The broad term 'alternative fuels' refers to fuels other than petrol and diesel that are used in internal combustion engines (ICEs). It usually includes biofuels. The following fuels fall within the alternative fuels definition: biodiesel, compressed natural gas (CNG), dimethyl ether, ethanol, liquefied natural gas (LNG), biogas, liquefied petroleum gas (LPG), hydrogen, and methanol.
Some 97 per cent of all the energy consumed by our vehicles and airplanes remains petroleum-based. But although most modern vehicles (sea, land and air) rely on it, oil is a non-renewable resource that is fast diminishing. Vehicle engines continue to become more efficient, reducing the fuel burn and the average emissions per km travelled, but this is offset by continued growth in the Australian and global vehicle fleet. Much of the known global reserve of existing oil is concentrated in a few key countries, with implications for energy security. In addition, the combustion of oil products (petrol or gasoline, diesel and the kerosene-based aviation fuels) produces emissions that are harmful to health (such as carbon monoxide, nitrogen oxides and particulates) and also emissions of environmental concern (principally carbon dioxide, a greenhouse gas). For these reasons, alternative fuels are desirable.
Some factors come into play regarding the introduction of alternative fuels. These include the fuel providers, existing markets, and infrastructure for fossil fuels: principally petrol, diesel, ethanol and natural gas. (Whilst conventional diesel and petrol are both refined derivatives of oil, they are different products and their prices differ, being affected by forces of global supply and demand.) The following summary provides a brief overview of some of the issues involved, including existing infrastructure, production, economics, distribution and retailing. Existing energy producers, principally petroleum sellers, will no doubt implement strategies to protect their markets or take steps to introduce new technologies as their profits permit.
ISSUES AND ARGUMENTS
Here we look at alternatives to diesel and petrol:
Biofuels: Biodiesel and Ethanol
Compressed and Liquefied Natural Gas and Liquefied Petroleum Gas
Biofuel: Biodiesel and Ethanol
Concern over the level of emissions from the use of fossil fuels has prompted a number of countries to promote alternatives to the use of petrol and diesel in transport. In particular, these countries have promoted the production and use of biofuels—ethanol and biodiesel. Advocates argue that biofuels would result in environmental benefits including lower air pollutant emissions and lower greenhouse gas emissions. While it generally costs more to produce energy from renewable resources than from fossil fuels, this does not take account of the costs of ‘negative externalities’ resulting from fossil fuel use (such as air pollution), nor of ‘positive externalities’ of biofuels (such as reduced greenhouse gas emissions). High oil prices and increasing reliance on imported oil have also given impetus to the promotion of biofuels. Advocates of biofuels cite increased fuel security, a smaller trade deficit, regional agricultural development, as well as environmental benefits, as reasons for using biofuels.
In late 2008, the Australian Academy of Technological Sciences and Engineering launched a new report Biofuels for Transport: A Roadmap for Development in Australia with an emphasis on second generation biofuels (ethanol from lignocellulose wastes, biodiesel from enzyme or algae sources) rather than the first generation which relied heavily on competing food resource stocks. The study found Australian R&D very good, but limited and requiring linkages both here and overseas. The report recommended that a National Biofuels Institute be established with co-production investment needed with less developed countries.
First and second generation biofuels:
First generation biofuels are those derived from sugar, corn, maize, wheat, oats, sorghum etc., and thus use human and animal foods as their sources. Examples can include ethanol and biodiesel depending on sources. Clearing of land to grow additional crops for fuel manufacture has environmental consequences and increases demand for scarce water supplies.
Second generation biofuels use a wider range of sources—such as woody wastes and agricultural residues (lignocellulosic)—and alternative processing methods to lower costs and increase yields of biofuels. Second generation biofuels may provide not only ethanol but a wider range of fuels—such as synthetic diesel and methanol—and may provide a direct path to hydrogen production.
Programs are being conducted worldwide on second generation biofuel production. For example, D1 Oils in India is cultivating Jatropha curcas, a wild tree that is common in the tropics and carries fruit that yields a crude oil suitable for making biodiesel. Jatropha weed and algae resource stock alternatives are under study as Australia’s wide open areas might suit algae derived fuel production. However, according to the CSIRO, research into these types of biofuels in Australia is a long way off.
