TO GO WITH AFP STORY: Climate-warming-COP21-Japan-hydrogen, FOCUS by Anne Beade Japanese auto giant Toyota Motor's fuel cell vehicle Mirai leaves a hydrogen station of Japan's gas distributor Iwatani in Tokyo on October 29, 2015. Japan has lofty visions of becoming a "hydrogen society" where homes and fuel-cell cars are powered by the emissions-free energy source, but observers say cost, convenience and policy hurdles are preventing the plan from taking off. Tokyo wants to see buses, buildings and cars powered by the clean energy in the coming years, and has even laid out plans for a "hydrogen highway", all in time for the Tokyo 2020 Olympics. AFP PHOTO / Yoshikazu TSUNO (Photo credit should read YOSHIKAZU TSUNO/AFP/Getty Images)
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