“…In fact, the contribution made by renewable energy to energy needs is expected to exceed that made by natural gas and double that made by nuclear power within the next four decades, though progress needs to be accelerated and the relevant policies put in place accelerated to create a sustainable energy system (Nersesian, 2007;Langeveld et al, 2010;Seifried and Witzel, 2010;Zatzman, 2012;Hamilton, 2013). In fact, the contribution made by renewable energy to energy needs is expected to exceed that made by natural gas and double that made by nuclear power within the next four decades, though progress needs to be accelerated and the relevant policies put in place accelerated to create a sustainable energy system (Nersesian, 2007;Langeveld et al, 2010;Seifried and Witzel, 2010;Zatzman, 2012;Hamilton, 2013).…”