More than a half a dozen groups in the USA, Canada and Europe have developed, built and operated multi-million dollar pilot plants to investigate different feed materials (such as wood, municipal solid wastes and agricultural residues), hydrolysis routes (acid and enzyme) and fermentation pathways. Ongoing research and development work—particularly by the National Renewable Energy Laboratory in the USA—has identified a range of opportunities for improvements that, if achieved, could reduce the cost of ethanol from wood by up to 50 per cent over the next 15 years. Also in the USA, the Department of Energy is providing US$385 million to fund a number of second generation biomass-to-ethanol plants. The plan is for the bio-refineries to produce 130 million gallons of ethanol a year at a cost competitive with gasoline. In March 2010, the Victorian Government announced formation of a consortium with vehicle industry members to investigate the viability of establishing Australia’s first ethanol plant capable of converting urban rubbish and waste into the fuel.
In August 2008, the Rural Industries Research and Development Corporation released the study report Future biofuels for Australia–issues and opportunities for conversion of second generation lignocellulosics:
Unlike first generation biofuels that are limited by agronomic characteristics of annual crops and production on arable land, second generation biofuels have the potential to replace a significant proportion of our transport fuel requirements as they can be sourced from a wide selection of plant and woody materials. There are many technologies that can be applied to second generation biofuel production and this is reflected in the broad spectrum of research efforts being undertaken worldwide…Most conversion processes involve some manner of pre-treatment step which facilitates the actual chemical conversion to a biofuel. Most processes are also feedstock-dependent, meaning they need to be modified to provide a consistent conversion rate if the feedstock changes. Most processes claim to be competitive with oil at around US$40 - 60 per barrel.
Source: Andrew Warden & Victoria Haritos, Future biofuels for Australia–issues and opportunities for conversion of second generation lignocellulosics, Pub. No. 08/117, Rural Industries Research and Development Corporation, 2008
More recently, the Corporation has completed an Overview of BioEnergy in Australia report which looks more broadly at options for the sector. The Corporation also provides a range of detailed publications for the sector.
According to the Department of Resources, Energy and Tourism, Australian production of biofuels in 2006 was 106 million litres (ML), of which ethanol comprised 62ML and biodiesel 44ML. In 2007-08, production of biofuels was 199 million litres (ML), of which ethanol comprised 149ML and biodiesel 50ML.
Small quantities of biodiesel have been produced in Australia. Biodiesel typically costs two to three times more to produce than petroleum fuels but can be mixed with regular diesel without requiring substantial modifications to the engine. Biodiesel is a solvent, so when first used, it can clog filters with newly dissolved materials as it cleans the engine and fuel system. An economic negative is that, as with ethanol, biodiesel production in most countries requires a subsidy. As well, such biofuels may have to utilise scarce agricultural resources.
Biodiesel is typically produced using oil from plants, such as soy bean oil, waste cooking oil, sunflower or rapeseed oil. Algae are a promising source of oil too. Waste oils or animal fat can also be used. The oil is reacted with an alcohol, such as ethanol or methanol, in the presence of a catalyst to yield mono-alkyl esters (of which biodiesel is composed) and glycerine, which must be removed. Depending on the feedstock and processes employed, by-products in addition to glycerine include fatty acids, fertiliser and oilseed meal (for grain-fed stock). Oil-seed crops such as rapeseed, soybean and sunflower can be converted into methyl esters, a liquid fuel which can be either blended with conventional diesel fuel or burnt as pure biodiesel.
Biodiesel and diesel may differ slightly in terms of energy content, cetane number (analogous to gasoline’s octane rating in terms of engine performance) or other physical properties. Biodiesel can be blended with conventional diesel fuel or used as a neat fuel (100 per cent biodiesel – B100). Biodiesel is typically used as a fuel additive in five per cent (B5) and 20 (B20) per cent blends.
Source: http://www.ret.gov.au/resources/fuels/alternative_transport_fuels/Pages/Biodiesel.aspx, December 2008
A biodiesel production plant at Barnawartha near Albury is operated by Biodiesel Producers Ltd and provides glycerine and fertiliser, from animal tallow input. Such a (second generation biofuel process) plant has had to establish its quality credentials with its fleet customers, offering a variety of B100, B20 and B5 biodiesel products. Australian Biodiesel Group Limited constructed a plant at Narangba, Queensland. The plant was commissioned in the second half of 2006 to produce fuel.
