Diesel engines will be around for a long time to come, and good old fossil-based diesel fuel can and will power most of your trucks for at least a couple of decades. But things really are changing. There's way too much information out there, and more contradiction than you'll find in the average politician's collected campaign speeches. You won't have much choice in the matter of how fuels evolve, but it's good to know what's happening just the same.
"Liquid diesel-like fuels will be the mainstay for the foreseeable future, but how those fuels are produced is already in a period of transition," says Shawn Whitacre, Director of Chemical Technology at Cummins Engine Company. "Diesel fuels are no longer exclusively derived from refined petroleum crude. Non-traditional sources including the oil sands in western Canada already have significant penetration. The recent run-up in crude prices have made the oil shale that is abundant in the western United States more economically viable.
"This expansion of the fuel supply base, if it progresses responsibly, will be critical as our world supply of traditional crude diminishes - regardless of whose estimate of petroleum reserves you believe," Whitacre says.
"There currently are not any legitimate alternatives to liquid-fueled internal combustion engines that offer the efficiency, durability, low cost, and abundant fuel supply that is required for heavy truck transport."
A particularly interesting presentation about oil's future was made at a Daimler Trucks event in Stuttgart, Germany by Dr. Wolfgang Warnecke, global manager of automotive fuels development for Royal Dutch Shell.
"Transportation continues to be the preserve of oil," said Warnecke, adding that oil supply and use will peak by about 2050. Biofuels are the only viable non-fossil-fuel option in the short term, he added, but "not all biofuels are created equal."
First-generation biofuels like ethanol and its variations have limited usefulness, Warnecke said, while second-generation fuels, like biomass-to-liquid (BTL), that use whole plants and such waste as wood chips are more promising. The key, he said, will be having standards that guarantee users fuel of the right quality.
There are arguments about oil reserves, many of them, and the rising price of oil drawn from conventional sources means that exploitation of expensive non-traditional sources is viable, pushing up the reserves number significantly. Still, data is scarce on the subject.
"Some 94 percent of the world's oil reserves are held by governments that don't know or won't reveal the size of their holdings," says Amory B. Lovins, co-founder, CEO, and chief scientist of the Rocky Mountain Institute, writing in The Economist. "But no matter how much oil there is, we should save it whenever doing so is cheaper than buying it, and nowadays that is always."
All of that said, there's broad agreement - though it's a long way from universal - that the diesel fuel we know and smell is bad news in terms of creating carbon dioxide, the main ‘greenhouse' gas said to be the cause of global warming.
For reasons that usually have as much or more to do with national security as with environmental issues or efficient transportation, there has been an enormous amount of effort poured into diesel alternatives since the 1970s. We know about natural gas and propane, and we're moving fast into diesel/electric and diesel/hydraulic hybrids for niche applications, but what else is there? What's going to power your trucks in five or 10 or 20 years' time?
At least two global truck manufacturers have weighed in on the subject thus far.
Volvo's Fuel View
Speaking at the recent 2007 European Transport Forum in Brussels, a two-day conference organized jointly by Volvo and Forum Europe, Volvo Group CEO Leif Johansson's opening remarkes noted that by 2010 diesel engines will emit virtually no particulate matter or nitrous oxides. After that, the target will be CO2. He estimated that cargo transport accounts for about 4-5 percent of total global carbon-dioxide emissions.
Each of the seven Volvo 380 trucks that rolled into view behind the outdoor podium as he spoke had a 9-litre diesel engine, modified in some cases, operating on a renewable fuel or combination of fuels (see sidebar, "Fuels of the Future?").
Volvo's analyses of renewable fuels, and its choice of the seven best suited to carbon-dioxide-free transport, considered several elements - impact on the environment, energy efficiency, the relative efficiency of land used for cultivating crops to produce a given fuel, the amounts of the different fuels that can potentially be produced, the difficulty of vehicle adaptation required in purely technical terms, the cost of the various fuels, and how easy it would be to distribute them.
Johansson also called for much more investment in future fuels, and in second-generation biofuels particularly. He noted that there is more fuel research and development going on in North America than in Europe, adding that he would support a rise in U.S. fuel taxes if the additional revenue were applied to such R&D.
Daimler's View
Meanwhile, over in Stuttgart Germany, Andreas Renschler, head of Daimler Trucks, is predicting the global commercial vehicle market will grow by 50 percent over the next 10 years, making the demand for oil - and alternatives - a crucial issue. As well, increasingly stringent emissions legislation, much of it mandated by cities, demands action.
"Our long-term goal is to make the vision of the zero-emissions commercial vehicle a reality," he said. "We believe that two factors will play key roles in turning that vision into reality. The first is the achievement of clean combustion through the use of alternative fuels, including everything from natural gas to biodiesel and hydrogen. Secondly, such combustion must be made efficient with the help of modern drive system technologies like [selective catalytic reduction] diesel technology, hybrid drives, and fuel cells."
