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Growing greener fuel for cleaner transport


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Growing greener fuel for cleaner transport

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Plants might be the source of a new renewable fuel for planes, or new greener ingredients to replace fossil resources used to produce plastics.

At an experimental agriculture plot near Athens in Greece, agricultural engineers are growing plants which could produce these new greener fuels.

They are studying the oil content of various plants, their yield and adaptation to the Mediterranean climate and predominant soils. Each of the plants has advantages and disadvantages.

Myrsini Christou, an Agricultural Engineer, at the Centre for Renewable Energy Sources - CRES – explained: “Castor is an annual, oily plant from the Mediterranean. Its annual production is around four to five tons per hectare, with a high oil concentration, of around 40-50 percent (of its total mass).

“Cuphea is a plant that comes from America. It is still in the experimental stage. Its yield is still very low, less than one ton per hectare in seeds. And it has just around 20 percent in oil concentration.

“Safflower is a plant from Asia. We think that it is very good for Mediterranean agriculture. We have varieties in autumn and spring, suitable for every variety of climate and soil. We think that it can be in agriculture practice in an horizon of around five years”.

Chemists research how green ingredients from plants can replace existing molecules which are currently extracted from fossil resources in highly specialised labs like the one at Lille1 University in Northern France.

Franck Dumeignil, a chemist, at the university and project coordinator on the Eurobioref project, said: “We have developed a new type of aviation fuel that we have already tested on a real reactor. We have made 15 cubic metres of a fuel mix; between 10 and 20 percent of this mix came from a new ingredient from plant biomass.

“This new green ingredient made the fuel more efficient and less polluting. We are now seeking a certification for this new ingredient. Because once you have a new aviation fuel, you need that certification to be able to use it in an aircraft.”

And once green oil is extracted from the plants in special bio-refineries, researchers are using an experimental reactor to discover which plant waste produces most gases, like hydrogen or carbon monoxide, which could eventually be used to produce heat or electricity.

Kyriakos Panapoulos, a chemist at the Centre for Research and Technology Hellas - CERTH – says the final waste can be easily, harmlessly, recycled: “The only thing left after the use of biomass content from this gasification is ash. This contains a very small percentage of inorganic content from the biomass, like potassium, calcium or iron. All of which were extracted from the earth by the plants. After gasification, we can usually replace them in the earth as compost, closing the cycle of these plant contents.”

The project in Greece is just one of a many funded under the umbrella of what is known as JTIs, Joint Technology Initiatives, a wide array of public and private common initiatives promoting European research in various strategic areas.

And those areas include bio-based industries coming up with greener everyday products, and developing a new generation of vaccines, medical treatments and medicines.

There are also systems to manage European airspace better and design cleaner, quieter aircraft, along with developing safer trains and railway infrastructure, and better tools to manufacture more efficient electronics.

And finally, technologies to expand the use of fuel cells and hydrogen in industry, energy and transportation.

Everybody on the bus

A bus in Brugg, Switzerland, runs on hydrogen, partly produced using renewable energy. Similar buses run in Bolzano and Milan, Italy; and also in London and Oslo. The use hydrogen fuel cells to produce electricity while emitting only water vapor. It is cleaner but also quieter than a diesel bus.

Postbus driver Peter Amsler says it handles slightly differently: “Driving this, the biggest difference is that the centre of gravity is higher, where the hydrogen is placed. The bus carries a ton more weight that a normal diesel bus. And when going round corners you do notice the difference compared to a normal bus.”

The bus was built in Mannheim, Germany, where hydrogen buses are for now being assembled only as prototypes. Researchers say that industrial production could start as soon as the technical know-how improves.

Helmut Warth, a mechanical engineer at Daimler Buses and a Clean Hydrogen In European Cities project coordinator, explained: “The disadvantages of these vehicles is that the price is still well above the price of diesel buses, and operators have to set up the infrastructure for hydrogen filling stations.”

So researchers keep working to produce more efficient hydrogen fuel cells. Felix N. Büchi, a chemist at the Paul Scherrer Institute, said: “The most important factor is cost. All parts must be more affordable, otherwise the fuel cell drive system is too expensive. The second factor is duration and endurance. The fuel cell must have the same life expectancy as the vehicle. And the third issue is efficiency and power density. That means we want to transform as much energy from the hydrogen as possible into power and do it with as little weight and volume as possible.”

Hydrogen buses are already being designed and built in a factory in Belgium. They have produced a prototype which will soon be running round Antwerp, and others are already operating in San Remo and Aberdeen, with autonomy of around 300 kms.

Researchers say its hybrid technology could mean saving around 1,000 tons of CO2 emissions by the end of its life cycle, compared to a normal diesel bus.

Paul Jenné, Bus project manager with Van Hool, and High V.LO-City project coordinator, said: “The main feature is that this is a hybrid-fuel cell bus. Hybrid means that it has two sources of traction. One is the fuel cell that provides electricity directly to the electric motors. And the other is traction batteries that do the same thing. All of it is controlled electronically so that the energy utilisation is maximised.”

The prototype bus has to be filled up at special refueling stations. To charge the inboard hydrogen tanks takes around 11 minutes, depending on outside temperature. Safety regulations are similar to those of a normal petrol station.

Sabine Thabert, a civil chemical engineer at Solvay, showed us a refueling station: “It was a challenge to build a compact refueling station. We needed a station that could easily be installed anywhere where we have access to a hydrogen source. And we had to ensure that safety measures were respected, and embed a security system allowing remote surveillance. That was the main challenge of this project.”

A hydrogen bus is around six times more expensive than a normal diesel one, and maintenance costs are also higher. But city bus operators would still be prepared to invest, under certain conditions.

Roger Kesteloot, the CEO of Belgium bus company De Lijn, summed it all up: “We are in an experimental point at this point. Also from an economical point of view. But I think in time the prices will go down, of course. And that opens some possibilities in the middle or in the long term to incorporate more hydrogen buses into our fleets.”

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