For the production of the alcohol ethanol, cereals, grains, sugar crops and other starches can be fermented for its use either as a motor fuel in pure form or blended in petrol. Cellulose materials, such as grasses and trees, and waste products (from crops, wood processing facilities and municipal solid waste) can also be converted to ethanol. This is at the commercial stage now with America’s Iogen Corporation producing cellulose-derived methanol. Other organic waste material can be converted into materials that can be used as automotive fuel; for example, animal manure and organic household wastes are a source of gas such as methane.
Ethanol can be used in light-duty, medium and heavy-duty trucks and buses – flexible fuel vehicles that can be fuelled with E85 (15 percent petroleum and 85 percent ethanol), gasoline, or any combination of the two fuels. In Australia, E10 (90 percent petroleum blended with 10 percent ethanol) is the maximum permitted ethanol content in petrol.
Under certain circumstances, ethanol can achieve environmental benefits. The use of E10 in place of unblended petrol reduces the emissions of certain pollutants from the vehicle exhaust. Ethanol as a transport fuel may also realise a greenhouse benefit when it is produced from a waste product (for example, C-grade molasses) or the energy source used in its production is relatively clean (for example, co-generation).
The use of ethanol as an alternative transport fuel has grown considerably as a result of growing consumer confidence in the use of the fuel, production and other grants to encourage uptake of ethanol and as a result of the development and implementation of state Government ethanol and biofuel targets.
Source: http://www.ret.gov.au/resources/fuels/alternative_transport_fuels/Pages/Ethanol.aspx, December 2008
Renewable Fuels Australia provides ethanol-blended fuel and biodiesel information as well as details on where to buy ethanol and biodiesel.
The Howard Government’s 2005 Biofuels Taskforce found that the benefits of ethanol-blended fuels to lower Australian transportation emissions were mixed. Consequently, the taskforce was unable to quantify the health costs and benefits of blends containing 10 per cent ethanol. Nor was the taskforce able to be definitive about the benefits of biofuels in terms of reduced greenhouse gases because the benefits depend on many factors including the type of crop; the greenhouse emissions associated with any fertilizer used, the water used and greenhouse emissions associated with its extraction and distribution, and so on.
A number of Australian government initiatives support the uptake of biofuels such as ethanol (and biodiesel), including the $37.6 million Biofuels Capital Grants Program to support new or expanded biofuel production capacity, Commonwealth fleet use of E10, and simplification of the ethanol label. There are also many international efforts to increase the use of biofuels, including E85 (15 percent petroleum and 85 percent ethanol) in the United States, E100 (100 percent ethanol) in Brazil and tax incentives for biofuels in Germany.
Source: Department of Innovation, Industry, Science and Research, Review of Australia’s Automotive Industry, Final Report, prepared by S. Bracks for the Automotive Review, Commonwealth of Australia, Canberra, 22 July 2008
On 27 February 2008, the Prime Minister requested that the Minister for Resources and Energy and the Minister for Agriculture, Fisheries and Forestry undertake an internal government review of existing Australian biofuels programs and policies. The review is currently underway. Under its alternative fuel policies, the Government has committed to:
use the $500 million National Clean Coal Fund to support projects that deliver ultra-clean synthetic fuels from coal with minimum carbon emissions;
encourage the development of gas-to-liquids projects that can convert some of our vast gas reserves into liquid fuels;
support the research and development of new biofuel technologies, including the production of ethanol from cellulose. This will include a new $15 million grant program to help develop next generation ethanol technology. These grants, worth up to $5 million each, will help Australian companies to commercialise new technology using sugar cane waste and other woody material as alternative fuel sources;
establish a $500 million Green Car Innovation Fund to generate $2 billion in investment in the automotive industry and tackle climate change by manufacturing low emission vehicles in Australia;
include projections of future liquid fuel supply and demand in a regular National Energy Security Assessment to better inform industry about the probable use of liquid fuels in the future; and
invest $150 million in critical clean energy technology research under a new Energy Innovation Fund including $50 million for general clean energy research and development, including on energy efficiency, energy storage technologies and hydrogen transport fuels.
Source: http://www.ret.gov.au/resources/fuels/alternative_transport_fuels/Pages/AlternativeTransportFuels.aspx, December 2008
The Australian Government also has a number of existing programs in place to encourage the production and use of alternative fuels. The Alternative Fuels Programs guide gives details.
