It is available for free in huge quantities, is not owned by Saudi Arabia and it contributes minimally towards climate change. The latest green fuel might seem like the dream answer to climate crisis, but until recently raw sewage has been seen as a waste disposal problem rather than a power source. Now Norway’s capital city is proving that its citizens can contribute to the city’s green credentials without even realising it.
In Oslo, air pollution from public and private transport has increased by approximately 10% since 2000, contributing to more than 50% of total CO2 emissions in the city. With Norway’s ambitious target of being carbon neutral by 2050 Oslo City Council began investigating alternatives to fossil fuel-powered public transport and decided on biomethane.
Biomethane is a by-product of treated sewage. Microbes break down the raw material and release the gas, which can then be used in slightly modified engines. Previously at one of the sewage plants in the city half of the gas was flared off, emitting 17,00 tonnes of CO2. From September 2009, this gas will be trapped and converted into biomethane to run 200 of the city’s public buses.