Alternative fuel

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Alternative fuel (alternate fuel), also known as non-conventional fuels, is any material or substance that can be used as a fuel, other than fossil fuels, or conventional fuels of petroleum (oil), coal, propane, and natural gas. The term "alternative fuels" usually refers to a source of which energy is renewable.

1 Background to fuel
2 Alternative fuels
3 Alternative Fuel Vehicles (AFVs)
- 3.1 Types of Alternative Fuels
4 Alternatives to oil
5 See also
6 References

[edit] Background to fuel

The main purpose of fuel is to store energy in a form that is stable and can be easily transported from the place of production to the end user which helps in many ways such as transportation. Almost all fuels are chemical fuels, that store chemical potential energy. The end user is then able to consume the fuel at will, and release energy, usually in the form of heat for a variety of applications, such as powering an engine, or heating a building, such as a home

Some well known alternative fuels include biodiesel, ethanol, butanol, chemically stored electricity (batteries and fuel cells), hydrogen, methane, natural gas, vegetable oil, biomass, and peanut oil.

[edit] Alternative fuels

In the year 2000, there were about eight million vehicles around the world that ran on alternative fuels, indicating the increasing popularity of alternative fuels^{[citation needed]}. There is growing social interest, and an economic and political need for the development of alternative fuel sources. This is due to general concerns of sustainability, both environmental, economic, and geopolitical. A primary concern is that the fact that the use of conventional fuels directly contributes to the global warming crisis. Another concern is the problem of peak oil, which predicts a rising cost of oil derived fuels caused by severe shortages of oil during an era of growing energy consumption. According to the 'peak oil' phenomenon, the demand for oil will exceed supply and this gap will continue to grow, which could cause a growing energy crisis by the year 2010 or 2020. Lastly, the majority of the known petroleum reserves are located in the middle east. There is general concern that worldwide fuel shortages could intensify the unrest that exists in the region, leading to further conflict and war. (See future energy development for a general discussion)

[edit] Alternative Fuel Vehicles (AFVs)

Interest in vehicles powered by alternative energy sources has been gaining traction in large part due to high gas prices and and an increased awareness of global warming, which according to a recent Intergovernmental Panel of Climate Change (IPCC) report[1] is 90% likely caused by humans. The "fuel is the set of chemicals which are oxidized and reduced to release the stored energy. In a battery or fuel cell powered vehicle, this is electricity. In some circumstances, however, electricity may be provided directly to a mobile electric engine, such as an electrified trolley or train, or a magnetically levitated train. In such cases, electricity itself may be treated as an alternative "fuel," since it replaces fuel energy used in transportation.

[edit] Types of Alternative Fuels

Some alternative fuels and the cars they power are:

Gasoline type biofuels

15% gasoline, 85% ethanol blend

P-series fuels- can be used in any E85 compatible engine
Hydrogen internal-combustion car (see hydrogen car)

Diesel type biofuels

Hempseed oil fuel or other Straight vegetable oils
Biodiesel

Others with internal combustion

Natural gas- compressed or liquified
Autogas (aka LPG, LP gas, Propane)
Synfuel- synthetic fuels
Plug-in hybrid electric vehicle

External combustion

Steam engine cars (like the Stanley Steamer)
Coal-oven steam cars
Organic waste fuel
Wood gas on-board gasification

No combustion

Electric vehicle
Solar cell- powered or charged electric cars
Tesla's electric car (with antenna)
Hydrogen fuel cell (see hydrogen car) liquefied or compressed hydrogen
MAGLEV- with induction drive (a variety of electric mass transit)
Air car- working on compressed air

Some less conventional alternative fueled cars are:

Nuclear powered
Solar Radiation
Sail
Wind-powered sail cars

Alternative fuels are designed to meet the needs of humans whether it be economic, political, or environmental. For example E85 is cheaper to purchase than gasoline, economic, in the Midwest of the United States specifically Minnesota and Illinois. Electric cars pollute 90% less than gasoline driven cars, environmental. Finally, many governments offer tax breaks to companies developing alternative fueled cars.

[edit] Alternatives to oil

[edit] Renewable energy

Main article: Renewable energy

A possible solution to a potential future energy shortage would be to use some of the world's remaining fossil fuel reserves as an investment in renewable energy infrastructure such as wind power, solar power, tidal power, geothermal power, hydropower, thermal depolymerization, methanol, ethanol and biodiesel, or in an oil lamp; try olive oil, canola oil, safflower oil, or sunflower oil which do not suffer from finite energy reserves, but do have a finite energy flow. The construction of sufficiently large renewable energy infrastructure might avoid the economic consequences of an extended period of decline in fossil fuel energy supply per capita.

