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Long Live Diesel?

Posted: August 1, 2014 by Rolf Lockwood

Understanding even the near-term future of transport fuel is tough for the ordinary mortal. There’s way too much information out there, and more contradiction than you’ll find in the average politician’s collected campaign speeches. Making the right strategic decisions, always difficult, is in this case enough to render even the hardiest fleet owner or manager nearly catatonic.

There isn’t enough room here to pin it all down, but let’s start with what we know.

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.

“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. We are seeing biodiesel and other renewable fuels being embraced on a much larger scale.

“This expansion of the fuel-supply base, if it progresses responsibly, will be critical as our world supply of traditional crude diminishes — 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.”

Volvo’s position on the subject is more or less the same:

“In spite of carbon dioxide emissions, increasing costs and declining reserves, conventional diesel fuel — gradually improved, including possibly synthetic fuel components — will probably remain the dominant fuel for commercial vehicles for at least two decades,” says Volvo Group CEO Leif Johansson.

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 (RMI), 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.”

RMI, incidentally, is the Colorado not-for-profit consultancy that produced the “Truck Efficiency and GHG Reduction Opportunities” report just published by the Canadian Trucking Alliance (CTA). And Lovins will soon be presented with the prestigious Volvo Environment Prize, one of the world’s top environmental awards for contributions to sustainability. It’s the second major award he’s won this year.

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. That’s a different subject altogether, so we won’t get into that here.

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?

Volvo’s Fuel View:

Volvo says it’s ready to build and sell, at just 24 months’ notice, diesel-engined trucks that run on any of seven different renewable liquid and gaseous fuels that won’t produce a net gain of carbon dioxide in the atmosphere after being manufactured, distributed, and burned.

“We are ready,” says Leif Johansson with some passion. “Let’s get going.”

Higher blends of biodiesel are only practical in niche
applications because there’s not enough to go around.

He was speaking at the recent 2007 European Transport Forum in Brussels, a two-day conference organized jointly by Volvo and Forum Europe. In his opening remarks, Johansson noted that by 2010 diesel engines will emit virtually no particulate matter or nitrous oxides. After that, the target will be CO2, and he estimated that cargo transport accounts for about four-to-five 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.

All of them produced from renewable raw materials, all of them providing no net carbon-dioxide contributions to the ecosystem. The fuels, some of them still pretty exotic and not yet readily available, are:

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 one percent. It’s a non-toxic and biodegradable fuel with a higher flash point than petroleum diesel.

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 as in a Montreal plant operated by a Maple Leaf Foods subsidiary, Rothsay Biodiesel.

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 and it takes more fuel to manufacture it than is needed to make diesel — a unit of fuel makes 2.5 units of biodiesel, but four 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.”

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. The biogas in this alternative is in a cooled and liquid form that increases its range.

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.

Volvo chief Johansson said 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.

“It depends on local conditions,” he said, “though second-generation biofuels are very promising.” Those include synthetic diesel and methanol.

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 use 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.

Volvo CEO Johansson is keen on biofuel sin the
short term, synthetic diesel in the longer term.

“The ideal answer would be one fuel worldwide,” 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.”

Technology is not the challenge here, he said. The issue is availability of fuels, and he expressed some frustration that there are not yet any technical standards for his seven favorite fuels to meet.

Future emissions standards will be tough to reach if those standards aren’t created soon, he said, and they must be international.
“What we are trying to say is, take away the uncertainty.”

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.

Just days after the Volvo event, Scania, its arch Swedish rival, issued an interesting statement that went down a similar path, urging biofuel standards.

“In view of conflicting messages and opinions, vehicle operators must be able to feel confident about the renewable fuels they choose to use. Scania therefore proposes that a uniform system for certification and marking of biofuels is developed,” an official company statement said.

“To be viable, biofuels must give substantial net reductions in CO2 emissions compared with fossil fuels without competing directly with food production or threatening biodiversity.

“Scania is convinced that biofuels can fulfill these criteria and that they can contribute to economic growth and welfare in developing countries.”

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 types of fuels have been made for close to 80 years but are now seeing more large-scale commercial production.

“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. We have some limited experience with them and plan to do continued research.”

Their emissions performance compared to conventional diesel is good, with nitrous oxides down by about 18 percent, particulates down by something like 28 percent, and in the case of BTL fuel, CO2 reductions up to 80 percent.

There doesn’t seem to be a downside in performance or emissions terms, given that it can be mixed freely with ordinary diesel fuel and is 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.

Production is being expanded both for GTL (primarily in oil-producing regions) and BTL fuels (local production possible in any country), but there’s a very long way to go to replace all fossil diesel fuel.

In the meantime, you really don’t have to do a thing except manage costs by getting the most out of your present equipment. Hybrids will make a difference in some operations, and if you have an environmental conscience, you can hope for a Canadian source of biodiesel. Just note that in the U.S., as of October 8, 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?


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