Sonoma News. The Sonoma Valley Unified School District (SVUSD) is using a $440,000 grant from the Bay Area Quality Management District to purchase four “Green Diesel” school buses from International Truck and Engine and to retrofit 11 others in the current fleet of 18.

International’s Green Diesel technology combines a catalyzed diesel particulate filter and ultra low-sulfur fuel with an engine performance design resulting in a drop in PM emissions of some 90% from a conventional diesel platform, a 25% drop in NO_x and practically no unburned hydrocarbons.

International positions its Green Diesel as better than CNG from a cost and emissions point of view. The chart below compares the Green Diesel Technology school bus engine (the International brand T444E), with two 1999 certified natural gas school bus engines (emissions data in g/bhp-hr).

The new buses should arrive this summer before school starts. All the retrofitting should be completed by December.

The grant comes from the Bay Area Quality Management District as part of its lower-emission school bus program.

The new buses alone cost approximately $113,000 each; of that the district pays $25,000 each. The grant also pays $8,500 for each retrofit of other buses, with $500 offsetting fuel costs.