The Spanish Environmental Sensitivity Index (ISA)#
In 2020, the Ministry for Ecological Transition and the Demographic Challenge (MITECO) created a tool for identifying areas across the national territory that present significant environmental constraints for the installation of wind farms and photovoltaic plants. This was achieved through a territorial model that produces environmental sensitivity zoning, aiming to facilitate decision-making and public participation from the early stages of authorization.
The methodology relies on multi-criteria evaluation techniques using Geographic Information Systems (GIS) and a comprehensive analysis of documentation and legislation. It includes indicators at the following levels:
Urban areas
Water bodies and flood zones
Plans for threatened species
Protection areas for birds against collision and electrocution on high voltage power lines
Ecological connectivity and wild highways
Important Bird and Biodiversity Conservation Areas in Spain
Habitats of Community interest
Natura 2000 sites (ZEPA, LIC and ZEC)
Protected Natural Areas
RAMSAR wetlands
Specially Protected Areas of Mediterranean Importance
Biosphere Reserves
Sites of Geological Interest
Visibility
The Camino de Santiago
Traditional livestock routes
Public Utility Forests
UNESCO World Heritage sites
As a result, an Environmental Sensitivity Index (ISA) was calculated for each 25x25 meter pixel across the territory, and for each energy type (wind power and solar PV). Five levels were defined:
ISA level |
Sensitivity level |
Surface (wind power) |
Surface (solar PV) |
|---|---|---|---|
0 |
Maximum (not recommended) |
50.87% |
32.85% |
1 |
Very high |
5.47% |
3.47% |
2 |
High |
8.15% |
11.19% |
3 |
Moderate |
15.32% |
16.37% |
4 |
Low |
20.18% |
36.12% |
|
|
See more details on the ISA index here (in Spanish).
PyPSA-Spain allows land elegibility to be defined according to the ISA index (see config section).
The following figures show the potential capacity computed with PyPSA-Spain according to different ISA levels and NUTS 2 regions. For example, High means that eligible land includes ISA levels 2, 3 and 4. The horizontal lines indicate the installed capacity of the corresponding technology in 2025, and the target for 2030 as defined in the Spanish National Energy and Climate Plan (NECP). Energy densities of 10 MW/km2 and 50 MW/km2 were assumed for wind power and solar PV, respectively. A land occupation factor of 25% was assumed, meaning that only this percentage of eligible land was considered when determining the potential capacity.
For a deeper analysis on the wind powe potential in Spain restricted to low sensitivity areas, see [1].
Cristobal Gallego-Castillo, Fidel González-Rouco, Alvaro Cuerva-Tejero, Elena Garcia-Bustamante, Oscar Lopez-Garcia, and Jorge Navarro. Wind power potential in low environmental sensitivity areas of spain: a regional assessment. 2026. doi:10.5281/zenodo.18196580.