The Department of Energy today issued $187 million in grants to improve the energy efficiency of long-haul trucks and passenger cars, but the core of today's grants revolves around three projects for trucks.

Cummins will get $38.8 million to build an aerodynamic Peterbilt tractor with a clean diesel engine sporting a waste heat recovery system while Navistar will get $37.3 to develop an aerodynamic hybrid rig with tires with easier rolling resistance. Meanwhile, Daimler Trucks North America gets $39.6 million for studying small engines and a waste heat device. Cummins also gets an additional $15 million for developing a diesel engine for light duty vehicles. The rest of the grants were in the $15 to $7 million range and went to Ford, Chrysler etc. for light duty vehicles.

The transportation sector accounts for 28 percent of energy consumption in the U.S. but big rigs could be a particularly fruitful segment. Because many trucks run on older diesel engines, rigs account for a disproportionate amount of emissions caused by transportation. Idling is also an issue--drivers often have to run their engines at night so their heaters and air conditioners stay on. The Environmental Protection Agency estimates that 960 million gallons of fuel get burned by idling rigs every year.  California has also imposed anti-idling regulations.

Other companies in the space: Firefly Energy (carbon membrane to improve lead acid batteries), Nanostellar (chemical additives for catalytic converters) and Quallion (lithium ion batteries)