By Jeffrey Abrahams, GroundUp
This landfill, one of the largest in Cape Town, is currently running a pioneering project that converts methane gas into enough electricity to power more than 4,300 homes monthly. (Photo: GroundUp)
Imagine your weekly rubbish contributing directly to the power that makes your TV and boiler work – at the Coastal Park landfill site near Muizenberg this is already a reality.
This landfill, one of the largest in Cape Town, is currently running a pioneering project that converts methane gas into enough electricity to power more than 4,300 homes monthly.
The most harmful byproduct of any landfill is the release of methane gas. This gas is created when organic matter begins to decompose. According to estimates, between 20% and 30% of global warming is due to methane.
To counteract this process, the methane is collected in the landfill and burned in special engines. This is then converted into water vapor and carbon dioxide. Although carbon dioxide is also a greenhouse gas, methane per ton causes much more global warming if it is released directly into the atmosphere.
To counteract this process, the methane is collected in the landfill and burned in special engines. (Photo: GroundUp)
The Coastal Park project was set up at a cost of R93 million and was specifically designed to prevent waste from polluting the environment or transmitting diseases. Since November, gas has been extracted from the waste through a network of pipes.
There are a total of 49 vertical gas extraction pipes, each drilled 30 m deep into the waste. In addition, there are approximately the same number of horizontal pipes in ditches that form a network and lead the methane to a main pipe that transports the gas to the plant.
There are a total of 49 vertical gas extraction pipes, each drilled 30 m deep into the waste. (Photo: GroundUp)
However, before the gas can be used, it must first be cleaned. The gas is treated to remove liquid. It then passes through a heat exchanger where a 110 kW cooler uses water at 7 °C to further cool the gas and remove more moisture. This step is crucial because it also removes impurities that can damage the generators.
The project currently produces around 1.3 gigawatts per hour (1.3 million kWh) of electricity per month.
“Part of the generated electricity is supplied to the power grid, while the rest is used to keep the landfill itself operating,” says Grant Twigg, mayoral committee member for urban waste management.
“This initiative turns what was previously a net loss operation into something much more positive.”
The project currently produces around 1.3 gigawatts per hour (1.3 million kWh) of electricity per month. (Photo: GroundUp)
According to Twigg, the project protects the environment by reducing emissions while at the same time reducing the city’s dependence on Eskom. He believes that such projects will pay for themselves over time.
“Carbon credits worth R36 million have already been realized thanks to the reduction in gas emissions at landfill sites. This reinforces the belief that these initiatives are financially sustainable,” says Twigg.
The City of Cape Town is so pleased with the results that it plans to expand the project further. An additional investment of R82 million will be used to increase the capacity of the plant and utilize even more gas effectively.
- This reported was originally posted on GroundUp and is used with permission.
According to Twigg, the project protects the environment by reducing emissions while at the same time reducing the city’s dependence on Eskom. (Photo: GroundUp)