Búrfell Wind Farm
Where does the wind come from?
Wind is the movement of air driven by the pressure gradient force. Air molecules in areas of high-pressure rush toward low-pressure areas. The greater the pressure differential is in this process, the higher the wind speed is that results from the force. The Earth’s rotation also affects global wind patterns and causes circular motion in weather systems. All wind and weather conditions can be traced to the Earth’s radiation budget (i.e. the radiation absorbed and reflected or emitted by the Earth.) Warm-up from the sun is mainly controlled by sun height but also on how different type of the earth surface absorbs sun radiation. Sun height is controlled by latitude and time of day and year. Warm-up of the earth surface is controlled on how much radiation is reflected from the surface and how much warm it can hold. The air above warm surface expands, it becomes lighter and travels upwards causing low pressure to form next to the surface. The process is opposite for air movements above cold surface. Iceland is located high in the northern hemisphere; therefore, solar radiation is not adequate enough to sustain heat. Air and ocean currents carry thermal energy to Iceland from southern latitudes, which are mostly traced to radiation from the sun.
Wind energy in Iceland
Iceland is located in a part of the world where onshore areas are rich in wind energy resources. Research has indicated that the conditions in Iceland are highly favourable for the utilisation of wind energy. The potential for harnessing wind power in Iceland is extensive.
A wind farm is the phrase used to describe an area where a number of wind turbines are constructed in a cluster. Wind turbines are erected on platforms within the wind farm. The platforms are in most cases circular or octagonal shaped with diameter up to 25 m. An access track and crane hardstanding is needed for each wind turbine. The wind turbines are connected to the electricity grid via a buried cable to collection station where the voltage is raised. From the collection station the electricity is transported via a buried cable to Landsnet´s electricity grid.
An environmentally friendly option
Wind energy is one of the cleanest sources of energy currently available. Wind turbines produce significantly more electricity throughout their lifetime than the amount of energy used to construct, move, and dismantle the technologies. Additionally, throughout their operational period, the turbines do not emit greenhouse gasses. It typically only takes five months for a wind turbine to repay its energy footprint (i.e. generate the amount of energy it consumes throughout its lifetime.) Wind turbines can be located in most areas, and the development of wind farms does not diminish the potential for re-vegetation or agriculture in the same area. This results in an insignificant environmental impact that is largely reversible.
Why are wind turbines so large?
Geographical conditions affect wind patterns on land, often creating wind patterns specific to regional areas. The average wind speed and prevailing wind direction can vary significantly between adjacent areas. This is mainly attributed to elevation changes since wind speeds are generally greater on higher ground (e.g. hills) than on lower ground (e.g. valleys).
Air closer to the surface of the earth moves slower than air farther from the ground; this is a result of the friction created with the earth’s surface. The farther away from the earth (increase in altitude), the higher the wind speed becomes until it is no longer affected by the earth’s surface. Diverse terrain creates varying surface friction (resistance), which affects wind levels near the surface in a number of ways. A forested area creates more friction than a flatland area, resulting in lower wind forces in and around forests. The experienced affects decrease with increased surface height, and the average wind speed increases concurrently. Wind turbines are often large-scale structures in order to take advantage of the wind speeds available at these higher heights. Energy capacity is higher and surface friction has a smaller impact as a result of these engineering decisions.
The power of a wind turbine
The figure above shows how wind turbines harness the kinetic energy of the wind.
- Electrical generation quadruples if the length of the blades is doubled
- Doubling the wind speed results in an 8-fold increase in power
The Búrfell Wind Farm
This proposed development consists of the construction and operation phases of the first commercial size wind farm in Iceland. The development will have a total installed generating capacity up to 200 MW and will include access tracks, crane hardstandings, temporary construction compounds, an electrical control building and associated infrastructure. The area proposed for use spans up to 40 km2 of lava and sand plain and is located to the east of the Thjorsa River in the Haf area where Landsvirkjun already operates two wind turbines for research purposes.
Búrfell Wind Farm will consist of up to 67 turbines, each with a maximum height of 150 m to the tip of the blade. Each turbine will have a capacity of 3.0 -3.5 MW depending on the final turbine selection. It is estimated that the wind farm will generate approximately 705 GWh per annum using the natural power of the wind.
Wind patterns at the Búrfell Wind Farm
Wind patterns at the proposed Búrfell Wind Farm site are favourable for wind energy utilisation. The adjacent mountain ranges create a wind tunnel from the highland area down through the development area. Vast sand plains are prevalent in the area, which subsequently has low surface friction. The wind patterns in the area are characterised by high wind forces close to the surface. The yearly average capacity factor for the research wind turbines at Hafid is over 40% on average, and preliminary calculations for the potential capacity of the Búrfell Wind Farm indicate that the average capacity factor could reach 50% on average.
Environmental Impact assessment
Due to the size of the wind farm, the project is subject to an Environmental Impact Assessment (EIA) to remain in accordance with the Environmental Impact Assessment Act No. 106/2000. This Non-technical Summary provides an overview of the key findings of the EIA.
Proposals for the demarcation of the Búrfell Wind Farm
Three proposals for the demarcation of the Búrfell Wind Farm were examined in the EIA, and their respective environmental impacts were assessed. The proposals were as follows:
A total area of 34 km2 in the Rangárþing ytra Municipality.
A total area of 40 km2 in the Rangárþing ytra and Skeiða- & Gnúpverjahreppur Municipalities
A total area of 33 km2 in the Rangárþing ytra Municipality. The area is located within the limits outlined in proposals 1 and 2.
The EIA assumes that the area within each proposal can be utilised for the wind farm, and the layout shown is only an example. The final layout for the area will be determined in a later stage of the project once the turbine type has been chosen.
The EIA is based on 63 wind turbines, each with a height of 149 m to the tip of the blade. The maximum impact of the wind farm is determined through an assessment of equally distributed wind turbines placed throughout the proposed area, up to the periphery of the demarcations.
Mannvit Consulting Engineers is the consultant for the EIA, and Efla Consulting Engineers made the preliminary design work for the Búrfell Wind Farm. Numerous studies were specifically conducted to create a wholesome EIA. The resulting data can be found in the appendices.
Environmental impact – natural environment
A detailed study on birdlife was performed for the Búrfell Wind Farm EIA. Additionally, a topographic analysis was completed with a focus on geological formations, and the Icelandic Institute of Natural History completed a vegetation study.
Environmental impact - society
An emphasis was placed on assessing the proposed wind farm’s visual impact on the physical landscape. The noise effects of the wind farm were also assessed, and they were based on noise level models. Throughout the EIA process, perspectives and concerns from local residents, tourists, and tourist operators were considered. The Archaeological Office also conducted a special inventory of archaeological remains within the area.
The results of the EIA show that the development and operation of the wind turbines will likely have a positive impact on the municipalities in the area. Employment opportunities will be created, and revenue to the area will increase. The results also show that the visual impact from the Búrfell Wind Farm will be the most negative effect experienced from the development. This will affect the landscape, local communities, the tourism industry and tourists. The impact on noise levels, geological formations, vegetation and birdlife are believed to be negligible.
Búrfellslundur Wind Farm EIA report
The Búrfell Wind Farm EIA report can be accessed here on Acrobat format (Pdf)
186 MB PDF