Diesel is, literally, the driving force behind mine sites across the country, however it’s expensive, dirty, and diesel emissions can cause serious, even life-threatening, health complaints amongst workers. With the price of fossil fuels also on the rise, is it time to get serious about biodiesel? Asks Tracey Mackay.
In 2010-2011, consumption of diesel by the mining industry was 3,627 GL which is 18% of the total diesel used in Australia that year<>sup1. This high level of diesel use is a significant contributor to the industry’s total output of greenhouse gas emissions and an area of environmental concern for the whole sector.
In addition, uncertainty around remaining crude oil reserves continues to drive fuel prices ever upwards and some sectors of the transport industry, such as off-road heavy transport, have now had their fuel use subjected to a carbon tax based on greenhouse gas emissions.
Can biodiesel provide at least part of the answer to the myriad of problems fossil fuels present? While still in its infancy in this country, the biofuel industry is starting to gain traction.
Biodiesel proponents claim biodiesel has some specific advantages, such as better lubricity, reduced engine and fuel pump wear and tear and, quite often, a longer engine life. In Australia, biofuels are not subject to the carbon tax and deliver substantial reductions in greenhouse gas emissions. Evidence from multiple studies also shows that the use of biodiesel reduces harmful particulate matter compared with conventional diesel.
It’s a novel notion, but could we one day see remote mine sites in Australia being run on fuel produced on site from locally sourced vegetation and food scraps from the kitchen? That day may be closer than we think…
Case Study
IMPROVING AIR QUALITY
In 2009, the United States’ Mine Safety and Health Administration (MSHA) documented two studies of biodiesel use in Carmeuse limestone mines in the state of Kentucky. The results point to significant improvements in air quality when an underground mine site makes the switch to biodiesel.
In the Black River mine study, B35 use resulted in diesel particulate matter (DPM) reductions between 16% and 33%. Inside equipment cabs, where DPM concentrations are higher, the DPM reductions were between 40% and 55%. In the Mayfield mine study, B50 use resulted in DPM reductions between 49% and 71%. Since the studies were done, both mines have switched to using B99.
Other mines using biodiesel, including a Barrick gold mine in Nevada, have reported similar improvements. Combining methods can further improve air quality. For example, the Stillwater palladium and platinum mine, Montana’s largest biodiesel user, uses B70 in conjunction with emission control devices.3
Case Study
DOWNER EDI MINING
In 2009 Downer EDI Mining conducted a year-long biodiesel trial at their Commodore coal mine in Queensland which the company claimed resulted in a reduction in greenhouse gas emissions of almost 20%.
This impressive result led the company to introduce biodiesel blend into all its heavy earthmoving equipment at the Commodore mine as well as expand the program to their Boggabri operations in New South Wales.
Downer EDI Mining Chief Executive Officer, David Overall, said that emissions from the mining fleet equipment involved in the biodiesel trial had dropped by 1,025 tonnes CO2 since the beginning of the trial in November 2007.
“By changing over to a biodiesel blend in 27 major plant items at Commodore, our annual greenhouse gas emissions at the site will reduce by approximately 4,100 tonnes CO2 which is equivalent to the total emissions from more than 1,000 cars or approximately 300 Australian households.”
The trial not only looked at the impact on the environment, but also at the implications for engine life, maintenance requirements and fuel efficiency. The biodiesel (B20) blend comprises 80% petroleum diesel and 20% biodiesel. The biodiesel is manufactured from tallow and waste cooking oil by Biodiesel Producers Limited (BPL) at its plant at Barnawartha, Victoria, 20km south of Albury Wodonga.
“The biodiesel fuel produced by AshOil can help mining companies reduce their costs and the environmental impacts of their operations.”.
Case Study
COOKING OIL POWERS THE PILBARA
A unique partnership between a mine catering company and Ashburton Aboriginal Corporation (AAC) has seen used cooking oil recycled into biodiesel fuel for use in the Western Australian mining sector.
Under the agreement, 200,000 litres of used cooking oil is recycled by AAC’s subsidiary AshOil into biodiesel fuel every year. The used cooking oil is provided to AshOil by partner company ESS Support Services Worldwide (ESS).
At present AshOil produces about 10,000 litres of biodiesel each week. A Supply Agreement with Rio Tinto guarantees the purchase 5-7,000 litres of fuel for drill and blast operations at the Tom Price mine in Western Australia’s Pilbara region. The balance of the biodiesel is used for AAC operations at Jigalong, Nullagine and Marble Bar.
While current production levels are modest, the scheme is being watched with interest as a model for future, much larger projects in a range of diverse and remote areas of the country.
Used oil for biodiesel production is currently collected by AshOil from Port Hedland, Newman, Karratha, Roebourne and satellite mine camps such as Area C, Hope Downs and West Angeles, and the number of collection points is on the increase.
AAC’s CEO Janet Brown said, “The mining companies operating in the Pilbara region go through one billion litres of mineral diesel every year, a cost that is now impacted by the carbon tax.”
“The biodiesel fuel produced by AshOil can help mining companies reduce their costs and the environmental impacts of their operations.
