Sewage sludge: Next alternative energy?

TOKYO -- A group of Japanese companies is developing what might be the ultimate in reusable alternative energy for vehicles.

The idea: Turn sewage sludge into hydrogen for use in fuel cell vehicles. The consortium started testing the method this week.

Japan’s Nikkei business daily says getting hydrogen from sewage is cheaper and cleaner than the traditional method of generating it from liquefied natural gas or other fossil fuels.

It cuts carbon emissions 75 percent, the Nikkei says.

Cooperating on the project are Toyota Motor Corp. affiliate Toyota Tsusho Corp., Mitsui Chemicals Inc., Daiwa Lease Co. and Japan Blue Energy Co. They want to commercialize it by 2015.

The process involves drying the sludge in multiple steps. First, methane is generated. Then, the methane is reheated to cook out a high concentration of hydrogen gas.

The process is envisioned as a source of hydrogen for use in fuel cell vehicles. Many automakers, including Toyota and Honda, are planning new fuel cell vehicles in the coming years.

The cars are seen as a boon to fighting carbon emissions because they convert hydrogen into electricity, while emitting only water vapor. But getting the initial hydrogen can be expensive and complicated.

The Japanese are betting that human waste holds a breakthrough.