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Focus On: CNG Presented by:

Table of Contents


About Atlas Copco


Why CNG?


Fuel savings


Environmental benefits of CNG


CNG requires a little TLC


What’s next for CNG fueling systems?



We are a world-leading provider of sustainable productivity solutions. Customers benefit from our innovative compressors, vacuum solutions and air treatment systems, construction and mining equipment, power tools and assembly systems. Our products and services focus on productivity, energy efficiency, safety and ergonomics. We add value wherever we do business. Our products and professional services increase customers’ productivity and competitiveness while benefiting society and minimizing the environmental impact. We call it sustainable productivity. •F  ounded in 1873, Atlas Copco has more than 140 years of experience of innovating for sustainable productivity. •O  ur products and services include compressors, vacuum solutions and air treatment systems, construction and mining equipment, power tools and assembly systems. •O  ur customers are located all over the world. To them, we are a local company; at the same time, the Atlas Copco Group is a global enterprise with worldwide resources. •A  tlas Copco’s global reach spans more than 180 countries, including own operations in more than 90 countries. •W  e innovate and produce in more than 20 countries. Manufacturing is mainly concentrated in Belgium, Sweden, Germany, the United States, India and China.

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BUSRide met with George Kalet, CNG applications and key account manager for Atlas Copco Gas and Process Division to discuss compressed natural gas (CNG) for transit buses. We compare CNG to diesel fuel and discuss the environmental benefits of natural gas. Furthermore, Kalet provides methods for overcoming the barriers to CNG conversion. Why is CNG a better alternative to diesel fuel? George Kalet: The overriding factor right now is still the cost of CNG compared to diesel fuel. I would characterize that as price stability when compared to the roller coaster ride that we’ve been on with diesel fuel prices. Over the next two decades, all estimates and forecasts indicate that the price for natural gas is going to be very stable and, if anything, decrease – simply because of the new supplies that have been discovered in North America. Horizontal drilling allows us to recover natural gas from shale fields and other locations that were previously inaccessible. It has essentially turned the U.S. into the Saudi Arabia of natural gas. What are the environmental benefits of CNG? Kalet: The biggest advantage is that natural gas is a pure gas and does not leave any carbon particulate matter behind when it is burned. The other big thing about CNG is the NOx . Natural gas is a lower NOx fuel so it reduces NOx emissions quite a bit. What are some of the barriers to converting to CNG? How can agencies and operators overcome those barriers? Kalet: The barriers are, of course, the additional costs of the fuel storage system onboard the vehicle. There are additional costs for both the natural gas engine and the fuel storage containers. Historically, 4


CNG presents cost, fuel and operational savings for transit switching from Photo: Atlas Copco. there has always been a agencies fairly significant premium the neighborhood

of $20,000 to $25,000 for a heavy-duty vehicle. Two things have happened to change that. First, the Environmental Protection Agency (EPA) has continually lowered the emissions standards for diesel engines. That’s resulted in the engine manufacturers having to add components like after treatment and catalytic converters onto their engines, thus increasing the costs. CNG engines did not require these additional systems in order to comply. The cost for diesel engines is going up while the cost for natural gas engines is going down. Secondly, significant developments were made on the fuel storage side when manufacturers released heavy-duty, lightweight CNG storage cylinders that are much more competitive. They’re still significantly more expensive than the standard space-conforming steel diesel tank, but the overall weight of the fuel system has decreased dramatically in the last five years. The range of CNG vehicles 10 years ago was approximately 50 percent of the range of similar diesel vehicles. That turned out to be a huge barrier to entry that has been overcome by technology developments in the fuel storage systems. So much of the initial capital expenditure for transit fleets and infrastructure is funded by the Federal Transit Administration (FTA), and that funding is enhanced if it’s for an alternative fuel vehicle. That helps agencies recover their costs and provide a better service to the community. Because gasoline and diesel prices are being artificially held down this year, CNG is currently cost neutral. However, CNG is a very clean burning fuel that doesn’t leave any particulate deposits in the engine. Operators get much longer life out of the engine oil. Agencies can extend engine oil change intervals for longer periods of time and that can be a very significant cost saving. Visit for more information.

