Onshore Wind - FAQ's

Manx Utilities has a legal obligation under the Electricity Act, 1996, to provide electricity from the most economic source. Onshore wind is currently the lowest cost source of electricity available for the Isle of Man (even after factoring in balancing costs), and so  onshore wind is the most economic source at this time.

Electricity on the Island is primarily produced from imported natural gas, which contributes to climate change and puts the Island at risk in terms of energy security. As such, the Proposed Development can also protect the Island against volatile external energy prices.

In addition, one of the key purposes of the project is to facilitate the national energy objectives detailed within the Climate Change Plan 2022 – 2027, and the Island Plan, which mandates at least 20MW of onshore renewable electricity by 2026. This Climate Act, 2021, requires a Climate Plan to be produced every five years to agree a pathway to progressing towards any interim targets. The subsequent Energy policy document also stipulates that this will be delivered primarily from onshore wind. As such there is a national need for onshore wind.

Tynwald has established a legally binding Target of 35% reduction in emissions by 2030; the Climate Plan, 2022 – 2027 stipulates that this shall be achieved via the 100% decarbonisation of electricity.

On Island, we use more electricity in winter than we do in summer. Generally this is because the days are shorter and there is a need to use lighting earlier in our homes. Electric heating is also utilised in winter where the temperature is cooler and hot electric showers are more likely to be used.

Wind speeds are highest in winter on Island which means a windfarm will produce most of its power in winter, when our demand is the highest.

Solar panels produce most of their power over the summer months, with longer days and with the sun higher in the sky. The time solar power produces most power, is the time when demand is lowest. If this excess power cannot be exported, it must be curtailed which results in higher costs to consumers.

While the cost of generating from solar can be very low, the total system costs resulting from curtailment and balancing of solar are actually significantly higher. The cost of wind once system costs are factored in are actually much lower than solar.

We have collaborated with Culture Vannin and after much discussion chosen ‘Cair Vie’ as the name for our new Wind Farm. In modern language this means ‘Fair wind’ which is relevant given a Cair Vie will be powering the wind turbines and propelling us into a sustainable future. 

The Isle of Man Strategic Plan, 2016, requires any onshore wind site to have a comprehensive Environmental Impact Assessment (EIA), which must follow the guidance provided by the Town and Country Planning Act (Environmental Impact Assessment) England and Wales, 2017. EIAs take a minimum of 18 months – two years. This allows enough time for us to understand local factors such as bird and bat migration patterns, noise, changes to the landscape, visual impact, cultural heritage, local archaeology, social impacts and how turbines can be transported to the site.

Considering all of these areas allows us to ensure that not only is the most suitable site selected but that we also mitigate any adverse impacts as we design the turbines. Following a period of consultation with the local and wider Island community, a Planning Application will be submitted. Manx Utilities are following the Major Planning Process for this project.

An indicative business case which provided the anticipated cost for the project including; feasibility, first stage design, second stage design, environmental impact assessments, site preparation, construction and commissioning was endorsed by the Manx Utilities’ Board in June 2023. The schedule of costs have been validated by a cost consultant.

Although the cost parameters for this project are known, we will be running competitive commercial procurement exercises in the near future and we do not wish to compromise the process. Following the completion of the tender exercise we will be seeking Tynwald approval for the full cost of the project

The height of the turbines will depend on the type and class of wind turbine we select after completing our technical studies to determine the optimal wind turbine for the site. The initial design could be up to 180 metres total height.  Between 4 and 5 turbines will be needed to achieve the minimum 20MW target.

The hub, which is the casing in the centre of the blades which supports the motor will be at a similar height as the stack at Pulrose power station including the spire.

The Isle of Man Civil Aviation Administration (CAA) is the division of Government responsible for regulating aviation safety on the Isle of Man.  The Isle of Man CAA is also responsible for ensuring aviation legislation in the Isle of Man meets International Civil Aviation Organisation ('ICAO') Standards and Recommended Practices. We have been in contact with the Isle of Man Civil Aviation Administration, and will be abiding by Air Navigation (Isle of Man) Order 2015 (SI 2015 No. 870 as amended), where any site may impact the air traffic zone.

