Saturday may mark a new era in energy for Japan as the country powers down the last of its 50 nuclear reactors. Thousands of Japanese, waving fish-shaped banners, a symbol of the anti-nuclear movement, took to the streets to celebrate the shutting off of the Tomari nuclear power plant for maintenance. No plant shut off for maintenance since the earthquake and tsunami in March of last year has been turned back on. But many in the government are enthusiastic about restarting them, worried about the country’s increased reliance on oil and gas. Before the crisis last year and new restrictions passed to prevent against future disasters, more than 30 percent of Japan’s electricity was provided by nuclear plants.