FUEL SAVINGS BUSRide spoke with George Kalet, CNG applications and key account manager for Atlas Copco Gas and Process Division this month to discuss compressed natural gas (CNG) for transit buses. In this issue, we discuss the fuel savings benefits of CNG, as well as the current price of diesel and sustainability considerations associated with natural gas. In general, how do natural gas prices compare to diesel prices? The price of CNG is usually much lower and more stable than the “roller coaster ride” of diesel fuel prices. When we take each factor into account, be it vehicle cost or maintenance facility modification, we find that CNG presents a significant cost benefit along with a quality of life benefit from environmental impacts and noise pollution. Initial costs are higher, but those costs are repaid in fuel savings. Now, in many markets, gasoline and diesel comes at a lower price than natural gas. This, however, is both temporary and “artificial.” The worldwide market is flooded with oil, as production is up, but prices are down as European states’ demand for oil is low because of floundering economies and increased production of more energyefficient vehicles. Furthermore, the U.S. “shale boom,” which we’ll explain later, is also driving down prices. Overall, it’s a very temporary situation. Are natural gas prices volatile? Natural gas prices are very stable, though they used to be very volatile like the price of oil. When the price of oil went up, the price of natural gas went up with it because they were essentially coming from the same place – natural gas had been a byproduct of petroleum processing. However, the prices have been decoupled from petroleum totally because of shale discoveries in the U.S. Producers have developed a cost-effective way to recover that gas, which has held prices very stable. That’s in spite of the fact that consumption is going up, as power plants and large utility users come online with natural gas – the price still isn’t rising. It’s forecasted to hold stable for the next 15 years.

Prices have been decoupled from petroleum. Aside from fuel savings, what other savings can be gleaned from adopting CNG? Cleaner-burning fuel means less frequent oil changes, which saves money. It affects the overall operating costs of the fleet, because it’s a gaseous fuel and there are no carbon deposits left in the engine to be picked up by the lube oil system. With the number of heavy-duty trucks and tour buses coming onboard with CNG, we’re seeing a big increase in the amount of fueling stations around the country. Around 907 fueling stations are operating in the United States, with more coming into service each day. What quality-of-life benefits does CNG present? This should play into cost savings but it is almost an intangible benefit: CNG lessens the health risks of people around it. That’s a big incentive for bus fleets to go with natural gas, because of diesel exhaust pollutants and vapor fumes coming from the fuel system. It’s and much healthier experience for drivers, passengers and mechanics to not have to deal with the dirt and grime and everything else associated with liquid petroleum fuels. Visit for more information. | BUSRIDE


Environmental benefits of CNG By George Kalet

Compressed natural gas (CNG) is often called the cleanest burning natural source of fossil fuel propulsion; much more environmentally friendly than conventional gasoline and diesel fuels. The combustion of natural gas produces negligible amounts of sulfur, mercury and particulates. This mostly has to do with its chemical composition. The process of cleaner burning fuels involves the elimination of carbon molecules that are the root cause of contamination to the environment. The evolution of combustible fuels has moved from coal, which is essentially 100-percent carbon, to liquid petroleum that combines carbon and hydrogen, and then methane, which is comprised of one carbon molecule and four hydrogen molecules, and considered a greenhouse because of its lone carbon molecule. Burning natural gas does produce nitrogen oxides (NOx), which are precursors to smog, but at lower levels than gasoline and diesel used for motor vehicles. The one downside: methane burns at approximately twice the combustion temperatures of liquid petroleum fuels; close to 1,100 F 6


