The yellow roses ofMinnesota?
No one is singing about them yet, but power company officials are whistling about 130,000 long-stemmed beauties they grew in an experimental greenhouse in Sherburne County, Minn. The structure needs no fuel: excess heat from a coal-burning electricity plant near by is used to keep temperatures in the 60°-to-75° range. Hot waste water from the plant is pumped into the greenhouse through pipes buried in the soil. The sponsors of the $700,000 experiment the Northern States Power Co., the University of Minnesota and the Environmental Protection Agencyfound its potential intriguing. Along with the roses, some 25,000 Ibs. of...