A bus of line V3 has been circulating through the streets of Barcelona that has been operating exclusively with a renewable fuel generated from what we least imagine: human waste. And best of all, the experiment has been considered a success.
A project that has managed to evolve. This project was baptized as ‘Nimbus’, and is the result of a collaboration agreement between the local water management company Veolia, Metropolitan Transport of Barcelona (TMB) and the Autonomous University of Barcelona (UAB). Together they have turned the concept of circular economy into something very tangible: transform the sludge of wastewater into biomethane for public transport.
Five years later, and with good results in the hand, the project is ready to move on to the next level and start with large -scale production thanks to European funds. The ultimate goal is to make the production of this fuel based on the solid waste of the city to end in the deposits of the buses themselves in the future that is not very distant.
This creates this fuel. The heart of this innovation is found in the purification of Baix Llobregat, one of the largest in Europe. Every day, this plant processes about 400,000 cubic meters of wastewater. While 95% of the water is regenerated for agricultural or urban uses, the remaining solid waste, known as sludge, usually end as dry material for agriculture.
The Nimbus project has given it a new purpose. Using an innovative process, researchers have managed to transform four cubic meters of mud per hour into high purity biomethane. This gas is pure enough to be used in vehicles with natural gas engines without any modification.
The secret is to refine the initial biogas. Initially, gas contains 65% methane and 35% carbon dioxide. Instead of separating gases, the Veolia equipment combines carbon dioxide with hydrogen that is obtained in renewable sources. In this way, almost all the biomás becomes biomethane, making the resulting fuel emit so much carbon dioxide.
A fuel responsible with the environment. The figures that result from this first phase have shown that this biomethane works very well. It emits 80% less carbon dioxide than traditional natural gas and complies with the strict EU EU VI emissions regulations, although it produces nitrogen oxide to very small amounts.
An alternative to electric buses. Right now, Barcelona’s periphery routes need a bus that has a high passenger capacity and greater autonomy. This is something that electric buses cannot offer today, but biomethane, maintaining the reduction in the emission of carbon dioxide.
The future: more buses and production at an industrial scale. After five years of success, the Nimbus experiment gave way to a new phase: the Sempre-Bio project. The objective is now climbing production, going from generating biomethane for a bus line to do it for two.
For this they have a budget of more than eleven million dollars, with financing from the European Union. As detailed in the project, with this budget they will “reduce the investment and exploitation costs of biomethane production plants and expand the biomethane production potential through new routes of waste valorization.”
Many projects to find the ideal fuel. Synthetic fuel is one of the great research results for finding an alternative to natural oil. One of the examples is e-Diésel, which is based on “water and air” for conventional engines, or even Toyota already works with hydrogen to turn it into an alternative to maintain the combustion engine.
But the reality is that right now combustion cars are in danger of extinction. Electric cars do not stop growing, and the Chinese market does not stop promoting this sector on other continents such as Europe.
Images | Wang Xiong
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