Biofuel Cost-effectiveness and Environmental Benefits:
The cost-effectiveness of biofuels is questionable. An OECD study from September 2007 titled Biofuels: Is the Cure Worse Than the Disease? concluded that the cost-effectiveness of biofuels was low in almost all cases and that far more reductions could result from spending the same amount of money on CO2-equivalent offsets at the market price. Another OECD study found that:
Generally, the costs of reducing GHG emissions by saving energy are much lower than by substituting energy sources.
Source: OECD, Biofuel Support Policies An Ecnonomic Assessment, 2008
Concern over the environmental consequences of promoting biofuels—and their effect in pushing up food prices—has led the European Commission to reconsider its biofuels target.
The environmental benefits of biofuels are being increasingly questioned because the production of biofuels also generates negative externalities. The OECD study noted above concluded that whenever natural ecosystems are replaced with bio-energy crops, the environmental credentials of biofuels will be harmed. 'When such impacts as soil acidification, fertilizer use, biodiversity loss and toxicity of agricultural pesticides are taken into account, the overall environmental impacts of ethanol and biodiesel can very easily exceed those of petrol and mineral diesel.'
Biofuels and agriculture:
As noted, concern has been expressed about the consequences of diverting crops to biofuels production. The OECD, in a February 2006 paper titled Agricultural market impacts of future growth in the production of biofuels, concluded that US, Canada and EU (15) would require between 30 per cent and 70 per cent of their respective current crop area if they are to replace 10% of their transport fuel consumption by biofuels. However, only 3 per cent would be required in Brazil.
Additional demand for agricultural commodities resulting from increased biofuel production is likely to greatly affect the outlook for their markets. The above OECD paper estimated that crop prices in 2014 could increase by between 2 per cent in the case of oilseeds and almost 60 per cent in the case of sugar. The paper also shows that commodity markets are strongly influenced by crude oil prices. Higher oil prices increase production costs in agriculture, but also create higher incentives for biofuel production, thus stimulating demand for feedstock products.
In a short time, attitudes to biofuels have changed markedly. Having once been seen as playing a major role in helping to reduce greenhouse gas emissions and providing an apparently sustainable substitute for large volumes of petrol and diesel, concerns over the effects of biofuel production on food prices, the environmental consequences of clearing land for feedstock, and the capacity to produce enough biofuel to replace substantial quantities of petrol and diesel have led to the scaling back of plans to produce biofuels using first generation technologies. Second generation technologies may, however, change this outlook.
Indeed, the October 2008 ANZ Industry Report: Biofuels is very bullish on global biofuel technologies and production. It anticipates global consumption growth at 5 per cent annually.
Compressed and Liquefied Natural Gas and Liquefied Petroleum Gas
Natural Gas comes from underground reserves, with methane (CH4) as the major component, or it can be produced from biomass although in a blend of other gases, including significant quantities of ethane, propane, butane and pentane. It is therefore a hydrocarbon fuel, like existing traditional fuels, and its combustion adds to the total atmospheric concentration of carbon dioxide. Compressed natural gas (CNG) is made by pressurizing natural gas to less than 1 per cent of its volume at standard atmospheric pressure. (CNG) is not widely used as a fuel in Australia. Suitable vehicles may be refuelled at home with a gas compressor, but there are few CNG filling stations and most are for fleet use only.
Liquefied natural gas (LNG) is primarily methane converted to liquid form for transportation. To use LNG, medium and heavy-duty trucks and buses require a robust fuel tank, plus changed pistons and engine controls. CNG and LNG vehicles can demonstrate a reduction in ozone-forming emissions compared to some conventional fuels, but 'HYDROCARBON' emissions may increase. While CNG had a lower energy density than petrol it has higher octane value and infrastructure requirements, requiring further demonstration, pricing and roll-out.
Demonstrating such infrastructure provision, Wesfarmers Energy Ltd provides LNG fuel to heavy duty truck fleets. The Kwinana facility produces CNG for use by over 100 rigs, while a separate Melbourne gas storage now serves a growing eastern state operation. LNG is compatible with diesel, enables fast refuelling and can be fleet cost effective.
LNG-fuelled vehicles have ranges and refuelling times comparable to those of diesel-fuelled vehicles without any power to weight disadvantages. Vacuum-insulated LNG storage tanks are designed to replace the diesel units without any vehicle modifications, minimising down time for truck/bus conversions.
