1. Research Scholar, Centre for Energy Studies, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India (corresponding author). E-mail: acmezenith@rediffmail.com
2. PSO, Centre for Energy Studies, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India. E-mail: tsb@ces.iitd.ernet.in
3. Professor, Centre for Energy Studies, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India. E-mail: dkothari@ces.iitd.ernet.in