India's bright green idea: compressed biogas for cars

We have been making the case for the use of compressed biogas (CBG) as an automotive fuel for a long time now. A recent EU well-to-wheel study showed that of over 70 different automotive fuels and fuel paths, biogas is by far the most environmentally friendly and yielding considerably more well-to-tank energy than any other biofuel including second generation fuels like cellulosic ethanol, methanol or BTL-diesel (earlier post). Biogas can be produced in a decentralised manner from a wide range of organic waste streams (municipal, agricultural or industrial waste) making feedstock supplies highly dynamic. But more and more producers are using dedicated energy crops (such as sorghum and sudan grass, or specially bred biogas 'super' maize and hybrid grasses) to increase yields. The anaerobic fermentation of biogas maize, for example, yields some 4000 liters of petro-diesel equivalent energy. In Europe, several countries are betting big on using CBG, with Sweden, Norway, Germany and Austria all recently opening CBG pumps for cars. Three car manufacturers have CBG-compatible vehicles on the market, often in a bi- or tri-fuel configuration (earlier post).

Meanwhile, several developing countries have demonstrated that it is possible to introduce compressed natural gas (CNG) vehicles on a massive scale. Pakistan for example succeeded in getting over 1 million CNG cars on the road, in a crash-program that lasted two years and that consisted of building compressor outlets and tank stations (earlier post).

In a very important development, India is now going a step further and is taking concrete action towards realising the vision of using compressed biogas to fuel its rapidly growing car fleet. Over 70% of the world's longterm (2030) growth in demand for automotive fuels will come from rapidly developing countries like India, which is why this news is so important. If a country like India succeeds in proving the viability of CBG, then other countries in the Global South will follow (see the argumentation on this mechanism in professor John Mathews' Biofuels Manifesto).

The technology to compress biogas has already been devised, and it will not be too long before our cars will be running on CBG. In India biogas is primarily used in rural households for cooking purposes. This biogas can be purified to match natural gas standards by use of advanced technologies (earlier post), and fed into the natural gas grid. India recently announced it has started doing exactly this (earlier post). The purified form will match the methane content of CNG which is 95%.

The Indian Institute of Technology in Delhi (IIT), and the Indian institute of Science (IIS) in Bangalore have already brought to life such technologies, with the IIT filing a patent for their invention which is in the process of being sealed.

The Indian government has given licence to Delhi-based Indian Compressors Ltd to incorporate this technology. With regard to compressing purified biogas, Gaushala society of Kanpur and Gorakhpur have devised feasible methods, as has Didwania Compressor Works. “The CBG produced can be used in the same cylinders that store CNG and will match the efficiency of CNG,” said a government official. He added that compression of purified biogas and the marketing of CBG can be taken care of by the existing CNG stations. The government will make a beginning with pilot projects for use of CBG in vehicles. Gail has already been roped in to identify locations for such projects:
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Being a product of cowdung, sewage, sludge, non-edible oils and organic fractions of municipal solid waste and crop residues not suitable for fodder, biogas when used as a fuel, recycles carbon dioxide, not emitting a net amount. This makes it a cleaner fuel than CNG.

To add to automotive, biogas can also be used in diesel engines that are used for irrigation. According to data by the ministry of non conventional energy sources, with 8m diesel engines being used for irrigation, our farmers can save on 75% of diesel by use of biogas which can be supplied through a pipeline to the engines.

For this, the biogas digestive plants have to be set up in farms. While some rural areas of Punjab and Uttar Pradesh have already started such practices, Greaves India is already selling diesel engines that use only biogas as fuel. However, for such engines, additional batteries are essential.