Generating energy from waste is not new but it is yet to reach its full potential. In fact, it is not getting as much attention as it deserves yet. The World bank estimates that in low and middle-income countries, daily per capita waste generation is expected to increase by nearly 40% or more as compared to 19% in high-income countries by 2050. Sub-Saharan Africa is the fastest growing region where waste growth rate is expected to be the highest (see figure 1) with the total waste generation expected to treble by 2050 compared to the 2016 level. In this part of the world, like in the other low and middle-income countries, waste growth will have a huge impact on the environment, health, and prosperity due to open dumping in these regions.
Average waste collection rates vary from 39% in low-income countries to 96% in high-income countries. The collection of waste is positively correlated with the level of economic development of a country, and so is its sustainable treatment.
State of waste-to-energy market globally
Statista estimates that the waste-to-energy (WtE) market will grow at a CAGR of 4.6% for the forecast period of 2020-2027, with its market size growing from USD 35.1 billion in 2019 to USD 50.1 billion by 2027 (see figure 2).
Developed countries are home to 80% of thermal WtE plants worldwide with Europe and the United States at the forefront, making this technology more topical in these regions unlike the developing world. Numerous large-scale WtE installations have been in operation for over 30 years now. However, with a view of reducing energy consumption by 3-5 times, a number of countries in Europe and Asia-Pacific will focus more on recycling in the coming years, which may limit the WtE market in these regions.
Adapting waste-to-energy technology to a context
Four main WtE conversion technologies in use today are incineration, pyrolysis, gasification, and biomethanation or anaerobic digestion. There is no one-size-fits-all WtE method, therefore customised solutions must be adopted from country to country. To do so, there are criteria that make it possible to choose the technology best suited in context and in line with national priorities. Thus, scores and weight can be assigned to the following factors for decision-making purposes:
environmental impact measured by air pollution;
cost;
side products;
capacity;
maturity;
energy efficiency; and
waste type
Without giving special weightage for any of these factors, incineration and biomethanation are proven to be the most attractive options, followed by pyrolysis and gasification, according to a study led by the Department of Chemical Engineering of the Aligarh Muslim University in India. While anaerobic digestion is the most environmental-friendly option, incineration is recognised for its capacity and maturity. Therefore, in a context where environmental impact and cost are primary considerations and therefore weighted, anaerobic digestion is found to be the most attractive solution. Be that as it may, the latter can be constrained by factors such as energy production efficiency and waste treatment capacity.
Increasing urbanisation remains the key driver that dictates the growth of the WtE market and the great anticipation for a green recovery post-Covid-19 could further propel this market alongside other renewable energy options.