Diesel generators are the primary source of power supply in places without connection to the central power grid. This is associated with high electricity costs and dependency on volatile oil prices. Additionally, greenhouse gases and other pollutants are emitted. Renewable energy systems can step by step replace diesel generators to ensure a sustainable supply. This way, power can be supplied more reliable, more cost effective and less harmful. Project description: Despite the economic and environmental benefits of upgrading former diesel mini-grids with renewables energies these opportunities are rarely realized. One reason is the lack of information regarding global usage of diesel generators and underlying business models. Therefore, the aim of this project is to analyse the present power supply with diesel generators to assess the potential for an upgrade with renewable energies. Isolated diesel-based power systems located in 220 states and semi-autonomous regions are identified via GIS analysis. Subsequently, the respective installed capacities are calculated. For the case studies of Algeria, Australia, Peru, the Philippines and Tanzania the operator structure and business models are investigated. Results: Worldwide, more than 22.5 GW of installed power capacity in isolated diesel-based power systems are detected, more than two thirds of the systems located in developing and emerging countries. Island states and large territorial states have the highest installed diesel capacities. In the case study countries, the majority of the diesel energy systems have a capacity of below one MW. Two predominant operational models can be identified: First, diesel generators operated by state-owned utilities with often subsidized power generation. Here, the purpose is to supply remote and underdeveloped regions. In contrast, private companies run remote diesel generators for value-adding purposes, and mainly target the power supply of remote mining sites. Overall, a great potential for upgrading isolated diesel grids with renewable energies is demonstrated. The results can be used to facilitate the further dissemination of sustainable renewable technologies.