The prospects of electricity generation from municipal solid waste (MSW) in Ghana: A better waste management option
Highlights
► Waste management is a serious challenge in Ghana as its population keeps increasing. ► MSW generated in Ghana could produce 1.5–2.0 GWh electricity/year. ► Electricity generation from MSW is a better option for waste management in Ghana. ► Electricity generation from engineered landfills is the most economical option.
Introduction
The population of Ghana is estimated at about 24.7 million with a growth rate of 1.822% (since 2010) according to 2010 population and housing census [1]. With an overwhelming increase in birth rate (27.55 births/1000 people) compared to death rate (8.75 deaths/1000 people) coupled with rapid urbanization (urban population of about 12 million with urban growth rate of 3.4% annual rate of change in 2010) and industrialization, waste generation has also increased tremendously especially in the urban areas [1]. In 2010, the average amount of waste generated in Ghana was 0.51 kg per capita per day with annual waste generation capacity of about 4.5 million tons [2], [3]. Only about 10% of these wastes are managed well through proper incineration and landfilling. Uncontrolled dumping of wastes at unauthorized places, inappropriate technologies for landfilling and incineration as well as the weak enforcement of environmental regulations (i.e. the National Sanitation Policy) in Ghana has resulted in great burden on the Ghanaian environment. The aim of this paper is to assess the feasibility of three main electricity production technologies namely engineered landfilling, landfilling without engineered sites and controlled incineration from municipal solid waste (MSW) generated in Ghana.
Effective waste management has been a big challenge in most developing countries including Ghana. Collection and sorting of municipal wastes at source in Ghana with the hope of reducing the indiscriminate dumping of wastes has never been realized. Presently, MSW in Ghana is mainly managed by either disposal in landfill sites, recycling (only insignificant fraction), incineration or sometimes the combination of any two of these methods. Sites for incineration and landfilling are limited and mostly located in open areas within towns and cities creating great sanitation problems. As a result of anaerobic digestion of organic wastes in landfills releasing gases such as methane (CH4), NOx, and SO2 coupled with the emission of particulate matter into the air during incineration, the current methods of wastes management (landfilling and incineration) in Ghana become inappropriate.
When wastes-to-energy (WTE) plants which utilize MSW are constructed according to the standards of the Environmental Protection Agency (EPA), an environmentally sound MSW management is achieved in a sustainable way. As a way of reducing the environmental burdens caused by global warming as a result of fossil fuel combustion; and promoting cost effective means of waste management, the utilization of energy from MSW (especially non-hazardous wastes) incineration and landfill plants for the generation of electricity has received much attention in recent years [4], [5]. Results of previous studies [6], [7], [8], [9], [10] on the tracking of the changes in greenhouse gas (GHG) emissions from MSW management technologies in the United States and some developing countries revealed that there are significant reductions in GHG emissions by technologies that are employed to recover energy and recycle materials. Controlled operations involved with incineration, composting, landfilling, gasification, pyrolysis etc. of MSW present good options for energy recovery since the volume of wastes generated is reduced through the respective treatment method [11], [12], [13], [14]. Apart from the need to minimize its local impact [15], [16], a significant problem with MSW incineration is the management of the ash produced from the combustible materials. These ashes however can be transformed into value added products such as concrete materials.
The world produces about 190 million tons of MSW annually of which about 60% is normally burnt in more than 800 WTE plants to generate electricity and steam for heating purposes [18]. About 400 WTE power plants in Europe currently generate energy from over 50 million tons of MSW [18] through various processes such combustion and anaerobic digestion. This energy, in a form of superheated steam is converted to electricity to serve about 27 million people and heat for 13 million people [18]. In Africa however, the production of electricity from MSW remains largely untapped notwithstanding the fact that large amounts of MSW are generated and not managed properly. Kathirvale et al. [19] have reported that Malaysia has the potential of processing about 0.55 million tons of MSW per year to generate over 5.6 GWh/year electricity via controlled incineration plant with energy recovery.
Section snippets
Status of electricity production and consumption in Ghana
Electricity in Ghana accounts for about 11% of the nation's final energy consumption with about 45–47% of the population having access to grid electricity with a per capita electricity consumption of 358 kWh per person [20]. Electricity in Ghana is produced and delivered from two main hydro-power plants (namely Akosombo and Kpong hydro-power plants) and six thermal plants (namely Takoradi Power Company, TAPCO; Takoradi International Company, TICO; Sunon Asogli Power (Ghana) Limited; Tema Thermal
MSW generation and management in Ghana
There are 10 regions, 49 main cities and 166 districts in Ghana [1]. According to the 2011 census, out of the total Ghana's population of about 24.7 million, about 12.62 million (representing 51.1%) are found dwelling in the urban areas. This is however projected to increase by 3.4% every year [1]. With regard to the average waste generation per capita per person (i.e. 0.51 kg in 2010) in Ghana, the highly-dense population in the urban areas tends to place huge burden on the environment because
MSW management methods capable of producing electricity in Ghana
Many technologies can be applied for the management all kinds of wastes. However those that are applicable for MSW management for the generation of electricity in Ghana include biochemical and thermo-chemical conversion technologies [33], [34], [35]. Fig. 2 summarizes the procedures for generating electricity by these two technologies.
Feasibility study of WTE plant operations in Ghana
The four major factors that justify the feasibility of electricity or energy production from MSW are (1) the amount of MSW generated, (2) characteristics and quality of the wastes, (3) the type of technology used for the energy production and (4) economic conditions of the location of the WTE plant. For instance, in 2010, Ghana produced about 4.5 million tons of MSW which could produce about 2 GWh electricity/year by controlled incineration and 1.0–1.5 GWh electricity/year by landfilling according to
Conclusion
Electricity generation from MSW is highly feasible in Ghana considering the large amount of waste generated which are not managed efficiently. Even though the costs of these power plants are high at present, the rationale for putting up these plants should be waste management to improve environmental safety. It was found out from the various feasibility studies that landfills with already existing engineering sites have the potential of being the most economical method of managing waste as well
Acknowledgment
The authors would like to thank the Universiti Sains Malaysia (Research University grant no. 854002 and USM fellowship) for the financial support given.
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