Landfill gas to energy is the process of generating energy in the form of electricity. Waste to energy (WtE) is a form of energy recovery and consists of the construction of pipelines to extract gas (e.g. gas turbine).
Most WtE processes produce electricity and/or heat directly through combustion, or produce a combustible fuel commodity, such as methane, methanol, ethanol or synthetic fuels.
- Capture of gas from decomposition requires significant infrastructure to cover entire site
- There will always be landfill gas that escapes to atmosphere and smaller quantities that are uneconomic to capture
- Land intensive option with no material recovery
Main license requirements for landfill gas to energy
- Between 60% and 90% of methane is captured and converted to water and carbon dioxide
- Producing energy from LFG displaces the use of non-renewable resources
- Displacement avoids GHG emissions from fossil fuel combustion by an end user facility or power plant
- Requires large area of land for infrastructure
- Operational landfill site must be open for a long period of time
- Pipelines need to be constructed during design phase
- Unwanted and unsorted waste may contaminate existing landfill site
Landfill gas capture and electricity generation, Durban, KwaZulu-Natal
In 2002 the World Bank approached the South African Government with a view to implementing a Clean Development Mechanism (CDM) renewable energy project in South Africa. Through the University of Kwa-Zulu Natal (UKZN), Durban Solid Waste (DSW) was approached to initiate the technology development in July 2003, and subsequently the first landfill gas to electricity project in Africa was developed. The project was split into two components: part 1 was a 1 MWe installation at the Mariannhill Landfill site, and part 2 a larger 6.5 MWe installation at Bisasar Road Landfill site.
Mariannhill landfill site: the project is a collaboration with the World Bank’s Proto Carbon Fund who purchases all Carbon Emission Reductions (CERs) that are generated. A total of 180,864 CERs have been issued, with the plant generating 24,911 MWh of electricity, saving the eThekwini Municipality R10,400m.
Bisasar road landfill site: an Emissions Reductions Purchase Agreement (ERPA) is in place for CERs produced from landfill gas captured at Bisasar Road. To date, 815,344 CERS have been issued, and sold to Nedbank. The plant has generated 239,638 MWh of electricity, therefore saving the municipality R95,300m.
When the projects first commenced there was no expertise in the country to guide or assist in decision making. Therefore the decision made was to own the project outright and to tender for the expertise required. Several of the projects that followed have sold the rights to the gas to private enterprises and merely receive a royalty percentage of the profits. Should carbon tax become a reality in South Africa, these projects could become extremely profitable and a source of revenue income for municipalities.
As this is a substantial investment for the municipality, a dedicated project manager has been appointed to manage the project. As the work is specialised, the municipality uses a quality based approach to the tenders where the companies tendering first have to show that they have the expertise, and have to obtain a minimum score before the issue of price is considered. Many skills are required in order to run a successful project and therefore seven separate contractors have been appointed. The appointed contractors’ activities include construction and pipe laying, engine maintenance and repair, gas field management, air quality monitoring, data management for CDM, electrical maintenance, and supplying equipment and spares.
Ekurhuleni Metropolitan Municipality Project: Landfill Site grid-tied electricity generation
In September 2014, Ekurhuleni Metropolitan Municipality commissioned a 1 MW landfill gas to electricity generation unit at the Simmer and Jack landfill site in Germiston, Gauteng. The landfill receives approximately 430,000 tonnes of waste per year. This project has the potential to reduce electricity purchases from Eskom by 7 GWh/year.
As of 22 October 2014, the generator has been operational for 727 Hours and 594,600 kWh of electricity has been generated. The gas capture has also greatly improved local air quality and environmental conditions of the communities living alongside or nearby the site. The municipality is planning to add additional electricity generation capacity at the Simmer and Jack landfill site and in other landfill sites in their area of jurisdiction. The full case study (coming soon) provides background to the project and the technology used, describes the business model and highlights key challenges, successes and lessons learnt.