Phelim Kelly

Using Ireland's Wind Energy to reduce its dependence on fossil fuels

Abstract

Wind turbine technologies offer a viable alternative to Ireland’s reliance on fossil fuels for its power generation. Fossil fuel reliance is problematic due to the fluctuation in market prices, the production of carbon emissions and their depletion due to their finite nature. Whilst heavily reliant on fossil fuels as a means of generating power, Ireland can never have security of supply. Irelands high wind speeds make it an ideal region to exploit the winds energy, which is clean and renewable. However, the installation of wind farms requires careful planning. Average wind speeds, proximity to the electricity grid and infrastructure are all crucial factors. Also, local wildlife disruption, noise pollution and shadow flicker are possible side-effects which must be minimized. Planning approval must be sought from the relevant authorities. Potential revenue from wind farms will depend on land values, complexity of grid connection and type of turbine. A plan to guarantee Ireland’s energy future involves promoting the continued expansion of wind farm projects. In addition, to overcome the intermittent nature of wind energy, these turbines are used to supply water to large hydro facilities on the west coast which can satisfy a large proportion of Ireland’s everyday electricity needs. This is a large scale project which will require promotion and public awareness. Government investment and tax incentives will also play a crucial role. If successful, this plan will lead Ireland towards a future where it is in greater control of its energy requirements and not as vulnerable to the uncertain future of fossil fuels.

Introduction

Ireland's current energy status

As an island nation on the periphery of Europe, when it comes to the global energy market, Ireland is in a vulnerable position. In 2006 91% of our energy needs were imported. This dependency was reduced to 88.6% in 2009, due to increase in the usage of domestic renewable energy. Clearly this figure is still a cause for concern because we are in a weak position in terms of our security of supply. In terms of both future energy prices and availability we are left at the mercy of the international market. Examining the following trends, it can be seen that our own production of fossil fuels has decreased over the last 20 years, whilst our dependence on importing these fuels has increased. Our importation of coal has stayed steady, but our importation of oil has nearly doubled since 1990. Gas importation started in the mid nineties and has increased significantly since then to account for three times the level of coal imports.

[1]

Ireland's Importation of energy 1990-2009

Ireland's domestic harvesting of fossil fuels has mainly been attributed to gas and peat. A recent peak in 1995 saw slightly under 4 Mtoe (million tonnes of oil equivalent) being used. But this has declined steadily since, to the extent that in 2009 just 0.8 Mtoe was harvested. This is due to a decline in new discoveries coupled with existing resources being depleted.

Indigenous production of energy 1990-2009

In broad terms, our energy usage is evenly divided between transport applications (34%), Thermal applications (34%) and electricity generating applications (32%).

All statistics from “Energy in Ireland 1990 – 2009” from Sustainable energy Ireland, Located [1]

Status of fossil fuels world wide

In 2005 US department of Energy commissioned the Hirsch report on the peaking of the World’s oil supply [2]. The peaking of the world’s oil supply refers to the point in time when oil production is at a maximum. After this point in time, the amount of oil being produced will be declining. The report indicates that it is impossible to predict precisely when this peak will occur. However many expert opinions suggest a time range from 2006 to 2016. The Shell Oil Company has forecast post 2025 as a peak date. However, it must be remembered that oil companies may have vested interests which lead them to” kick the can down the road” when forecasting the peak. The arrival of this peak was not foreseen in countries that have already reached their peak production. These countries experienced a post peak trend of sharp decline in production. The Hirsch report also states that some OPEC countries have predicted that within the next 10 to 15 years not enough oil will be produced to satisfy global demand.

The same forecast is not applicable to the production of gas. This is due to the ongoing discovery of gas fields, which leads to an increase in global production. That said, ultimately gas is also a finite resource whose production will eventually peak. Therefore natural gas is not a reliable source of energy in the long-run. A summary of peak gas [3], predicts worldwide gas production will peak at 2020

A report on coal, produced by the Energy Watch Group in 2007 [4] estimates that peak coal production could happen in as little as 15 years.

Clearly an alternative renewable energy option is required. Wind energy offers a valuable alternative to fossil fuel reliance for the island of Ireland.

Consequences if we do nothing

As previously noted, Ireland is heavily dependent on imported energy, which counts for 88.6% of our needs. Of this imported energy the vast majority of it comes from fossil fuels, with oil counting for 60% of these imports, and coal and gas taking up most of the remaining amounts. There is a small amount of imported electricity – but this imported electricity is quite possibly generated from fossil fuels in the country of origin.

If you combine this information with the forecasts for fossil fuel production over the coming years it can be reasonably assumed that Ireland is in a very vulnerable position. A decrease in fossil fuel production will inevitably result in a decrease in availability and ultimately an increase in price. A reasonable prediction of the future for the average Irish person will see him spending ever increasing amounts on basic energy requirements, resulting in less discretionary spending which helps keep an economy thriving. The consequences for Irish industry are that fuel prices will become an increasingly dominant factor in the running costs of businesses. Increasing energy prices will mean less capital for employment and in many cases will contribute to the failure of businesses.

An introduction to Wind Energy - including when it first emerged, how it has developed since

Wind is generated because of temperature differentials on the earth’s surface. The earth is heated from solar radiation, and this heat radiates into the surrounding air. But because the earth is heated unevenly (the equator receives more heat than the poles for example), we end up with areas of hotter air with lower pressure and cooler air with higher pressure. As pressure differentials always want to equalise, air moves from areas of high pressure to areas of low pressure. This is what we experience as wind. Wind patterns can be on a large scale such as the trade winds. These winds are formed as a result of air movement from the equator to the poles. Winds can also be on a more localised scale, as with sea breezes that form from a difference in land and sea temperatures.