At this stage, any onshore wind turbine must also have lighting fixtures in place (similar to those on telecommunications masts already in place on the Island) to warn approaching aircraft of their presence. This is in compliance with article 136 of the Air Navigation (Isle of Man) Order, 2015 (SI 2015 No. 870 as amended).

However, trials for Aircraft Detection Lighting Systems (ADLS) which can automatically turn wind turbine lights on and off depending on approaching aircraft are already in progress at UK airports. These trials are due to complete in 2024 and it if successful, we will look to incorporate such a system into the wind turbine design to minimise any visual impact as much as possible. However, it is not intended that the turbines, once constructed, would be floodlit at night, as this is not an aviation safety requirement.

Turbines within a wind farm in the UK are typically spaced 500 metres or more apart depending on the size of the turbine. In order to make best use of the wind resource, turbine spacing is proportional to the rotor size and the down-wind wake effect created.

5 x 4.2 MW turbines would require at least 0.5 km².

However, the bases of the turbines on the site will only require a maximum of 10% of this area.

The visual impact of the wind farm to local residents has been assessed in the early stages of our investigations. Visual impact is somewhat difficult to measure as it is often a personal subjective opinion. However, within the process of our technical studies and development and submission of our Environmental Impact Assessment (EIA) we will carry out work to mitigate this in the design of our windfarm. This is one of the major considerations of the design process and this work will be carried out prior to submitting the planning application.

Investigations into possible windfarm locations on the Isle of Man extend as far back as 2005 with a 2010 report by AEA identifying ten possible locations for onshore wind across the Island.

Given the dominant south westerly wind direction on the Isle of Man, sites facing the south west typically have better energy yield for onshore wind.

Peatland in particular can be a major barrier to onshore wind, as the damage caused to peat by the onshore wind turbine foundations can release more carbon dioxide than the windfarm ultimately saves. It is therefore very difficult to justify that peatland should be developed. This is problematic as after further review, all sites identified in the AEA study actually lie on peat and heathland. Heathland is a protected habitat on the Island as it has a very high biodiversity value. It is difficult to mitigate the ecological impact of constructing windfarms in such areas and this is why there have not been any windfarm developments on heathland in the British Isles since 1990s.

A study by Bureau Veritas in 2022 identified three suitable onshore windfarm sites on Island from over 500 sites across the public estate. The evaluation by Bureau Veritas considered both energy yield from onshore wind and the environmental impacts of such a development. The three sites identified by Bureau Veritas all fall within the high wind bands identified in the 2019 IMPACT report, but also lie in three regions which are not entirely made up of heathland.

In order to select these sites, Bureau Veritas utilised GIS data from the Isle of Man Government. The information was used in tandem with Manx Utilities’ 33kV and 11kV Transmission and Distribution networks. This information is mostly available on the MANNGIS website. There are over 500 sites on the Isle of Man which are owned by the public estate and could have been selected in the shortlist. Note that this study was carried out in tandem with a study to identify suitable sites on public estate for the deployment of solar panels.

The study reviewed the entire Island to enable a shortlist to be drawn up. Bureau Veritas applied their own modelling to the GIS data to combine the locations with NOABL (a global wind data set) wind speeds for the Island as provided by Ronaldsway Meteorological Office, the prevailing wind direction (South West), access of a site to the prevailing wind direction, the locations of buildings, topography of the site, transport access and crucially the environmental and ecological maps which are publicly available.

Each of these areas are equally important however there are some hard constraints:

Wind speeds must be >6 m/s to ensure the windfarm is commercially viable. Typically on the Isle of Man these are all upland areas.

• Wind turbines must be located a minimum of 500m from the nearest property in line with Technical Advice Note 8 (TAN 8) (England & Wales) to mitigate noise impact.  
• Heathland should be avoided where possible due to the high net biodiversity value of the land; the upland areas which do not have heathland are typically all catchment areas for water.
• The local network must be capable of supporting a minimum of 20MW generation input.

Once these key areas are considered our iterative selection process has indicated there are only three broad areas on the Isle of Man where windfarms can be accommodated. Within these three broad areas at Ronague, Baldwin and Sulby reservoir, the public estate owns the majority of the upland areas because they are also catchment areas for reservoirs.

