City gears up for carbon-free fuel future
16-10-2014
Johannesburg is almost certain to become the first city in South Africa to convert its fleet to carbon-free fuel within the next two years. The City began piloting the conversion in its Metrobus fleet at the beginning of this year.
Johannesburg Executive Mayor Mpho Parks Tau says the City has been ready to make the switch to a carbon-free fuel for a while now. “The city subscribes to the notion of the reduction of greenhouse gas emissions. It is imperative that we find alternative energy sources that will also meet our objectives of enterprise development and job creation,” Mayor Tau recently told delegates atthe Gas Mobility Conference where the City’s Transport Month was launched.
Biogas - a product of anaerobic digestion of biomass, which includes animal dung and grass cuttings, has already been identifiedby the City as the most likely energy source that will fast track the economic hub of the country into the future. It contains between 50% and 70% methane, which is the component that aids the City’s drive to switch to a carbon-free energy source. Methane has already been tested and proven to be an ideal fuel source for the future. It is also currently being used to propel car engines and generate electricity.
Mayor Tau says the City has completed a pre-feasibility study on the potential of the Johannesburg Market waste stream to produce bio-methane. The study has found that there is potentially sufficient bio-methane to supply about 700 000 litres of diesel-equivalent fuel a year.
He says biogas will be upgraded through a process of cleaning and compression before it is either used on a production site or injected into the existing compressed natural gas pipeline to be used wherever it is required.
“The City has been piloting alternative gas use in its Metrobus fleet for some time. The results have been positive and we are now exploring the possibility of scaling the project to other municipality-owned entities,” Mayor Tau says.
He urged industry players to move with speed towards changing to alternative energy sources that can help to reduce greenhouse gas emissions. “The time for talking is over. We must now move towards the implementation stage” the Mayor says.
“The discovery of alternative energy sources will not only serve to reduce greenhouse gas emissions – even though this is one of the primary objectives, but it will also ensure less reliance on imported oil,” he says.
Carel Snyman, the Executive Director of Sanedi, a company at the forefront of the production of biogas, said it was imperative that the country find alternative sources of energy due to the current high cost of oil.
The country has to find local sources of energy to power mobility because of the high costs involved in the importation of oil, he said.
“Also, burning petrol and diesel has proven to be very inefficient in terms of converting energy into kilometres. Only about 15% to20% of the energy in the tank gets converted into distance - the rest is lost in the production of mostly heat.
“In the cities, because of the high density of vehicles, the production of gas emissions becomes harmful and needs to be avoided if we care about people living in cities,” Snyman says.
The use of biogas as an alternative source of energy is probably the most attractive of all other available sources because of the conversion of waste, which would normally be discarded or converted to methane anyway, contributing to global warming.
But, with the new process, methane is used to produce carbon dioxide, which in turn is used by plants to create new biomass. So, the circulation is repeated. This also augurs well for the environment.
Most important is that biogas is compatible with current vehicle engines. Snyman says it is better for engines than the conventional fuels currently in use because it contains less unburnt hydrocarbons and produces less friction in the engine.
“So, engines require less oil changes and last a little longer,” he says. According to Snyman, the product was now available in major centres.
“All that is required is the finalisation of the decision to sell it to the public,” Snyman says.