Energy from wind has been harnessed for thousands of years. Earliest applications include sailboats, ventilation and irrigation projects. The earliest windmills appeared around the 9^th century and were used to grind corn and pump water. The first windmill for the production of electricity was built in Scotland in 1887 to supply electricity to the holiday home of the professor who built it. In the early 20^th century the technology developed to supply electricity in remote locations such as rural farms, via standalone turbines. In the 1970’s the US led technological advances towards multi Megawatt turbines for large scale electricity production. Lowering oil prices in the 1980’s led to a slowdown in this development for a number of years, but since the turn of the century there has been an increased awareness in the limitations of fossil fuels as a long term solution, and interest in wind technology has renewed.

This is illustrated by this graph which highlights the global energy harnessed from wind energy from 1996 to 2010

[1]

[5]

Global Wind power Cumulative Capacity

The technology to harness the wind has evolved from early days where a windmill with many wooden and fabric constructed sails performed a direct mechanical function (milling), to nowadays where a wind turbine, consisting of normally 2 or 3 aerofoil blades typically made from metals or composite material, are harnessed to convert the rotational mechanical movement of the turbine into electrical energy. Air has mass, so when it moves it exerts a force on anything it comes across. Aerofoil blades exploit this movement of air. The shape of the blade is designed so that air travels slower over the curved part than the flat part, thus creating an area of differing pressures. This difference in pressures causes the aerofoil to move in the direction of the low pressure. This phenomenon is evident in the lift of an airplane taking off. It is the same lift that causes a wind turbine to rotate. The rotational energy of the blades is converted into electrical energy by means of an induction generator built into the turbine.

[6]

How a Wind Turbine works

The key factor that affects how much power can be harnessed from a turbine is the wind speed. This is the standard wind power formula:

So it can be seen that there is a cubic relationship between the wind speed and the power. If the wind speed doubles, the power increases by a factor of 8.

Ireland’s suitability for harnessing Wind Energy.

Situated on the edge of Europe, with a west coast fully exposed to the Atlantic Ocean, Ireland is ideally located to exploit Wind Energy for the generation of electricity. The following graph illustrates by means of shading, the average wind speeds experienced across Europe. Purple and red are the highest categories and represent the majority of the country

Wind resources at 50 meters above ground level for five different topographic conditions:

1) Sheltered terrain, 2) Open plain, 3) At a coast, 4) Open sea and 5) Hills and ridges.

[7]

European Wind Speeds

This graph shows that Ireland’s entire west coast is in the highest category, receiving winds above 8.5 m/s at the coast and above 11.5 m/s on hills and ridges. Much of the remainder of the country is categorised as receiving winds of up to 11.5 m/s. Most wind turbines start generating electricity at wind speeds of around 3-4 m/s, and generate maximum ‘rated’ power at around 15 m/s [8] Clearly, if installed in the correct locations, wind turbines offer a viable option for power generation for the entire island.

However, considering as a nation we have possibly the best wind resources in Europe, we have fallen behind in terms of our capacity to harness this. The following graph shows that by the end of 2010 Denmark, Spain, Portugal and Germany had more wind power capacity per thousand inhabitants than Ireland. Denmark, with a smaller land mass than Ireland and quite possibly not receiving the same wind speeds, has twice the wind generating capacity of Ireland.

[9]

Planning a Wind Energy project

There are many considerations when planning a wind energy project in Ireland.

Choosing a location

Primarily, a suitable location for wind turbine installation must be identified. As the suitability of turbines is site specific and subject to planning requirements, it is not advisable to purchase the turbines before finalizing your site. As turbine parts will be quite large when unassembled, storage may be problematic, so it makes sense to organise and prepare the site prior to delivery of the turbines.

Finalising the location of the turbine installation involves a lot of detailed research. Initially the area should be visited to get a “feel” for its suitability. Immediate impressions as to the suitability would include assessing the openness of the area. Ideally the site will be a broad open plane with no obstructions, or raised land with no other development. This initial ‘scout’ will also rule out other areas, for reasons such as recent building development which may not be obvious on a map or satellite footage.

Determining wind speeds

An excellent resource developed by the Sustainable Energy Association of Ireland, called the Wind Atlas for Ireland [10] is available. This atlas maps the results of a study of wind patterns throughout Ireland and gives the user a highly informative overview when considering locations. It couples mean wind speeds at various heights (for different turbine types) with other environmental concerns such as special areas of conservation which would affect the choice of a location.

[10]

Technical report Wind Atlas [11]

Choosing County Clare as an example, the user is presented with a simple map of the area, as in Google maps. The user can then select the criteria they require, such as wind speeds at various heights. Multiple criteria can be selected and is layered onto the initial map to give a very detailed and informative picture of the site in question. For example, by selecting “onshore wind speeds at 75m”, a colour scheme is introduced to the map so it can be seen which are the areas with optimum mean wind speeds. On top of this, areas can be highlighted where wind farm development would potentially not be permitted – these are Natural heritage areas (purple), Special Protection areas (orange) and Special Areas of Conservation (dark green). With the County Clare example implemented as described , an area south of Lahinch was selected that showed higher mean wind speeds than its surroundings. Clicking on a precise location, the user is then given the location co-ordinates and the wind speed information at various heights.

A similar resource is the wind energy plans that have been drawn up by many County Councils. These are possibly more specific when it comes to finding a suitable location, as they classify the whole region in terms of areas where wind farms would be considered acceptable and areas where they would not be permitted. As planning permission is needed, these plans should be consulted at the very beginning of the location process. Presented below is an example of the way Fingal County Council in North Dublin have approached these plans. As well as categorising the region into areas where wind farm development is allowed or refused, they also give an overview of wind speeds for the region. Below is a close-up of some of the Fingal area as an example:

[12] [12]

This Wind Atlas and County Council plans should be used as an initial tool to research various areas. After identifying possible sites, more in-depth research would be needed to try to avoid future planning and technical complications.

