Current hydrogen production methods require non-renewable fossil fuels but Toyota found a plentiful source, poop.
A sewage processing plant in Fukuoka, Japan in a primary treatment, physically separates the 'solids' in settling basins. In the secondary treatment they treat the sludge with micro-organism/biodigesters using anaerobic digestion to breakdown the biological matter creating biogas. Instead of burning it off, the Fukuoka plant filters out the CO2 and catalyses hydrogen gas formation to be used by Toyota Mirai fuel cell vehicles.
Additional benefits from the human waste process; prevents algal blooms, red tide, and dead zones, conserves nutrients (especially nitrogen compounds) and reduces anthropozoonotic pathogens. Actually an old technology, India uses this bio-sewage treatment to produce biogas, an important part of their energy infrastructure.
Toyota's project in Fukuoka will use human waste to create the biogas needed to power their Mirai hydrogen fuel cell car