The use of natural gas as a transport fuel presents a number of practical impediments. CNG and LNG are stored under pressure and require specialised heavy-duty storage tanks on board the vehicle. These storage tanks affect the amount of fuel that a vehicle can carry and its operating range, therefore limiting its broader application within the Australian vehicle fleet. In addition, specialist refuelling facilities are required to handle both fuels, thus reflecting the greater uptake in heavy vehicles sector.
Source:http://www.ret.gov.au/resources/fuels/alternative_transport_fuels/Pages/CNGandLNG.aspx, December 2008
Liquefied Petroleum Gas (LPG) or propane/butane is a by-product of petroleum refining or natural gas processing. Light-duty vehicles can be fuelled with propane or gasoline, while medium and heavy-duty trucks and buses can run on propane. LPG vehicles are the most widely produced alternative but may give reduced performance compared to petrol engine vehicles.
LPG Australia (previously the Australian Liquefied Petroleum Gas Association Ltd.) provides information on the LPG industry, safety, statistics and development programs. LP Autogas contains information on conversions and systems for private, small business and corporate use, filling locations, payback calculators, equipment lists, and the location of installers.
LPG has lower greenhouse gas emissions per litre of fuel consumed than petrol, but also has a lower energy content. 'Therefore equivalent vehicles [of a similar size and type] tend to consume more of LPG than petrol to travel a given distance.' However, there is evidence to suggest that the level of CO2 emissions from LPG is lower than that of petrol.…The Australian Alternative Fuels Registration Board contended in its submission to the Review that LPG contains 80 per cent less toxins and 60 per cent less carbon monoxide emissions compared to petrol. Autogas fuel standards are dictated by the Fuel Quality Standards Act and the Fuel Standard (Autogas) Determination 2003.
Source: Department of Innovation, Industry, Science and Research, Review of Australia’s Automotive Industry, Final Report, prepared by S. Bracks for the Automotive Review, Commonwealth of Australia, Canberra, 22 July 2008
Australian fuel standards are regulated by the Fuel Quality Standards Act 2000 (the Act) that places an obligation on the fuel industry, including fuel suppliers, to supply fuels that meet strict environmental requirements. The Department of Sustainability, Environment, Water, Population and Communities is responsible for developing and enforcing a number of fuel quality standards made under the Act. Fuel quality standards have been set for petrol, diesel, biodiesel and autogas.
Biogas is derived from the breakdown of organic matter in the absence of oxygen to produce methane and carbon dioxide. The methane can be combusted with oxygen in air as a fuel. Biogas is also called swamp, marsh, landfill or digester gas and may be derived from manure or sewerage and municipal waste. Biomass as gas entails harvesting methane from the natural breakdown of organic material—principally human or animal sewerage, municipal rubbish, and waste from food processing—or biochemical processing. Landfill gas can be explosive when the methane escapes and mixes with oxygen, but it can be compressed to replace natural gas for use in vehicles. For use as an engine fuel, the methane content has to be boosted to around 97 per cent, which is achieved by chemically removing most of the carbon dioxide.
Most of Australia’s capacity for biogas electricity production is through burning methane at sewage treatment plants and from landfill gas collected from municipal waste depots. In the future there is potential to generate hydrogen from biomass, to contribute to a hydrogen economy which some believe is the energy base of the future. A biogas powered train has been in service in Sweden since 2005. Various biogas powered cars have been produced over the years including examples in Britain, India and China.
Methanol is a clear liquid alcohol that can be produced from natural gas, coal, crude oil and biomass crops such as wood residues. Unlike biofuel production, methanol does not require use of agricultural resources. Methanol can also be converted to ethylene or propylene which constitute the elements of synthetic hydrocarbons, now sourced from oil and gas resources.
Methanol can be used as a fuel for engines or in fuel cells by reaction with atmospheric oxygen and as such is an alternative fuel to petrol but at a higher cost. However, methanol is corrosive and modifications have to be undertaken to the conventional vehicle's fuel system. In the liquid form, methanol can store energy perhaps more conveniently and safely compared to hydrogen. Note that methanol as a fuel has a lower energy content than petrol, is somewhat corrosive as a solvent and extremely poisonous, but can be used by redesigning engines. On the other hand, when burnt it does not produce particulates or carcinogens, unlike petrol or diesel.
Methanol has been used in racing cars and special bus prototypes as demonstration projects. Proponents believe that conversion of retail storage and distribution systems could be achieved cheaply but it will no doubt take time to fully investigate the economic and safety aspects involved.