Ground Roughness

This is a term used to categorize the condition of various land surface types with respect to how they affect wind. It is fairly intuitive that wind will receive less interference and therefore be faster when travelling over smooth surfaces such as calm water or closely mown grass, compared to rougher surfaces such as forests or urban dwellings. This has been represented in a table which gives approximations of these Roughness lengths:

Roughness Lengths [13]

The Danish Wind Energy Association has devised an equation which uses these Roughness values to calculate wind speeds in various situations:

v(z) = v_ref log(z/z_o) / log(z_ref/z₀)

where v(z) is the wind speed at a desired height. V_ref is the sampled wind speed at a height Z_ref.

As an example, select two separate locations, one a forested area and the other flat grassy plains. If there are wind speeds of 18 m/s at a sample height of 300m above ground, when this formula is then applied to a realistic hub height of 75m the following can be seen:

Forested area:

V(z) = 18Log(75/0.7)/Log(300/0.7) = 13.88 m/s

Grassy Plains

V(z) = 18Log(75/.01)/Log(300/.01) = 15.57 m/s

Evidently, higher wind speeds are experienced where the wind has a smoother passage to the turbine.

Additional Wind speed testing

The figures from the Wind Atlas are given as a guideline. To properly move a project forward, the authorities such as County Councils for planning permission and banks for funding will require statistical evidence that your exact location is suitable for development. For this, the wind will need to be tested for a period of at least 1 year, by means of an anemometer.

Potential problems with a location

Wildlife concerns:

Great care must be taken when planning a wind farm that local wildlife is not adversely affected in any way. This involves consulting local or national wildlife groups to figure out patterns such as mating and nesting cycles, for local species that may be affected. There are two main considerations – species that reside on the land surrounding the wind farm site, and the migrating patterns for birds flying in the area.

For example, when selecting a site an inspection should be taken of the land to ascertain whether there are any nesting grounds in the vicinity. If there are, steps may need to be taken to relocate these, if possible, to other suitable locations. The SEAI note in their summary on the effect on birds by wind farms that only between 2% and 4% of a site is disturbed by roads and foundations, so the majority of a site remains intact [14] The main disturbance occurs during the construction phase, when habitats up to 800m from the site can be affected. Research in advance and clear planning in consultation with wildlife groups are essential if habitats of local flora and fauna are to be disrupted to a minimum. A positive effect of wind farms to the local terrain is that once the site is completed, future development in the vicinity is highly unlikely, so the habitat is protected for the foreseeable future.

The same report from the SEAI highlights that most birds are able to notice wind turbines and avoid them when approaching, but that some species have less mobility or poorer eyesight and are at a much higher risk of collision. In locations where these species predominate, clearly wind turbine installation should be avoided. An example of such a case is the Altamont Pass wind farm in the San Francisco bay [15]. It is estimated that up to 1300 birds such as red-tailed hawks and golden eagles are killed there every year due to collision with turbines. Legal threats arising out of the desire to conserve these species resulted in the closure of half of the turbines as a preventative measure. This is an example of poor consultation at an initial planning stage of the Altamont Pass project leading to avoidable difficulties. Clearly there is also a negative impact on the public perception of wind turbines.

Infrastructural Requirements

On selecting a site, another consideration is existing infrastructure. A major factor is adequate road access to the site. Even when unassembled, turbine parts are still very large and will be delivered on flat bed trucks. A route needs to be fully planned for the trucks from supplier to installation site. A trial run of the route allows for the identification of unexpected obstacles, such as low bridges or tight turns. See the following as an example [16].

Other planning proposed for the nearby area

As part of considering a site, it is recommended to check that there are no other plans for the immediate area by consulting the local authority. If, for example there were plans for industrial development, this could adversely effect a wind turbine application. The application could fail due to the incompatibility of the two projects. If the two projects are compatible, and proceed, time must be spent considering whether the expected wind patterns will be interfered with. A decision must then be made as to whether the wind project is still viable.

Geological survey of the ground for turbine suitability

Foundations for building the turbines upon must be solid and reliable. A geological survey will ascertain whether there are any features in the land that could have an effect on the foundations at a later date. An example would be an underground stream that erodes the bedrock gradually, and could eventually cause a shift in the ground close to the turbine foundation. The Derrybrien mudslide illustrates the consequences of not taking the geological conditions into account when planning a wind farm. “In October 2003 a landslide at Derrybrien dislodged 450,000 cubic metres of peat over a 32km area, polluting a river and killing 50,000 fish. The Government argued that this was caused by poor construction work, but the court found that it was because a proper environmental impact assessment or EIA had not been carried out” [39]

Proximity to the National Grid, and the terrain in-between

The ability to connect the wind farm to either the Transmission (38/110/220/400Kv) or Distribution (10/20Kv) electricity networks is crucial and will depend on the size of wind farm in question. Maps of these electricity networks are available from ESB Networks [17]. The layout of these networks will have a major impact on the selection of the site, as well as the choice and number of turbines. For example, when considering a site that has potential for large scale turbine deployment, connection to the Transmission network is required. However, if the site is 50km away from the Transmission network, with towns or roads or housing in between, it may not be feasible to choose this site, as running the lines to connect to the electricity network would be too much of a logistical challenge. This may be an extreme example, but a precise examination of where the site is in relation to the electricity network is crucial, as even on a small scale it is still quite likely that the connecting lines will have to cross other people’s land, and permission will need to be sought for this. Also, depending on the land between the site and the electricity network, it may be impossible to safely bury the cables – or erect pylons. A case where the route chosen by Eirgrid to run their pylons caused a huge controversy was the case of Teresa Treacy. She protested against a compulsory order which involved running pylons through her land and felling 14 acres of trees. The situation escalated to the extent that she was jailed for contempt of court and the whole project received a huge amount of bad publicity [18].