In March 2023, following the approval of the Island plan, Manx Utilities appointed multidisciplinary Environmental, Engineering and Mining consultants, Wardell-Armstrong, to carry out the initial environmental and technical appraisals for all three sites. The Baldwin & Injebreck site was ruled out on the basis it cannot accommodate more than 3MW due to access limitations and topographical challenges.

The Sulby & Druidale site had high average wind speeds >8.5m/s which could enable a windfarm to generate more than 81 GWh per year. However, it would need between 7 and 12 turbines installed over 1.5km2 in order to achieve a minimum output of 20MW. Sulby was ruled out in a decision making process on the basis that it was adjacent to Sulby reservoir, the main drinking water supply for the island along with topographical and access challenges.

The Earystane & Scard site was selected due to having higher average wind speeds which would only require between 4 and 5 turbines to deliver a minimum of 20MW capacity. This capacity could deliver between 104 and 149 GWh per year (enough to meet 1/3 of current Island demand). The road infrastructure between the potential delivery locations and the wind turbine sites would also require very little modification to accommodate turbine components when they arrive on Island in 2026.

Manx Utilities & Wardell-Armstrong will now proceed with the full Environmental Impact Assessment and detailed design which will help to assess how best to mitigate any environmental and social risks identified.

The installation of offshore wind-turbines requires extensive planning and it would not have been possible to deliver a minimum of 20MW offshore wind by 2026. The cost of power produced from offshore wind is also typically higher than onshore wind because of the environmental challenges at sea.

The Manx Utilities’ Future Energy Delivery Strategy highlighted that the commercial limitation of onshore renewables on the Island electricity network is currently linked to average Island demand, which is c. 40MW. This is primarily because Manx Utilities cannot guarantee export into other energy markets such as GB and the system costs, which arise from the curtailment of offshore renewables during periods of low demand, could significantly increase the cost to Manx Utilities customers.

However, it is also noted that where any privately owned offshore renewable installation also has its own direct connection to another market, the curtailment risk, and subsequently the risk of increased system costs may be removed or reduced. This is because the development would have a commercial agreement such as a PPA, or CFD directly with another jurisdiction and the risk would either lie with the developer, or with the other jurisdiction. 

Such a development would therefore offer the opportunity for the Isle of Man to take a proportion of the power with no/little commercial risk and increase the proportion of renewables on the system. For a very large development e.g. 1GW scale, the renewable development would also have a high capacity factor relative to the Isle of Man’s needs and could possibly meet demand for up to 90% of the year.

A renewable development which readily lends itself to connections to multiple jurisdictions is an offshore windfarm.

Manx Utilities are actively exploring the possibility of connecting into an offshore windfarm to deliver additional renewable power to the Island over the next seven years.

Manx Utilities have been working progressively over the last few years completing feasibility work in the form of detailed technical studies. Investigations on sites suitable for onshore wind actually go as far back as 2005. Since these initial studies, Manx Utilities have taken into account changes in planning rules, consideration for protecting vulnerable areas of our environment, and detailed assessments on the limitations of our network.

The work done since 2021 has helped us to identify the most suitable site for an onshore windfarm, the technical and commercial limitations for renewables on the power system, and helped us identify how an onshore windfarm would fit into the overarching strategy for decarbonising our power system alongside other renewable technologies.

All the work done to date has helped to inform the best solutions to bring renewable electricity to our island at lowest cost and best value to our customers.

We have now commenced full Environmental Impact Assessment (EIA) to identify how to mitigate the impact of wind turbines on the local community and environment in Earystane and Scard as well as carrying out the design work for the wind farm. This work typically takes at least 18 months to allow for two seasons of bird and bat migrations.

Manufacturing contracts may need to be secured before the EIA process is complete to ensure the wind-turbines can be delivered to the site in time to meet our 2026 target.

We will be consulting with the local and wider Isle of Man community on the development throughout the EIA phase. On completion of our EIA we will submit our formal planning application aiming to start our site preparations in January 2026. Once this work is complete we will be able to install our wind turbines and start to generate clean renewable electricity, with a target commissioning date of September 2026.

Since the Island Plan targets and the Council of Ministers decision were announced work has been ongoing to deliver the windfarm by our target of 2026. We have now completed the initial studies. The Environmental Impact Assessments (EIA) and design will take between 18 months and 2 years. This is a requirement of the Strategic Island Plan, 2016 and it is necessary to make sure any environmental impact is limited as far as possible.

