This case study evaluates the process and business potential of investing in compressed natural gas (CNG) for commercial fleets. Specifically, this study will explore the results from a project under a U.S. Department of Energy (DOE) Clean Cities grant through the American Recovery and Reinvestment Act (ARRA) to fund the purchase of 14 concrete mixer trucks.


In August 2011, Ozinga Bros., Inc., a leading supplier of ready-mix concrete and materials to customers in the Chicagoland area, partnered in the Chicago Area Clean Cities (CACC) grant to deploy 14 CNG-powered concrete mixers. The critical first-hand experience gained through these grant vehicles allowed them to quickly expand their alternative fuel plans using their own funds.

In September 2012, Ozinga opened one of Chicago’s first privately owned natural gas fueling stations to local businesses and government agencies.

The CNG fueling station, located at Ozinga’s Pilsen headquarters, serves the company’s fleet of iconic red-and-white concrete mixing trucks.

Since 2011, Ozinga’s green fleet has grown considerably. Ozinga now has over 110 CNG cement mixers in its fleet as well as 25 CNG support vehicles (pick-ups, vans, and cars). The company has plans to replace or convert its entire fleet of more than 500 mixing trucks and support vehicles by 2020 in an effort to achieve energy independence and promote alternative energy in Chicago.

“Building the fueling station and converting our fleet to natural gas reinforces our commitment to the foundation of Chicago’s new energy infrastructure,” said Tim Ozinga, Ozinga’s Director of Communications, noting that the company’s diesel-powered fleet consumes millions of gallons of fuel each year. “It satisfies a growing demand for energy that is greener, more affordable, and contributes to America’s energy independence.”

The station is open to Chicago-area businesses and municipalities, and fuels commercial vehicles, including medium- and heavy-duty trucks, as well as other fleets. In additional to the commercial “fast-fill” pump, their private “time-fill” station has the capacity to fill more than 30 of their trucks at a time.

“We wanted to make this fueling station accessible to small, medium, and large businesses,” Ozinga said. “The demand for natural gas vehicles will increase with greater availability to potential consumers. With more refueling stations, more businesses, consumers, and car manufacturers will embrace and invest in CNG-powered vehicles.”

With gasoline prices rising and natural gas prices plummeting, CNG-fueled vehicles make more sense for cost-conscious businesses, particularly businesses like Ozinga that rely heavily on their fleets for meeting business objectives. A gallon of CNG is about $2 cheaper than gasoline.

Ozinga has constructed additional CNG fueling stations at their locations in Des Plaines, Mokena, and Gary and they have plans for more in the Chicago area and throughout the Midwest. Ozinga is also considering opening all of its stations to the public for general use, so that motorists can fill up their personal CNG vehicles. The Illinois EPA designated Ozinga as an Illinois Green Fleet in 2012 in recognition of their environmental stewardship and commitment to alternative fueled vehicles.

Motivation for Project

One of the main reasons that the company has made the transition to natural gas is to create a stronger partnership with governing organizations by investing in fuels that are more abundant in the United States. It was also a sound financial decision, because of the availability of government funding–incentives and grants designed to promote clean fuels.

“We’re asking our government agencies to work together with us to reduce our independence on foreign oil and improving air quality and creating more jobs.” Carl Lisek, Coordinator of South Shore Clean Cities, said. “We want fleet partners that share the same vision and we feel this is another way to create a better working environment in northwest Indiana. This is just the beginning.”

“It’s inevitable that it’s coming, because this country–some people say it’s the Saudi Arabia of natural gas,” Ozinga said. “It’s inevitable, it’s going to be here, because it reduces our dependence on foreign oil, and this is an opportunity for this country. It’s a game changer, economically, for everybody in this country.”


Ozinga hadn’t purchased new trucks since 2006, so by 2011, it was time to start replacing them. Now run by the fourth generation of Ozingas, the company began to evaluate CNG. They worked closely with Kenworth, McNeilus, and Cummins-Westport in developing optimal specifications, and bought 14 new trucks in November 2011 powered by 9-liter ISL G engines with 320 hp and 1,000 pound-feet of torque. Fuel capacity, measured in diesel gallon equivalents (DGE), and fuel economy are comparable to the diesel trucks that were replaced.

“Before we could put the trucks into service, we needed to put in a refueling system,” says Tim Ozinga. “Then we had to train our drivers on how to operate them, as well as all the safety procedures.” After contracting with Peoples Gas to supply the fuel, Ozinga purchased the system for fueling the trucks. High-pressure storage tanks were installed, along with a compressor to provide the 3,600 pounds per square inch (psi) of storage pressure needed for CNG. To get the power required to drive the compressor, Ozinga installed a dedicated transformer next to the compressor.

The weight of the CNG trucks is about 1,000 pounds heavier than typical diesel trucks, largely due to the weight of the CNG fuel tanks, however they are able to carry the same payload of 8.5 to 9 yards of concrete. The CNG trucks average five to seven loads per day, or three to five loads in rural locations. “We added time-fill fueling in our Mokena location and we’ve expanded CNG to northwest Indiana,” Tim Ozinga says.

For 40 CNG trucks currently in service at Mokena, the producer has 30 time-fill hoses in operation, along with three fast-fill pumps. Trucks using time-fill refueling are left overnight, while the fast-fill pumps can refuel a truck in as little as 10 minutes. Fast-fill can bring the tanks to between 85 and 90 percent of capacity; while time-fill takes them to 100 percent.

At Ozinga’s Chinatown facility, a driver brought a truck in and connected it to the time-fill connection. It took longer for the driver to don the required safety gear than to actually connect the high-pressure hose. The whole process took about 10 seconds.

If a truck runs out of CNG on the road, it can be refilled from any other CNG truck in the fleet. A hose carried on each truck connects to a refueling fitting. Within a short time, depending on gas pressure in the donor truck, the two trucks will equalize fuel pressure and each will leave with half the range that the donor truck had at the beginning of the process.


Types of Natural Gas Vehicles

The vehicles in the Ozinga fleet are dedicated natural gas vehicles, which means that they run on natural gas and natural gas only–not bi-fuel vehicles, which can run on either gasoline or natural gas or dual-fuel vehicles, which can run on a mixture of diesel and natural gas at the same time. The benefits of dedicated natural gas vehicles include increased fuel cost savings, qualification for larger incentives, lower emission levels, and greater cargo capacity.


The Ozinga cement trucks, which idle constantly, not only reduce emissions, they also are about 90 percent quieter than their diesel counterparts. The trucks offer approximately the same mileage (i.e. fuel economy)and provide typical cost savings of $1.50 per gallon, compared with diesel. Savings reached $2.50 per gallon for CNG when diesel prices spiked during the summer.


This material is based upon work supported by the Department of Energy under Award Number DE-EE0002541.

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

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