Shadow Flicker and noise pollution

Two of the major causes for objections to wind farm development are the shadow flicker and noise levels that they cause. Shadow flicker is caused when light from the sun is intermittently blocked by the rotating turbine blades to create a flicker effect on the ground. If this coincides with residential dwellings, it can be a very distracting and disorienting annoyance. It’s affects can be seen in the accompanied video. Careful planning is needed in the initial stages, by mapping the sun’s path in the sky in comparison to a proposed turbine location to see where shadow flicker may occur.

[19]

[21]

The noise experienced from a wind turbine is not realistically a major issue. A study by the British wind energy association concluded that “A significant amount of effort is put into minimising any noise impact but it should be emphasised that typical noise levels are so low for a carefully considered site that they would normally be drowned out by a nearby stream or by a moderate breeze in nearby trees and hedgerows.” [20]. This video also highlights the typical sounds in everyday environments, and highlights the minimal noise cause by wind turbines

Planning permission and legality

Below is a guideline of the steps to be followed to have a wind farm fully authorised.

Apply to the local County Council for planning permission to install a wind farm at the proposed location. If the proposed installation is over 5 MW an Environmental Impact Assessment is also required. Permission, if granted, expires after 5 years. This may be an issue, as currently there are quite long delays with connecting to the grid, and there is a chance that the planning permission will expire before a connection to the grid has been arranged. Careful planning of how things are timed is important.
Apply to ESB Networks or Eirgrid to seek a connection agreement. This is essential, as without a deal to connect a wind farm to the electricity grid, revenue cannot be generated in this manner. Due to a large increase in demand for connections to the national grid, ESB Networks and Eirgrid have had to come up with a formal procedure for dealing with all requests. This is known as the gate system, whereby a number of applications nationwide, which satisfy the criteria for connection, are grouped together and planned collectively. In recent years, this procedure has led to delays of five to eight years.
Apply to Commission for Energy Regulation (CER) for a Generator License. A wind farm developer just needs one of these licenses.
Apply to the CER for an Authorisation to construct. This is a site specific authorisation and is needed for every individual wind farm installation
Apply to the local County Council for planning permission to build your own connection to the grid if you intend to do this. An alternative is to just allow ESB Networks or Eirgrid manage the connection, but you may prefer to do this yourself.

Summary of planning steps required sourced from IWEA and SEAI: [22], [23]

Technological Considerations

Type of Turbines

When it comes to the equipment used in the wind farm, there are many alternatives to consider. The first of these is the type of turbine used. There are 2 main classifications for turbines, Vertical Axis and Horizontal Axis.

Vertical axis turbine [24] Horizontal axis turbines [25]

The vertical axis turbine has the rotor shaft positioned vertically. This is the large column in the picture shown. When the blades catch the wind, this shaft rotates. The main advantages of this design are that the gear and generator equipment are located at ground level, making access and maintenance easier. Also, because of the nature of the design, the blades will always harness the wind energy, even if the wind changes direction – as opposed to horizontal turbines, which need a yaw mechanism to turn the turbine towards the direction of the wind. The disadvantage of these turbines however is that they harness winds that are lower to the ground in comparison to horizontal turbines, therefore slower speed winds. Also, to do major repair work on the gear system involves dismantling the entire system which is obviously quite a drawback.

Horizontal axis turbines have the rotor shaft positioned horizontally, which sits in the nacelle – the housing that sits on top of the shaft. They have generally beeen shown to be more efficient at harnessing the wind’s energy – and mainly for this reason horizontal axis turbines are the ones used in the vast majority of installations at present.

For the most cost-efficient, practical design, the gear mechanism and generator in modern turbines are engineered to work at their maximum efficiency at speeds of around 15 m/s. It would not make economic sense to increase the complexity of turbines so that they can handle higher wind speeds, as these are generally infrequent. But if turbines are only designed to handle winds of up to 15 m/s, higher winds will damage them. For this reason, all turbines have cut-off features for higher winds. There are various ways of doing this:

Pitch Controlled wind turbines.

These turbines, when they reach the upper limit of capable wind speeds, turn the rotor blade out of the wind, so that less lift is experienced, and therefore the rotors don’t pick up speed

Stall Controlled wind turbines

On these turbines, the rotor is set at a fixed angle on to the main body of the turbine – but the aerofoil shape of the rotor is engineered so that when the wind reaches a certain speed the ‘stall’ effect happens. This is when the air pattern on one side of the aerofoil goes into turbulence, and the normal difference in air pressure on each side of the aerofoil disappears, causing the lift to stop – and thus the rotor blade stops turning. It is quite a complex engineering challenge to get stall controlled rotor blades working correctly – but this design is still the most popular used today, accounting for roughly two thirds of turbines.

Active Stall Controlled wind turbines

This method is used on more modern turbines larger than 1 MW. It effectively combines the two methods above. At low winds the blades are turned into the wind to harness more power – but as the upper limit of wind speed is reached, the blades are actually turned more into the wind to induce a stall. These turbines run more efficiently than the other two types, as they manage to stay at rated power for longer – but there are obviously cost implications with this, as they are more expensive.

Size of Turbines

The next technical consideration is the size of the turbine(s) to be used at each wind farm. In general the larger the turbine the more power is generated. Below is a guideline illustration of the typical power that is generated by turbines of varying rotor diameter.

Rotor Diameter / Generated Power [26]

So it is fairly intuitive that the larger the rotor diameter, the more power that is generated from a turbine, an 80m turbine generates ten times the power that a 27m does.

Connecting to the grid

Another technical area to consider is the equipment used to connect to the grid. Step-up transformers are used to convert the voltage of the electricity that the turbines generate to a voltage that matches the grid connection. These transformers can be located in the nacelle of the turbine, or separate to the turbine on the ground.

Storage of generated energy

It is accepted that problems arise when trying to tie the intermittent nature of Wind Energy to the varying energy demands of domestic/commercial use. Electricity demands rise and fall throughout the day and there is no guarantee that wind will be blowing when this demand increases. Conversely, at periods of low electricity demand there may be high winds resulting in a wind farm running at maximum output. It makes sense to try to save this unwanted energy for later use. However, electricity is not a simple physical quantity and it is not easy to store it. This is an area that still presents major challenges to this day. Outlined below are just some of the different methods for storing electricity:

Pumped Hydro storage.

