Grapevine

China's new ban on plastic bags goes into effect on June 1. The law could save 37 million barrels of crude oil each year. * A power system planned for Sweden's Stockholm Central Station will capture body heat generated by the traveling masses and use it to heat water that warms a nearby 13-story building. * Walking has new power, thanks to a high-tech knee brace that produces enough electricity to juice ten cell phones. --Lea Hartog