How did the Portuguese government encourage rooftop solar panels?
Portugal’s national energy transmission company, Redes Energéticas Nacionais (REN), uses sophisticated modeling to predict weather, especially wind patterns, and computer programs to calculate energy from the various renewable-energy plants. Before the solar/wind revolution, Portugal had generated electricity from hydropower plants on its rivers for decades. New programs combine wind and water: wind-driven turbines pump water uphill at night, the most blustery period; then the water flows downhill by day, generating electricity, when consumer demand is highest. Portugal’s distribution system is also now a two-way street. Instead of just delivering electricity, it draws electricity from even the smallest generators, like rooftop solar panels. The government aggressively encouraged such contributions by setting a premium price for those who buy rooftop-generated solar electricity.