This involves the use of a two level water system – one reservoir raised a significant height above another. The wind turbines are used to power water pumps at off peak times to move water from the lower reservoir to the higher one. Then when there is peak demand, this water is released through a narrow channel to the lower reservoir. There is a water turbine in this channel which harnesses the kinetic energy of the water for electricity generation.

Compressed air.

Another emerging means of storing energy is to use unwanted electricity to pump air into old underground natural gas chambers. This air is stored at high pressure and can be released when needed to drive turbines and generate electricity.

Battery storage.

In theory excess electricity could simply be used to charge large batteries which are then discharged when needed. In reality the technology isn’t quite available yet to make this a practical and economical option. They tend to be quite expensive and have limited life spans of typically three to five years. The world’s largest battery backup is in use in Fairbanks Alaska. The battery weighing 1300 metric tonnes is larger than a football field but is still only is capable of powering 12,000 residents for 7 minutes. Battery storage that is equivalent to a modern coal plant would be in the magnitude of hundreds of times the size of this Fairbanks battery [27]

Hydrogen generation.

This involves using the excess electricity to produce hydrogen which is then used in fuel cells to power cars or homes. This technology is still in the early days.

In summary, pumped hydro storage and compressed gas storage are the only two real methods where the technology already exits but even these methods involve large scale and expensive engineering works to be carried out.

Economic Considerations

Planning your design for maximum return

So far, the various building blocks of a wind farm installation have been considered. Now this report will examine how these can be tailored to make the wind farm as economically viable as possible.

Land Prices.

As mentioned previously there are many technical considerations when it comes to selecting a site for a wind farm, but obviously the cost of acquiring land is also a major factor. One site may have a distinct advantage over another in terms of wind speeds, proximity to the grid etc but if it happens to be in a location with much higher land prices (e.g., nearer a city), this extra cost might make a difference when it comes to either financing the project initially, or eventually turning the site into a profit making entity.

Cost of grid connection.

Also mentioned previously, the proximity to the grid and the terrain in between will have a major influence on the cost of setting up the wind farm. To give a rough idea of typical costs when connecting a generator site to the grid, here are figures from Sustainable Energy Ireland, based on ESB Network’s ‘Standard Prices for Generator 2008’.

Typical Grid Connection Costs [28]

From this, it can be seen that 7 km of cabling counts for a large proportion of the grid connection costs and it can be deduced that the longer the grid connection needed, the steeper the costs will be. So a larger site may seem attractive at first in terms of the amount of turbines that can be accommodated but a smaller site nearer the grid might make more economic sense in the long term.

Choice of turbines

As shown previously, the larger the turbine, the bigger the generator it drives and obviously the cost for the turbine will be higher also. But in terms of economies of scale it would be cheaper to buy one 54m turbine producing 1 MW of electricity than four 27 m turbines producing 225 KW of electricity each. There would also be saving in terms of land needed and foundation works required. But this is in a case where a given location allows for both these turbines to produce their rated power for a high proportion of the time. Larger turbines have higher ‘cut in’ speeds. This refers to the speed the wind needs to be at before the turbine starts. Let’s say a particular site only intermittently has winds above 8 m/s and this is the cut in speed of a larger turbine. Even though there would be a greater initial investment required, it would make more economic sense to have a few smaller turbines as these would be generating electricity for a greater percentage of time. One 1 MW turbine working for three hours a day will give 3 MWh, whereas three 225 KW turbines working for six hours a day will give 4 MWh.

Typical costs of starting and running a wind farm

As can be seen, each wind farm is a unique project with many variations which will affect the end price of set-up. That said current trends in the market have lead to a general rule of thumb about how much a wind farm will cost to get up and running. This is a figure of between 1.6 to 2 million euro per MW of installed capacity [29]. This figure covers every cost that could be incurred, from the planning stages right through to an operational wind farm with regular maintenance costs and the eventual decommissioning of the farm. So a smaller wind farm consisting of three 700KW turbines would cost in the region €3.4m to €4.2m – whereas a larger wind farm with ten 2.5 MW turbines would cost in the region of €40m to €50m to establish.

As a guide, this expenditure can be broken down as follows: Wind Turbine Procurement 70%, Civil Engineering Works 11%, Electrical Infrastructure and Commissioning 7%, Electrical Network Connection 5%, Project Development and O&M Costs 7 % [29].

Potential revenues from a Wind Farm

A wind farm operator has two options when it comes to selling the electricity they generate. They can sign a Power Purchase Agreement (PPA) with an electricity supplier and benefit from the REFIT scheme or they can sell the electricity directly to the market and receive the current market price for energy at that time.

REFIT Scheme:

As an initiative to help support renewable generators, the Department of Communications, Energy and Natural Resources (DCENR) in 2005 introduced the REFIT scheme (Renewable Energy Feed in Tariff). This gives a guaranteed price for energy generated by various renewable sources. The payment goes to the electricity supplier who then strikes up a Power Purchase Agreement with an electricity generator. This scheme encourages uptake in wind energy, as people know in advance the potential revenues they will receive.

SEMO scheme.

SEMO are the Single Electricity Market Operators. They are the central body that control the purchase of electricity nationwide. Generators sell their electricity to the supplier who in turn sells it on to the SEM. The price offered by the SEM, referred to as the Single Market Price (SMP) is updated on a half hourly basis throughout the day. An electricity generator can choose to sell straight to the SEMO, and benefit from SMP’s that are higher than that offered by the REFIT scheme but they take the risk that over time the SMP will average out lower than the price they would have received from the REFIT scheme.

Below are the reference prices for the REFIT scheme from the DCENR from 2005 to present. They represent the price per Megawatt hour generated.

