cost recovery with marginal generation prices. On the transmission side, he demonstrated why marginal prices fail to recover the total incurred network costs. Later on, he added major contributions to the security of supply debate, formulating in the context of the redesign of the Colombian capacity payments mechanism in 1999 the reliability options mechanism, the base of the capacity auction mechanisms later implemented in Colombia and New England. He has also worked intensively on the regulatory design of regional markets (both in Central America and in European Union) as well as on end-user tariff design. In 2013 he edited the book “Regulation of the Power Sector” (Springer-Verlag), used as textbook in his MIT course as well as in the annual training program for energy regulators of the Florence School of Regulation of the European University Institute. Currently he is Principal Investigator of the Comillas University - Massachusetts Institute of Technology Electricity Systems Program . He was the principal investigator of the MIT Utility of the Future study, published in 2016. Mid-2010s to date: Universal energy access Pérez-Arriaga's current research interests are focused on the analysis of the sustainability of energy models and universal energy access (regulation for the electrification of isolated rural areas). He is the principal investigator of the MIT-Comillas Universal Energy Access Research Group. The group does research in developing countries, builds computational models for electrification planning, and provides regulatory advice. Articles Pérez-Arriaga has supervised more than 25 doctoral theses, one hundred master theses, edited three books, published one book and more than two hundred articles in international conferences and journals. Some selected references of his work are: "Selective Modal Analysis with Application to Electric Power Systems, Part I: Heuristic Introduction", IEEE Transactions on Power Apparatus and Systems, Vol. PAS-101, no.9, September 1982, pp. 3117–3125 (co-authors: G.C. Verghese and F.C. Schweppe). "JUANAC: A model for computation of spot prices in interconnected power systems", 10th PSCC Conference, Graz. Austria, Aug. 1989 (co-authors: M. Rivier and G. Luengo). "A security constrained decomposition approach to optimal reactive power planning", IEEE Transactions on Power Systems, vol. 6, no. 2, August 1991, pp. 1069–1076 (co-authors: T. Gómez, J. Lumbreras and V.M. Parra). "On sensitivities, Residues and Participations. Applications to Oscillatory Stability Analysis and Control", IEEE Transactions on Power Systems, vol. PWRS-4, no. 1, February 1989, pp. 278–285 (co-authors: F. Luis Pagola, George C. Verghese). "Multi-area analysis of small signal stability in large electric