In collaboration with the companies BeePlanet, EOSOL and Ingeteam, researchers from the Institute of Smart Cities (ISC) at the Public University of Navarre (UPNA) have developed a microgrid in Pamplona to charge eBuses quickly and smartly. The system obtains renewable energy from the sun (photovoltaic solar energy) and stores it in second-life stationary batteries from electric vehicles. This technology, located at the Teaching block on the Arrosadia campus can be used to support bus charging stations. The system will also have a dedicated website and an informative monitoring station inside the Teaching block to show the main energy flows in real time.
Project researchers (from left to right): Alberto Berrueta Irigoyen, Idoia San Martín Biurrun, Luis Marroyo Palomo, Pablo Sanchis Gúrpide, Guillermo Puy Pérez de Laborda and Alfredo Ursúa Rubio) in front of the line 9 pantograph outside the Teaching block as it charges a bus.
According to the researcher Pablo Sanchis Gúrpide, coordinator of the project, which is expected to last three years, the initiative seeks to ‘cut peak electricity demand for buses and manage battery charging smartly to facilitate the implementation of a sustainable electric transport network integrated into the Pamplona District electricity grid’. He works alongside the researchers from the Electrical Engineering, Power Electronics and Renewable Energies Group (INGEPER) Alberto Berrueta Irigoyen, Elisa Braco Sola, Luis Marroyo Palomo, Iñaki Ojer Palacios, Julio Pascual Miqueleiz, Guillermo Puy Pérez de Laborda, Idoia San Martín Biurrun, Adrián Soto Cabria and Alfredo Ursúa Rubio.
The project, which goes by the name of ‘Design and installation of an industrial microgrid based on renewable energy with backup storage’, relies on the collaboration of the Federation of Local Councils in the Pamplona District and is financially supported by the Government of Navarre (Department of Economic and Business Development) through an agreement. It is also partially integrated into the European project STARDUST, which aims to make Pamplona a ‘smart city’ and is coordinated by the National Renewable Energy Centre (Cener) with the participation of the UPNA, whose principal investigator is Professor Ignacio Matías Maestro. The work at the Teaching block was managed by EOSOL; the inverters and converters were supplied by Ingeteam, and BeePlanet provided the second-life battery system. The firm El Colectivo has also been involved, designing the infographics for the entire project.
Authorities, researchers and representatives from the participating companies visiting the UPNA microgrid.
Mikel Irujo Amezaga, Government of Navarre Minister of Economic and Business Development visited the UPNA on the 25th of January to see the microgrid in the company of representatives from the different institutions and entities involved in the project, headed by Ramón Gonzalo, rector of the UPNA.
Challenges of urban electric mobility
Electric mobility poses several challenges for urban public transport services. ‘First of all, charging buses is subject to compliance with the timetables and frequencies planned for each line,’ explains Pablo Sanchis, ‘so the length of time a bus stays at the terminus is key to guaranteeing a sufficient charge of the bus' energy storage system. Secondly, the vehicle’s limited charging time means a very high electrical power demand to ensure the charge.’
The capacity to supply this power peak depends on the characteristics of the grid to which the charging station is connected. ‘The best access to these networks does not necessarily coincide with the location of the bus terminuses, which can mean an additional limitation for the deployment of the urban eBus fleet. The expected increase in electricity consumption may also be an additional incentive to install photovoltaic renewable generation units which try to rebalance electricity generation and demand in a city like Pamplona,’ the project coordinator points out.
The project is explained during the tour.
In this context, ‘the design of advanced charging stations with not only the electronics needed to connect the bus to the electricity grid but also a stationary backup electrical storage system and a renewable electricity generation system could help overcome the aforementioned drawbacks and facilitate the transition to an electric urban transport system,’ points out team researcher Alfredo Ursúa.
The installation associated with the project consists of several parts. ‘The backup storage system, consisting of second-life lithium-ion batteries, is on the ground floor of the Teaching block, on whose roof the photovoltaic installation is located,’ Alfredo Ursúa tells us. ‘Both installations form an electrical microgrid and can be connected both to the Teaching block’s internal ring circuit —to carry out experimental validation tests— and to the input on the Regional Urban Transport line 9 pantograph post, already electrified, installed next to the building. The microgrid is managed and controlled in a coordinated manner from a control unit also located on the ground floor of the Teaching block, which can also be accessed remotely.’
Monitoring station
In the view of the researchers, an installation of this kind, which includes renewable generation, a fleet of electric vehicles and lithium-ion batteries both for electric mobility and to improve integration into the electricity grid, has ‘great instructive and informational potential’. ‘It brings several of the technologies that engineering students will have to deal with during their professional life closer to hand, and the rest of the university community can become familiar with systems which will mushroom over the next few years. It may also serve to spread the word about the potential of electric mobility and its contribution to energy sustainability in society,’ adds Alberto Berrueta, another of the researchers.
The photovoltaic panels installed on the roof of the Teaching block
For this reason, there are plans to install an informative monitoring station in the University Teaching block. ‘The monitor will show information on the main energy flows —photovoltaic generation, station consumption and the status of the battery installed at the UPNA— in real time. It will also allow you to consult more detailed information through graphs or energy tables. This monitoring system will be available remotely through a dedicated website,’ comments Alberto.
The researchers hope that both the university community and society ‘will perceive the effort that the institutions are making in favour of renewable energy, energy storage and electric mobility at a time when Navarre could pioneer the electrification of urban transport in its capital, having already become a world leader and benchmark in the development of wind energy.’