What do you think is more toxic to the environment? Petrol or biogas? New research from Sweden shows that petrol is more harmful since biogas from refuse generates 95% less greenhouse gas emissions; previously the figure was thought to be 80%. Giving an even stronger edge to biogas is the revelation that a few tweaks to biogas plants could boost this level to 120%, rendering biogas more than climate neutral.
Researchers from Lund University in Sweden analysed
a biogas plant in Scania on behalf of the Swedish Energy Agency to
determine production emissions. The analysis performed at this plant
will help researchers to further investigate and optimise other biogas
Sweden is home to around 20 facilities that generate biogas
earmarked for the automotive industry. According to the researchers,
the biogas output from these plants is as great as that from sewage
treatment works that use sewage sludge.
'The plant we have studied is fairly representative of an average
biogas plant that processes waste and manure. In our study, we have
calculated emissions for the entire production chain and included both
direct and indirect emissions,' explained Mikael Lantz, a PhD student
in Environmental and Energy Systems Studies at Lund University.
'What is particular to our study is that we have included indirect
factors that have not previously been taken into account, for example
how the ground is affected when mineral fertiliser is replaced with
bio-fertiliser,' he added. 'In addition, methane leaching from the
plant is measured and not based on standard data that is often
otherwise used in this kind of analysis.'
The study found that biogas releases 16 grams of the greenhouse
gases methane, carbon dioxide (CO2) and laughing gas per kilowatt hour
of biogas. Compared with petrol, these emissions are some 95% lower and
more optimal than the standard values that are being used today.
The team suggested that the biogas could become even friendlier to
the environment if wood chips were used to heat the facilities that
produce the gas. Also, this method may be even better for the
producers' pockets in the long run.
'Another suggestion is to cover the bio-fertiliser stores to reduce
the losses of nitrogen and reduce dilution with rain water,' Mr Lantz
said. 'The plant has already implemented this measure. By using a few
other recommendations as well, the emissions can be reduced to 120%
lower than petrol, without increasing the production costs by more than
a couple of [Swedish] öre [equivalent to a fraction of a euro cent] per
kWh of vehicle gas.'
Europeans are more aware than ever of the problems that are
impacting the environment. Experts believe that biogas could benefit
myriad sectors, especially agriculture. Not only would biogas give
fertilisation efficiency a boost, but farmers would benefit from bigger
savings. We now know that biogas produces fewer greenhouse gas
emissions, and that it is a cheaper alternative. The experts also point
out that biogas generates fewer odours and attracts fewer pests.
With the EU calling for a reduction in CO2 emissions by no less
than 20% in the next decade, biogas seems to be a viable energy
alternative. Experts note that biogas can be used for combined heat and
power production, and transportation fuel. It can also be integrated in
the European gas grid.