It is well-known that the developed world wants future transport fuels and technologies that deliver lower toxic emissions, lower greenhouse emissions, greater efficiency of energy use, less dependence on foreign oil imports and affordable transport.
 
For many people, this kind of future invokes the idea of a 'hydrogen economy'. However, there are commercial and environmental uncertainties associated with the hydrogen-powered world and the only certainty is that it is still a long way in the future. The extent of investment in research and development highlights how little is known and how much effort is still required to develop hydrogen technology and new energy innovation. Can the world wait to 'see what happens with hydrogen'? The answer is 'no'.
 
Ultra-clean diesel fuel with advanced diesel and diesel-electric hybrid technology offers the most cost-effective near- to mid-term transport solution for the developed world to achieve these objectives for transport fuels and technologies.
 
GLOBAL DIESEL MARKET
Diesel and jet fuel are the fastest growing segments of the refined products market. According to Petroleum Economist, global diesel demand is likely to continue to grow at around 3% per year while demand for certain other refined products is likely to flatten and even decline.
 
Refiners face significant challenges both to meet future diesel demand and to produce cleaner diesel. Concerns over air pollution in many jurisdictions have led to a continuing tightening of diesel vehicle emission specifications. Vehicle manufacturers have improved exhaust treatment technology and enhanced engines significantly, but these technology advances have required the introduction of clean diesel fuels. Even in developed economies there is still some way to go to achieve the 'sulphur-free' diesel (10 ppm sulphur or less) that is required by vehicle manufacturers for further advancement of emission control systems.
 
Significant refinery investment will be required to meet the sulphur-free specifications. In Europe, tight specifications for other parameters such as cetane (min 51) and polyaromatic hydrocarbons (max 11%wt) pose additional challenges.
 
ROLE OF GTL DIESEL
GTL diesel could play a significant role in assisting refiners with both quantity and quality. Typically, the diesel yield of GTL plants, at 70%, is higher than refineries, at 40%. With virtually no sulphur or aromatics and a very high cetane of over 70, GTL diesel today meets the clean fuel specifications of tomorrow. GTL diesel can be used as a neat fuel or as a fuel blend in existing diesel engines and future advanced diesel, diesel-electric hybrid and some fuel cell technologies. It can also utilise existing fuel distribution infrastructure, which provides significant market penetration and economic efficiency advantages compared to many other clean fuels.
 
One of the concerns raised about the GTL process is that it produces more CO2 than the refinery process although the end-use of GTL fuels is more efficient. In 2002, PricewaterhouseCoopers was commissioned by Sasol Chevron to conduct a lifecycle assessment of transportation fuel processes including a modern complex refinery and a GTL production facility, using the ISO 14040 standard for such assessments. The finding was that GTL offers substantial air quality benefits compared to a refinery as a result of its lower sulphur oxide, nitrogen oxide and hydrocarbon emissions. These benefits are achieved without incurring a greenhouse gas penalty compared to crude oil refining. The benefit of GTL technology lies in the fact that it can produce ultra-clean diesel without producing the heavy residual fuel (with high associated environmental burden) that a refinery produces.
 
Unlike other fuel lifecycles where greenhouse gas emissions are predominantly generated through distributed exhaust emission, one of the advantages of the GTL process is that the waste is a pure CO2 stream that can be sequestered.
 
ADVANCED DIESEL TECHNOLOGY
While diesels naturally perform better than petrol engines in terms of hydrocarbon, CO and CO2 emissions, they tend to produce more particulate matter and NOx than petrol engines. Historically, the sulphur in diesel fuel has prevented use of effective exhaust treatment technologies such as catalysts and particulate filters in diesel vehicles, although catalysts are widely used in petrol cars. With the advent of ultra-low sulphur diesel fuels, however, both of these technologies can now be used effectively in diesel cars.
 
There are two key areas of technological advancement. These are advanced direct injection lean-burn combustion technology and advanced light-duty diesel emissions control technology (combined with a shift to ultra-low sulphur diesel fuel). Advanced lean-burn operation provides a 20% to 40% improvement in fuel efficiency over conventional diesel technology and 40% to 60% compared to conventional petrol engines. The technology also delivers better efficiency than petrol-electric hybrid cars. Lower toxic emissions are also achieved.
 
