Durban pioneers gas-to-electricity from landfills
Wednesday, 27 January 2010 13:44
After eight years of work eThekwini Municipality is finally launching its landfill gas-to-electricity project. Completed in July 2009, it is the first of its kind in Africa.
The system functions by capturing methane gas from decomposing waste to burn in several small power plants that generate electricity. Landfill gas electricity plants produce less carbon dioxide than conventional coal-fired power stations and the gas extraction and destruction further reduces green house gas emissions, as well as improving air quality in the surrounding community.
For several months now the project’s two landfill sites have been generating a total of 7.5MW of power, which is pumped back into the city’s electricity grid, with the electricity generated enough to supply around 3750 houses. The municipality, meanwhile, makes around R4.5 million a month from the sale of the electricity and carbon credits.
Due to legal and regulatory deadlocks, the bulk of the project was delayed for several years, with two small pilot plants initially launched with 1MW and 0.5MW generators. The 1MW plant at Marianhill landfill site is still operational, and the lessons learnt were incorporated into the large 6MW project that began operations at Bisasar Road landfill site last year.
“There were so many unknowns which had to be dealt with, and none of the regulatory frameworks existed, so it took a lot longer than it needed to,” says Mark Wright, the municipality’s project manager. But now that everything is in place, he says, it will be much easier and quicker for other municipalities to do a project like this.
The project has cost R100 million to implement, but Wright says that a lot of this was also spent on legal fees that would not be necessary to repeat.
The Bisasar Road plant has the capacity to supply enough gas for another 1MW generator, but Wright says that the purchase of further plants will only happen when the plant has paid itself off.
It is estimated that further landfill electricity generation projects in South Africa would cost around R10 million per MW, and although this is much more expensive than conventional electricity generation, the costs are much lower if the site is used to sell carbon credits.
eThekwini Municipality has also shown that landfill gas electricity plants are very well suited to South Africa, as South African landfills generate gas much faster than European landfills. This led eThekwini to use a new form of gas extraction involving horizontal ‘wells’ in the landfill rather than vertical wells.