“By ESS giving AshOil guaranteed access to its used cooking oil, the organisation can pursue additional business opportunities in the region and build on its program of economic engagement for the local Indigenous community.”
AshOil claims biodiesel has the following advantages over traditional fuels:
- Biodiesel is simple to make and cheaper than petroleum diesel
- Biodiesel is non-toxic and environmentally friendly
- Used oil would otherwise go to waste
- One litre of used oil converts to one litre of biodiesel
- It can be used neat or blended in any ratio with petroleum diesel
- It has higher lubrication qualities than petroleum diesel and prolongs engine life.
“By 2030, biodiesels will become the dominant fuel used in heavy vehicles and represent more than 75 per cent of total fuel use by 2050.”
Case Study
BIODIESEL KEEPS ON TRUCKIN’
Federal Government Treasury modelling appears to be banking on trucking to propel the investment in cleaner technologies with biodiesel expected to displace diesel as the most commonly available fuel to power heavy vehicles and generators.
The treasury modelling is available at www.treasury.gov.au
The modelling anticipates that biodiesel will begin to supplant conventional diesel from 2020. As the road transport sector is responsible for 85% of the total of transport emissions, Treasury expects that emission abatements will come from changes in fuel use.
“The most significant change in fuel mix is the adoption of biodiesel blends. By 2030, biodiesels will become the dominant fuel used in heavy vehicles and represent more than 75 per cent of total fuel use by 2050,” the modelling suggests. “Changes in transport fuels and technologies driven by heavy vehicle demand are also projected to provide spillover benefits to light vehicle users. In particular, strong heavy vehicle demand aids the development of the biofuels industry. This leads to cheaper and more widely available biofuels for light vehicles.”
Treasury quite rightly highlights that the uptake of electric alternatives will be limited in the heavy vehicle sector – mainly through rigid trucks and buses – but anticipates that electric alternatives will flow-through to general motorists.
“Similarly, as heavy vehicle demand drives the development of the infrastructure required for electric vehicles, this will encourage the uptake of light electric vehicles. Nevertheless, conventional petrol remains the dominant fuel used in light vehicles,” the modelling says. Treasury also highlights that there will be limited abatement in emissions from transport in the near term under a carbon tax due to the time needed to turnover existing vehicle fleets and the high upfront costs of switching to new and cleaner technologies. Currently the average heavy vehicle has a life span of 14 years, compared to 9 years for the lighter vehicles.
Treasury argues that rigid truck emissions will be about 75% below 2010 levels by 2050: “Passenger vehicle emissions fall to nearly 30 per cent below today’s levels, while emissions from articulated trucks, buses and light commercial vehicles increase, but at a slower rate than in the global action scenarios.”
Treasury believes that this shift will occur regardless of a carbon tax, which the modelling suggests will increase diesel prices by 6.85 cents per litre when it applies to trucking from July 1, 2014. The Centre for International Economics says a $30 carbon tax will increase the cost of diesel by about 8 cents per litre based on the current price of around $1.50 per litre.
It remains to be seen how all of this will intersect with the Fuel Tax Credit scheme and the Road User Charges. Watch this space.4
Case Study
BENEFITS OF BIODIESEL
Dr Victoria Haritos from the CSIRO looks at the case for biodiesel in the resources sector.
In Australia biodiesel is most often blended with conventional diesel fuel in 5% (B5) or 20% (B20) mixtures although it can also be used as a neat fuel (B100) with suitable modifications and where permitted by the vehicle manufacturer.
The Alternative Fuels Data Center at the US Department of Energy describes B20 as having similar fuel consumption, horsepower, and torque to engines running on conventional diesel.2 B20 also has a higher cetane number giving shorter ignition delay periods and therefore cleaner and more complete burn per compression cycle, and higher lubricity, than conventional diesel.
Diesel engines depend on the lubricity of the fuel to keep fuel pumps and fuel injectors from wearing prematurely. As new low sulphur, low aromatic diesel fuels have concomitantly low lubricity, biodiesel can be used to increase lubricity of these ultra low sulphur diesel fuels even at low blend levels. Biodiesel causes far less impact than conventional diesel if spilled or released into the environment as it is readily biodegradable. The flashpoint for biodiesel is above 150°C, compared with about 52°C for conventional diesel.
No new technology or engine modification is usually required to use B20 and lower-level blends as opposed to LNG or other such products where you need to invest in new infrastructure and technology.
Compared with petroleum diesel, using biodiesel in a conventional diesel engine substantially reduces tailpipe emissions of a range of toxic and regulated substances. A major study published by the US EPA (2002) concluded that replacing conventional diesel with a B20 blend prepared from soybean oil would reduce particulate matter (PM) emissions by 10%, carbon monoxide by 11%, and unburned hydrocarbons by 21% but raises nitrogen oxides (NOx) by about. 2%. These figures were obtained from engines that were not equipped with exhaust gas recirculation, NOx adsorbers or PM traps.
Resources
1. (Australian Bureau of Agricultural and Resource Economics and Sciences and Australian Bureau of Statistics, 2012).
2. http://www.afdc.energy.gov/fuels/biodiesel_blends.html
3. U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.
4. Biofuels Association of Australia www.biofuelsassociation.com.au
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