There are certain technology challenges which have waited in vain over several decades for a satisfactory solution. The economical storage of electricity is one of them. But intensive work in the meantime is driving advances along various avenues.
Links:
[1] http://admin.indiaenvironmentportal.org.in/feature-article/electricity-demand
[2] http://admin.indiaenvironmentportal.org.in/category/author/jorn-iken
[3] http://admin.indiaenvironmentportal.org.in/category/author/alexander-morhart
[4] http://admin.indiaenvironmentportal.org.in/category/journal/sun-and-wind-energy
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/solar-energy
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/energy
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/energy-technology
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/energy-storage
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/electricity
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/hydrogen-energy
[11] http://admin.indiaenvironmentportal.org.in/category/thesaurus/fuel-cell
[12] http://admin.indiaenvironmentportal.org.in/category/thesaurus/france
[13] http://admin.indiaenvironmentportal.org.in/category/thesaurus/germany