Biofuels are fuels produced from renewable organic sources. The term biofuels can refer to fuels for electricity and fuels for transportation. Biofuels for transportation include ethanol, biodiesel and pyrolysis oils.
Biofuels with commercial prospects in Australia are ethanol and biodiesel. These are the most common types of biofuels that are being developed and used in Australia . This is due to several factors including the state and feasibility of feedstock conversion technology, feedstock availability and fuel usability.
Almost all current and proposed biofuel plants are located close to feedstock supplies in regional areas across Australia . Successful development of fully commercial biofuel refineries may produce regional benefits including additional employment, broadening of economic activity and alternative markets for some agricultural activities. The cost of producing biofuels relative to petrol and diesel is the fundamental factor influencing the commercial viability of biofuels.
LIQUID FUELS FOR TRANSPORTATION
Most transportation fuels are liquids, because vehicles usually require high energy density, as occurs in liquids and solids. Vehicles usually need high power density as can be provided most inexpensively by an internal combustion engine. These engines require clean burning fuels, in order to keep the engine clean and minimize air pollution.
The fuels that are easier to burn cleanly are typically liquids and gases. Thus liquids (and gases that can be stored in liquid form) meet the requirements of being both portable and clean burning. Also, liquids and gases can be pumped, which means handling is easily mechanized, and thus less laborious.
TYPES OF BIOFUELS
(I) FIRST GENERATION BIOFUELS
'First-generation biofuels' are biofuels made from sugar, starch, vegetable oil, or animal fats using conventional technology. The basic feedstocks for the production of first generation biofuels are often seeds or grains such as wheat, which yields starch that is fermented into bioethanol, or sunflower seeds, which are pressed to yield vegetable oil that can be used in biodiesel. These feedstocks could instead enter the animal or human food chain, and as the global population has raised their use in producing biofuels has been criticised for diverting food away from the human food chain, leading to food shortages and price rises.
(1) Vegetable oil
Edible vegetable oil is generally not used as fuel, but lower quality oil can be used for this purpose. Used vegetable oil is increasingly being processed into biodiesel, or (more rarely) cleaned of water and particulates and used as a fuel. To ensure that the fuel injectors atomize the fuel in the correct pattern for efficient combustion, vegetable oil fuel must be heated to reduce its viscosity to that of diesel, either by electric coils or heat exchangers. This is easier in warm or temperate climates. MAN B&W Diesel, Wartsila and Deutz AG offer engines that are compatible with straight vegetable oil, without the need for after-market modifications. Vegetable oil can also be used in many older diesel engines that do not use common rail or unit injection electronic diesel injection systems. Due to the design of the combustion chambers in indirect injection engines, these are the best engines for use with vegetable oil. This system allows the relatively larger oil molecules more time to burn. However, a handful of drivers have experienced limited success with earlier pre- "pumped use" VW TDI engines and other similar engines with direct injection.
Biodiesel is the most common biofuel in Europe . It is produced from oils or fats using transesterification and is a liquid similar in composition to fossil/mineral diesel. Its chemical name is fatty acid methyl (or ethyl) ester. Oils are mixed with sodium hydroxide and methanol (or ethanol) and the chemical reaction produces biodiesel (FAME) and glycerol. One part glycerol is produced for every 10 parts biodiesel. Feedstocks for biodiesel include animal fats, vegetable oils, soy, rapeseed, jatropha, mahua, mustard, flax, sunflower, palm oil, hemp, field pennycress, and algae. Pure biodiesel (B100) is by far the lowest emission diesel fuel. Although liquefied petroleum gas and hydrogen have cleaner combustion, they are used to fuel much less efficient petrol engines and are not as widely available.
Biodiesel can be used in any diesel engine when mixed with mineral diesel. The majority of vehicle manufacturers limit their recommendations to 15% biodiesel blended with mineral diesel. In some countries manufacturers cover their diesel engines under warranty for B100 use, although Volkswagen of Germany, for example, asks drivers to check by telephone with the VW environmental services department before switching to B100. B100 may become more viscous at lower temperatures, depending on the feedstock used, and requiring vehicles to have fuel line heaters.