Most alternative fuels assume a source of renewable energy or at least sustainable energy (such as nuclear power) as a source of the fuel. A few alternative fuels (for example, hydrogen) may be made by sustainable or non-sustainable means. If they are made by non-sustainable means, such fuels are offered as alternatives usually because they offer to cause less pollution at the point of use, and perhaps less pollution overall.

[edit] Non-conventional oil

Non-conventional oil is another source of oil separate from conventional or traditional oil. Non-conventional sources include: tar sands, oil shale and bitumen. Enormous deposits of non-conventional oil include the Athabasca Oil Sands site in northwestern (Alberta) Canada and the Venezuelan Orinoco tar sands. Oil companies estimate that the Athabasca and Orinoco sites (both of similar size) have as much as two-thirds of total global oil deposits. However, the ability to 'see' underground is limited, so as with all oil reserves, the quantity of available oil is uncertain, even for so-called 'proven' reserves. Large mining operations are currently producing oil, and to some people, this proves the viability of the entire process. Others argue that since the technology is still relatively new, it remains unclear whether it is feasible for a significant percentage of world oil production to be extracted from tar sands. One fact that is agreed upon, is that the current extraction process takes a great deal of energy for heat and electrical power, presently coming from local natural gas, which itself is in short supply. There are some proposals to build a series of nuclear reactors to supply this energy. Non-conventional oil production is currently less energy-efficient, and has a larger environmental impact than conventional oil production.

[edit] Other fossil fuels and the Fischer-Tropsch process

It's expected by geologists that natural gas will peak 5-15 years after oil does. There are large but finite coal reserves which may increasingly be used as a fuel source during oil depletion. The Fischer-Tropsch process converts carbon dioxide, carbon monoxide, access to crude oil supplies. It is used today in South Africa to produce most of that country's diesel from coal. The Karrick process is an improved methodology for coal liquefaction, with higher efficiency. Since there are large but finite coal reserves in the world, this technology could be used as an interim transportation fuel if conventional oil were to become scarce. There are several companies developing the process to enable practical exploitation of so-called stranded gas reserves, those reserves which are impractical to exploit with conventional gas pipelines and LNG technology.

Another potential source of methane is methane hydrate. This substance consists of methane molecules trapped within the crystalline structure of water ice and is found in naturally-occurring deposits under ocean sediments or within continental sedimentary rock formations. It is estimated that the global inventory of methane hydrate may equal as much as 10x the amount of natural gas. With current technology, most gas hydrate deposits are unlikely to be commercially exploited as an energy source. In addition, the combustion of methane results in the formation of carbon dioxide and would thus continue to contribute to global warming, but in other respects it has the same problems of fossil fuel).

Methanol (methanol economy) from any source can be used in internal combustion engines with minor modifications. It usually is made from natural gas, sometimes from coal, and could be made from any carbon source including CO₂. Flexible fuel vehicles may run with a high percentage of ethanol (ethanol economy) (up to 85% Ethanol plus 15% gasoline for cold-starting vapor pressure).

Methanol and ethanol are typically not primary sources of energy; however, they are a convenient way to store the energy for transportation. No type of fuel production is 100% energy-efficient, thus some energy is always lost in the conversion. This energy can be supplied by the original source, or from other sources like fossil fuel reserves, or solar radiation (either through photosynthesis or photovoltaic panels), or hydro, wind or nuclear energy (see below). The use of energy to produce alcohol fuels could potentially proceed via production of hydrogen by electrolysis of water, or possibly (in the case of heat from nuclear energy) by the sulfur-iodine cycle; then use of the hydrogen in the Fischer-Tropsch process along with CO₂ from another source. Such a process might store and use hydrogen more efficiently than attempting to use hydrogen directly as fuel (a gallon of alcohol contains about 50% more hydrogen by weight than a gallon of liquid hydrogen). Since such a process would not liberate net quantities of new CO₂ at the point of combustion, it would be greenhouse neutral, similar to alcohols made from biomass.

[edit] Nuclear power and transportation energy and fuel

If nuclear energy were to replace gasoline and fossil fuels used for generation of electricity, then the U.S. would require at least an eightfold increase in nuclear power production, increasing from about 10% of all energy supplied to about 90%^{[citation needed]}.

[edit] Fission reactors

Nuclear engineers estimate that the world could derive 400,000 quads (quadrillion, 10¹⁵, British thermal units), or about 420,000 EJ (exajoules = 10¹⁸ joules), of energy (1000 years at current levels of consumption, assuming new technology) from uranium isotope 235, if reprocessing is not employed. As uranium ore supplies are limited, a majority of this uranium would have to somehow be cost-effectively extracted from seawater. But this technology does not exist. However, at the current technology and consumption, the reserves will last 50 years.