There was a proposal in 2003 by a multinational firm, Methanex, to build a methanol plant in Darwin or Western Australia to process gas from the Woodside Petroleum and Shell's Sunrise gas field located in the Timor Sea. For the project, Methanex requested clarification on future abatement measures it needed to implement and expectations for greenhouse gas reductions that would apply to new state of the art plants like that being proposed by the company. However, in the end the proposal did not proceed in Australia.
MEO Australia Limited is an upstream gas to liquids (GTL) company listed on the ASX. MEO Australia is focused on advancing the Tassie Shoal Methanol Project (TSMP) and the Timor Sea LNG Project (TSLNG).
Theoretically inexhaustible and non-polluting, hydrogen (H2) is described as the fuel for our future energy needs. The idea seems rather simple: take hydrogen, one of the most plentiful elements on Earth and use it as a clean-burning fuel or in fuel cells with oxygen to power cars, heat houses and offices, etc. It produces only water as a by-product. The problem is that hydrogen gas does not exist on Earth in any quantity. It must be produced (either from methane or water), and this requires considerable energy.
Many governments and large energy-related companies, automobile manufactures and other industries have been involved in some way in the so-called 'hydrogen economy'. The United States and the European Union have committed large sums of research monies to better develop the use of hydrogen. Additionally, most automobile manufacturers have already invested large amounts of money in the development of hydrogen fuel cell-powered cars.
Despite considerable worldwide efforts, the challenges that lie in the way of the hydrogen economy are enormous. Fundamental problems will have to be solved if hydrogen gas is ever to become a practical, everyday fuel that can be filled into the tanks of our motor cars or delivered to our homes as easily and as safely as petrol or natural gas are today.
It is the production of hydrogen that remains the principal stumbling block. If some form of renewable energy such as solar or wind power can be used economically to generate the power necessary to create hydrogen, through electrolysis or chemical process, then a way ahead may be possible. Successful solid state hydrogen batteries remain elusive, but safe storage and transportation of the gaseous form prose problems.
The possible hydrogen economy that de-carbonises energy can be built up by using advanced nanotechnology techniques, in the view of Professor Max Lu of the University of Queensland's ARC Centre of Excellence for Functional Nanomaterials. The technology would provide photo-catalytic solar production, at nano-metre size, of hydrogen using nano-tube solar cells. High temperature membranes would provide H2 purification as well as fuel cell applications and advanced storage systems. This development work is proceeding.
Perth had a successful hydrogen fuel cell bus trial, according to the WA Department for Planning and Infrastructure. It conducted a trial of three hydrogen fuel cell buses, known as EcoBuses from September 2004 to September 2007. This was the first major use of hydrogen as a transport fuel on public roads in Australia. At the conclusion of the trial EcoBuses had travelled approximately 258 000km, consumed over 46 tonnes of hydrogen and carried over 320 000 passengers. Note that there is a separate Tindo solar electric bus trial in Adelaide.
Nonetheless, the promises of the hydrogen economy seem forever ‘just a few years away’. In the view of the 2006 OECD Innovation in Energy Technology study, hydrogen fuel cell technology is complex with numerous technical and economic hurdles to be overcome. Fuel cell innovation may be a powerful driver for energy innovation by major automobile makers. This involves extensive R&D activities involving both government and private agencies.
Further reading and sources:
Andrew Warden & Victoria Haritos, Future biofuels for Australia–issues and opportunities for conversion of second generation lignocellulosics, Pub. No. 08/117, Rural Industries Research and Development Corporation, 2008.
D Strahan, A tank of the green stuff, New Scientist, v 199, 16 August 2008.
David Strahan, ‘Hydrogen’s long road to nowhere’, New Scientist, 29 November 2008.
Department of the Environment, Water, Heritage and the Arts, Ethanol labelling standard, June 2007.
George A. Olah, Alain Goeppert and G.K. Prakash, Beyond Oil and Gas: The Methanol Economy, WILEY –VCH Verlag GMbH & Co. KGaA, Weinheim, Germany, 2006.
International Energy Agency (IEA), ‘Clean coal technologies: Accelerating commercial and policy drivers for deployment’, Coal Industry Advisory Board, OECD/IEA, 2008, p.42.
Joseph Romm, ‘The car and fuel of the future’, Energy Policy, Vol. 34, 2006, pp. 2609–2614.
Matthew James, ‘The (green) car of the future’, Australian Parliamentary Library Background Note, 25 August 2009,
26 November, 2010