a
Electrical Energy and Power Systems Group, School of Electrical and Electronic Engineering, University of Manchester, Ferranti Building, Sackville Street, Manchester, United Kingdom
E-mail: brian.azzopardi@postgrad.manchester.ac.uk
;
Tel: + 44 (0) 161 306 8721
b
Department of Physics and Grantham Institute for Climate Change, Imperial College London, London, United Kingdom
c
Department of Electronics, Technical University of Cartagena, Plza. Hospital 1, Cartagena, Spain
d
Risø National Laboratory for Sustainable Energy, Technical University of Denmark, Frederiksborgvej 399, Roskilde, Denmark