Our project team are working hard to ensure our parts of the EIA and planning application process are completed on time and to the highest standard possible.

One of the misconceptions about the planning application process on Island is that it could be sped up via the use of a “National Policy Directive” (NPD). NPDs can be used where there is no strategic aim or objective within planning policy to help projects move quickly without waiting on policy change. However, developing onshore wind is already a strategic aim of the Isle of Man Strategic Plan, 2016. This means that providing the planning process is followed, the development is already broadly supported by existing policy. An NPD therefore would not help to speed-up the process.

The Manx Utilities’ windfarm will be publicly owned. 

The cost of generating a unit of electricity from wind can be lower than the cost of generating from fossil fuels such as gas at the point of generation. However, the total system costs for all intermittent renewable power is expected to be higher because balancing the system is more challenging when output predictions are dependent on the weather forecast.

Current projections indicate that the wind farm will not have a significant impact on the cost of electricity. However, having a fixed operational cost from a renewable energy source, will help stabilise electricity costs in the long term. Onshore wind generation is not affected by fluctuations and instability in gas and oil prices.

It is also worth noting that once a wind farm has been constructed there is no fuel costs associated for the life of the project.

The electricity produced by a windfarm depends on the quality of wind available and the design of the windfarm.

An average 20MW capacity windfarm on the Isle of Man is expected to generate at least 58GWh per year.

A windfarm at Earystane and Scard of at least 20MW could be expected to produce between 104 and 149 GWh of renewable electricity per year which is enough electricity to supply more than a third of current electricity demand on the Isle of Man.

Security of Supply on Island is the primary duty of Manx Utilities and it is our job to ensure the power system remains stable. The stability of our power system is primarily controlled by the HVAC interconnector between GB and the Isle of Man. When the interconnector is not in service, our existing gas-fired power station as well as the diesel engines can also provide this stabilising function. In the future our clean on-demand generators will also be able to maintain stability of the power system in “Island mode”.

Detailed network stability studies into the impact of intermittent renewables such as onshore wind, have been completed by engineering consultant, WSP. These studies look at both the stability of the whole Island power system as well as the localised impacts on our 33kV Transmission Network.

When the interconnector is available, 20MW of onshore wind can be comfortably accommodated at our location in all scenarios. When the interconnector is not available (currently less than 5% of the year) the output of the onshore wind turbines will be limited to maintain the stability of our network. This will be a design feature of the wind farm.

The impact of wind turbines on both birds and bats has been a key consideration of our initial environmental and technical feasibility studies. Windfarms can harm birds through disturbance, displacement, acting as barriers, habitat loss and collision. However, as noted by the Royal Society for the Protection of Birds (RSPB), the impacts of onshore windfarms can be minimised through thorough design processes.

The colour of the wind-turbines actually helps birds and bats to identify the wind-turbines from the air as white will stand-out against the brown/green backdrop of the land. Raptors especially will actively avoid wind-turbines of the size being considered for the Isle of Man in this project and there is no clear evidence to suggest direct harm to these species: Interactions between Hen Harriers and Wind Turbines. The slower rotational speed of the larger wind-turbines is significantly less likely to cause harm than smaller faster rotating domestic-scale turbines.

Nevertheless, bird impact is one of the major areas which will be considered as part of the wider Environmental Impact Assessment (EIA) in Phase 2 of the project, and any possible impact will be actively mitigated within the design of the windfarm itself.

Following construction of the turbines, we will continue to monitor the impact on wildlife, and take measures to reduce any adverse impact identified.

The RSPB also notes that in the context of rapid and unprecedented renewables expansion, avoiding and reducing harm will not be enough to give nature a chance. Manx Utilities plan for the deployment of onshore wind turbines is pragmatic and we are not seeking to install more power than the Island’s average demand, to enable our wildlife to adapt to the transition.

Throughout the initial feasibility studies, both Manx Utilities and our onshore wind specialist, Wardell-Armstrong, have been carrying out engagement with local residents, local hobbyists, and different environmental groups on Island as well as the different departments across the Isle of Man Government. This process will continue throughout the EIA and design stage and we will actively consult with stakeholders as our designs progresses with a view to mitigating any concerns raised.