REFIT Prices [30]

So a large wind farm will receive €66.353 per MWh supplied under the REFIT scheme.

Here is a sample of the Single Market prices offered by the SEMO for the 9^th December 2011:

Single Market Prices from SEM [31]

From this graph it can be seen that for the majority of the day the SMP hovers around €45 per MWh. It rises dramatically from approximately 4pm to match evening demand, reaching prices up to €625 per MWh.

So it can be deduced that if a wind farm is fully operational between 4 and 8pm, there are substantial revenues to be made. In the case of the sample day above, the average over these four hours is €275 per MWh. This means that a large 25 MW farm could generate in the region of €48,000 for this period.

But when entering a market where prices can fluctuate dramatically and the reliability of product availability is not guaranteed, it is very difficult to forecast exactly what the potential revenues are. It is possibly easier to do this when operating under the REFIT scheme.

Take the same sample site that is operating with ten 2.5 MW turbines, making it a 25 MW site. In theory this site can produce 219 GWh in a year (24 hours x 365 days x 25 MW). But obviously this won’t be the case. The ‘capacity factor’ of a generating plant is the percentage of its potential output that it actually achieves. For wind farms this capacity factor is typically in the region of 30%. So, this sample site can be expected to produce roughly 65.7GWh in a year (65700 MWh).

Tying these figures of produced energy to the guaranteed prices from the REFIT scheme it can be seen that this site would generate in the region of €4.4 million in one year (65700 MWh x €66.353). With installation costs of between €40 and €50 million it can be broadly stated that this site would take ten years of operation before it has paid for itself.

A Plan for Ireland

So far we have looked at the details behind establishing individual wind farms in Ireland. Now we need to look at how, as a planned strategy, Ireland as a whole can use this renewable resource to its own advantage to help secure its energy future.

The Big Picture

In 2010 wind energy counted for 11.3% of the electricity used in Ireland, and renewable sources in general counted for 14.6%. Wind installations have continued into 2011, and as of this September the installed capacity of wind turbines is 1585 MW, so the figure of 11.3% will have increased now. But this means that at least 85% of Irish electricity is still coming from fossil fuels. The west coast of Ireland’s high winds are a magnificent resource and the area has a relatively low population density. So even though there has been strong growth in the number of wind farms over the past few years, there is still plenty of scope for expansion. With bigger and better turbines being developed, even more power can be harnessed out of new wind farms.

Currently the world’s largest wind turbine is the E126 developed by Enercon, one of the words foremost turbine manufacturers, and has a generating capacity of 7.5 MW. A recent development is that Enercon has announced an expansion of its operations in Ireland and will be manufacturing here. (Newstalk 106FM radio headline, early December 2011). Typically in Ireland, even modern wind farms are using turbines in the region of 3 MW. Obviously there will be cost implications, but if developers could be encouraged to use bigger turbines, and local authorities could be encouraged to allow them, each wind farm could have a much bigger contribution to the electricity network. Consider the earlier example of ten 2.5MW turbines generating 65700 MWh of electricity in a typical year. The same site using ten E126 turbines would potentially generate three times the power per year – 197100 MW/hours of electricity. Possibly the figure of ten turbines is slightly ‘small scale’. To address the energy issues that are eminent, Ireland needs to be prepared and look to the future. The lack of foresight during the development of the M50 is an example of millions spent on developments that quickly required up scaling after a few short years. Ireland should avoid a similar scenario when it comes to energy generation. Wind farms with 30 turbines are seen to be more practical if the following example is considered. If ten such sites using E126 turbines (or future equivalent) were developed this would more than double the wind energy capacity that the country currently has (7.5 x 20 x 10 = 2250 MW). In addition, offshore wind farms can be further developed. In terms of the potential for generated electricity, more turbines can be installed per site and they are exposed to higher winds. If five sites of forty E126 turbines were installed off shore this would also add another 1500 MW to the wind energy capacity. These plans are not overly ambitious, as current plans in the Netherlands for “Wind Farm N33” and “Wind farm Wieringermeer” consist of up to 40 E126 turbines and more than 60 E126 turbines respectively. [32]

Wind Farm with E126 turbines – Estinnes, Belgium [32]

However, when it comes to wind energy there is always the question of reliability. There is no guarantee that the wind will be blowing when required. This means that wind energy cannot be relied upon during periods of high demand. As previously mentioned, the most proven and reliable way of storing electrical energy is to convert it into stored hydro energy by means of pumping water to a high reservoir, ready to be released and harnessed with water turbines. So rather than directly supplying electricity to the national grid, wind turbines would be used to operate large hydro facilities. Here is an illustration of how this is achieved:

Hydro Storage Facility [33]

In this way, wind energy that is not needed during off-peak hours can be converted, ready for later use. This plan has been put forward by an initiative called “Spirit of Ireland”, launched in May 2009 [33]. This a joint venture of highly experienced engineers from a range of fields, accountants and lawyers. They have carried out a comprehensive study of Ireland’s resources and identified a path to follow to greatly reduce our dependence on fossil fuels. The main focus of their research was to identify how exactly hydro storage capacity can be expanded in Ireland. The only existing hydro storage facility in Ireland is at Turlough Hill in Wicklow. It has the capacity to produce 292 MW of electricity for five hours. Spirit of Ireland’s (SOI) research has concluded that there is no more possibility for similar projects to Turlough Hill. There are no feasible locations with 2 lakes at different heights in close proximity. This means that artificially creating this setup would prove too difficult and costly. In addition, all of our river hydro possibilities have been exploited already. However, there is another alternative for hydro storage. In the west of Ireland there are numerous valleys along the coastline which could be dammed up by creating an artificial wall between the valley opening and the sea. Water can be pumped from the sea into this valley and then released back into the sea through turbines to generate electricity. A similar project has been operational at Okinawa in Japan for over 10 years:

[33]

Okinawa Hydro plant

Their proposal is to develop three such sites of 1000 MW capacity each. In recent years many major civil engineering projects have been undertaken in Ireland, in particular the building of many new roadways. They suggest that this is mainly an earth moving project, so there is plenty of experience available to undertake this task. It would be an easier task than an inland 2 lake system, as above ground manmade pipes would serve as the tunnel for releasing the water. These would be covered over so as not to be noticeable. This would do away with the need for complicated underground tunnels, which exist at Turlough hill.

