Cities are responsible for approximately two-thirds of the world’s energy consumption, and as the world’s population continues to grow, more people move to cities. Johannesburg, as the economic center of South Africa, has a population of approximately five million people, and this number continues to grow every day. Unfortunately, the city is currently experiencing an energy crisis due to ongoing and escalating electricity cuts. The lack of leadership or access to alternative energy sources at the city level has resulted in big businesses installing diesel-powered generators or harnessing solar energy. More affluent households are also beginning to use alternative sources of energy to protect themselves against water and electricity interruptions. However, this development has negative implications for low-income households, which rely on cross-subsidies from high-end users to access municipal services. To explore the social and climate change implications of the rich seceding from state-provided infrastructure networks, the National Research Foundation (NRF) and the Gauteng City Region Observatory (GCRO) are co-funding a research project called Off-Grid Cities.
The Need for an Enabling Environment
While households are gradually driving the uptake of alternative energy systems, the mass movement to sustainable and environmentally friendly energy sources is dependent on the government creating an enabling environment. Discussions about energy-efficient cities must go beyond promoting large-scale and decentralized renewable energy generation. According to Professor Daniel Irurah in the School of Architecture and Planning, Faculty of Engineering and the Built Environment, we need to reimagine what cities like Johannesburg should look like in the next 10, 20, or 30 years. This includes a blend of transport modes powered by biofuels, green hydrogen, and electric vehicles to ease commuter congestion. Transport accounts for significant levels of direct energy consumption in the city, and fuel production and vehicle operation result in carbon emissions. Energy-efficient cities need to place this at the center of discussions on the just energy transition. Green buildings that require less heating in winter and less cooling in summer will need to be common practice rather than a ‘nice to have’.
Electrifying Buses for Cleaner Cities
The University of the Witwatersrand (Wits) is exploring how buses can be made more efficient and less pollutant. Dr. Lesedi Masisi, a Senior Lecturer in the School of Electrical and Information Engineering, began researching how to electrify the University’s diesel buses in 2019. Electrified buses are a step in the right direction towards cleaner cities as combustion engines release significant amounts of greenhouse gases. However, there remains much to be done before Wits moves entirely to electric buses. “Range anxiety” is a key factor in the electrification of buses, which refers to how far the bus can drive before requiring a recharge. The engine of diesel buses at best only makes use of 25 to 27% of the energy towards the wheels, with the rest guzzled by the heat under the process of conversion. Conversely, emission-free electric buses use above 85% of the electrical energy from the battery. Even if solutions are found for range anxiety and skills set shortages, electricity supply reliability remains a significant concern in the country.
Building sustainable cities requires considering long-term economic and social side effects. Cities need to be less dependent on fossil fuels, and discussions about energy-efficient cities must go beyond promoting large-scale and decentralized renewable energy generation. We need to reimagine what cities should look like in the next few decades, including a blend of transport modes powered by biofuels, green hydrogen, and electric vehicles. Green buildings that require less heating in winter and less cooling in summer will need to be common practice. The electrification of buses is a step in the right direction towards cleaner cities, but much needs to be done before we can transition entirely to emission-free transport.
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