Wind is an intermittent renewable resource which means it is reliant on weather which we cannot control; it is therefore not considered “firm” i.e. always available. The Isle of Man’s high levels of security of supply arises because we have three independent ‘firm’ sources of generation which can all meet demand on Island whenever necessary. At the moment, the sources that we rely on include the existing interconnector, the gas-fired power station at Pulrose and the diesel engines we have at Pulrose. After 2030, except in an emergency, we will no longer be able to use our fossil-fuelled generators for normal operation to deliver ‘firm’ generation, so we are planning to build a new additional interconnector to GB and new carbon-neutral on-demand generators which will continue to provide the same high level of security of supply. When it is windy, we will always use the wind turbines to generate power, providing there are no additional operational issues.

In addition to our onshore windfarm, Manx Utilities is also exploring several other projects including 10MW solar, which when taking into account private installations will take our total installed solar capacity on Island to 20MW by 2026 along the connection to an offshore windfarm which Manx Utilities are actively exploring. By 2030, at least 90% of our power could be supplied by Manx intermittent renewables including our onshore windfarm, with the remaining 10% of our power needs supplied from on-demand carbon-neutral renewable generators.

Wind turbines do produce noise but modern design has significantly reduced mechanical noise so most of the noise is wind noise across the blades. The sound they make can be described as a cyclic whooshing or swishing sound. In most cases, it is possible to carry on a conversation at the base of a wind turbine without having to raise your voice. Noise can vary depending on the background noise, geography of the site, including structures and vegetation, and the speed and direction of the wind.

Based on initial noise studies, the wind turbines at the site will be located at least 500m away from the closest buildings to minimise the impact. As the Environmental Impact Assessment (EIA) work progresses, the consultants will also consider how any impact from noise can be mitigated by both the wind turbine design and the site design.

During very high winds, the level of background noise is also very high and it is not likely that the noise from a wind turbine would be discernible during these times.

Wind turbines are designed to survive stormy weather. If the wind is too strong or gusty the wind turbine will shut itself down and the blades will ‘feather’ and become stationary much like an aeroplane propeller. The wind then passes over the blades without causing damage. They have safety systems designed to protect them from other severe weather events. There are also different classes of wind turbine for more inclement weather areas which are stronger. We will install the optimal wind turbine for the expected site conditions.

Investigations into possible windfarm locations on the Isle of Man extend as far back as 2005 with a 2010 report by AEA identifying ten possible locations for onshore wind across the Island.

Given the dominant south westerly wind direction on the Isle of Man, sites facing the south west typically have better energy yield for onshore wind.

The primary driver for selection of these sites was wind speed on Island. However, there was no requirement at the time to consider the environmental impact of windfarms on these locations. Subsequently critical issues such as land contamination from mining activities, visual impact, noise and damage to peatland have become factors in site selection. In 2016, the Isle of Man Strategic Plan was produced, which stipulated that Environmental Impact Assessments (EIAs) must be carried out for onshore windfarms on the Isle of Man. It also stipulated that any EIA should follow the guidelines outlined in the Town and Country Planning Act, England and Wales; the latest update in 2017 contains specific guidance for onshore wind EIAs.

Peatland in particular can be a major barrier to onshore wind, as the damage caused to peat by the turbine foundations can release more carbon dioxide than the windfarm ultimately saves. It is therefore very difficult to justify that peatland should be developed. This is problematic as after further review, all sites identified in the AEA study actually lie on peat or heathland. Heathland is a protected habitat on the Island as it has a very high biodiversity value. It is difficult to mitigate the ecological impact of constructing windfarms in such areas and this is why there have not been any windfarm developments on heathland in the British Isles since 1990s.

A study by Bureau Veritas in 2022 identified three suitable onshore windfarm sites on Island from over 500 sites across public estate. The evaluation by Bureau Veritas considered both energy yield form onshore wind and the environmental impacts of such a development. The three sites identified by Bureau Veritas all fall within the high wind bands identified in the 2019 IMPACT report, but also lie in the only three regions, which do not contain heathland.

In March 2023, following the approval of the Island plan, Manx Utilities appointed multi-disciplinary Environmental, Engineering and Mining consultants, Wardell-Armstrong, to carry out the initial environmental and technical appraisals for all three sites. The Baldwin & Injebreck site was ruled out on the basis it cannot accommodate more than 3MW due to access limitations and topographical challenges.

