of future offshore wind power sites but as you can see they are not in the areas that get the strongest winds.
SEAI Wind Atlas – Offshore Wind Resources
The best sites for offshore wind turbines are along the west coast particularly off the coasts of Mayo and Donegal where wind speeds can reach up to 11m/s for a turbine at 100m height.[17]
The only problem with trying to install a turbine in these places is the water depth which according to Google Earth can be as deep as 200m at the locations with the greatest potential. One way to overcome could be to use floating offshore wind turbines but these are not yet commercially viable.
Future Designs
What is the future of wind power? There are many designs being developed particularly in the Vertical Axis Wind Turbines (VAWT) category but these designs have yet to be fully commercially exploited as most large scale wind turbine production is done with the established Horizontal Axis Wind Turbine design. There are some ambitious projects being developed include floating wind turbines, airborne wind turbines and hybrid wind turbines.
Floating Wind Turbine
This type of technology is still in its infancy but it involves taking a traditional wind turbine and anchoring it offshore to take advantage of more powerful offshore winds.
The advantages of this approach are:
Like standard offshore turbines they are out of sight from the public which will overcome the Not in My Back Yard problem from residents that usually occurs with onshore wind turbines. This gives the opportunity to install nosier but more powerful turbines.
Turbines can be placed in deep water sites where standard offshore (permanently anchored) turbines could not be placed. This would also have a much less environmental impact with the need for a permanent base structure not necessary.
Turbines can be positioned relatively quickly as no permanent base structure needs to be built. The possibility to transport the turbine also exists if wind patterns shift, a better site is found or if the owner wishes to sell the turbine.
Maintenance could be potentially easier with the possibility to tow the turbine back to shore where it would be safer and easier to do the work.
Disadvantages:
These designs are very expensive as they are in early development stages but they could be potentially cheaper than permanently emplaced shallow water offshore turbines which according the World Energy Council costs between $2.4 and $3 million per megawatt to install. [21]
Because these designs would potentially be further out to sea than standard offshore designs the logistical problem of how to get the electricity back to shore presents itself. The common approach is to run a power cable from the turbine back to the shore. This option is still viable but would require a lot more cable which could be expensive. Another approach would be to store the power generated in a battery which could be discharged by a ship periodically.
The possibility of damage due to severe weather and high swells also presents itself but semi permanent floating structures such as offshore oil rigs are already established and proven as stable, secure platforms.
Some of the current projects under development include Blue H being developed by the Dutch, Hywind being developed by Norwegian company Statoil and Windfloat being developed by American company Principle Power. These along with other projects are focusing on large scale prototypes i.e. greater than 2MW turbines.[22]
Airborne Wind Turbines
This type of technology is still in the early development stages and so far is only being trailed on a small scale though a large scale (2MW) design has been proposed [23] The idea is that a turbine is raised or floated into the air by a kite or helium balloon and is tethered to the ground with its power cable. The concept aims to capture the power of high altitude winds which are stronger and more predictable than those closer to the ground.[24]
[25] Airborne Wind Turbine
The advantages of an airborne wind turbine are that they can be deployed quickly and are ideal for isolated locations. They would be less intrusive on the landscape than standard wind turbines as they would be operating at a great height and they could be deployed only at night if it was deemed that they were spoiling the scenery. It is estimated that the energy could be produced cheaper than standard wind turbines [24] It has been shown that the capacity factor for these designs can be as high as 52.2% which is a considerable increase over standard wind turbines which usually have a capacity factor of 30%.[26] This shows a lot of potential seeing as the maximum energy that can be extracted from the wind according to German physicist Albert Betz back in 1919 is 59.3% known as the Betz Limit.[35]
The disadvantages are that they are not commercially viable yet and are only being trialed by a few companies. [27] Another disadvantage is that they could interfere with aircraft.
Other suggestions for future wind turbine design include the concept of creating a hybrid model which could include attaching solar panels to a standard wind turbine which could provide power when there is a lull in the wind. Another suggestion could be to combine a tidal stream generator which is essentially an underwater turbine with an offshore wind turbine. These ideas are good in theory but raise many questions such about cost, efficiency and location.
Economic Considerations
Wind energy is expensive to get started particularly offshore wind. It requires a large initial capital investment which can appear to be a disincentive for some.
[28] – Lifetime generation costs by technology (€/MWh)
The above graph shows data from 2008 and the lifetime generation costs by technology. The graph clearly shows that onshore wind is quite cost effective but that offshore is more costly than most other technologies. This figure would appear to show that offshore wind is unattractive due to cost but if you look at the graphic below it clearly shows that investments in offshore are increasing and are expected to keep increasing into the foreseeable future.
