99 % of the electricity supply on Caribbean islands is currently provided by fossil fuel based power plants which is very expensive and polluting. The use of renewable energy technologies can be a cost-effective and sustainable solution to these problems. Implementing renewable energies has been rather slow despite sufficient natural resources. This has guided the two main research questions of this PhD thesis: (1) What is the techno-economic potential for renewable energies on Caribbean islands and (2) which barriers and solutions exist in the utilization of this potential? Firstly, a technical analysis was conducted based on a self-developed island energy supply model. 60 of the 62 analyzed islands demonstrate high to very high techno-economic potential for implementing renewable energies. The optimal renewable energy share is 45 % as opposed to the current 1 %, which would result in a decrease in LCOE from 0.30 to 0.22 USD/kWh and the added benefit of a 22m tons per year decrease in CO2 emissions. Initial investments of 35bn USD are required to reach the optimized renewable capacities in GW: 0.8 hydro, 8.8 PV, 6.3 wind, and 0.5 geothermal plus 3,120 MWh of battery storage. Empirical analyses were conducted to answer the second research question. The most important barriers are distributed among three main clusters. The 1st cluster is regulatory frameworks and policies, for example lack of regulatory framework and legislation for private investors. The 2nd is costs and financing, of which high initial investments is the most important barrier. The 3rd cluster is the clout of conventional power suppliers. To overcome these barriers most crucial are improvements to the regulatory frameworks, incentives such as a ‚ “renewable fuel surcharge”, and financing options.