To the north of Búrfell, approx. 70 km from the coastline, is a lava field by the name of Hafið. Landsvirkjun has erected two 900 kW wind turbines in the area, for research purposes. The wind turbines have been operated since the end of January, 2013, and together their generating capacity could be up to 6 GWh per year. The energy generated would be enough to serve 1400 households. Operations have been successful so far and the results of the project indicate that Hafið is a particularly advantageous area for generating electricity via wind power.
Opportunities in wind power
Wind power is volatile by nature and generation is therefore reliant upon the weather. Hydropower and wind power can work well in unison as Iceland experiences high wind levels during the winter months and water flow to the hydropower stations is at its highest point during the summer. More wind turbines could be constructed in the near future and could work alongside hydropower stations in producing electricity year around.
The main effects of wind turbines on the environment are: visual impact, noise levels and effects on the ecosystem.
Visual impact, noise levels and effects on the ecosystem
The Hafið area is particularly suitable for wind energy utilisation as it is not in close proximity to any residential areas but is close to necessary infrastructure such as high voltage transmission lines and main roads. Research is conducted on various aspects including visual impact, noise levels and effects on the ecosystem.
Manmade structures of this size have an unavoidable visual impact on their surroundings. However, these effects are mostly reversible as wind turbines and the foundation they stand on can be easily dismantled, leaving little trace of their existence, if energy generation ceases.
When the wind turbines are at full power the noise level in close proximity to them reaches 103dB (A) whereas the noise levels reach 45dB (A) at a distance of 340 metres. The noise levels are lower as the distance is greater and blend in with other noises from nature such as the wind and the roar of rivers. According to model calculations based on recognised methods, where the baseline wind level is 8 m/s, the noise level drops rapidly at Hafið as the distance from the wind turbines increases (this is evident in the noise map). As a comparison, reference limits for residential areas state that sound levels should not exceed 50 dB(A).
Calculated model values for noise levels from the wind turbines at Hafið
Research on the possible effects on the ecosystem has mainly focused on birdlife. Preliminary investigations on birdlife and flight patterns were conducted in 2013, as a result of potential wind farm projects by Bjarnalón and Hafið. The main results were as follows:
Density measurements identified 5 bird species. Three of these species are likely nesting birds in the area.
Flight pattern monitoring identified 17 species, the Pink-footed goose being the most common species. Other common species included the European Golden plover, the Whimbrel, the Common ringed plover, the Lesser black-backed gull and the raven.
The danger of collision was calculated for the Pink-footed goose and the European golden plover and is considered low.
The results indicate that the impact of these projects will mostly be in the form of disturbance to the habitat of birds by Bjarnalón in the Hafið and in the surrounding area during the construction period.
Landsvirkjun has made the decision to assess the capacity of the Hafið area more extensively. An analysis on the possible size and location of potential wind farms will be conducted for the first time in Iceland. The research will include wind velocity measurements and simulations, effects on the environment and society, the feasibility of development and operations and opportunities in the interplay between hydropower and wind power. The research will also focus on the operation of wind turbines within the unique Icelandic environment including ice, snowdrift, ash fall and sand encroachment alongside visual effects, noise impact, the natural environment and fauna.
Further research on birdlife will be based on experience at the international level. Experience elsewhere has shown that the negative impact on birdlife can be divided into four categories: collision, migration as a result of disturbance, inhibitory effects and loss of habitat. The Northeast Iceland Nature Research Center is already involved in further research on birdlife in Iceland in cooperation with Aarhus University. The main focus of this research is the mapping of migratory birds in the area around Hafið (from the spring period to the autumn period) as well as basic mapping of nesting birds.
Success in the first year of operations
The yearly average capacity factor for Hafið is above the world average and there are clear indications that Iceland is an advantageous location for electricity generation, utilising wind power. The wind levels at Hafið have been mostly typical to that of previous years and have been close to the average rate since the wind turbines were installed.
The efficiency ratio of the wind turbines has been good. Up-time is the period of time that wind turbines are in operation (any ‘down-time’ as a result of maintenance work is excluded). Up-time is expected to be 98% and one of the wind turbines has fulfilled these expectations. However, the second turbine experienced problems with its weather station in April and May and so up-time was reduced to 86%. The incident underlines the importance of operating two wind turbines for research purposes.
Wind turbine capacity in 2013
After nearly one year of operation, the average capacity factor for the wind turbines is approx. 40%, which exceeds all expectations. In comparison, the average capacity factor worldwide is approx. 28%.
Landsvirkjun’s wind turbines are relatively small (approx. 55 metres hub height), and this makes the high capacity factor even more remarkable. This is explained by the fact that wind velocity is relatively high, at a relatively low height in Iceland due to low surface roughness. This significantly reduces the cost of energy as hub heights can be kept quite low.
A natural wind tunnel forms in the Hafið area and winds at a height of 55 metres can reach an average speed of 10 to 12 metres per second. When the spades are at their highest position the wind turbines reach a height of 77 metres.
Wind turbines elsewhere in the world are generally located by the sea or in lowland areas where wind levels are generally more stable than they are in inland areas. The yearly average capacity factor for Hafið is approx. 40% which is unusually high. In comparison, the average capacity factor worldwide is approx. 28%.
More information on the wind turbine project at Hafið can be found on Landsvirkjun’s website. Real time information on the energy generated by the wind turbines can also be seen.
How can we utilise the wind?
Wind energy and hydropower are generated using the same technology. A large magnetised rotor rotates within a copper wire covering, transforming kinetic energy into electrical energy. The wind turbines are gearless direct drive mechanism wind turbines which have fewer rotating components, reducing mechanical stress and reducing maintenance and operating costs, as the system’s lifespan is longer. It also minimises noise emission and energy losses are significantly reduced.
Wind turbines use wind force to generate electricity; they slow down the wind force that they entrap, converting kinetic wind energy into mechanical power. The actual capacity of a wind turbine is therefore the difference between the wind speed in front of the blades and behind them. Theoretically, wind turbine efficiency is limited to 59.3% which is consistent with an 88.9% loss of kinetic energy. The size of the blades and the nature of the wind are determining factors in how much kinetic energy can be harnessed. Further determining factors include:
Specific gravity of air. Specific gravity is determined by the height above sea level, temperature and pressure. The greater the air pressure, the denser the air and high- density air is more energy rich.
Wind speed. Wind speed is the most important factor in utilising wind energy. If wind speed doubles then wind energy can become eightfold. Most wind turbines generate electricity at wind speeds of 3 – 25 m/s.
The ‘power factor’ of wind turbines. This coefficient determines how much kinetic energy a wind turbine can capture. The maximum limit is 59.3% and most wind turbines capture approx. 45-50%.
Surface area of blades. A larger surface area on a wind turbine blade increases the force captured from wind energy. The surface area increases in proportion to the diameter squared, and doubling the blade size can result in four times more generation capacity.