The long-term forecasting of energy supply and demand is of prime importance in Africa due to the steady increase in energy requirements, the non-availability of sufficient resources, the high dependence on fossil-fuels to meet these requirements, and the global concerns over the energy-induced environmental issues. This paper is concerned with modelling possible future paths for Africa's energy future and the related emissions. Future energy demand is forecasted based on socio-economic variables such as gross domestic product, income per capita, population, and urbanisation. The Long-range Energy Alternative Planning System (LEAP) modelling framework is employed to analyse and project energy demand and the related emissions under alternative strategies for the period of 2010-2040. Results of scenarios including business-as-usual (RAU) policies, moderate energy access and accelerate energy access policies, renewable energies promotion and energy efficiency policies and their environmental implications are provided. The study provides some policy insights and identifies synergies and trade-offs relating to the potential for energy policies to promote universal energy access, enable a transition to renewable energy, and mitigate climate change for a sustainable development.