The development of alternative powertrains has been a key megatrend that has encompassed the industry for a number of years. The pursuit of engine efficiency and fuel consumption reduction has seen not only new powertrain technology development, but also the combination of technologies. In the latest Automotive Megatrends webinar, titled ‘Dual fuel for on-highway HD applications’, FEV experts examined the potential for dual fuel combustion engines and how they can help meet future emissions legislation.
Rising fuel prices
According to Erik Koehler, Manager of Commercial Diesel Engines at FEV, the main driver for using natural gas in powertrains is the cost of fuel. Citing recently released data from the US Energy Information Administration (EIA), Koehler suggests that natural gas will continue to be much cheaper than oil. “The oil and natural gas prices were strongly aligned up until 2006. Since then, natural gas prices have fallen as a result of abundant domestic supplies and production, specifically the addition of hydraulic factoring techniques.” On the other hand, oil prices have dramatically increased over the past two decades due to global demand. The US EIA predicts that oil prices will continue to rise, and by 2040 natural gas will remain more than three times cheaper than oil. Consequently, the transportation sector will see natural gas usage increase by a factor of more than 20.
Why use dual fuel technology?
“In addition to the economic drivers, we also have legislation drivers that will be important for the adoption of natural gases” states Koehler. In using a combination of diesel and CNG within the powertrain, notable reductions in emissions are achievable. The burning of natural gas within the engine is approximately half as carbon-intensive as burning oil. Koehler believes that by adopting a dual-fuel approach within engines, vehicles across a variety of segments can meet emissions requirements that are set to become progressively more stringent towards the end of 2020.
Along with the substantial savings in fuel that using natural gas brings, Koehler also points out the fact that the US government hopes to build on and subsidise the natural gas sector. President Obama’s climate action plan programme, he says, will “encourage the development of a global market for gas”. This could see further savings, specifically on the initial investments, for those that adopt the use of dual-fuel vehicles.
What is more, Koehler points out the fact that the infrastructure of natural gas refuelling stations is rapidly developing. Focusing on the US, he states that “significant efforts are currently ongoing to grow the natural gas highway, including the installation of more LNG stations along long haul routes.” However, he is also keen to point out that many of the refuelling stations are open to the public. “As the natural gas infrastructures continue to develop in the US and other countries, dual-fuel diesel CNG engines can provide an effective solution to bridge the gap to a more complex infrastructure,” he added. By using a dual-fuel system in the powertrain, vehicles are not necessarily completely reliant on natural gas fuelling stations, as they are able to run purely on diesel until reaching a station.
LNG or CNG?
Natural gas currently comes in two forms – compressed natural gas (CNG) or liquefied natural gas (LNG). Koehler points out that although production costs of LNG remain far higher than those of oil, the gas itself is still far cheaper. The potential saving is currently US$1.48 per gallon when using LNG over diesel, a gap that is forecasted to increase to US$1.77 by 2040.
“Those transportation sectors with the highest consumption rates are positioned to see the largest growth in adoption of natural gas engines,” said Koehler. “High fuel consumption allows these applications to quickly pay off the significant initial investment for these natural gas systems.” As a result, Koehler believes that long haul trucks will see the biggest adoption of natural gas in their fleets. Statistics supplied by the EIA suggest that medium- and heavy-duty vehicles (over 10,000 lbs) will become the largest consumers of natural gas. The bus segment is also set to drastically increase its usage of natural gas by up to 35%.
There is always a downside
So, with the potential savings apparent with both CNG and LNG, why is more not being done to push the use of natural gas? One reason is the high initial investment. “Tanks are often a significant portion of the total cost of a natural gas conversion,” states Koehler. As a result, “the system costs would include not only the engine, but also the gas storage media, whether it be CNG or LNG tanks.” According to Koehler, however, financial payback is certainly achievable over time – a major incentive for fleets considering adopting natural gas vehicle technology.
Although cost seems to be the primary motivation for the adoption of natural gas vehicles, convenience issues in installing the stations and even fuelling the vehicles remain a significant barrier. Yet, Koehler is confident that natural gas vehicles will see substantial growth from 2014 to 2040.
Michael Nash
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