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The ExternE methodology provides a framework for transforming impacts that are expressed in different units into a common unit - monetary values. It has the following principal stages: 1) Definition of the activity to be assessed and the background scenario where the activity is embedded. Definition of the important impact categories and externalities. 2) Estimation of the impacts or effects of the activity (in physical units). In general, the impacts allocated to the activity are the difference between the impacts of the scenario with and the scenario without the activity. 3) Monetisation of the impacts, leading to external costs. 4) Assessment of uncertainties, sensitivity analysis. 5) Analysis of the results, drawing of conclusions. The ExternE methodology aims to cover all relevant (i.e. not negligible) external effects. The purpose of ongoing research is to cover more effects and thus reduce gaps and in addition refine the methodology to reduce uncertainties. Currently, the following impact categories are included in the methodology and described in detail in this report: 1) Environmental impacts: Impacts that are caused by releasing either substances (e.g. fine particles) or energy (noise, radiation, heat) into the environmental media air, soil and water. The methodology used here is the impact pathway approach. 2) Global warming impacts: For global warming, two approaches are followed. First, the quantifiable damage is estimated. However, due to large uncertainties and possible gaps, an avoidance cost approach is used as the recommended methodology. 3) Accidents: Accidents are rare unwanted events in contrast to normal operation. A distinction can be made between impacts to the public and occupational accident risks. Public risks can in principle be assessed by describing the possible accidents, calculating the damage and by multiplying the damage with the probability of the accidents. An issue not yet accounted for here is the valuation so-called ���Damocles��� risks, for which high impacts with low probability are seen as more problematic than vice versa, even if the expected value is the same. A method for addressing this risk type has still to be developed.

The interest in studying energy systems’ resilience is increasing due to a rising awareness of the importance of having a secure energy supply. This growing trend is a result of a series of recent disruptions, among others also affecting electricity systems. Therefore, it is of crucial importance for policymakers to determine whether their country has a resilient electricity supply. Starting from a set of 12 indicators, this paper uses data envelopment analysis (DEA) to comprehensively evaluate the electricity supply resilience of 140 countries worldwide. Two DEA models are applied: (1) the original ratio-based Charnes, Cooper, and Rhodes (CCR) model and (2) a novel hybrid framework for robust efficiency analysis incorporating linear programming and Monte Carlo simulations. Results show that the CCR model deems 31 countries as efficient and hence lacks the capability to differentiate them. Furthermore, the CCR model considers only the best weight vectors for each country, which are not necessarily representative of the overall performance of the countries. The robustness analysis explores these limitations and identifies South Korea, Singapore and Canada as the most resilient countries. Finally, country analyses are conducted, where Singapore’s and Japan’s performances and improvement potentials are discussed., Energies, 13 (7), ISSN:1996-1073