Massive waste in African megacities calls for sustainable waste-to-energy facilities

25.09.2018 / Torben Kristiansen

As cities grow, the global demand for waste-to-energy (WtE) facilities, as well as advanced recycling and bio-waste processing facilities, is rising to meet the need for sustainable urban living, improved resource efficiency and avoidance of further climate change. The potential of the technology on the African continent is paramount. Still, facilities are rare. Why?

With rapid population growth and urbanisation, the annual waste generation is expected to increase by 70% from 2016 levels to 3.40 billion tonnes in 2050. 

The Sub-Saharan Africa region is the fastest growing region with waste expected to nearly triple by 2050, according to the World Bank. 

Fortunately, there are ways to deal with the challenges. One of them is Waste-to-energy (WtE), which is a well-proven, advanced waste management technology that has been in use for more than 100 years in Europe and has undergone significant technological evolution over this period.

Today, there are more than 500 European and 90 North American WtE facilities in operation (ISWA 2012) and there are now more than 350 WtE facilities in operation in South-East Asia, primarily China. China is also experiencing the highest growth in capacity with an estimated 400+ WtE facilities to be built in the coming 20 years.

In Africa, however, the technology has not yet picked up speed. Why is that?

First, is WtE even a relevant technology in Africa? The short answer is; yes, absolutely.

Especially for Africa’s megacities and high growth urban areas, the simple collect-and-dump waste solutions are no longer sustainable or possible owing to a lack of landfill capacity, increasing transport distances and the increasing cost of land.

And these challenges will only grow as the continent’s population is set to double and waste to nearly triple by 2050.

Typically, economies of scale are acceptable for plants capable of treating in excess of 250,000 – 350,000 tonnes per year. There may be an acceptable business case for even 50,000-150,000 tonne per year plants located on remote islands or in isolated mountain communities.

African experience with WtE and the challenges ahead

But there are a range of other key decision criteria and considerations that halt investments in WtE facilities in Africa.

First of all, there is only very limited and largely negative experience with WtE in Africa today. This is largely because most facilities in operation in Africa are very small waste incinerators based on 1970 type technology, mostly used for health care risk waste or certain types of hazardous waste and operated with limited or no flue gas cleaning systems (i.e. flue gas cleaning based on 1980 or early 1990 European flue gas cleaning standards).

Other critical considerations and issues include:

• WtE is capital intensive, typically requiring an initial investment in the range of US$800–1,100 per tonne of annual plant capacity (i.e. a 500,000 tonne per year plant would cost in the range of US$400–550 million)).
  
  
• Annual operation and maintenance costs are also significant and highly dependent on the revenue from sale of energy, etc. This means that there will always be the need for a significant gate fee for the waste, even when the energy produced can be sold at a premium.
  
  
• Business risks. The critical ones include: i) waste quality and quantity risk, ii) gate fee payment risk, iii) permitting and planning risks, iv) change of legislation and policy risks, v) cost of residue disposal risk, v) revenue from energy sale risk, vi) plant availability risk, vii) currency exchange risk, viii) technology risk including obsolete technology risk and viii) political risk.
  
  
• Successful planning and procurement of WtE facilities requires international and local experience to ensure that the business case is sound and robust, all business case risks are managed well and that excellent design choices are made.
  
  
• Operation and maintenance require access to skilled and qualified staff, as well as access to supplies and spare and wear parts of suitable quality.
  
  
• Well-defined and predictable waste quality, in particular in terms of calorific value, is critically important for the functioning of the plant, the available plant capacity, energy yield and the total business case. Waste flow and waste quality needs to be well understood and can be controlled.
  
  
• Finally, and especially in emerging economies, it is critically important to understand the informal waste management sector, including informal and formal waste picking, which can significantly affect the quality of residual waste arriving at the WtE facility.

Facilities with minimal environmental impact

In Africa’s megacities and high growth urban areas, rapid economic growth has resulted in an explosion in waste quantities, and waste quality approximates that of many European cities.