compared to 500-600 F. In terms of efficiency, the degree of power generated from the same amount of fuel is an energy to power ratio. Look at the two side by side, for the same amount of energy produced, and you’ll find that methane burns off more oxides of nitrogen at these temperatures, but not for as long a time. Natural gas has often, and perhaps unjustly, received a bad reputation, but only because of its being burned in an engine designed for gasoline or diesel combustion. CNG burns at a lower compression ratio, and responds much more efficiently in engines engineered specifically to burn CNG. Compared with conventional diesel and gasoline powered vehicles, natural gas produces lower emission levels; and because CNG fuel systems are completely sealed, they do not produce any evaporative emissions. Only about one-tenth of 1 percent of processed and used CNG goes toward automotive transportation fuel. In the event of a leak or emergency venting, because it is lighter than air, CNG dissipates much more rapidly into the atmosphere. Methane burns within a very narrow fuel-to-air ratio, between 5 and 15 percent in air, meaning it takes in less air to realize the same degree of combustion. Released and mixed into the air, CNG becomes flammable only when the mixture is within 5 to 15 percent natural gas. At less than 5 percent natural gas, the mixture doesn’t burn; and at more than 15 percent natural gas, there is not enough oxygen to allow the mixture to burn. Methane is a cleaner, environmentally friendlier fuel than propane, which is a heavier-than-air gas that runs to the lowest point and typically pools on the ground. In terms of efforts to meet U.S. Environmental Protection Agency (EPA) emissions standards, environmental protective appliances fitted on CNG-powered vehicles are less expensive than the emission systems and filters on fossil fuel engines. As the EPA continues to drill down on the emissions performances of various fuels, the requirements for efficient emissions control on gasoline and diesel engines have driven up the costs — but are not required for today’s natural gas engines, which already surpass the 2020 EPA emissions standards. See the August /September issue of BUSRide for the next chapter in this series, detailing CNG conversions – installation, maintenance and training best practices! George Kalet is CNG applications and key account manager for Atlas Copco Gas and Process Division. Atlas Copco develops innovative sustainable solutions that create value for its customers in more than 180 countries. The company’s expertise is in compressors, vacuum solutions and air treatment systems, construction and mining equipment, power tools and assembly systems. Visit for more information.

CNG requires a little TLC By George Kalet Among the many considerations when converting your bus fleet to compressed natural gas (CNG), the service and maintenance practices are paramount, and demand a special set of requirements and practices for safety and compliance. The fact is, in its natural state as a gas and not a liquid, CNG behaves entirely different than gasoline and diesel. As simple as that may sound, everyone working on or around CNG-powered vehicles and related equipment must be aware and continually reminded of the technical and safety guidelines. Training is key in gaining the familiarity to work safely within a CNG environment. Assuming the conversion to the maintenance facility and fueling station is complete and up to code, here are some basic safety practices. Because CNG is a flammable gas – the less of it, the better. Meaning, the first rule is to always defuel the vehicle before doing any kind of maintenance. Any CNG remaining in the tank and lines must be removed and stored. This step sounds easy enough, but is often sidestepped or overlooked. Technicians working on CNG vehicles are dealing with the elevated fuel pressure and need to understand the added dangers of highpressure fuel lines, sources of fire and explosions, as well as exposure that can cause asphyxiation. They should always wear standard of safety gear that includes face shields and work gloves. Ideally, among the specific modifications to the shop and service area would be a dedicated area or bay for only the CNG vehicles, equipped for proper ventilation, and certainly containing no electric equipment that could cause a spark. Techs also need to be cognizant of the danger of static electricity, both in the shop and at the fueling station. A CNG bay must employ a monitor and warning device to sound the alert when flammable limits reach 20 percent and another once they reach 60 percent. At that point, it initiates action to ventilate the space, such as opening the bay door or activating exhaust fans to avoid the CNG from accumulating in any area of the shop. The fuel dispenser and hose assembly need to be equipped and installed in accordance with codes to prevent any static electric charges. The same precautions apply in defueling the system. In fact, special defueling panels are available for this function. Technicians have a few options for taking CNG off the vehicle. Some fleets return it to the pipeline, which is typically the most difficult

When emptying a bus of CNG, it’s often best to return gas through the compressor suction and put it back into

method. Unless the gas utility is heavily involved on the front end of the program, it has no way of controlling the defueled gas coming back to them. Another method is to return CNG through the compressor suction and put it back into storage. Atlas Copco advises fleets to consider the CNG fuel levels before conducting any sort of scheduled maintenance. Avoid any routine refueling regimen prior to bringing the vehicle into the shop for maintenance or repair. The less fuel on board, the better – as the pressure is lower. From a safety standpoint, it’s also important to know that federal motor vehicle standards require the fuel storage system onboard the vehicles to be officially inspected every three years or 36,000 miles. A vehicle involved in any kind of accident, not just accidents involving other vehicles, requires an internal inspection of the control systems, in terms of the piping and connection and particularly the storage tank. Always be sure the integrity of the pressure vessel has not been compromised. A number of CNG training programs are commercially available throughout North America. One in particular is through the Natural Gas Vehicle Institute. Many local community colleges in states where natural gas is a popular vehicle fuel, like California, Louisiana and Oklahoma, offer basic CNG safety and maintenance training. George Kalet serves as CNG applications and key account manager for Atlas Copco Gas and Process Division. Visit for more information. | BUSRIDE


WHAT’S NEXT for CNG fueling systems?

