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Injecting Biomethane into the German Grid

Germany that has a natural gas consumption of 100 billion cubic metres has set itself a target of substituting 6 billion cubic metres of biomethane by 2020 and up to 10 billion cubic metres by 2030, writes TheBioenergySite senior editor, Chris Harris.

The goals, which have been set in law, have been laid down by the German gas industry and farming community, Dr Gerrit Volk, Head of Division Grid Injection in Bundesnetzagentur, Germany, told the GreenPower Biogas conference in London.

Dr Volk said that Germany has more than 4,000 biogas plants across the country but to date all the biogas is converted into electricity in situ and hardly any use is made of the heat that is produced in the process.

In the future, he said that biogas will be used as a substitute for natural gas with all the same energy advantages and having the other advantage of being independent of the place of generation, and where heat is produced it is also to be used in a combined heat and power plant.

"At present most of the plants are on farms and there is no need for combined heat and power, so all the heat is just being released into the air," said Dr Volk.

"Therefore we have to transfer the gas to a place where the heat can be used."

The main problem with feeding biogas into the national grid gas is its purity.

Untreated biogas with a methane content of up to 60 per cent does not work with natural gas and therefore the methane content is raised to 98 per cent through pressure swing adsorption or chemical cleaning.

When biogas is fed into the grid it also tends to lose some of its inherent characteristics.

In April last year, Germany passed a new law governing the way the biogas is fed into the natural gas grid.

Within the framework of the biogas balancing contract there 25 per cent flexibility at a subsidised price of 0.1 cent/kWh.

It also lays down the criteria for the determination of the gas quality at the point of delivery in accordance with the DVGW work sheets.

The regulations also require a detailed report to the BNetzA by 30 May 2011 and annually thereafter.

"It is important that the quality of the biogas is the same quality as the natural gas in the grid system," Dr Volk said.

The regulations have also set a target of 6 billion cubic metres of biogas to be fed into the grid by 2020. Last yea, Dr Volk, said the amount fed in was 42 million cubic metres.

The costs of feeding the biogas into the grid are split between the grid owner and the biogas producer for transporting the gas up to 10 km by pipe.

Friedrich Wolf from E.ON E Climate & Renewables said that the advantages of biomethane, the purified product of biogas are that it is storeable, dispatchable and has many uses.

It also has savings of 90 per cent CO2 in Germany with the current production systems and cost savings of 80 per cent.

The use of biomethane also offers technical advances in crop production and diversification in the use of feedstocks.

There is an expected increase in arable land available for production of crops dedicated to biofuels from 1.6 million hectares in 2005 to 3 million hectares by 2030.

This gives a growing potential of biogas from seven per cent to 17 per cent in 2030 of natural gas consumption in Germany at present level, said Mr Wolf.

Mr Wolf said that the feedstock supply determines biomethane potential. Waste and liquid manure are obvious candidates for biomethane feedstocks, but they are difficult to access and now easily transported and they have limited expandability.

He said that crops offer the highest growth Potential, even under restrictions imposed by the food industry and cattle breeders. However, he added that these also involve labour costs.

July 2009
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