Sustainable Energy Transitions in sub-Saharan Africa: Impacts on Air Quality, Economics, and Fuel Consumption

Historically, the United States, Europe, and China have produced the most greenhouse gas (GHG) emissions, with the largest share (25%) coming from the electricity and heating sector. With declining growth rate projections and access to electricity services all near or at 100%, developed countries have increased their share of sustainable energy sources such as wind and solar power. Unlike the most developed nations, populations are expected to increase drastically throughout the developing world in the 21st century. Recent estimates indicate 97% of the world’s population growth through 2030 (1.3 billion more people) will occur in the developing world. The countries of sub-Saharan Africa alone are projected to add over a billion people through 2050. Such population growth in developing countries will result in growing energy demand and thus growing emissions. The United Nations has underscored the importance of ushering in responsible and equitable energy pathways through their Sustainable Development Goals (SDGs). With a set of goals emphasizing access to affordable and reliable power, access to modern energy services, and reducing poor air quality and GHG emissions, the SDGs aim to improve quality of life across key areas of concern. The aim of this dissertation is to identify and evaluate opportunities for avoiding continued increases in fossil fuel use in sub-Saharan Africa, which would in turn reduce and avoid emissions of greenhouse gases and criteria air pollution and reduce some associated costs.
In Chapter 2 we analyze the energy, emissions, and consumer costs of power outages in sub-Saharan African countries. By modeling the fuel mix for the central electricity grid in each country and the diesel fuel needed to produce backup electricity during outages, we estimate the magnitude of these impacts in the region. We show that use of backup generators leads to higher fossil energy consumption (compared to the central grid) in all countries, even countries that already rely on fossil fuels for power generation at centralized plants. Furthermore, for all countries in the analysis, backup diesel generators result in increased mean emissions of at least three of the five pollutants analyzed, compared to the grid. Our analysis highlights the magnitude of potential avoided emissions and economic savings from increased grid reliability, and has implications for achieving Sustainable Development Goals. Increased reliability may not lead to decreases in generator ownership, but it is likely to lead to decreases in generator use, thus avoiding additional emissions and reducing costs for consumers.
In Chapter 3 we assess the emissions, health, and economic outcomes of electrifying motorcycle taxis in Kigali, Rwanda. By modeling fleet demand using observed driving distributions, we are able to estimate travel of this unique subset of all motorcycles which form the basis for all estimates. Our analysis reveals that emissions of key pollutants already identified by government officials (NOx, CO, HCs) as well as the greenhouse gas CO2 and health risks from PM2.5 can be drastically reduced via motorcycle fleet electrification. While a reduction of primary and secondary PM2.5 exposure and thus deaths can be achieved with the electrification of motorcycles, such benefits are dependent on the marginal generating unit. Finally, the Levelized Costs of Driving analysis reveals that at least one of the electric motorcycle alternatives presented in this work is cost competitive over a five-year period, and cost competitiveness improves as vehicle life is extended.
In Chapter 4 we extend the vehicle electrification analysis to assess the benefits and costs of bus electrification in Rwanda. We employ a Monte Carlo Analysis to assess how the emissions, health impacts, and non-infrastructure costs associated with diesel powered buses compare to those associated with their electric counterparts. We find that mean emissions of CO2, PM2.5, NOx, CO, and HC all decline significantly when travel provided by diesel buses is replaced with electric buses. However, we also observe increased emissions of SO2 with bus electrification due in part to the prevalence of heavy fuel oil and peat electricity generation. Despite this increased SO2, the health analysis reveals that electrification can result in less annual deaths from primary and secondary PM2.5 but not if peat is the marginal electricity generating unit. Our economic analysis shows that electric buses have greater present levelized costs but given a decrease in capital cost and longer lifetime, electric buses can reach parity with the diesel buses. The final analysis in this chapter compares the normalized emissions and costs of conventional motorcycles, electric motorcycles, conventional buses, and electric buses. We find that the electric buses offer the greatest emission reductions (per passenger-kilometer) while the diesel buses offer the cheapest levelized costs. This research highlights the important role public transit electrification could play in achieving the Sustainable Development Goals as countries commit to lower greenhouse gas and harmful air pollutant emissions
Finally, in Chapter 5 we discuss the important role developing countries will play in achieving global sustainability as their population, mobility, and electricity usage rise over the coming decades. We discuss the implications that reliable power and electrification efforts could have for the Sustainable Development Goals and urge developed nations to assist developing countries in implementing some of the technologies necessary for their completion. This thesis provides the framework for policy makers throughout SSA to assess the benefits and costs associated with modernizing their electricity systems.