Peugeot provides a good example of the significant advances in emissions control technology. The latest Peugeot particulate filter is regenerative and has achieved particulate emissions reduction of more than 95%. The system uses common rail fuel injection to increase the temperature of exhaust when necessary to oxidise or burn excess soot from the filter. This occurs every 400 to 450 km, takes only two to three minutes and has no effect on driving.
 
In summary, advanced diesel passenger cars deliver all the key sustainable transport objectives desired in the developed world in high-performance vehicles with broad-based consumer appeal.
 
THE EUROPEAN EXPERIENCE
European consumers are taking up advanced diesel technology to get better fuel efficiency, more power and more durability, as well as quiet, clean, premium vehicles that were previously the domain of petrol cars. Over 40% of new passenger cars in Europe now have diesel engines compared to less than 20% a decade ago. Initially, fuel tax and vehicle sales tax policies drove diesel uptake in Europe, although it is likely that consumer preference for power and comfort is now a significant factor. In France, Austria and Belgium, well over 60% of new passenger cars, and over 80% of luxury cars, are diesels.
 
THE AMERICAN EXPERIENCE
In the United States, consumer uptake and automotive technology development of diesel cars is negligible. There are a number of reasons for this.
 
1. Diesel fuel quality requirements lag behind the European Union.
2. Therefore, the advanced diesel technology is not available.
3. Americans associate diesel with lower performance standards than petrol.
4. Lower fuel prices and taxation structures do not encourage diesel fuel and technology.
5. Emission standards create barriers to light duty diesel vehicles because of their focus on particulates and NOx.
 
There are signs that this is changing. The introduction of a broader range of emission-compliant diesel cars to the US market will allow consumers to make their own choices about diesel technology. In addition to market-based factors, there is emerging evidence that US regulators may also encourage a shift to diesel. The US Department of Energy has estimated that increasing the market share of light-duty diesel technology to 30% would reduce net crude oil imports by 700 000 barrels per day by 2020 - an amount equivalent to halving California's total daily energy consumption. A recent study by the California Energy Commission and the California Air Resource Board that compared a number of fuel substitution options found that the GTL diesel blend was the only fuel substitution option modelled that resulted in a positive direct net benefit at today's fuel prices.
 
POSSIBILITIES FOR AUSTRALIA
In Australia, transport demand growth over the next two decades is forecast to be highest in road freight and air and sea transport. These sectors predominantly use diesel and other middle distillate fuels. Combined with the potential for broader migration to diesel in the passenger car market in line with global trends to achieve greater energy and greenhouse efficiency, diesel demand growth in Australia could rise significantly, while petrol demand growth could remain flat or decline over the next two decades.
 
By 2010, Australia will need to import 50% to 60% of its crude oil requirements and an increasing proportion of its refined products. Conversely, Australia has abundant natural gas reserves and over the past 20 years new natural gas discoveries have exceeded gas production. Reserves represent 105 years of supply at 2002 production levels. These gas discoveries tend to be in the north-west, distant from the eastern states gas markets. GTL technology could open up diesel fuel markets in Asia and Australia.
 
Only 8% of Australia's vehicle fleet runs on diesel today, and most of that is in the heavy-duty vehicle sector. A GTL industry could reduce Australia's dependence on imported crude oil and refined products. The availability of GTL diesel and refined ultra-low sulphur diesel later this decade would allow the introduction of advanced diesel technology. Australia could achieve significant reductions in greenhouse gas emissions.
 
In addition to the transport benefits, a GTL industry would offer Australia the tangible economic benefits that come with multi-billion dollar investments. Developing remote gas fields for this market could also underpin the infrastructure necessary to bring more natural gas to markets where CNG can be used in niche urban transport applications.
 
Sasol Chevron is committed to supporting the development of the GTL industry globally and remains confident that Australia will become a major player in the industry, building on its already successful remote north-west gas developments and its success in marketing LNG as a clean fuel for power generation and distribution in the Asian region, and reaping the substantial economic benefits that could flow from this industry to the people of Australia.
For more information about Sasol Chevron and GTL technology, visit www.sasolchevron.com.

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