Territorial impact of wind farms: the case of Muras

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Muras has 19 wind farms within its territory and a total of 380 wind turbines totaling 264.42 MW of installed power. In the case of the wind farms of Muras I, Bustelo, Álabe-Ventoada, Álabe-Lomba, Silán, Pena Grande, Leboreiro and Coruxeiras all the power is installed solely in the Muras town hall. Yet the remaining 10 ( San Xoán, Álabe-Nordés, Álabe-Soán, Muras II, Carba, Montouto, Pena Luísa, Álabe-Soán Ampliación, Goia Peñote, Do Chao and Vilachá) shared it with neighboring municipalities.

The accumulation of power began in 1998 and ended in 2009; four companies were the main wind power developers in the mountains of the municipality through their respective business wind plans (BWP): Acciona, Gamesa, Endesa and Norvento. At the end of the period, two developers without a BWP joined this group: Hidroeléctrica del Arnoya, S.L., and Sociedad Eólica de Ourol, S.L.

Power accumulation came about in a rapidly explosive manner, as it did in the rest of Galicia after the approval of the first Autonomous Decree of 1995. Consequently, the current average wind turbine size (0.69 MW) is low as compared to the most recent models. Nearly 25 years later, wind farms with wind turbines of 0.33 MW of unit power are still operating. The two wind farms of the developers without the corporate plan, the last to be installed in Muras, are the ones with the largest wind turbines (2 MW).

Wind farms are present in 7 of the 8 parishes of the city council. The surface of Sisto is the only one without turbines. Almost 64% of the wind turbines are concentrated between the parishes of Muras (153) and Silán (87). O Viveiró (56), A Balsa (52), Irixoa (19), Ambosores (12) and O Burgo (1) also have turbines.

Wind power dynamics in the municipality of Muras, as in the rest of the Galician municipalities, has had a territorial impact on two large areas presented below.

Urban Impact

The area linked to the wind farms went from its previous classification as a rustic area in one of its categories (rustic common protection, special forest protection, agrarian, natural spaces…) to that of a rustic area for infrastructure protection linked to wind energy.

This has resulted in some direct limitations of the domain of these affected lands (established in the sectoral projects of supra-municipal incident (PSIS) of each wind farm approved by the Council of the Xunta de Galicia), either by way of the direct and material occupation of the land or by the constitution of easements according to the criteria established in section 3.2.2 of the Report of the Galician Wind Sector Plan.

The GWO estimated the area related to the turbines, freehold as well as easement, and eliminated the overlaps between wind turbines and wind farms. A total of 2,016.3 hectares now have a different urban classification; thus, their permitted uses have also changed. This surface represents almost 25% of the total surface of the Wind Development Areas (WDA) located in Muras with installed power, and it represents 12.4% of the entire municipal surface.

Exclusion of competitors

Law 5/2017, of 19 October promoting the implementation of business initiatives in Galicia added a clause/article to the Galician Wind Power Law (LAEGA) included in the 6th transitory provision establishing how to avoid territorial overlaps between wind proposals.

These overlaps are set considering predominant northeast and southwest winds in Galicia. A distance of 10 diameters from the swept area of each wind turbine is set for these wind directions, while a distance of 4 times the swept area is established for the less predominant directions. These zones are applied to wind farms in operation, regardless of whether they are authorized or in the administrative processing phase.

Although the rule speaks of overlaps between requests, the GWO coined the term competitor exclusion areas (CEA) because what actually happens when a wind farm is admitted for processing, whether already authorized or in operation, is that “wind space” is reserved for the owner of that right; this excludes third-party developers and the owners of the land from developing wind farms on these areas.

Based on this standard, the GWO estimated the total area represented by the CEA: the swept diameter of each turbine was taken and the formula for calculating the surface of an ellipse was applied. The overlaps between wind turbines and between wind farms were eliminated and only the CEA located within Muras was taken into account. The result was 3,850.4 hectares. This represents almost 47% of all the land included in a WDA that already has installed capacity, and almost 24% of the total area of the municipality.

Electricity infrastructures

So much installed wind power requires an evacuation infrastructure. The attached plan shows the global structure of the network of electrical substations and medium and high voltage lines that serve to evacuate the energy produced in Muras. A part of these infrastructures is located outside the municipal holdings; likewise, some of the evacuation facilities located in Muras are useful for wind farms located in other municipalities. Two 400 kV high voltage lines (HVL) that are part of the same electricity network in the north of Galicia run cross Muras. One of them directly transports energy from As Pontes to the Alcoa plant in San Cibrao. The other HVL from Mesón do Vento crosses Muras to the 400 kV Boimente substation located in Viveiro, which is also the destination of several 132 kV HVLs linked to the Muras wind farms. In addition to feeding Alcoa, this station is also a central part of the electrical interconnection between Galicia and Asturias.