Marker blog
Posted by admin at 5:47PM on 5/27/2011 with tags: , , ,

Grand Junction, Co. had the best of intentions when it decided to invest in several natural gas-powered trash trucks. However, due to the large tank size required for CNG storage, the town’s trash trucks have had nearly two feet added to their length. Since CNG is less dense than liquid fuels, the size of the fuel tank must be increased in order to make up for lost range.

“Drivers of the new garbage trucks that run on compressed natural gas recently purchased by the city are unable to navigate some tight city alleyways, according to Grand Junction Public Works spokeswoman Kristin Winn.” About 160 residents used to be able to push their trash cans to the alley for pick-up, but now have to haul their cans to the front of their homes.

In response to a few complaints, the city has started offering elderly or disabled citizens the option of requesting help with their cans. Despite the problems, however, the city has plans to add two more CNG trash trucks to its fleet in the coming year.

As for trying to navigate the alleyways, the city is “…still kind of looking at this and modifying the trucks,” according to Winn.

Note: While it is true that natural gas vehicles offer about a 29% overall reduction in emissions versus gasoline engines, the article’s author overstated this figure when she said that they “produce almost no greenhouse gases.”

Marker blog
Posted by admin at 6:51PM on 5/25/2011 with tags: , , , ,

Source: City of Palm Desert

The city of Palm Desert, Calif. (in Riverside County), announced this week that they plan to convert a retrofitted CNG-powered ambulance back to diesel, after the vehicle failed to meet expectations.

“The ambulance, which was unveiled by the city in January 2010, only put out 82 miles per tank, well below the mandated average of 250 miles in Riverside County, according to Capt. Scott Visyak of the Riverside County Fire Department, which contracts with Palm Desert for its firefighting services.”

 

Range is one of the biggest obstacles for natural gas vehicles, as it must be compressed at up to 3600 psi in bulky, heavy tanks. According to a 2010 Department of Energy study titled “Issues Affecting Adoption of Natural Gas Fuel in Light- and Heavy-Duty Vehicles,” the most common type of CNG tank occupies 3 times the volume and weighs “4 to 5 times as much” as a same-capacity gas tank. Therefore, lower gallon-equivalent-capacity causes a reduced driving range.

The failed experiment came with no small price tag. “The ambulance initially cost the city $186,000 to convert the emergency vehicle, according to the city.”

Fortunately, the city won’t have to pay quite that much to convert the vehicle back to diesel. One month and another $78,000 later, they’ll have a regular ambulance again.