Since biodiesel is an effective solvent and cleans residues deposited by mineral diesel, engine filters may need to be replaced more often, as the biofuel dissolves old deposits in the fuel tank and pipes. It also effectively cleans the engine combustion chamber of carbon deposits, helping to maintain efficiency. In many European countries, a 5% biodiesel blend is widely used and is available at thousands of gas stations. Biodiesel is also an oxygenated fuel , meaning that it contains a reduced amount of carbon and higher hydrogen and oxygen content than fossil diesel. This improves the combustion of fossil diesel and reduces the particulate emissions from un-burnt carbon.
In the USA , more than 80% of commercial trucks and city buses run on diesel. The emerging US biodiesel market is estimated to have grown 200% from 2004 to 2005. "By the end of 2006 biodiesel production was estimated to increase fourfold [from 2004] to more than 1 billion gallons".
Biologically produced alcohols, most commonly ethanol, and less commonly propanol and butanol, are produced by the action of microorganisms and enzymes through the fermentation of sugars or starches (easiest), or cellulose (which is more difficult). Biobutanol (also called biogasoline) is often claimed to provide a direct replacement for gasoline, because it can be used directly in a gasoline engine (in a similar way to biodiesel in diesel engines).
Butanol is formed by ABE fermentation (acetone, butanol, ethanol) and experimental modifications of the process show potentially high net energy gains with butanol as the only liquid product. Butanol will produce more energy and allegedly can be burned "straight" in existing gasoline engines (without modification to the engine or car), and is less corrosive and less water soluble than ethanol, and could be distributed via existing infrastructures. DuPont and BP are working together to help develop Butanol.
Ethanol fuel is the most common biofuel worldwide, particularly in Brazil . Alcohol fuels are produced by fermentation of sugars derived from wheat, corn, sugar beets, sugar cane, molasses and any sugar or starch that alcoholic beverages can be made from (like potato and fruit waste, etc.). The ethanol production methods used are enzyme digestion (to release sugars from stored starches, fermentation of the sugars, distillation and drying. The distillation process requires significant energy input for heat (often unsustainable natural gas fossil fuel, but cellulosic biomass such as bagasse, the waste left after sugar cane is pressed to extract its juice, can also be used more sustainably).
Ethanol can be used in petrol engines as a replacement for gasoline; it can be mixed with gasoline to any percentage. Most existing automobile petrol engines can run on blends of up to 15% bioethanol with petroleum/gasoline. Gasoline with ethanol added has higher octane, which means that your engine can typically burn hotter and more efficiently. In high altitude (thin air) locations, some states mandate a mix of gasoline and ethanol as a winter oxidizer to reduce atmospheric pollution emissions.
Methanol is currently produced from natural gas, a non-renewable fossil fuel. It can also be produced from biomass as biomethanol. The methanol economy is an interesting alternative to the hydrogen economy, compared to today's hydrogen produced from natural gas, but not hydrogen production directly from water and state-of-the-art clean solar thermal energy processes.
Biogas is produced by the process of anaerobic digestion of organic material by anaerobes. It can be produced either from biodegradable waste materials or by the use of energy crops fed into anaerobic digesters to supplement gas yields. The solid byproduct, digestate, can be used as a biofuel or a fertilizer. In the UK , the National Coal Board experimented with microorganisms that digested coal in situ converting it directly to gases such as methane.
Biogas contains methane and can be recovered from industrial anaerobic digesters and mechanical biological treatment systems. Landfill gas is a less clean form of biogas which is produced in landfills through naturally occurring anaerobic digestion. If it escapes into the atmosphere it is a potent greenhouse gas.
Oils and gases can be produced from various biological wastes :
Thermal depolymerization of waste can extract methane and other oils similar to petroleum.
Green Fuel Technologies Corporation developed a patented bioreactor system that uses nontoxic photosynthetic algae to take in smokestacks flue gases and produce biofuels such as biodiesel, biogas and a dry fuel comparable to coal.
Syngas is produced by the combined processes of pyrolysis, combustion, and gasification. Biofuel is converted into carbon monoxide and energy by pyrolysis. A limited supply of oxygen is introduced to support combustion. Gasification converts further organic material to hydrogen and additional carbon monoxide.
The resulting gas mixture, syngas, is itself a fuel. Using the syngas is more efficient than direct combustion of the original biofuel; more of the energy contained in the fuel is extracted.
Syngas may be burned directly in internal combustion engines. The wood gas generator is a wood-fueled gasification reactor mounted on an internal combustion engine. Syngas can be used to produce methanol and hydrogen, or converted via the Fischer-Tropsch process to produce a synthetic petroleum substitute. Gasification normally relies on temperatures >700°C. Lower temperature gasification is desirable when co-producing biochar.
