By 2016, it is anticipated that 19 megawatts of electricity will be produced from five landfill sites in the city – enough to power 16 500 medium-sized houses. A pilot project being done through the City of Joburg’s infrastructure and services department at the Robinson Deep landfill, southern Joburg, is already showing good progress.

Currently the toxic gases are being burnt through a flare, but by next year they will be used to power generators which will feed electricity into the grid.

The other landfill sites which will be used are Marie Louise, Ennerdale, Linbro Park and Goudkoppies. The gas is produced through decomposition, which happens when organic waste is broken down by bacteria that are naturally present in the waste, and in the soil used to cover the landfill.

Organic waste includes food, garden waste, street sweepings, textiles and wood and paper products. As the organic matter decomposes, biogas is produced. If unmanaged, this biogas is emitted into the atmosphere, and the methane content is 21 times more harmful to the environment than carbon dioxide.

The new system involves retrieving the methane gas and converting it into electricity. This is done by installing pipes into various places in the landfill. The gas is pumped through the pipes into a chimney where it is being combusted into harmless emissions, which is happening at Robinson Deep.

The next phase will be to install generators through which the gas will be channelled as fuel for electricity generation. The renewable electricity will be “exported” by connecting the generators to the municipal distribution grid, owned by either Eskom or City Power.

Robinson Deep covers about 10 hectares, but the total system will cover 26ha when complete in all five landfill sites. There are many benefits for the city, says Suren Maharaj, acting managing director of Pikitup. The main aim of the project is to mitigate the harmful greenhouse gases emitted from the landfills, and assist Eskom with its electricity shortage.

It also presents the city with a opportunity to generate energy from methane gas and to earn carbon credits on the international markets.

Dave Harris, general manager for landfill at Pikitup, said there was enough gas to keep the project running for another 15 to 20 years, but the rate of gas production was influenced by several factors, including the age and composition of the waste, and the temperature and moisture content of each site.

When completed, this will be the biggest landfill gas-to-energy project in South-Africa.