Joburg turns to renwable power

Joburg has invested about R250-million on developing its landfill sites so that the stored methane gas can be tapped and used to generate renewable power for the City's grid.
THE methane gas caused by the degradation of bio-organic compounds at the city’s landfill sites will now be drilled out and used to generate electricity for Joburg’s power grid, thanks to a partnership between the City and a private consortium.

Joburg GDS 2040The project, which is expected to be fully operational by 2012, is called the Landfill Gas to Energy Clean Development Mechanism Project and is the first of its kind in Africa and another first for Joburg.

Launching the project on 22 September, Joburg’s portfolio head of environment and infrastructure services, Roslynn Greeff, said it was aimed at mitigating harmful methane and other greenhouse gases being emitted from the landfills.

The City has made a capital investment of about R200-million on landfills and about 50-million on the Robinson Deep Landfill Site in Turfontein for the project to come to fruition.

It is the first of five projects to be developed across all landfill sites in the city. Work at the Marie Louise landfill is in progress and by June 2012 the Ennerdale, Linbro Park and Goudkoppies landfill sites would be complete.

Generating electricity
The utilisation of gas to generate electricity only commences once a landfill site has reached a reasonable depth and the potential for the ingress of oxygen has been reduced.

Greeff said Joburg’s landfill sites were at the depth and are “adversely affecting the environment and causing bad odours, which affect the quality of life of communities living near the landfill sites”.

Engineers have designed and drilled boreholes deep into the Robinson Deep Landfill Site and pipes have been inserted into the boreholes to extract the methane gas. Each borehole is however capped off at the wellhead and is built 30 to 40 meters apart.

MMC Roslynn GreeffMMC Roslynn Greeff opens the landfill gas project The pipes are directed to a manifold, which feeds into a carrier main that filters the gas to an engine compound. The gas is then fed into the engine unit to achieve an ideal gas mixture and is used to generate renewable power. The green electricity is available for use on site and is fed into the City’s grid which distributes it to the entire local network.

Revenue
Greeff said the extraction and destruction of greenhouse gases had provided the City with an opportunity to receive revenue from the generation of emission reductions certificates, trade in carbon credits and generate renewable energy.

“It is anticipated that the renewable energy generated will be fed into the municipal grid, thus off-setting largely coal derived electricity,” she said.

For environmental purposes, the engine compounds have been installed with gas flares, which burn the methane gas in the event that the engines are down for maintenance, thus ensuring that the harmful gas doesn’t go to the atmosphere. There is also a site manager who ensures that the site operates efficiently.

Methane gas is recognised around the world as having practical and commercial value. It emanates from landfills, natural gas and petroleum systems, agricultural activities, coal mining and wastewater treatment. It is however an important energy source and can provide significant energy, economic and environmental benefits.

There are now commercially viable techniques used around the world to optimise the use of methane rich gas. The process is cost-effective and ultramodern.

A gas engine compound will convert the lethal methane gas into electricityA gas engine compound will convert the lethal methane gas into electricityAn estimated 17MW of power will be generated from the project, comparable to electricity usage of about 13 000 kWh to 14 000 kWh in middle income households per annum. This will be sustainable for between 15 to 20 years, though the rate of gas production is dependent on the age and composition of the waste, the temperature and moisture content of each site and the design and operation of the site.

Landfill studies
Studies conducted at five landfill sites found that they had sufficient potential quantities of landfill gas to generate electricity.

A consortium headed by ENER•G Systems has been appointed to manage the project. “In terms of the contract, ENER•G Joburg will incur all costs relating to the development of the projects right up to the trading of carbon credits and power generation, while profits resulting from the sale of carbon credits and electricity will be shared between the consortium and the City,” she explained.

Greeff said an extensive environmental impact study and public participation process had been concluded before the green light was given for the project. All the landfill sites are still operational, except for Linbro Park which was closed in 2006.

Kyoto Protocol
The project supports South Africa’s commitments to the Kyoto Protocol, an international agreement linked to the United Nations Framework Convention on Climate Change (UNFCC), which aims to reduce greenhouse gas emissions and implement Clean Development Mechanism (CDM) projects.

Flora MokgohloaED in the City's environment department, Flora Mokgohloa at the launchThe clean development mechanism under the Kyoto Protocol supports renewable energy projects by providing additional income for the development and sale of carbon dioxide emission reductions.

The Kyoto Protocol is a legally binding commitment by developed countries to reduce greenhouse gas emissions and the implementation of supportive CDM projects in Third World countries. Its adoption is seen as a major step in tackling the scourge of global warming.

The project will be showcased at the UNFCC's 17th Conference of Parties (COP 17) in Durban in the latter part of the year to demonstrate Joburg’s commitment to the Kyoto Protocol.

The Landfill Gas to Energy Clean Development Mechanism Project was launched as part of the Growth and Development Strategy thematic week on environmental sustainability.