(6) Solid biofuels
Examples include wood, sawdust; grass cuttings, domestic refuse, charcoal, agricultural waste, non-food energy crops, and dried manure.
When raw biomass is already in a suitable form (such as firewood), it can burn directly in a stove or furnace to provide heat or raise steam. When raw biomass is in an inconvenient form (such as sawdust, wood chips, grass, agricultural wastes), another option is to pelletize the biomass with a pellet mill. The resulting fuel pellets are easier to burn in a pellet stove.
(II) SECOND GENERATION BIOFUELS
Supporters of biofuels claim that a more viable solution is to increase political and industrial support for, and rapidity of, second-generation biofuel implementation from non food crops, including cellulosic biofuels. Second-generation biofuel production processes can use a variety of non food crops. These include waste biomass, the stalks of wheat, corn, wood, and special-energy-or-biomass crops (e.g. Miscanthus). Second generation (2G) biofuels use biomass to liquid technology, including cellulosic biofuels from non food crops. Many second generation biofuels are under development such as biohydrogen, biomethanol, DMF, Bio-DME, Fischer-Tropsch diesel, biohydrogen diesel, mixed alcohols and wood diesel.
Cellulosic ethanol production uses non food crops or inedible waste products and does not divert food away from the animal or human food chain. Lignocellulose is the "woody" structural material of plants. This feedstock is abundant and diverse, and in some cases (like citrus peels or sawdust) it is a significant disposal problem.
Producing ethanol from cellulose is a difficult technical problem to solve. In nature, ruminant livestock (like cattle) eats grass and then use slow enzymatic digestive processes to break it into glucose (sugar). In cellulosic ethanol laboratories, various experimental processes are being developed to do the same thing, and then the sugars released can be fermented to make ethanol fuel.
The recent discovery of the fungus Gliocladium roseum points toward the production of so-called myco-diesel from cellulose. This organism was recently discovered in the rainforests of northern Patagonia and has the unique capability of converting cellulose into medium length hydrocarbons typically found in diesel fuel.
Scientists also work on experimental recombinant DNA genetic engineering organisms that could increase biofuel potential.
(III) THIRD GENERATION BIOFUELS
Algae fuel , also called oilgae or third generation biofuel , is a biofuel from algae. Algae are low-input, high-yield feedstocks to produce biofuels. It produces 30 times more energy per acre than land crops such as soybeans.With the higher prices of fossil fuels (petroleum), there is much interest in algaculture (farming algae). One advantage of many biofuels over most other fuel types is that they are biodegradable, and so relatively harmless to the environment if spilled.
The United States Department of Energy estimates that if algae fuel replaced all the petroleum fuel in the United States , it would require 15,000 square miles (38,849 square kilometers), which is roughly the size of Maryland .
Second and third generation biofuels are also called advanced biofuels .
Algae, such as Chlorella vulgaris, is relatively easy to grow, but the algal oil is hard to extract. There are several approaches, some of which work better than others.
(IV) FOURTH GENERATION BIOFUELS
An appealing fourth generation biofuel is based on the conversion of vegoil and biodiesel into gasoline.
Craig Venter's company Synthetic Genomics is genetically engineering microorganisms to produce fuel directly from carbon dioxide on an industrial scale.
ADVANTAGES OF BIOFUELS
The aim of all biofuels is to be carbon neutral. They reduce greenhouse gas emissions when compared to conventional transport fuels.
In reality, biofuels are not carbon neutral simply because it requires energy to grow the crops and convert them into fuel. The amount of fuel used during this production (to power machinery, to transport crops, etc) does have a large impact on the overall savings achieved by biofuels. However, biofuels still prove to be substantially more environmentally friendly than their alternatives.
In fact, according to a technique called Life Cycle Analysis (LCA) first generation biofuels can save up to 60% of carbon emissions compared to fossil fuels. Second generation biofuels offer carbon emission savings up to 80%. This was backed by a recent UK Government publication which stated biofuels can reduce emissions by 50-60%.
Another advantage of biofuels is that they save drivers money. The UK Government in particular has introduced many incentives to drivers of 'green cars' based on emissions - with reduced taxation dependent on how environmentally friendly your vehicle is. With petrol prices on the rise, replacing petroleum with a renewable energy source should also offer significant savings at the pump in the long term, particularly when biofuels are more readily available.