The Sulby & Druidale site was ruled out because it could need between 7 and 12 turbines to be installed over 1.5km2 in order to achieve an output of 20MW. Sulby and Druidale was also ruled out due to topographical and access challenges and on the basis it was also adjacent to Sulby reservoir, the main drinking water supply for the island.

The Earystane & Scard site has much higher average wind speeds which could only require between 4 and 5 turbines to deliver at least 20MW. This could deliver between 104 and 149 GWh per year (enough to meet 1/3 of current Island demand each year).

Manx Utilities & Wardell-Armstrong are proceeding with the Earystane and Scard site to the full Environmental Impact Assessment and detailed design stage, which will help to assess how best to mitigate any environmental and social risks identified.

There are several reasons why wind turbines are white. These include the neutral appearance when seen from the ground where white will blend in with the sky and the clouds. However, when they are seen from the air by pilots in planes, white makes them stand-out more against the ground, which is an important safety consideration. This also helps birds to identify the wind-turbines from the air which can help to reduce collisions.

There are many options for delivery to the Earystane and Scard site which will be considered in detail at the Environmental Impact Assessment stage however it is envisaged they will be delivered and transported by road to the site. This will be confirmed in a detailed transport plan during the design phase of the EIA.

The third site was at Baldwin and Injebreck. The major restriction for this particular site was the limited access to the area and challenging topographical issues, which would have prevented construction of the full 20 Megawatt windfarm. For example it would not be possible to drive the construction or load carrying vehicles up the slope to the plateau at the top of the Baldwin site where more wind turbines could be accommodated. The only accessible part of Baldwin can accommodate a maximum of 3MW and would require the removal of several buildings. 

Before carrying out survey work it was necessary to speak to local residents for access purposes at each site.

The surveys provided the information we needed to start the consultation process and it also assisted in deciding the Earystane and Scard site would be taken forward to the Environmental Impact Assessment (EIA) stage. The EIA includes significant survey work from detailed studies in twelve key areas:

• Ecological and biodiversity
• Geotechnical
• Aviation studies
• Transport and super-load studies
• Noise
• Energy yield and climate
• Landscape and visual impact
• Water
• Social impact
• Air quality
• Heritage and archaeology
• Planning

From the start of the EIA we will be going through a consultation process with the residents and members of the community surrounding the site and the wider Isle of Man community. This will allow us to provide feedback on the outcomes of these studies but also allows residents and the wider Isle of Man community to actively participate in the decisions relating to the design. The consultation process will start from September 2023 and will carry on throughout the 1.5 – 2 year EIA process.

This will enable local residents and the wider community to find out more about the project, how impacts will be mitigated and to actively participate in the design to ensure impacts are mitigated as far as reasonably practicable. Public engagement sessions will also be provided, these sessions will be open to all residents of the Isle of Man allowing all residents to engage fully in the consultation process and submit their views. Initial public engagement sessions have been held in Peel, Ramsey, Douglas and Port Erin.

We absolutely respect that those in close proximity are part of our key stakeholder group and we intend to ensure our stakeholders have every opportunity to comment on the plans.

Manx Utilities are not currently seeking to deploy any storage on Island as part of our Energy Transition plans. Storage can be used to balance grid frequency in power systems in conjunction with variable power sources such as wind and solar which cannot be guaranteed.

On the Isle of Man, grid frequency is instead tied to the frequency of the power grid in Great Britain when the interconnector is in service. In terms of the frequency control, an interconnector can be thought of as ‘long-term storage media’, which is typically available for 350 days per year. The interconnector can respond to any changes in renewable output instantaneously.

In the UK, if a major power station trips, another power station is brought on-line. On the Isle of Man, if one of our generators trip, the interconnector immediately picks up the load without any impact to the power system, or loss of supply.

Because the existing interconnector already provides the same function but with much higher availability, storage would only be used on Island if the cost of stored electricity is cheaper than any other source available. At this point in time, storage is not commercially viable for the Isle of Man but Manx Utilities continues to monitor improvements in technology. Should storage become commercially viable in the future we will certainly consider it as part of our future energy mix.

