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Biomethane for use as a transport fuel

Biomethane for transport is one of the options being supported by the European Green Cars Initiative (a €5 billion PPP boost to the European car industry).

Biogas is a mixture of biomethane CH4 (65-70%) and CO2 (30-35%) and small amounts of other gases. It is created by anaerobic digestion of organic wastes such as sewage, manure, food wastes, landfill, etc. This is an established technology. After removal of contaminants, biomethane is the same as natural gas, and can be used as a transport fuel in the form of Liquid Natural Gas (LNG) or Compressed Natural Gas (CNG).

Bio-SNG (Bio Synthetic Natural Gas) is produced by gasification of lignocellulosic (woody materials). A number of Bio-SNG demonstration projects are discussed on this website.

Anaerobic Digestion technology is well established, hence biogas is generally considered as a first generation biofuel. However, when biogas is derived from organic wastes and not crops, is is considered to be sustainable. Biomethane for transport is the focus of several projects such as MADEGASCAR, GasHighWay and BioGas Max, which aim to increase its use in the market.

Use of gas as a transport fuel in Europe

Gas is widely used as a transport fuel in many European countries, notably Italy, which boasts 650,000 gas powered vehicles. Sweden is a world leader in upgrading and use of biomethane for transport, and has many 'biogas vehicles', including private cars, buses, and even a biogas train and a biogas powered touring car team.

Chemrec Pitea gasification plant

© Copyright E.ON www.biogas.se
To promote the potential of biomethane as a transport fuel, E.ON has entered the 2009 Swedish Touring Car Championship (STCC) with two gas-driven Volkswagen Sciroccos. E.ON is Sweden’s leading player in biogas. The company produces biogas, builds refueling stations and sells biogas. View at larger size >>

Pretreatment of agricultural residues for enhanced production of biogas

Researchers at the Fraunhofer Institute IKTS, Germany, have developed the first-ever biogas plant to run purely on agricultural wastes. This demonstrates that pretreatment with enzymes can greatly increase biogas yields from cellulosic residues such as corn stalks.

In China, 3 pilot facilities have been built to demonstrate the production of biogas from rice straw pretreated with Sodium Hydroxide.

With 23 day anaerobic digestion at mesophilic temperature of 35°C, rice straw pretreated with 10% NaOH at 20°C for 24 hours had the biogas yield of 0.6 L /g VS, 50% higher than the biogas yield from untreated straw. After enzymatic hydrolysis using cellulase from Trichoderma reesei ATCC 26921 and cellobiase from Aspergillus niger, the pretreated straw had the reducing sugar yield of 298 mg glucose/g VS, 185% higher than the untreated straw (Source: Dong Yang et al, published April 2009 American Society of Agricultural and Biological Engineers)

Methane Slip and certification

If methane is accidentally released into the atmosphere, it is much more damaging than carbon diocide as a GHG. In 2008, the Naturemade certification system was initiated in Switzerland to guarantee the ecological quality of the biomethane injected into the grid. To qualify, the emission of biomethane (also known as 'methane slip') must not exceed 1% of the total biomethane generated by a plant. (Source: BioGas Max)

Chemrec Pitea gasification plant

© Copyright UEA
In the UK, the University of East Anglia (UEA) Low Carbon Innovation Centre (LCIC) and Hardstaff Group (Nottingham, UK), have modified a standard Optare Solo single-deck diesel midibus from the Anglian Bus fleet. Originally powered entirely by diesel, the Mercedes-Benz engine has been adapted to run for 60-80 per cent of the time on biomethane.

Further links on biogas R&D&D in Europe

The following links provide further information on EC R&D&D on Biogas production and its use as a transport fuel:

European Biogas Association

MADEGASCAR - Market development for gas driven cars

Biogas Max - A driving force

GasHighWay

Agrobiogas

Biogas Regions

UK Anaerobic Digestion and Biogas portal

Biomethane Transport Forum UK

Biogas as a Road Transport Fuel Report

IEA Task 37 - Energy from Biogas and Landfill Gas

Biogas Upgrading to Vehicle Fuel Standards and Grid Injection