Skip to main content
EU Urban Mobility Observatory
News article30 March 20222 min read

Public University of Navarra uses microgrid with renewable energy to charge buses

A pilot project has been launched by the Public University of Navarra (UPNA), Spain, involving charging electric buses quickly and efficiently using solar energy. The energy created is stored in recycled batteries, which are part of a smart charging system that can predict when to charge, depending on arrival times, length of stay or even weather conditions.

Researchers from the Institute of Smart Cities of the UPNA have developed an intelligent electrical microgrid which charges electric buses at the UPNA. Solar panels installed at the roof of the university produce a quarter of the energy consumed by the six buses that arrive at the UPNA and 2% of the energy consumed by the UPNA.

Across Europe, cities and public transport authorities are replacing their fleet of diesel-fuelled buses for alternatively fuelled vehicles, many of them electric buses. But electrifying the public transport fleet is not without challenges. For one, batteries within the buses need to be sufficiently charged in order to provide reliable transport services. Charging can occur at the head station and at stops along the route. As timetables do not allow lengthy stops, charging along the route requires very high electrical power to secure sufficient loading. The electricity network is not equipped equally well everywhere to meet the demand for high (peak) capacity. Ensuring appropriate charging can be a costly challenge.

The microgrid solution developed at UPNA can produce and distribute power within its local distribution network, as well as get power from the general network. The solar panels at UNPA provide clean energy stored in batteries that can be charged or discharged according to need. Algorithms have been developed to determine when best to charge or use energy from the batteries. In this way the microgrid can improve the electrical network through an optimised balance between supply and demand. The batteries are made up of 90% reusable material, adding circularity to the project.

It is an initiative that includes all the pillars of self-consumption”, stated Regional Minister for Economic and Business Development in Navarra, Mikel Irujo at the presentation of the project at the university. “We must direct our production system towards sustainability and the efficient use of resources based on the bio-economy and circularity”, Irujo added and also highlighted that initiatives like this are well aligned with the vision established in Navarra's Smart Specialization Strategy for Sustainability (S4), which “is that of a reference region in Europe, in the transition towards a sustainable and digital economy”.

The renewable charging and microgrid project, is part of the European project STARDUST. In STARDUST, intelligent solutions for energy, mobility and ICT will be integrated in cities together with innovative business models, which will serve as blueprints for replication across Europe and abroad.


Publication date
30 March 2022
  • Clean and energy-efficient vehicles
  • Collective passenger transport
  • Spain