[29] Wind energy investments 2000-2030
The main cost associated with wind power is the initial capital investment which can account for up to 75% of the total price which includes cost of the turbine, connection to the electricity grid etc. This is what is known as being capital intensive. That is it requires a large initial investment but after that relatively low maintenance costs over its lifetime make it economically feasible. Below is listed the cost breakdown of a typical 2MW turbine.
Note: this table was created using 2006 data so costs are likely to have gone down.
Cost structure of a typical 2 MW wind turbine installed in Europe(2008)
If you compare this to a standard natural gas plant where operational and maintenance costs can vary from 40-70%. It is estimated that operation and maintenance costs for a typical onshore wind turbine cost between 1.2 and 1.5 c€ per kWh of power production for the lifecycle of the turbine.[30]
If you put this into perspective then it seems that investment in wind technology is a smart move economically. The figure below obtained in a report from the European Wind Energy Association shows the carbon dioxide and fuel cost that can be avoided over the expected lifetime of the wind turbines. The report states that “Wind energy avoids an average of 690g CO2/kWh produced; that the average price of a CO2allowance is €25/t CO2and that €42 million worth of fuel is avoided for each TWh of wind power produced, equivalent to an oil price throughout the period of $90 per barrel”. [31]
Wind investments compared with life time avoided fuel and CO2 costs (Oil – $90/barrel; CO2 – €25/t)
The graph below shows data taken from the IEA World Energy Outlook 2008 and it shows the predicted cost for coal, gas and wind power generation. Part of the reason why coal and gas will be more expensive are due to European Union carbon taxes which push up the price of coal and gas considerably. The reason that wind energy cost appears to be falling would be due to factors government subsidies for renewable energy, deregulation of the energy market and the fact that prices for wind power are usually negotiated in the form of long term contracts with the electricity grid provider.
[32] Electricity generating costs in the European Union, 2015 and 2030
Brief Comparison with Other Countries
According to the Global World Energy Council Ireland ranks tenth in the EU for installed wind capacity at the end of 2010. This might seem ok but with the strong wind resources the country posses it really should be doing much more to exploit this. Denmark, which is a similar size to Ireland geographically is producing over twice the amount of energy as Ireland. [36]
Global Installed Wind Power Capacity (MW)
In terms of offshore wind production Ireland is also under performing.
[37]Total offshore wind power installed by end 2008, EWEA
From the above graph it is clear that Ireland needs to be doing more in order to catch up with its European neighbors. Denmark is again way ahead of Ireland in terms of offshore wind power generation having a 28% share of the European offshore wind market compared to Ireland’s 1%.
The factors that will change Ireland’s positioning in Europe will be a combination of Government policy, private enterprise and public attitude.
Summary
In conclusion what I have learned from this report is that Wind Power has the potential to provide for the majority of Ireland’s energy needs. Ireland is strategically positioned to take full advantage of our strong winds both onshore and offshore. There are a number of factors that will affect how quickly the country transitions to majority wind power generation and they are:
· Government Policy
· Investment
· Research and Development
· Public Perception and Attitude
With the right levels of investment and the right government policies Ireland could become a world leader in wind power which could lead to the creation of hundreds of jobs in the sector. Ireland also has the opportunity to export electricity to the UK via the existing Northern Ireland to Scotland interconnector or the new East West Interconnector which will go from Wales to Dublin. These interconnectors have a 500MW capacity meaning that we have not only the opportunity to export electricity but also import from the UK should that be required.[33]
References:
[1] http://upload.wikimedia.org/wikipedia/commons/0/0f/Brent_Spot_monthly.svg
