Assessing the costs of contributing to climate change targets in sub-Saharan Africa: The case of the Ghanaian electricity system Felix Amankwah Diawuo a,b, ⁎ ,1 , Ian J. Scott a,c,1 , Patricia C. Baptista a , Carlos A. Silva a a Center for Innovation, Technology and Policy Research - IN+, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal b School of Engineering, University of Energy and Natural Resources (UENR), P. O. Box 214, Sunyani, Ghana c Laboratory for Information and Decision Systems, Massachusetts Institute of Technology, Cambridge, MA, USA abstract article info Article history: Received 31 July 2019 Revised 10 April 2020 Accepted 17 May 2020 Available online xxxx Keywords: Generation expansion plan Unit commitment Renewable energy integration Mixed-integer linear programming CO 2 emissions Ghana is one of the few countries within the sub-Saharan region which has been successful in reducing energy poverty. However, ensuring energy security, affordability, and environmental sustainability remains a significant challenge for the future development of the sub-region. Here, we examine how the electricity supply can evolve into the future to meet potential emission obligations for the period of 2020–2040. A generation expansion plan- ning model which is able to incorporate the reality of fuel shortages and fuel switching typical of a developing country's power system is used. In doing so, we generate a range of emission reduction costs that provide impor- tant benchmarks for the relatively under-studied sub-Saharan region and identify drivers of these costs specific to developing countries. Results indicate that the total discounted cost in expanding generation to meet the demand for all scenarios range from 13–17 billion US$, while the expected emission ranges from 99–189 mtCO 2 . Subsequently, the cost of meeting different emission targets up to 2040 was quantified for each scenario ranging from 11–39 US$/tonne, which could be used as a benchmark for comparison in developed countries. We find that discount rates, representing Ghana's access to capital, are a particularly important variable for develop- ing countries. We find that lower discount rates can lead to more investment in capital intensive renewable energy in the long run but can also lock in an additional conventional generation investment in the short term. Sensitivity analysis of demand growth reduction shows that with a 1% growth rate, the requirement of generation capacity could be reduced by 84%, providing initial evidence for the benefits of investing in demand-side mea- sures. The study provides data and policy recommendations needed to inform decision-makers in developing countries as well as a comparison point for identifying decarbonization costs internationally. © 2020 International Energy Initiative. Published by Elsevier Inc. All rights reserved. Introduction The provision of reliable, secure, sustainable and affordable modern energy for all citizens is key to poverty liberation and economic growth (International Energy Agency, 2017; Mentis et al., 2015). In the sub- Saharan African region alone, which hosts a population of over 950 mil- lion, more than 590 million are without access to electricity, making it the most electricity-poor region in the world (International Energy Agency, 2017). It is estimated that most of the countries within the re- gion have an electricity access rate of about 43%, while the average an- nual residential electricity use hovers around 488 kWh/capita, which represents about 5% of the electricity use in the US (Avila, Carvallo, Shaw, & Kammen, 2017). This recognition led to the adoption in 2015 of the new United Nations Sustainable Development Goals (SDGs), signed by 193 developed and developing countries with the objective of ensuring access to affordable and sustainable modern energy for all by 2030 (International Energy Agency, 2017; Riva, Ahlborg, Hartvigsson, Pachauri, & Colombo, 2018). Indeed, the Paris Agreement also acknowledges this need and further promotes access to sustainable energy especially in Africa. Electricity demand is constrained by supply and the threatening energy security is attributed to various factors in- cluding poor system reliability, limited infrastructure, fuel import de- pendence, and heavy reliance on fossil fuels, hydropower, and traditional biomass resources (ECREEE, 2014). Ghana is one of the few countries within the sub-region which has been successful in reducing energy poverty, having shown long and strong political commitment since the launch of its National Electrifica- tion Scheme (NES) in 1989 (International Energy Agency, 2014). The objective of the NES was to attain 100% universal electricity access by 2020. By 2017, the country had recorded an electrification rate of about 84% (Nunoo, 2017), which is one of the highest in the sub- Energy for Sustainable Development 57 (2020) 32–47 ⁎ Corresponding author at: Center for Innovation, Technology and Policy Research - IN +, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais 1, 1049- 001 Lisbon, Portugal. E-mail addresses: felix.diawuo@tecnico.ulisboa.pt, felix.diawuo@uenr.edu.gh (F.A. Diawuo), ian.scott@tecnico.ulisboa.pt (I.J. Scott), patricia.baptista@tecnico.ulisboa.pt (P.C. Baptista), carlos.santos.silva@tecnico.ulisboa.pt (C.A. Silva). 1 Co-first authors. https://doi.org/10.1016/j.esd.2020.05.001 0973-0826/© 2020 International Energy Initiative. Published by Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect Energy for Sustainable Development