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Natural gas is coming to roads near you


SMART aims to save money using compressed natural gas-powered buses

by: SPOKESMAN PHOTO: JOSH KULLA - Part of SMART's fueling facilities at its new Boberg Road headquarters in Wilsonville. A significant change is coming to the South Metro Area Transit Agency’s fleet of buses. They only thing that remains up in the air is the timing.

Already, SMART operates a pair of small Ford cutaway buses powered by compressed natural gas, an increasingly popular fuel that boasts lower costs than traditional fossil fuels, fewer carbon emissions and less engine maintenance.

And in the future, the agency hopes to acquire a lot more vehicles utilizing this or other alternative fuels.

“When I started at SMART a year-and-a-half ago one of the things I heard a lot about was the need for new buses,” said SMART Director Stephan Lashbrook. “They were keeping them roadworthy with a lot of great effort by (Fleet Services Manager) Scott (Simonton)’s crew.”

Since then, SMART has a new $6.5 million headquarters on Boberg Road that includes a CNG fueling station that can accommodate up to seven vehicles at a time. It’s part of an ongoing modernization effort that aims to upgrade a fleet featuring buses with as many as a million miles on their respective odometers.

“Two of them,” said Lashbrook, singling out a pair of 35-foot, diesel-powered Gillig buses built in 1990, “are dead to the point where no one should be allowed to drive them. Others have paid their dues and it’s time to replace them.”

Designed in-house by Simonton, SMART’s CNG fueling station is one of the few such facilities in the area. But SMART has big plans in store, primarily because the agency envisions an ongoing conversion to CNG, electric and other alternative fuel sources in coming years.

The agency’s first two CNG buses were purchased in 2011, Simonton said, and are a sort of experiment for the agency.

“We wanted to see what the return on investment was,” he said. “They are fairly expensive, and we wanted to see what kind of operational difficulties we might have.”

Upfront costs higher

The upfront cost of a CNG-powered bus is roughly $30,000 more than an equivalent gasoline-powered bus, which remains the cheapest type of vehicle to purchase. By comparison, a similar bus with a diesel engine costs roughly $10,000 more than the gasoline version.

SMART now has buses using all three of those fuel types, allowing the agency to finally make accurate comparisons between them.

“Basically we came up with a set of priorities, as best as we could, to standardize the vehicles,” Lashbrook said. “Our goals there were to increase efficiency and match bus size to the intended purpose, move to less expensive and less polluting fuels and use grant funds where they are available.” by: JOSH KULLA - One of SMARTs compressed natural gas-powered cutaway buses fuels up at the agencys CNG fueling station.

One area where CNG is fast making a difference is in the per-gallon cost of fuel. Domestic natural gas production has skyrocketed in Canada, North Dakota and other locales in recent years. Accordingly, the cost of compressed and liquefied natural gas, both of which are more widely used than ever before, has remained well below that of gasoline and diesel. Prices are expected to remain stable in coming years, which counts for a lot in today’s market.

A report prepared by SMART states that over the past year gasoline costs have averaged $3.79 a gallon, while diesel has averaged $3.36 per gallon. CNG costs, on the other hand, have hovered around $1.54 a gallon during that same period.

When fuel efficiency is taken into account the picture is slightly more murky — diesel buses get an average of 6.8 miles per gallon, gasoline buses 9.1 miles per gallon and CNG buses just 4.8 miles per gallon.

But when you take the vehicles in for service there are wider differences in cost.

“The other side of the equation are maintenance costs,” Simonton said. “Diesel has the highest costs, while CNG are basically converted gasoline so the maintenance is similar. Diesel’s climb in maintenance costs is also due to the emissions equipment we’ve added in the past two years.”

In the end, research shows that the cost of gasoline-driven vehicles is slightly lower than CNG and substantially lower than diesel-powered buses. The biggest differences are the additional emissions equipment required by diesel engines, their larger oil capacity, shorter drain intervals and higher fuel filter costs.

“Basically, what we learned is there is nothing unusual about maintaining them,” Simonton said, noting that CNG and gasoline-powered engines are quite similar in design.

Upgrading from gasoline to CNG-powered buses, by comparison, cost SMART an extra $6,000 per grant-funded bus when compared to the gasoline version. But when road performance is singled out, CNG buses will save the city almost .23 cents per gallon when compared with other fuel types. The savings means the extra $6,000 in purchase cost is recouped after around 26,000 miles are driven — roughly one year of service for a SMART bus.

Because it is purchased though Northwest Natural Gas, CNG fuel is sold at the same rate as the household fuel, something that makes annual budgeting much easier than coping with volatile gasoline and diesel prices.

A mix of fuel types

Simonton said SMART is likely to stick with a mixture of fuel types for the foreseeable future, even as it moves more and more into CNG and even electric vehicles.

“If you choose certain applications to use CNG and certain applications to use diesel you can take advantage of the high points of both,” he said.

Wilsonville Mayor Tim Knapp agreed.

“I think there’s lots of indication that natural gas is going to be less volatile in the next decade compared to the last decade,” he said. “I think it’s a prudent approach to take advantage of that. I agree we should not have all our vehicles on one fuel, especially CNG, which is challenging at this point.”

Lashbrook noted that electric vehicles are another option the agency likely will examine further down the road. He noted that the gigantic Los Angeles Metropolitan Transportation Authority announced this summer it will purchase 25 electric buses from Chinese company BYD at a total cost of around $30 million. With electricity costs roughly the same as current CNG rates, the cost savings are likely to be substantial over the long haul, Lashbrook said, even if the upfront cost is much higher.

“That’s going to bring some competition into the marketplace that wasn’t there before,” he said.