[2] Energy Security in Ireland: A Statistical Overview – SEAI – 2011 - Page 3 http://www.seai.ie/Publications/Statistics_Publications/EPSSU_Publications/Energy_Security_in_Ireland/Energy_Security_in_Ireland_A_Statistical_Overview.pdf
[3] Energy Security in Ireland: A Statistical Overview – SEAI – 2011 - Page 23 http://www.seai.ie/Publications/Statistics_Publications/EPSSU_Publications/Energy_Security_in_Ireland/Energy_Security_in_Ireland_A_Statistical_Overview.pdf
[4] Offshore Technology http://www.offshore-technology.com/projects/corrib/
[5] Energy in Ireland 1990 – 2010 –SEAI – 2011 - Page 29 http://www.seai.ie/Publications/Statistics_Publications/EPSSU_Publications/Energy%20In%20Ireland%201990%20-2010%20-%202011%20report.PDF
[6] Irish Times - 2011 http://www.irishtimes.com/indepth/budget2012/speeches/#section18]
[7] Energy Security in Ireland: A Statistical Overview – SEAI – 2011 - Page 49 http://www.seai.ie/Publications/Statistics_Publications/EPSSU_Publications/Energy_Security_in_Ireland/Energy_Security_in_Ireland_A_Statistical_Overview.pdf
[8] Eirgrid - http://www.eirgrid.com/operations/systemperformancedata/systemdemand/
[9] http://upload.wikimedia.org/wikipedia/commons/5/52/EERE_illust_large_turbine.gif
[10] http://www.seai.ie/Renewables/Wind_Energy/Technology_of_Wind_Energy/
[11] http://en.wikipedia.org/wiki/File:Darrieus-windmill.jpg
[12] http://en.wikipedia.org/wiki/File:Veladero_01.png
[13] The Economics of Wind Energy –European Wind Energy Association – 2009 - Page 49 http://www.ewea.org/fileadmin/ewea_documents/documents/00_POLICY_document/Economics_of_Wind_Energy__March_2009_.pdf Page 49
[14] Cork Independent - http://archive.corkindependent.com/local-news/local-news/kinsale-gas-field-to-be-used-for-carbon-storage/
[15] European Wind Atlas - Risø National Laboratory - http://www.windatlas.dk/europe/index.htm]
[16] Irish Wind Energy Association - 2011 http://www.iwea.com/index.cfm/page/countycomparison
[17] SEAI Wind Atlas - http://maps.seai.ie/wind/
[18] Irish Wind Energy Association – 2011 http://www.iwea.com/index.cfm/page/windmap
[19] The National Offshore Wind Energy Association of Ireland - http://www.nowireland.ie/
[20] The National Offshore Wind Energy Association of Ireland - http://www.nowireland.ie/offshore-wind-ireland.html
[21] IEEE – 2009 http://spectrum.ieee.org/green-tech/wind/floating-wind-turbines-to-be-tested
[22]Renewable Energy World – 2011 http://www.renewableenergyworld.com/rea/news/article/2011/05/a-buoyant-future-for-floating-wind-turbines
[23] Green Tech Media - 2010 http://www.greentechmedia.com/articles/read/honeywells-take-on-wind-turbines-and-the-flying-donut-from-mit/
[24] The Economist - http://www.economist.com/node/9249242?story_id=9249242
[25] http://upload.wikimedia.org/wikipedia/commons/7/75/Airborne_wind_generator-en.svg
[26] Carbon Tracking – Assessing the Viability of High Altitude Wind Resources in
Ireland - Page 5 http://carbontracking.com/reports/High_Altitude_Wind_Resource_in_Ireland.pdf
[27] Discovery Channel http://news.discovery.com/tech/airborne-wind-turbines-lift-off.html
[28] Eirgrid - Low Carbon Generation Options For The All Island Market – 2010 - Page 20 -http://www.eirgrid.com/media/Low%20Carbon%20Generation%20Options%20for%20the%20All%20Island%20Market%20(2).pdf
[29] European Wind Energy Association – Economics of Wind Energy – 2009 -Page 33 -http://www.ewea.org/fileadmin/ewea_documents/documents/00_POLICY_document/Economics_of_Wind_Energy__March_2009_.pdf
[30] European Wind Energy Association – Economics of Wind Energy – 2009 - Page 9 -http://www.ewea.org/fileadmin/ewea_documents/documents/00_POLICY_document/Economics_of_Wind_Energy__March_2009_.pdf
[31] European Wind Energy Association – Economics of Wind Energy – 2009 - Page 12 -http://www.ewea.org/fileadmin/ewea_documents/documents/00_POLICY_document/Economics_of_Wind_Energy__March_2009_.pdf
[32] European Wind Energy Association – Economics of Wind Energy - 2009 - page 14
[33] Eirgrid – East/West Interconnector -2011 - http://www.eirgridprojects.com/projects/east-westinterconnector/overview/
[34] Sustainable Energy Without Hot Air – David MacKay – 2009 - Page 264
[35] Renewable Energy – Power for a Sustainable Future – Godfrey Boyle – 2004 - page 262
[36] Global World Energy Council – Annual Market Update 2010 – 2010 - page 11 http://www.gwec.net/fileadmin/images/Publications/GWEC_annual_market_update_2010_-_2nd_edition_April_2011.pdf
[37] European Wind Energy Association – Economics of Wind Energy – 2009 - Page 62 -http://www.ewea.org/fileadmin/ewea_documents/documents/00_POLICY_document/Economics_of_Wind_Energy__March_2009_.pdf