Electricity sales alone cannot sustain the Durban landfill gas to electricity project, and without the sale of carbon credits it would not be financially viable.

Speaking at a lecture hosted by the South African Energy Association at the Durban University of Technology, deputy head of plant and engineering at eThekwini muni- cipality John Parkin said the project, which has been running since 2003 and was the first in Africa, presented significant challenges.

“We were the first project to start, so we had to jump through all the big hoops. It has been pedantic and time consuming,” he said.

The project has two components: the Marianhill landfill site, to the west of Durban, which opened in 1997 and covers 22 ha, and the Bisasar Road landfill, one of the deepest in the world, at 100 m. The latter was opened in 1980 and is due to close next year.

Parkin said that this 44 ha site would still provide gas for 15 years.

Although the project began with vertical wells of up to 26 m, these were converted into more cost-effective horizontal wells because of the depth of the landfill. Gas is extracted through a roots blower system which maintains a partial vacuum in the pipes and sucks out the gas. The Marianhill site is served by a 1 MW engine, while the Bisasar Road site generates 6.5 MW of power. Together, the sites are adequate to meet the needs of 3 750 small houses. A gas chiller was added to the Bisasar Road site in 2008.

The total landfill gas flow is 4 000 Nm3/hour at 52 % methane. About 20 000 t of carbon- dioxide is destroyed a month. Parkin said monthly earnings from electricity and carbon credit sales were R1.85-million and R1-million respectively. This equated to potential earnings of R34-million a year. Capital expenditure so far amounted to R117-million.

He said one of the main obstacles faced was that the carbon credit price had “crashed”. This was at €15.07 when the project was commissioned but had since fallen to around €0.22.

Administrative challenges included a two-year environmental-impact assessment delay at the outset, ongoing problems with municipal procedures as set out by the Financial Management Act and an “onerous and expensive” verification process that had been drawn out by language barriers and the periodic suspension of bodies responsible for the certification of carbon credits in terms of the requirements of the United Nations Framework Convention on Climate Change under the Kyoto Protocol.

He said technical challenges had begun with extreme weather conditions during the construction phase of the project and included excess leachate from the Bisasar Road site, which had been poorly managed before the municipality took it over in 1995.

At the outset, he said, there was a lack of expertise and resources, which continued to the present. Lack of experience and technical ability in this field made it extremely difficult to replace staff. In addition to contending with suppliers that did not understand South African conditions and supplied the wrong equipment, he said understanding the gas field had proved difficult. The reason for fluctuations in yields was not understood and all that could be done was to shut off equipment and restart it later.