Non-IMpact BUS: Circular economy for sustainable transport

Nimbus is a European project co-funded by the LIFE Programme that aims to promote circular economy by generating biomethane from sewage sludge and power-to-gas technologies, and using it as a sustainable fuel for public transport.

Towards circular economy in public transport

The transport sector demands around 30% of total primary energy consumption in Europe, but only less than 10% of the fuels used for transport are renewable. In this context, the European Union aims to achieve over 30% of energy consumption for transport from renewable sources by 2030.

In view of this situation, NIMBUS aims to foster circular economy for a more sustainable transport. This project will develop and validate a system to produce biomethane, a sustainable and renewable fuel, from sewage sludge. Besides, the project will foster the concept of power-to-gas by turning the renewable energy surplus, which is difficult to store, into gas, which will also be used in the production of biomethane.

Nimbus in numbers

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Turning WWTP into ecofactories

NIMBUS will apply the circular economy to water treatment, transforming the traditional wastewater treatment plants into ecofactories; facilities that generate valuable resources from waste. In this project, the ecofactory will valorize sewage sludge turning it into biomethane, a sustainable fuel suitable for public transport.

Main outputs and achievements

Reduction of one public bus’ carbon footprint by over 85% 

by using biomethane as fuel

Increase of almost 70%

of the energy obtained from biogas due to the storage of renewables through biological methanation

Meet the team

Aigües de Barcelona (AB)

Aigües de Barcelona is the operator of Baix Llobregat WWTP.


Cetaqua is a model of public-private collaboration that was created to ensure the sustainability and efficiency of the water cycle while taking regional needs into account.

GENOCOV from UAB (Universitat Autònoma de Barcelona)

Genocov is a research group with experience in engineering urban/industrial wastewater treatment systems and leading a successful research line from lab- to demo-scale in bioelectrochemical systems (BES).

Transports Metropolitans de Barcelona (TMB)

TMB is the municipal company in charge of the management of the public transports in Barcelona.

Visit the virtual tour of the LIFE Nimbus project site

We are working on the virtual tour of the LIFE Nimbus project site. It will be available soon for online visit.

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