The question is - how will these hydro storage facilities meet Irelands electricity demands? One facility of 1000MW (1GW), will generate 24 GW hours of electricity in a day if fully operational. Ireland typically requires about 70 GWh per day. This means that in theory three of these hydro units could satisfy the demand. But this does not cater for peak demand in the evening when up to 5 GW of power is needed [34]. It is too early to suggest that fossil fuel plants are made redundant. Initially planning to build hydro plants to fully meet Ireland’s electricity requirements is possibly a bit premature. A target of two or three hydro units is currently more realistic. If they are installed and prove a success, the system can be expanded if needed. It can be seen from the following graphs that highlight the electricity demand for a day in July 2011, and another in December 2011, that even though demand is often over 3 GW , it would still contribute to quite a high percentage of the overall demand.

Demand 18th-July-2011 Demand 9th-December-2011 [35]

The proposed 3000 MW of hydro storage would require 3000 MW of wind energy to pump the water to the reservoirs. SOI suggest that this would require two thousand five hundred 3 MW turbines (2500 x 3MW x 40% efficiency). Their figures for turbine efficiency may be a little optimistic, but considering their proposal is two years old, it can now be reassessed in terms of the larger turbines that are now available. 3000 MW can be generated by roughly 1140 E126 turbines (1140 x 7.5MW x 35% efficiency). 1140 turbines is much more than the 300 suggested earlier, but one has to remember that when it comes to wind, there is a difference between installed capacity and actual output. To seriously take control of Ireland’s energy future, a large scale plan is needed.

SOI have worked out that 2500 turbines would take up 1% of Irelands land mass. This is seven times less than that taken up by forestry, so 1140 turbines would take up considerably less space again. In reality it would probably not be possible to use 7.5 MW turbines entirely, as geographical considerations and/or wind speeds could mean that they may not be the best choice. There may be a need to select a blend of larger and slightly smaller turbines.

What happens when there are fluctuations in the wind patterns? The capacity factor figures of turbines will give a general guideline as to what they can provide over a long period of time, but over short periods, wind speeds may be very low and there may not be enough wind energy to power the turbines to supply the hydro plants. Backup strategies need to be in place for these situations. These would include:

Efficient fossil fuel plants that can ‘ramp up’ their production at short notice
Importing cheap electricity from abroad at night time to refill the hydro plants.

Another potential backup strategy would be to build more hydro storage capacity than wind capacity. The model so far is based on the standard 30-35% capacity factor of a wind turbine. However there will be times when wind speeds are quite high and turbines will be working at near rated capacity for long periods of time. Couple this with times when electricity demand is lower, windy summer nights for example, and the excess wind could go towards filling an extra 2 GW of hydro storage for use at later stages when the wind is not there.

Who is to undertake this plan? The hydro plants project would likely be a Public Private Partnership, a combined effort of government agencies and private industries where a private company is tendered to take on the construction and reap some of the rewards when operational. The development of wind farms could be allowed continue as it has been so far, where private corporations take on these projects. The government could step in and push this along with their own projects if necessary.

Generate Public support

For such a large scale plan that will have a considerable impact on the countryside of Ireland, public support will play a crucial part if the plan is to have a serious chance of taking hold. SEI undertook a comprehensive study to find out public opinion on the use of wind turbines in Ireland [36]. Some of the key conclusions they found were “The study indicates that the overall attitude to wind farms is almost entirely positive. More than eight out of ten believe wind energy to be a very or fairly good thing”, and “Encouragingly, the study highlights that two-thirds of Irish adults are either very or fairly favourable to having a wind farm built in their locality, with little evidence of a ‘Not In My Back Yard’ effect.”. This is an encouraging start, but to further help in efforts to generate public support for such a large project the following measures could be taken

Start a national media campaign to raise public awareness of the drawbacks of fossil fuels, and of how wind energy can help guarantee our energy future. Public figures could deliver the message and residents living near existing wind farms could be used to provide assurances that it is not a nuisance technology.
Possibly provide financial incentives to residents living within 2 km of a proposed wind farm such as paying half their electricity bill (with fair usage restrictions).
Provide financial incentives to land owners to encourage the sale or rent of land for the use of wind farms. Considering that the land around a wind farm can still be used agriculturally, maybe there can be very low, or zero tax on crops produced on this land.

Provide financial incentives to encourage growth in the sector

If the Irish government made some key changes to financial regulations in the area of renewable energy, it could give a boost to efforts to make us more energy independent. Some of these include:

Reducing the corporate tax rate for renewable technology manufacturers. Our current corporate tax rate has already encouraged some the world’s top industries to have their European offices in Ireland. If an extra incentive was given to companies such as wind turbine manufacturers, it could possibly encourage them to set up manufacturing/assembly plants here. This would be with a view to making the process of purchasing and transporting turbines easier and cheaper for the Irish wind farm developer. Transport costs would be cheaper and as part of the reduced tax rate an arrangement could potentially be made to sell the turbines for 5% cheaper to Irish customers.
Establishing a government loan scheme for developers. Setting up a wind farm is a relatively expensive process. With banks tightening up their lending practices it might prove difficult for wind farm developers to get the capital they need to start projects. If the government were to provide the funds (at possibly lower interest rates), this might also encourage the setting up of wind farms.