There is more information on considerations for storage in Future Energy Delivery Strategy

A SoDAR device works by emitting a sound wave and recording the sound that bounces back off surfaces. When wind up to 200m high passes over top of the device, the turbulent air it creates reflects the sound wave back to the device. An analyser within the device interprets the signal to calculate the different wind speeds in the package of air above the SODAR from 0m all the way up to 200m.

There are already several existing sources of data for wind speed available for the Isle of Man:

• 30 year wind data from the NOABL (Numerical Objective Analysis of Boundary Layer) data base
• 12-month measured wind data from a study by MEA from the A36.
• 30 year wind data from Ronaldsway Meteorological Office.

The average wind speeds identified for each site have been published in the Phase 1 Environmental Assessment report. The Earystane site also has the benefit of data from MEA studies in 2000.

The NOABL data set is considered suitable for windfarm feasibility purposes and is particularly useful when comparing sites. This is standard industry practice.

However, a fully statically valid wind assessment will not be possible until there is at least 12 months recent on-site data. This data can be used to develop a design.

Multiple options were considered for the collection of representative wind data including LiDAR, SoDAR and anemometry masts.  Given the high energy requirements of LiDAR which required an onsite diesel generator and the potential impact to wildlife specifically in relation to guy lines which are required for the anemometry mast, SoDAR was selected as the most accurate and least impactful solution.

The sound emitted from the SoDAR is of low frequency, which is not typically disturbing for animals. It is high frequency sounds that tend to scare birds and bats away from a site, and instruments which produce high frequency noises are typically in place at airfields to limit the bird-strike risk for this reason.

There are 4 distinct pings emitted from the SoDAR which travel upwards in a vertical column; each ping varies in volume from the last. Sound pressure level (SPL) can be described subjectively based on the decibel (dB) scale. 

A typical chart showing the range of sound pressure levels (and typical sources of the sound) is shown below:

The pings emitted average 45dB (dBA) over 1h, and the absolute maximum peak delivered from the device is <80dBp (the remaining peaks are much lower in volume), which is well within safe hearing limits. The volume emitted is lower than the volume of HGVs passing over the nearby roads (as shown in the chart above).

At 50m distance from the device at ground level the volume is <35dB and at 100m distance from the device at ground level, the sound is inaudible.

Noise monitoring equipment records the average background noise level to understand the baseline noise in an area; this can then be compared with anticipated noise levels if a design was taken to construction. This supports an Environmental Impact Assessment and windfarm design as it informs the clearance distances between a property and the nearest wind turbine.

Because of the way sound volume levels diminish with distance, the focus will be on the closest properties.   In order to ensure that the spacing of turbines and overall design does not unreasonably impact on the residents of a property, the design process will ensure that noise levels at the property from the wind turbine remain below 35dBA (this is typically the volume of whispering in a library).

The equipment does not record individual sounds or record conversations; the equipment only records the volume reached.

There are already a number of windfarm developments in the UK and Isle of Man waters which require airport mitigations including potential upgrades to the radar systems on the Isle of Man.

All proposed sites are likely to have an impact to a varying degree. Airport safeguarding is a key consideration for the environmental and technical feasibility work being carried out by our consultants and senior airport staff have been included in the workshops to date. The Environmental Impact Assessment which would accompany any application for such a development will then look to mitigate any impact identified in these initial assessments, and the strategy will be agreed with the Department of Infrastructure/Airport Senior Officers in advance to ensure there are no adverse consequences.

At this stage, any onshore wind turbine must also have lighting fixtures in place (similar to those on telecommunications masts already in place on the Island) to warn approaching aircraft of their presence. This is in compliance with article 136 of the Air Navigation (Isle of Man) Order, 2015 (SI 2015 No. 870 as amended).

However, trials for Aircraft Detection Lighting Systems (ADLS) which can automatically turn wind turbine lights on and off depending on approaching aircraft are already in progress at UK airports. These trials are due to complete in 2024 and it if successful, we will look to incorporate such a system into the wind turbine design to minimise any visual impact as much as possible. However, it is not intended that the turbines, once constructed, would be floodlit at night, as this is not an aviation safety requirement.

Information on the safety statistics of various generation technologies is available on our Transition Programme FAQs page.

Images are a powerful way of conveying information, illustrating options and capturing our imagination. They also form an important part of planning applications and Environmental Statements.

