How sites for wind turbines are selected: good wind is not the only criteria

In order for Lithuania to produce all the electricity required in the country from renewable energy sources in just a few decades, wind energy will need to play a significant role. The conditions for the development of this type of energy are favourable, since wind turbines can be built in almost all areas of Lithuania. Therefore, how do the project developers decide where a new wind park should be located? How do they measure the wind direction and speed?

Lithuania’s good conditions for the development of wind energy projects are determined by the fact that it is a country of plains. This means there are no natural barriers that could block the wind, and there are no major differences between the north, south, east and west of the country in this regard. Although most of the wind parks in our country are currently operating near the sea, the latest large wind turbines could be built almost anywhere in Lithuania. 

“The largest wind park in Lithuania currently operates in Pagėgiai Municipality. It is comprised of 30 power plants with a total capacity of 73.5 MW. The site was chosen due to a so-called “lagoon corridor”, which is a phenomenon that results in stronger winds than the average in this area. However, wind parks are operating just as successfully in other parts of the country. For example, one of the most efficient wind parks is the one built near Anykščiai in the east of the country that has the highest three wind turbines in Lithuania – the highest vertical point of the blades reaches 180 metres in height. Due to this increased size, wind power plants can be built almost anywhere. At the same time, it means that fewer power plants are needed to produce the same amount of energy,” said Aistis Radavičius, Director of the Lithuanian Wind Power Association.

Although the conditions for the development of wind energy are favourable throughout Lithuania, choosing the site where the wind park should be located is a complex and complicated task. The companies developing these projects need to examine a wealth of information and assess different aspects, ranging from the wind speeds in a specific area and access to the electricity grids, to protecting local landscapes and cultural heritage areas. The location of a wind park must also be agreed with institutions such as the municipalities, the military, Environmental Protection Agency, National Public Health Centre and the Department of Cultural Heritage. Presentations are then made to the local communities, after which the plans are often adjusted and adapted once again. 

Who measures the wind speed and how?

The windiness of a specific area is one of the most important aspects in determining where a wind park will be situated. Wind strength is determined by factors such as the roughness of the ground surface in a particular area, as well as the amount greenery or tall buildings. For this reason, it is wind parks are seldom built near where there are numerous tall buildings.

Special technologies and software are used to measure the wind speed and direction. One such device involves LiDAR (Light Detection and Ranging) technology, which is based on laser beams. This technology can help specialists evaluate the wind parameters to properly adjust the wind turbine. 

Another way is wind conditions simulation. WindSim is a member of the Lithuanian Wind Power Association that has been conducting simulations of wind conditions in various countries for more than twenty years. These simulations are created using special CFD (Computational Fluid Dynamics) technology, which allows the wind energy resources to be estimated, both onshore and offshore. Special software provides the possibility to model where (and even at what height) is optimal to install the wind turbines. This analysis will include data on the windiness, terrain, distance to the electricity grids or residential buildings, as well as the potential environmental and legal constraints.

Furthermore, CFD modelling can also be used to assess the wind quality, where measurements simulate the conditions under which the turbines will rotate throughout their life. The wind parameters such as the average speed or possible turbulence are taken into account, as well as the project developer’s future construction plans. After a large amount of data is collected, it is possible to calculate and estimate how much electricity a particular wind park will produce per year.

Wind parks are usually planned near (less than 10 kilometres from) 35 kV-110kV-330kV power transmission lines. These lines must have a sufficient capacity to absorb the future load generated by the wind park.

Local communities and their activities

When choosing the site for a wind park, the developers must take various features of the local community into accounts, such as the population density, their activities, etc.

“Sparsely populated areas with an agrarian landscape and a large proportion of agricultural land are usually selected for the installation of wind power plants. In accordance with the provisions of the Republic of Lithuania’s Law on Special Land Use Conditions, a certain distance must be maintained between the wind power plant and residential buildings. This distance is approved by public health specialists,” explained Radavičius. 

He noted that wind power plants are often built on agricultural land as the electricity generation activities require the land around the wind parks to be converted to an engineering infrastructure, but the landowners can continue to farm on the site with additional income from their land lease. As has been shown from the long-term experience of Lithuania and other countries, wind energy and agriculture can happily co-exist in the same territory. 

Importance of landscape and cultural heritage sites

Other criteria that play a part in determining where a wind park will be developed are the landscape, the biodiversity, the cultural heritage sites and any protected areas. 

Generally, a more diverse and vivid landscape is more important for the overall Lithuanian identity. Therefore, when planning the areas where wind parks could potentially be built, the Lithuanian Landscape Diversity Study conducted in 2006 by the Department of Geography and Land Management of Vilnius University is used. It includes criteria such as the recreational potential of the area.

Assessments of the biodiversity, protected animal and plant species, as well as Natura 2000 sites are performed on the basis of research carried out in the area and information published in the existing databases, such as geoportal.lt, VENBIS and elsewhere. All of this makes it possible to identify areas where it is important to develop measures for the protection of biodiversity.

In addition, the wind parks are usually developed in areas with a minimum number of cultural heritage sites. The aim is to minimise both physical and visual exposure to these objects.