BUSRide spoke with George Kalet, CNG applications and key account manager for Atlas Copco, Gas and Process Group, to discuss the future of compressed natural gas (CNG) systems for buses and coaches. In this informative Q&A, Kalet assesses the current state of CNG fueling systems, as well as the perceptions, prices, trends and politics surrounding the market. Furthermore, he previews the technological advances expected to benefit operators in the near future.

What is your assessment of the state of CNG fuel and propulsion currently? The markets have been down a bit for obvious reasons, particularly because of the low petroleum prices. Now that the elections are over and the country begins to settle in, we’ll give the new president-elect some time to unveil his policies. I think ultimately this will be good for the natural gas businesses, though we are certainly facing some challenges with a Republican majority in both houses of government. By the same token, CNG fuel is definitely good for the country in terms of the environment, energy security and jobs. What advances and developments in CNG propulsion can operators in the bus and coach markets expect? We have seen a lot of new development, especially with heavyduty buses and trucks, where the cost of the onboard fuel storage has gotten more competitive and the capacity of the fuel storage systems has increased dramatically. This alone helps move CNG-powered vehicles toward more transparency with the competing diesel powered vehicles. Do you find it frustrating, given the benefits and the advantages of CNG, to run up against hurdles that seemingly have to do with perceptions, prices, market trends and politics? It’s very frustrating. Especially at this time because, as an industry, we felt we had really turned a corner as oil prices stabilized; not necessarily at 5 dollars per gallon, but trending up, and the cost of natural gas was 40 to 50 percent less in many cases. It was great for getting operators to jump on board. Our industry as a whole felt like it was gaining some momentum and staying power, with economics working in our favor. So the artificially low pricing for gasoline and diesel has presented a frustrating turn of events. I don’t think anyone every predicted or expected oil prices would be this low for this long. What steps are you taking amidst the challenges to build your case for natural gas? We are addressing them from the top down. We still face challenges with the infrastructure, which will drive a greater blanket adoption of natural gas vehicles. This will come from commercial vehicles and fleet customers. Private consumers will most likely be the last to jump on board. 8


Many transit and city utility fleets are moving toward CNG.

It’s a fact of economic life: the adoption of something as large-scale as this depends on high volume users to facilitate the development of infrastructure. I believe this is going to continue. Over-the-road vehicles, both buses and trucks, are starting to see real infrastructure development. For example, San Antonio’s VIA Metropolitan Transit just placed an order with Volvo’s Nova Bus for 425 new CNG buses. Atlas Copco is providing the fuel station infrastructure at the manufacturing facility for fueling the new buses for the drive from upstate New York to Texas. In the past, they would tow any CNG to the client, due to the lack of enough fueling infrastructure to drive across country. These trips from Plattsburgh to San Antonio will be a strong testimony for the cause of natural gas. Can you speak a little further to public transit? We see a lot of activity with municipalities for both transit and city utility fleets moving toward natural gas, simply because of the inherent environmental benefits. At this time, it’s probably close to being a cost “wash” in terms of any fuel savings, but two years ago it was just the opposite. It was a very short payback of less than three years. That’s a kind of benchmark for making those kinds of capital investment decisions. It is also very encouraging to see who have already made the commitment to natural gas continuing to expand their CNG fleets and installing new fuel station infrastructure to fuel those vehicles. Is it safe to say, with the cost being a wash against fossil fuels this time, you’ll be able to turn the focus to the benefits of CNG? Absolutely. We definitely need to drive those points home a lot harder than if it were solely a financial no-brainer, which it has been in the past. George Kalet serves as CNG applications and key account manager for Atlas Copco Gas and Process Division. Visit for more information | BUSRIDE


Focus On: CNG  

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