Two federal entities have added hybrid vehicles into their fleet in response to President Obama's call for tougher goals for renewable energy in federal buildings and lower emission vehicles in the federal fleet.

Lightning Hybrids has delivered two hydraulic hybrid shuttle buses to Denali National Park and Preserve, the parks first hybrid vehicles, and it has also installed hydraulic hybrid system on two shuttle buses for the Energy Department’s National Renewable Energy Laboratory (NREL).

The system equipped in the vehicles is a parallel hydraulic hybrid system that has no electric batteries and instead applies a hydraulic system to the driveline of a vehicle to regenerate braking energy. The braking energy is stored and used to provide power to the wheels, and it improves braking efficiency, according to the company.

The Colo.-based developer and manufacturer of hydraulic hybrid systems delivered a Chevrolet model and a Freightliner vehicle to the national park, which is located in Denali, Alaska, according to the company.

“The National Park Service has a long-standing commitment to using advanced clean technology in their fleet vehicles,” said David Brosky, vice president for sales of Lightning Hybrids. “Our hydraulic hybrid systems work well in harsh environments, and will help the park service to reduce emissions and save fuel.”

Lightning Hybrids also installed the hydraulic system onto a Ford E-450 that is serviced on NREL's campus. This is the second time Lightning Hybrids installed the system onto an NREL fleet vehicle; the company had done so on another E-450 more than a year ago.

“We are very proud of the fact that NREL, which represents the best of the best in federal research into sustainable vehicle technologies, has selected the Lightning Hybrids system,” said Tim Reeser, CEO of Lightning Hybrids.

Last year, President Obama scaled back on expectations he set in 2009 to have fully fuel-efficient government fleet and 1 million plug-in vehicles on the road by 2015.