Currently 86% of primary energy use in Iceland is derived from renewable and domestic energy resources. Two sectors still rely on imported fossil fuels: the fishing industry and transportation. Transitioning to a low-carbon, close to fossil fuel free economy is therefore a possibility in Iceland in the near future and the Icelandic government has proposed to reach carbon neutrality by 2040. Multiple different development pathways are possible towards a low-carbon and a more sustainable energy system in Iceland as the Icelandic energy resources can be developed and the energy used in diverse ways. Given the capital intensity and longevity of energy infrastructure and technologies it is important that decision-makers realize the multifaceted implications of energy development choices as these will influence the Icelandic society and government budgets for years to come. This presentation will provide insights to these issues, and present an integrated decision-making framework, based on system dynamics, multi-criteria decision-analysis and sustainability indicators that has been developed to assist decision-makers in Iceland make robust decisions.