The car park of the Alcampo shopping centre in Sant Boi de Llobregat hosts one of the most significant solar energy projects in the Barcelona metropolitan area. Promoted by the Metropolitan Area of Barcelona (AMB) and the Sant Boi City Council, this initiative aims to transform a large urban space used daily into a key infrastructure for renewable energy generation, with a strong impact in terms of energy self-consumption, sustainability, and urban quality.
In collaboration with the public company Tractament i Selecció de Residus (TERSA), a collective self-consumption photovoltaic installation was designed on newly constructed metal pergolas. The project scope includes the installation of solar panels, the structural design of the pergolas, the inverter system, and associated lighting.
The installation comprises 7,055 monocrystalline photovoltaic modules of 460 Wp each, with a total peak power of 3,245.3 kWp. These are distributed across 24 metal pergolas specifically designed for this project, with a central single-pillar structure and panels mounted in three rows per covered area. The energy generated is managed through 24 inverters with a nominal power of 115 kWn each, providing a total power of 2,760 kWn, thereby optimising conversion and injection into the grid.
The pergolas supporting the solar panels were designed to withstand wind and snow loads. Structural calculations were carried out to guarantee this resistance, which required redesigning the initial pergola model to ensure robustness under adverse weather conditions. These calculations considered both the structure’s own weight and the loads from wind and snow. The pergola design also facilitates maintenance of the photovoltaic installation. Whereas conventional pergolas usually measure 2.2 to 2.5 metres in height, this design reaches 3 metres to allow taller vehicles to park.
The pergolas are anchored to the ground with concrete foundations dimensioned according to whether they are located at the ends or central sections. In two cases, where they sit above a sewer line, the foundations were specifically designed to avoid interference.
Given the scale of excavation required for the foundations and the poor condition of the existing pavement, the opportunity was taken to repave the area. First, the old asphalt was milled. Then, the foundations for the pergolas were placed. Finally, the pavement was renewed with a recycled asphalt mix incorporating 25% reclaimed material from milling and a binder produced from recovered oily residues from marine pollution.
The project also includes an LED lighting system with 170 light points integrated into the pergolas. With different power levels distributed according to the area, the system guarantees a minimum of 15 lux on the driveways and 20 lux in the parking spaces, with uniformity above 40%. This improvement enhances both user safety and comfort.
The installation is expected to generate 4,443,427 MWh of energy annually, sufficient to supply 1,200 households or charge 2,400 electric vehicles. In addition, it will reduce CO₂ emissions by 1,155 tonnes per year. The energy will be used for the self-consumption of 39 municipal facilities, with the possibility of extension to groups in situations of energy vulnerability.
