Houston Contemplating Natural Gas-Powered Buses

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(Houston--Wendy Siegle, KUHF News) Over the last 10-15 years or so, transit agencies across the country have been switching to natural gas technology to fuel their bus fleets. Many cite the rising price of oil as an incentive for the shift. In Los Angeles, nearly 100 percent of the bus fleet runs on natural gas-powered vehicles. Transit officials there estimate that ditching diesel-fueled buses has slashed nearly 300,000 pounds of CO2 emissions per day. Other major cities, such as Chicago, are also considering adding CNG buses to their systems. Now, Houston's jumping on the bandwagon. . . well, maybe.

Houston's Metro has just launched a study into the viability of natural gas-fueled buses. Right now, Metro operates around 1250 buses, more than a quarter of  which are diesel-electric hybrids. The question is whether it would make sense to diversify the fleet with other kinds of alternative technologies. “One thing that’s happened is, all these technologies have come closer together in terms of their environmental impact," said Metro president and CEO George Greanias at today's board meeting. "They all work better in terms of keeping the environment as pristine as possible.”

The study will help determine what the overall cost will be for operating and maintaining a bus that runs on compressed natural gas (CNG). Greanias notes that cost factors, such as the price of CNG, are some of the big questions the study will address. "Can we control the cost factor better with a CNG vehicle?" he wonders. "But on the other side of the coin, there’s also significant infrastructure up front that you have to use with CNG technology.”

Metro tested natural gas buses a decade ago, but found it was too costly for the agency. Back then, the fleet had four CNG buses. They were converted into diesel-electric hybrids in 2002. But the technology has advanced a lot since then, which why METRO is taking another look.

Greanias says, in addition to cost, Metro will have to weigh the environmental benefits of CNG against other fuels, such as the hybrid technology that the agency has already adopted. Metro will also have to decide if it would be best to use the same technology across the entire fleet, or if it would work to mix it up a bit. “Right now we've been moving in a single direction," he says, referencing the diesel-electric hybrids. "As we go forward, will we want to expand that and have one or two or three different options?[That raises] operational questions and maintenance questions.”

Metro board member Christof Spieler stresses that it's important the agency not rush into anything. "When we’re buying a new bus it’s not like buying a new car; this is a 12 year commitment. We want to keep these buses on the road. So when we’re making a decision now it’s going to have ramifications for a long time to come.”

METRO expects to have the results of the natural gas study by autumn.