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March 12, 2012

Shell's Natural Gas Production Surpasses Oil

This year, Shell will produce more natural gas than oil for the first time in the 50 years it has been involved in natural gas production.

This astonishing fact underscores Shell's involvement in alternative fuels, especially natural gas as compressed (CNG) or as a liquid at -160 degrees C (LNG). To emphasize this commitment, Shell has embarked on an adventurous program that will see a natural gas infrastructure developing over the next five to 10 years, says James Burns, Shell's LNG manager in the United States. Burns was speaking at a Shell press briefing, held February in Park City, Utah, on the company’s involvement in natural gas and other forms of alternative energy around the world.

Natural Gas
Later this year, Shell will open the first LNG corridor in the NAFTA region, with LNG fueling stations in Calgary and Edmonton and a refueling midway point in Red Deer, Alberta. This is not a demonstration program, says Burns, but a fully fledged alternative fuel option for fleets servicing the busiest cities in the western Canadian province.

Shell is looking to LNG as its fuel of the future – at least to 2050 – for the commercial transportation sector in North America because of its greater energy density compared to CNG. That is important, says Burns, to get the range needed for medium and heavy trucks. He sees the truck transportation infrastructure as more easily enabled, as fueling points can be set up at strategic north-south and east-west truck-traffic nodes around the nation.

Shell has opted for LNG and even says it will assist fleets who want to make the switch by putting in suitable fueling points where there is demand. The bet here is that trucks, because of more predictable routes and destinations are a more likely user of natural gas than passenger cars. For a major switch of cars to CNG, a much more robust fueling infrastructure would need to be rolled out. "I don't really see a space for CNG-fueled cars in that timeframe," says Burns.

Comparing the relative fuel merits, Burns cited a hypothetical 100-mile trip in which a diesel truck would get 6.5 mpg, an LNG fueled truck would get 3.8 mpg while using CNG it would do only 1.7 mpg. So the trip using diesel would consume 15 gallons of fuel, the LNG truck would use 28 gallons of gas and the CNG, a whopping 58 gallons. So for a similar range, double the fuel capacity would have to be provided for LNG over diesel and significantly more for CNG even under 3,500 psi pressure. Another plus for LNG is that it can be pumped far faster than CNG – a concern for over-the-road truckers.

LNG, however, has the drawback that it has to be stored on the vehicle in giant vacuum flasks to keep the gas liquid at -160 deg C. Still, these tanks are so well insulated that very little will boil off during operation or while the vehicle is standing. In fact, tank trucks may sit for as long as 90 days, and there are technologies to capture the gas and consume it in the engine.

The tanks are one or the reasons the natural gas fueled trucks are expensive, often twice the cost of a diesel. But with a 30% lower cost for the fuel, fleets that do 100,000 miles a year can see a three-year return on investment. And that could come down as more of the expensive tanks are constructed to satisfy a growing volume of LNG heavy trucks.

So far the engines of choice appear to be the Cummins Westport, which uses pilot ignition by diesel fuel with gas injected into the combustion chamber for the power stroke, or the Cummins ISL G, which is spark ignited. These engines are available in Freightliner, Kenworth and Peterbilt highway trucks and Autocar refuse vehicles. Navistar says it is committed to developing a range of natural-gas MaxxForce engines for medium and heavy duty buses and trucks.

The pressure to use natural gas is driven partly by economics, partly by environmental concerns and partly by energy independence issues. Burns says the Cummins ISL G actually produced 20% less CO2 than diesel using the Canadian GHGenius model. It also has virtually no sulfur and less environmental impact and is virtually free of engine deposits for a longer engine life. As for energy independence, Burns says that natural gas is abundant, acceptable and affordable. Technology changes have meant the recovery of more natural gas from Shale. In the last five years, the United States has gone from an importer of natural gas with 40 terminals around the country to an exporter. U.S. gas reserves increased 22% between 2006 and 2009, he says.

1 comment:

  1. I concur that the pilot ignition in that Cummins engine is one for the books! I use it for my junk boat too that runs on 200hp.