There are arguments too that biofuels are helping to tackle poverty around the world. For example, the Overseas Development Institute has pointed to wider economic growth and increased employment opportunities along with the positive effect on energy prices, as reasons to back biofuel production. This is debated due to the pressures it places on agricultural resources but biodiesel could be a long term solution as it uses simpler technology and lower transportation costs alongside increased labour.
DISADVANTAGES OF BIOFUELS
There are several concerns about biofuels - and particularly including.
Biodiversity - A fear among environmentalists is that by adapting more land to produce crops for biofuels, more habitats will be lost for animals and wild plants. It is feared for example, that some Asian countries will sacrifice their rainforests to build more oil plantations.
The food V fuel debate - Another concern is that if biofuels become lucrative for farmers, they may grow crops for biofuel production instead of food production. Less food production will increase prices and cause a rise in inflation. It is hoped that this can be countered by second generation biofuels which use waste biomass - though again, this will impact the habitat of many organisms. The impact is particularly high in developing countries and it is estimated that around 100million people are at risk due to the food price increases.
Carbon emissions – Most LCA investigations show that the burning of biofuels substantially reduces greenhouse gas emissions when compared to petroleum and diesel. However, in 2007 a study was published by scientists from Britain , the USA , Germany and Austria which reported the burning of rapeseed or corn can contribute as much to nitrous oxide emissions than cooling through fossil fuel savings.
Non-sustainable biofuel production – Many first generation biofuels are not sustainable. It is necessary to create sustainable biofuel production that does not effect food production, and that doesn't cause environmental problems.
The production of non-sustainable biofuels has been criticised in reports by the UN, the IPCC and many other environmental and social groups. As a result many governments have switched their support towards sustainable biofuels, and alternatives such as hydrogen and compressed air. During 2008, the Roundtable of Sustainable Biofuels is developing principles for sustainable biofuel production.
ISSUES WITH BIOFUELS PRODUCTION AND USE
There are various current issues with biofuel production and use, which are presently being discussed in the popular media and scientific journals. These include: the effect of moderating oil prices, the "food vs fuel" debate, carbon emissions levels, sustainable biofuel production, deforestation and soil erosion, impact on water resources, human rights issues, poverty reduction potential, biofuel prices, energy balance and efficiency, and centralised versus decentralised production models.
FUTURE OF BIOFUELS
At present it is very hard to justify an aggressively pro biofuel policy simply due to high costs for comparatively low benefits.
In order to make biofuels more realistic there are a few things that could happen. Perhaps the main thing would be the complete depletion of the worlds oil reserves. Should this happen then biodiesel and bioethanol will become the only suitable alternative fuel for use in current I.C.E. vehicles. The problem with this scenario is the amount of land that would be required to produce anywhere near the quantities of fuel the UK requires would be quite staggering. By the time this happens it is quite likely that fuel cell technology will have reached a level of maturity whereby it is commercially viable. This is estimated to occur around 2010 to 2015. This would effectively make biofuels obsolete.
As oil reserves do become scarcer then the price of oil will invariably be driven up. Eventually the price of oil will be high enough that biofuels may be able to compete, however this is very difficult to predict for several reasons. As oil becomes scarcer then the price of energy as well as fuel will rise. This may mean that the energy inputs required for biofuel production will become more costly, driving up the price of biofuels.
At present biodiesel produced from waste vegetable oil is commercially viable due to lower duty (20p per litre lower than conventional diesel). The loss in duty associated with this will never amount to too high a value as there is only a limited amount of waste vegetable oil available. Although we feel that biofuel produced directly from agriculture is not worth while, we feel that biodiesel produced from waste vegetable oil is as it has a lower economic cost and produces a useful product from a waste material.
The first and most important way to meet our energy needs is to increase conservation and efficiency. The cheapest, most sustainable energy is the energy we never have to produce. To meet a portion of remaining energy needs, biofuel s – if done right – are an important part of the equation. They can be used within our existing infrastructure to help wean us off of oil, while simultaneously improving the quality of our environment. However if done wrong, biofuels could simply compound many of our environmental problems and exchange one kind of unsustainable energy for another.
With the proper incentives and awareness of these issues, Oregon has the potential for substantial (though limited) biofuels production. An Oregon biofuel s industry can support local economic development, reduce oil dependence, improve the environment, and reduce Oregon 's global warming footprint.