Daimler is also investigating alternative fuels somewhat more exotic than natural gas. The most promising fuels from renewable resources, they say, are vegetable oil-derived hydrated fuels (HVOs). Later, they'll be joined by second-generation biodiesel fuels known as BTL (biomass to liquid). These synthetic fuels made of straw and waste wood are carbon-dioxide neutral, emit 50 percent fewer particulates than diesel, and contain no sulfur. Happily, they can be used in today's diesels with no problem, Renschler said.
Beyond that we'll see a biofuel enriched with hydrogen, called NExBTL. Renschler said it has energy properties much like diesel.
The Longer Term
There seems to be general agreement amongst engine makers, both here and in Europe, that synthetic diesel - from fossil or renewable sources - is the fuel of choice for the future. Maybe 10 or so years out.
"Synthetic diesel fuels produced by the Fischer-Tropsch or similar processes can be produced from natural gas, coal, and from numerous types of biomass," says Shawn Whitacre of Cummins.
"These fuels, sometimes referred to as GTL (gas-to-liquids), CTL (coal-to-liquids), and BTL (biomass-to-liquids) have properties very similar to conventional diesel fuel and may provide additional benefits. They can be used alone or as a blend with conventional diesel fuel and can also be used to produce high-quality engine oils."
They can be mixed freely with ordinary diesel fuel and they're suitable for all diesel engines. And with gradually increasing mixing proportions, synthetic diesel produced from biomass could mean a smooth transition to renewable fuel for the entire diesel-powered
vehicle population.
And what about the fuel cell? Don't give up on it yet, but don't hold your breath either. Fuel cell vehicles have already proved their suitability for day-to-day operations, but Daimler says the fuel cell's service life needs to be substantially lengthened and its cost drastically reduced before the technology can be used in series-produced commercial vehicles.
In the meantime, you really don't have to do a thing except manage costs by getting the most out of your present equipment. Just note that in the U.S., as of mid-October, the average wholesale rack price for a little Yankee gallon of biodiesel was US$3.40, and just US$2.41 for diesel fuel sucked out of crude oil. Long live diesel?
Fuels of the Future? Or Just Hot Air.
Volvo chose these seven fuels from a list of 30 or more but would not say that any one of them was superior in every respect. Daimler Trucks is on more or less the same page. Technology is not the challenge here. The issue is availability of fuels - and the lack of any technical standards for these potential saviors.
"The ideal answer would be one fuel worldwide," Volvo's Johansson said, "but that's not going to happen… We have to accept that there will be different fuels in different parts of the world."
Here's what you may someday be pumping into your very expensive future diesel engine.
Biodiesel - produced in Europe by the esterification of vegetable oils such as rapeseed and sunflower. The European Union, incidentally, has a target of 10 percent biofuel for all road vehicles by 2020, 25 percent by 2030. The present number is 1 percent. It's a non-toxic and biodegradable fuel with a higher flash point than petroleum diesel.
Biogas - a gaseous fuel that's largely comprised of hydrocarboned methane. It can be extracted in sewage treatment works, at garbage dumps, and at other sites where biodegradable materials are found.
Biogas plus Biodiesel - these two fuels are combined in separate tanks and injection systems. A small percentage (10 percent) of biodiesel, or synthetic diesel, is used for achieving compression ignition.
DME (dimethyl ether) - a gas that's handled in liquid form under low pressure, produced through the gasification of biomass.
Ethanol/Methanol - methanol is produced through the gasification of biomass and ethanol through the fermentation of crops rich in sugar and starch.
Synthetic Diesel - a mixture of synthetically manufactured hydrocarbon produced through the gasification of biomass. Synthetic diesel can be mixed with conventional diesel fuel without a problem, says Volvo.
Hydrogen Gas plus Biogas - in this combination, hydrogen gas is mixed in small volumes with compressed biogas (8 percent volume). Higher mixture levels are also possible. The hydrogen gas can be produced through the gasification of biomass or electrolysis of water with renewable electricity.
Is Biodiesel the Great Green Hope?
Biodiesel is available now, of course, though it's not easy to find in Canada. Here it's more likely to come from canola or corn if the source is a vegetable oil, or from animal tallow and recycled restaurant grease.
It has a higher cetane number than conventional diesel and it's said to produce fewer life-cycle greenhouse gas emissions, even though its energy content is inherently lower by as much as 25 percent. It takes more fuel to manufacture it than is needed to make diesel - a unit of fuel makes 2.5 units of biodiesel, but 4.0 units of ordinary diesel. Also, its cold-weather performance seems to be a little suspect. Additives can help in this regard, by all accounts.
Major engine manufacturers have approved a B20 blend - 20 percent biodiesel/80 percent diesel - but will it prove to be a real alternative?
"No, not for widespread use," says Cummins chemist Shawn Whitacre. "Even with the most diverse base of feedstocks, there is not enough farmland available for purpose-grown crops to displace such a large fraction of our diesel fuel use.
"The U.S. alone uses more than 72 billion gallons of diesel fuel a year. The most optimistic projections for biodiesel production capacity and feedstock availability are inconsistent with widespread blending of biodiesel above a B20 mix. If higher blends are used, it can only be practical in niche applications because there just won't ever be enough of it to go around."
