The European LIFE NIMBUS project inaugurates its plant for the production of biomethane from sewage sludge

The consortium of the European LIFE NIMBUS project celebrated the start-up of the biomethane production plant using sewage sludge on 28 March, which will power a public bus in the Barcelona metropolitan area. This bus, part of the Transports Metropolitans de Barcelona (TMB) fleet, will be the first to run on biomethane obtained from sewage sludge and will reduce its carbon footprint by more than 85% thanks to the use of a high-quality, emission-neutral fuel of renewable origin.

In Europe, the transport sector consumes around 30% of total energy. However, only less than 10% of the fuels used for transport are renewable. Against this background, the European Union aims to raise this figure to over 30% by 2030. LIFE NIMBUS, a research project co-funded by the European Commission under the LIFE Programme, aims to promote more sustainable transport through the circular economy. This initiative is aligned with the Biogas Roadmap, approved in Spain in 2022, which identifies the challenges and opportunities for the development of this gas of renewable origin and plans to quadruple its national production by 2030.

During the opening ceremony, the importance of research and collaboration between the public and private sectors to provide solutions to decarbonise transport was highlighted. In this regard, the general manager of Aigües de Barcelona, Rubén Ruiz, insisted on the “need to promote innovation through alliances and public-private collaboration in order to respond to the main challenges arising from the climate emergency”. “Waste recovery projects to promote sustainable mobility in cities are necessary to achieve an ecological transformation of our environment and are a clear example of our commitment to a model that respects the environment, based on the circular economy and sustainable development,” added Rubén Ruiz. For his part, Cetaqua’s general manager, Carlos Montero, insisted on the “importance of involving the end user in the project from the ideation phase and ensuring their monitoring and involvement in its development”. Thanks to this, Carlos Montero pointed out that “we manage to make the transfer of results more agile”.

Representatives of the LIFE NIMBUS partners pose in front of the bus powered by biomethane generated from sewage sludge.

The rector of the Universitat Autònoma de Barcelona, Javier Lafuente, highlighted how the start-up of the plant is a “good example of transferring the knowledge generated in the laboratories for the improvement of society, one of the missions of the University. The UAB is involved in the production of biomethane from hydrogen using biological systems, which are much more sustainable than conventional ones. In addition, the project demonstrates for the first time the bioelectrochemical production of hydrogen on a pilot scale from wastewater, with very encouraging results at laboratory level. This technology fits perfectly into the current paradigm shift in which water treatment must become an opportunity to recover resources, both material and energy”.

The CEO of TMB, Gerardo Lertxundi, acknowledged the entire TMB team that has made this project a reality, stressing that “it is a sustainable circular economy project to which TMB is fully committed” and pointed out that “it is a strategic project for TMB and we hope that it will be continued so that we can use biomethane on a massive scale”.

Boosting ecofactories to promote the circular economy

LIFE NIMBUS has enabled the design and construction of a biological methanation demonstration plant at the Baix Llobregat ecofactory, managed by Aigües de Barcelona. This initiative is yet another example of Agbar’s commitment to innovation and sustainability, which promotes the ecofactory concept as a solution to promote the circular economy and reduce environmental impact.

The ecofactory converts the traditional wastewater treatment plant into a facility that generates valuable resources. In this case, the sludge from the sewage treatment plant will be used as a fuel gas to boost green transport in the metropolitan area of Barcelona, encouraging the city to move closer to the climate neutrality proposed for 2050.

“This initiative tests various technologies, focusing on the production of biomethane, a high quality and renewable fuel. In addition, LIFE NIMBUS promotes power-to-gas technology for storing surplus renewable energy. In the framework of the project, only the operation of a bus powered by biomethane has been envisaged, but depending on the results obtained, the operations can be scaled up to a larger volume,” says Oriol Casal, Project Manager of the LIFE NIMBUS project at Cetaqua.

An example of public-private collaboration for more sustainable urban transport

This project, whose acronym stands for Non-IMpact BUS and which proposes a green energy and transport model in Barcelona, is led by Cetaqua, the Water Technology Centre, with the participation of Aigües de Barcelona, manager of the Baix Llobregat WWTP; Transports Metropolitans de Barcelona (TMB), which has provided a bus from its fleet with a daily route of 100 km, and the GENOCOV research group of the Autonomous University of Barcelona (UAB), responsible for the design, construction and development of the bioelectrochemical technology (BES), which allows the production of hydrogen more efficiently, using less electricity. The project is also supported by the Barcelona Metropolitan Area.