OAKLAND, Calif. — In the last decade, papermaker Verso has reduced its greenhouse gas emissions per ton of production by 28 percent through a mix of new energy sources, efficiency projects and sustainable forestry.

In "Our Path: A Softer Step," Verso details its environmental progress and projects from 2007, noting where it has succeeded and where it needs more work.

Last year, 53 percent of the company's energy came from biomass, leftovers from the papermaking process such as bark, small limbs and wood lignin. The rest of the company's energy came from natural gas (23 percent), oil (9 percent), purchased electricity and steam (8 percent), coal (5 percent) and other sources.

In 2007 the company also invested $20 million to increase operating and energy efficiency of facilities, so far improving paper machine efficiency by 1.2 percent.

On the sustainable forestry side, the company's four mills received Forest Stewardship Council chain of custody certification and increased the amount of certified fibers in products to 60 percent. In 2006 the figure was at 57 percent, and Verso aims to hit 64 percent in 2008. Verso chooses fibers certified by the Forest Stewardship Council, Sustainable Forestry Initiative or Canadian Standards Association.

The sustainability report also touches on the company's efforts with water, chemical, air pollution and solid waste reduction. In 2007, Verso generated 12,507 fewer tons of waste than in 2006. Of the more than 212,000 tons of solid waste it produced, about a third was recovered and reused as fuel, less than a third was sold for uses such as soil improvement and the remaining 37 percent was send to landfills.

In addition, Verso purchased 11,423 tons of recovered fiber, a 78 percent increase over 2006, to produce recycled-content products.