This joint UNDP and Asia Development Bank report ‘Initial Assessment of Sri Lanka’s Power Sector – Electricity Generation through 100 per cent Renewable Energy’ describes the technical challenges to meet this ambitious 100 per cent renewables target and how this target could be financed. The report includes a step-wise approach for the assessment of the 100 per cent renewable electricity generation target, the composition of renewable energy generation and the direct and indirect costs associated with the target, including also the costs for the enabling infrastructure such as transmission systems and storage capacity. A favourable policy environment for additional regulations has also been analysed. Possible sources of financing for the transition of Sri Lanka’s electricity system have been assessed and finally, the sustainable development benefits of a 100% renewables scenario have been identified and quantified. While this study gives deep insights into the issues associated with 100 per cent renewable energy targets, it is understood that over the next decades a number of changes are likely to occur in technology, economics and regulatory environment.