The first rule of waste to energy: Is it feasible?
South Africa’s power supply is taking strain and with the country’s grid nearing peak demand, an intervention is needed. To this end, several alternatives are being explored but there is a growing need for more sustainable methods of power generation and demand side management.
According to the National Waste Information Baseline Report, of the total 108 million tonnes of waste, 90% goes to landfills. As a result, South Africa’s landfills quickly run out of space and a viable solution presents itself in the form of waste to energy.
Dr Urishanie Govender, General Manager of the Environmental Services Sector at leading black-owned engineering consulting firm, GIBB, indicated that waste to energy presents a crucial opportunity to address the energy gap. “Waste to energy is a proven and environmentally sound process that provides sustainable recovery of energy,” she said. Another expert on the subject of power, Paul Fitzsimons, GIBB’s General Manager for Power & Energy said that South Africa’s Integrated Resource Plan (IRP) 2010, allows for approximately 1% of alternative sources of energy, of which waste to energy can play a role.
“The process includes generating energy in the form of electricity and/or heat, generally through the combustion of waste that powers a steam-driven turbine. This is usually the first port of call, but another popular method is through landfill gas to energy, which involves capturing gases (primarily methane) produced from decomposing buried waste,” he said.
Govender meanwhile suggested that South Africa looks to the East and West for working examples of Waste to Energy programmes.
“The technology is used extensively in Europe and developed nations in Asia such as Russia, Japan, Singapore, and Taiwan. Interestingly, every ton of solid waste processed in a waste to energy facility avoids the mining of one third ton of coal and its associated impacts,” she said. While there is a strong case for waste to energy in South Africa, before any projects get underway, a bankable feasibility study needs to be conducted. GIBB is currently involved with two waste energy projects in the country. The firm assists by conducting informed feasibility studies to determine what alternative technologies will be best suited according to the waste characterisation.
The cost of equipment is weighed up against the proposed output of energy, the quality of the off-takers, potential benefits from the carbon savings and the value the company places on energy security. Actually conducting a waste characterisation study is no easy feat as landfill sites do not accurately monitor their waste streams. GIBB analyses the site and compiles detailed studies of what waste streams actually go into the site. After the waste has been characterised, it then follows a waste hierarchy process, where reusing and recycling become higher priorities.
“At the moment, our landfills don’t tend to recycle, which is always the first step. So once you have reused and recycled what you can and implemented a system to do that continuously, only then can you determine what kind of waste you have to work with, and thus, which technology is most suitable to produce energy,” said Govender. The issue is that most private firms and municipalities have hurdle rates for their capex projects, so due diligence needs to take its course.
Solid waste management funding is a major challenge for waste projects in this space. To assist, GIBB offers project preparation and advisory division which can contribute significantly. The division offers expertise towards the development of bankable feasibility studies necessary to unlock both funding and the implementation of waste to energy projects.
Source : SAHF October 2014