The LVIA is an integral part of the EIA planning process, and to ensure that the representations are robust and accurate, the below technical methodology is followed:

• Visualisation Type.
• Projection Planar or Cylindrical.
• Enlargement factor for intended sheet size.
• Date and Time of captured photography.
• Make and model of camera, and its sensor format.
• Make, focal length of the camera lens(es) used.
• Horizontal Field of View (HFoV) of photograph / visual.
• Direction of View: bearing from North (0°) or Compass Direction.
• Camera location grid coordinates: eastings & northings to relevant accuracy.
• Distance to the nearest site boundary, or key development feature.
• Height of the camera lens above ground level.
• Panorama Sheet viewing distance.

The Isle of Man adopts current practice from England and Wales and subsequently the guidance used for visual representation is taken from Landscape Institute Technical Guidance, and Scottish Natural Heritage.

Any images which have not been through this process should not be regarded as accurate.

By following the guidance we can avoid misrepresentation for the visual impacts of the windfarm.

Landscape Institute IGN Visual Representation

SNH Visual Representation of Wind Farms

View from Ballakilpheric Area (Below)

Picture taken from Ballakilpheric adjacent to Ballarhenney [distance to site boundary 900 m]

View from Castletown Area (Below)

Picture taken from Malew Road (A3) looking towards Slieau EairyStane [distance to site boundary 5.1 Km]

View from Port St Mary Area (Below)

Picture taken from Beach Road opposite Close Rheynn Wyllin [distance to site boundary 4.6 km] 

View from South Barrule Area (Below)

Picture taken from Cronk Ny Arrey Laa looking towards Slieau EairyStane and the south [distance to site boundary 550 m]

Heath refers to a type of open, uncultivated land with low-growing vegetation, often dominated by shrubs such as heather and gorse. Heathland, specifically refers to a type of heath that is characterised by acidic soils and a unique assemblage of plant and animal species. This is an important distinction because it is specifically heathland habitat that we are trying to avoid when we look at sites suitable for onshore wind.

Plantations on the Isle of Man may co-exist with some other species established in fringes and clearings, and uncultivated heath may be present, though is very different to the unique open habitat which makes up ‘heathland’.

None of the proposed windfarm locations at Earystane & Scard intersect either peat or heath at the plantation.

Maps of all sensitive habitats within the uplands, including heathland, are available on the Isle of Man Government website.

Peatland refers to a type of wetland habitat characterised by the presence of peat soils with at least 20% peat content which have wetland habitat on the surface. This may include raised bogs, blanket bogs and quaking bogs. Peatland is not the same as heathland though heathland may be underlain by peat, and peatland may have the presence of some heath species.

Peatlands actively sequester carbon dioxide and are therefore important for the Island’s carbon inventory. As such, peatland development should be avoided where practical.

A detailed map of peatland across the Island has already been developed by the Manx Wildlife Trust.

The map below shows the area of land that has been surveyed by the Manx Wildlife Trust as part of the Manx Mires project. None of the three sites undergoing feasibility studies were fully contained in the Manx Mires project. As such, additional peat studies were required within the Phase 1 Feasibility report.

The Wardell-Armstrong studies to date at Earystane & Scard have identified small pockets of peat across the site. These surveys note that it is likely that soils beneath the plantation still contain peat but these may not be actively peat forming at this moment.

The Environmental Impact Assessment will determine the mitigations required for any construction near to peat either to support the windfarm or to support access to the site.

The hierarchy for mitigation of peat is shown below:

• Avoidance (minimising the volume of peat disturbed);
• Minimisation through protection against damage (ensuring that excavated peat is managed so that it is suitable for reinstatement elsewhere within the site and does not become waste);
• Reinstatement (re-use) of excavated peat (the details of which are outlined in this Outline Peat and Habitat Management Plan (OPHMP)); and disposal (avoided using methods outlined in this OPHMP).

The bird’s-eye plan of the Earystane & Scard site shows the boundary where the initial Phase 1 surveys were undertaken. This does not represent the extent of the windfarm itself. The proposed indicative boundary of the windfarm is constrained to the plantation and the area at the very north of Scard.

None of the proposed windfarm locations at Earystane & Scard intersect peat at the plantation.