Interconnected electricity networks, or Supergrids, are considered as a possible solution to tackle challenges associated with near and far-future supply of electricity. These include, but are not limited to, reducing Green House Gas emissions and reliance on non-renewable fossil fuels. Supergrids can help to tackle these challenges, for example, by providing a reliable interconnection platform for wider application (and development) of renewable technologies. However, there is a range of risks and uncertainties associated with selecting appropriate interconnections. Heretofore these have been a hindrance to developing interconnections and therefore a Risk-Based Framework (RBF) which addresses these risks and uncertainties could encourage the wider uptake of Supergrids. This paper presents for the first time such a robust framework. The RBF comprises of four stages; (1) initial screening for selecting candidate countries, (2) risk identification, (3) risk semi-quantification and (4) risk quantification. In stage 4 the uncertainties associated with the identified risks are quantified using a cost-risk model under uncertainty based on a whole life appraisal approach. The usefulness of the approach, demonstrated using the UK as a case study, showed that greatest cost risks are associated with (a) regulatory framework, and (b) changes in energy policy. The most desirable interconnection option for the UK was identified as France.