Driven by the pressing need to find sustainable solutions to the accelerating urban growth, we do see that WtE is gaining some ground in Africa in spite of the challenges involved. 

Several WtE projects that comply with current European Union environmental standards are currently being considered or implemented. Environmental NGOs have been opposed to many of these, fuelled in part by the negative experience of the past.

There have, however, been significant improvements in combustion and flue gas cleaning technology, which means that all environmental impacts have been engineered away, so that WtE facilities built according to current European Union standards have no local environmental impacts, other than traffic and visual impacts.

At the moment, a modern 50 MW WtE facility is being built in Addis Ababa, Ethiopia. This project should be in operation by 2018, with construction having started in September 2014. 

This is a good example of how to implement WtE in Africa, where the Ethiopian power company has established the required momentum and addressed one of the critical risks, namely ensuring a reliable high revenue stream from sale of electricity.

A strong international consortium of engineering, procurement and construction (EPC) contractors, advisors and project developers and strong local support also made this possible. 

Several large cities in South Africa (e.g. Johannesburg, Cape Town, Pretoria, Pietermaritzburg and Rustenburg) have also sought to establish advanced waste treatment facilities, including WtE plants. No investment decisions have yet been made, however.

Plenty of waste but lack of institutional framework

Unfortunately, the experience from many past attempts to establish WtE facilities shows that projects fail or halt. Here are some of the reasons why:

• The planned public-private-partnerships (PPPs) have been unattractive for potential PPP concessionaires owing to one-sided allocation of most or all business critical risks to the private party.
  
  
• Unrealistic expectations of the revenue from the sale of electricity and recyclables and allocation of revenue risk to the PPP concessionaire and, hence, unrealistic expectations of low or no gate fees for waste.
  
  
• Inability of the public party to guarantee the put-or-pay payment and waste quality and quantity commitments, required to make the PPP concession bankable through commercial banks.
  
  
• Legal or financial obstacles limiting municipalities’ ability to either i) enter into PPP concession agreements or ii) finance, build and operate capital-intensive waste treatment infrastructure within the municipalities own structures or utilities.
  
  
• Resistance or regulatory barriers to securing long-term attractive power purchase agreements that secure long-term revenue and bankability of the WtE plant.

The institutional, regulatory, political and commercial barriers presented above have in many cases proved unsurmountable, even though the waste quality has often proved suitable for WtE.

Is it worth the investment?

For advanced waste treatment infrastructure such as WtE facilities to be an economically viable option, it is necessary not only to compare the cost of the WtE option with the cost of operating a non-compliant dump, where all initial investment costs have been sunk. You also need to calculate the actual costs of the complete current waste management system, including the avoided costs of long-distance waste transfer and well-engineered distant landfills, complete with leachate collection and treatment and landfill gas collection and treatment systems.

Typically, in most developing cities, the municipal budgets for waste management are currently far from reflective of the full and true costs, in part because major investments in such things as vehicles and new landfills are often financed via discretionary grants, with no reckoning of capital costs, amortisation etc. of the current assets.

Conclusion on WtE appropriateness for Africa

The combination of WtE supplemented with more emphasis on material recovery as well as possibly nutrient or biogas recovery from the biological part of the waste stream, can significantly reduce the continued and unsustainable dumping of waste in ever-growing landfills. 

WtE is one of a few suitable advanced waste management technologies that, in a multi-stringed collection and treatment system, support the overall objective of sustainable urban liveable cities, such as landfill diversion, resource efficiency, energy recovery, greenhouse gas avoidance and a high level of public service.

Based on technical and objective criteria, it is possible in most African megacities to establish WtE facilities that can contribute to much needed landfill diversion and electricity generation for the city, and support near-urban waste treatment, especially, if the sourcing of waste can be well-controlled.

In short, the critical factor for making WtE technology a success in Africa is not the technology itself, but the megacity's ability to evolve institutionally. This includes developing the ability to make and deliver on long-term financial and contractual commitments and the financial, institutional, enforcement and operational capacity to support a multi-stringed, capital-intensive waste management system, and securing the necessary specialised operational skills.