Upgrade the Electricity grid

Below is a map of the current Transmission Electricity network operated by Eirgrid

Electricity Transmission Network [37]

This is a map of the transmission network – the distribution system is not shown here. If the plan for a large scale expansion of wind turbines associated with hydro plants is to be advanced, an upgrade of the transmission network would be required. Much of the coast along west Cork, Kerry, Clare and Galway is quite a distance from the nearest 110 KV station. This would make grid connection quite an issue when it comes to developing new sites on the extremities of the west coast. Creating a new 110 KV line along the west coastline, connected to the existing network at a few strategic points would be another factor in making wind farms and hydro plants viable. It would potentially be easier to run this line along the sea bed and come back on-shore at certain necessary locations.

Other uses of excess electricity

The model that has been discussed would see the wind turbines using most of their generated power to pump their associated hydro plants. However, at times of high wind and/or low demand, using excess wind energy for other projects could help develop a new energy strategy for Ireland.

Use wind energy to charge small scale batteries.

It has already been mentioned that large scale battery storage for Ireland’s electricity usage is not very practical at the moment. However, small amounts of excess wind could be used to charge small batteries, maybe the capacity of ten car batteries. These could be used for various purposes nationwide such as street lighting at night time, backup batteries for different applications, power for small temporary buildings such as portakabins. These batteries would be charged at the turbine sites and collected and distributed daily. This would only be a small scale project which would not generate a large amount of revenue, but it would be an extra step towards reducing our fossil fuel usage and it would also increase the awareness of what wind energy can do

Charge batteries in homes nationwide

Further to the idea above, a plan for the future could be for many homes nationwide to have batteries integrated into their circuit board. These batteries could be enabled and charged by excess wind energy at night and then used for more light energy applications such as domestic lighting. There would need to be intelligence in the design so that ‘expensive’ daytime electricity is not used to charge the battery. Also the electricity from excess wind energy used to charge the battery could be at a very low cost, if not free. It would possibly not be practical to install a system like this on a older house, but it may be a useful idea for new builds or renovations.

Power greenhouses close to the wind turbines.

Whilst not a great revenue earner, small amounts of the wind farms electricity could be used to power greenhouses either beside, or on the land of the wind farm. This would be for growing fruits and vegetables that otherwise Ireland would have to import. This would not only help the local economy, but also contribute to a positive green image of wind farms.

Is this economically viable?

The European Wind Energy Association has done a detailed examination of what it costs to produce electricity from various forms of energy. They have done this using a Levelised Cost of Electricity model which “is defined as the actualised kWh cost over the complete lifetime of the project, taking into account the present value of all the cost components” [38]. They have surmised that currently it costs just over €60 per MWh for onshore wind. The graph below highlights how this currently compares to other forms of energy.

Electricity costs in 2010 [38]

The ‘with risk’ part of gas, coal and nuclear energy reflects the volatility that these forms of energy experience due to fluctuations in supply and the effect of CO₂ emissions. They have continued this analysis to give projected costs in 2020:

Electricity costs in 2020 [38]

Thus it can be seen that already wind energy has reached a stage where it is an economically viable form of energy, only gas is cheaper at present. But as we progress into the future wind energy will continue to stand out as a clean, dependable, affordable option. The wind price highlighted above closely matches the price that is currently offered under the REFIT scheme, therefore it would be a wise decision by the Department of Communications Energy and Natural resources to continue this scheme on into the future. A guaranteed €60 per MWh generated will give security to developers wishing to join this market as they will be able to go ahead with planning projects and securing funding, knowing with relative certainty what their returns will be. It can also be said that this €60 per MWh for wind energy will prove to be an increasingly cheaper price for energy as time goes on compared to other forms of electricity. Therefore maximising our wind generating capacity now will prove to be a wise economic move in the future.

When analyzing these figures it cannot be forgotten that the suggested plan for Ireland includes the building of hydro storage facilities to store the generated energy. The above figures represent a scenario where the wind farm is supplying its electricity directly to the national grid. They do not represent a model which includes the massive hydro storage project. This would indeed be a hugely expensive task to undertake and would rival some of the largest projects that have been completed in Ireland recently. This could potentially be used as an argument against such a project by those who feel that Ireland is too pressed financially at present. It must be stressed though, by both the government and every relevant authority, that it is of paramount importance to address Ireland’s future energy needs. As a country we have advanced our business practises and standard of living in recent times to the extent that energy plays an ever more crucial role. With even a slight amount of foresight it can be seen that an investment in our energy needs now is of paramount importance should Ireland hope to secure its energy supply and hence its own economic future.

Conclusion

Ireland has reached a pivotal point in its development as an industrialised nation. We have progressed to become a country with a high standard of living. This progression has come hand in hand with an ever increasing demand for electricity. This is a demand that has been mainly supplied by fossil fuels, which are now irreversibly in decline. We are a nation that has greatly relied on importing fossil fuels to meet our demands, so steps must now be taken to guarantee our energy future.

Wind energy is a clean, renewable, emission free form of energy which Ireland receives in abundance. As detailed in this report, much planning is required to design and install a functional, environmentally considerate and profitable wind farm. When a carefully considered plan is successfully implemented, wind technology offers a very real alternative to our dependence on fossil fuels. Technological advances have progressed the wind turbine design to a point where wind can be harnessed so effectively that it is a now a real option for nationwide electricity supply. In a future where fossil fuel prices continue to rise whilst availability decreases, our wind energy potential stands out as a truly viable renewable alternative.

As this report explains, maximising our wind harnessing capabilities with continued deployment of modern efficient wind turbines and storing the generated electricity in coastal hydro plants is a clean, viable, self sufficient way to reduce our dependence on fossil fuels. This alternative to fossil fuel dependence will only succeed with good planning and a combination of government investment, financial incentives and measures to raise public awareness and support of wind turbine technology. In return, developing wind turbine technologies will provide security of Ireland’s energy supply for generations to come. It will also provide employment opportunities, lower our carbon emissions and strengthen our economy. The technology and raw resources are readily available to us to make this vital change in our national energy supply, all that is needed now is the political and economic will to do it.