The Pentagon is pushing construction of independent power grids at military bases out of concern that utility companies are vulnerable to hackers, terrorists and natural disasters. The biomass facility has created nearly 200 jobs, including 34 full-time workers at the plant and dozens more in fuel supply, including additional timber company workers and truckers. Logging residue — mainly treetops and branches — makes up about 85 percent of the fuel mix at Fort Drum, said Larry Richardson, chief executive officer of Latham-based ReEnergy Holdings. The company is also collaborating with the State University of New York College of Environmental Science and Forestry to provide a market for shrub willow, an energy crop coming into production on about 500 acres in northern New York. ReEnergy is certified by the Sustainable Forestry Initiative, an independent non-profit organization that verifies that the wood-chip fuel used at its nine plants in six states is procured from loggers who follow responsible land management practices.