There is no doubt that green gas has commercial potential. This collective term covers any gas originating from organic material.
Today, green gas is used to produce heat and electricity, and as a fuel for transportation. Several industries are showing interest in this energy source. However, green gas is making relatively slow headway despite increased calls for responsible action towards the climate, the potential cost savings as fossil-fuel prices rise, and the backing of the EU.
Jürgen Jacoby, who is responsible for Gas R&D Projects at Vattenfall, says: “While the technology for producing biogas has been around for a long time, the business case has not. And this applies in particular to larger corporations such as Vattenfall.”
“To supply a large number of digestion plants with adequate biomass material or substrate, we would need to have many contracts with farmers in place, and that is a tricky process to handle.”
Two kinds of green gas
There are two kinds of green gas. One is biogas, which originates from the digestion of an organic material such as food waste or manure. The other is gas produced by the gasification of biomass.
With the right treatment, the latter variety is very similar to fossil natural gas, although it does not contribute to fossil CO2 emissions.
Green gas is gaining support as an alternative energy source in Europe, as it fits well into most government policies for refining domestic energy production, reducing emissions and handling waste.
Sweden is a leader in the use of green gas as a vehicle fuel, but only the southern part of the country has sufficient infrastructure for gas distribution. Biogas is produced at many small local sites and used mainly as fuel for heavy and public transport. It is upgraded to natural-gas quality and fed into the gas grid in seven Swedish cities, all in the southwest of the country.
In order for green gas to gain widespread acceptance, government support and business-sector investments are needed. In Germany, the Renewable Energy Act has resulted in substantial subsidies to support the production of electricity and heat from several sources, including biogas. These subsidies create a sound business case for green gas, according to Jürgen Jacoby.
There are about 7,000 biogas production sites in Germany, with a total installed capacity of around 3,000 MWel. In 2010, about two per cent of all the electricity consumed in the country was generated in biogas plants.
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