A study is under way to evaluate the feasibility, costs, and benefits of co-milling and direct injection cofiring of switchgrass with coal as a potential renewable energy source. Switchgrass is an American native prairie grass, ideally adapted to the eastern United States. The grass is highly productive, requires little fertilization and herbicide, and can be grown on marginal land. There are four phases in the study, which look at (1) farm production issues, (2) pilot co-milling, (3) pilot combustion tests, and (4) full-scale demonstration. To date, good data have been obtained on farm production costs and held processing and handling issues. Pilot-scale milling tests and combustion tests of blends of switchgrass with coal have been successfully completed, and a full-scale demonstration of direct pneumatic injection of switchgrass for co-firing in a pulverized coal boiler is planned for the spring of 2001. (C) 2000 Elsevier Science Ltd. All rights reserved.