Fast breeder reactors are another possibility. As opposed to current LWR (light water reactors), which burn the rare isotope of uranium U-235 (producing and burning about an equal amount of plutonium in the process), fast breeder reactors produce much larger amounts of plutonium from common U-238, then fission that to produce electricity and thermal heat. Because there is about 139 times more U-238 than U-235 on Earth, it has been estimated that there is anywhere from 10,000 to 5,000,000,000 years' worth (sustainable but not renewable, depending on future technology) of U-238 for use in these power plants, and that they can return a high ratio of energy returned on energy invested (EROEI), and avoid some of the problems of current reactors by being automated, passively safe, and reaching economies of scale via mass production. In addition, wastes produced by these plants are less toxic than those of conventional reactors. There are a few such research projects working on fast breeders. Lawrence Livermore National Laboratory is currently working on the small, sealed, transportable, autonomous reactor (SSTAR). Problems arise from the higher levels of heat and radiation produced by this reactor. There are other, more exotic nuclear projects (such as pebble bed reactors), each with their own technical problems.

The long-term radioactive waste storage problems of nuclear power have not been solved, although on-site spent fuel storage in casks has allowed power plants to make room in their spent fuel pools. Today, the only industrial solution lies with storage in underground repositories.

Since automobiles and trucks consume a great deal of the total energy budget of developed countries, some means would be required to deliver the energy generated from nuclear power to these vehicles. The most direct solution is to use electric vehicles. Mass transit will be an important aspect of this solution, as it is readily electrified. Some think that hydrogen may play a role (see below). If so, it could be produced by electrolysis, either conventionally or at high-temperatures supplied by reactor heat. Another possibility for producing hydrogen by nuclear power is the heat-driven sulfur-iodine cycle.

Hydrogen need not be used directly in transportation. A hybrid chemical-energy storage process might use such hydrogen to produce methanol from CO₂ (see above), which would then feed into the present internal-combustion-engine transportation infrastructure with far less modification than would be needed for hydrogen. See methanol economy.

[edit] Fusion reactors

It is relatively easy to start nuclear fusion reactions, which generate large amounts of energy (cf. thermonuclear weapons). However, to achieve controlled and sustained fusion requires a large amount of input energy to obtain either the required high-temperature electromagnetic confinement, or instantaneously high densities. The technology has not yet been developed to maintain significant energy gains.

Electricity produced in a typical fusion facility would create radioactive waste, thus there are some safety concerns. As compared to a fission nuclear plant, the risk of nuclear 'meltdown' is reduced, because the fuel available in a fusion reactor is only enough to sustain the reaction for minutes at a time (as opposed to fission which has enough fuel to power a reaction for hours)[2]. The main waste produced is simply Helium, however the process will irradiate the main chamber of power plant, which will need to be held securely until the radiation decays. However this will decay away to safe levels in hundreds, rather than tens of thousands of years[3]. The natural resources required for the implementation of the DT (Deuterium-Tritium) fuel cycle (the option that is most likely to be put into effect) are essentially inexhaustible since they can both be recovered from water - however since Tritiumis a lot rarer that Deuterium in water, plans for a Nuclear Fusion Power Plant would use the radiation from the reactor to cause Tritium to be released from a nuclear reaction with Lithium, which will line the walls of the reactor. Lithium is a very common element, however not quite as common as water. [4].

The research to make fusion power possible started in 1950, and has made notable progress since then [5]. ITER should be the first fusion reactor which will achieve burning plasmas, though there is some grounds to optimistically hope that it may reach ignition, it will cost a total of €10 billion over 30 years ($12.1 billion) and its construction will start in 2006, and is expected to be completed in 2015 [6]. The European Union, Japan, Russia, the USA, South Korea, India and China are jointly participating in ITER. ITER is only a scientific project, not a commercial power plant, however if ITER is successful a test commercial power plant will be built, currently called DEMO, to test the most fincially efficient technologies. If the current rate of research is maintained, fusion power may become a viable economic alternative to oil around 2050 [7].

Electricity from fusion power is an alternative to oil for generating electricity, however; unlike oil, the energy source is not directly usable as a fuel for transportation (assuming liquid fuels). In this respect, it has the same limitations as electricity from fission, solar, and other sources, which for now must rely on the use of batteries for transportation. One possible alternative would be an intermediate chemical energy storage economy (such as hydrogen economy, methanol economy or ethanol economy) which could make use of nuclear power for chemical synthesis.

[edit] Hydrogen

Main article: Hydrogen economy

Proponents of a hydrogen economy think hydrogen could hold the key to ongoing energy demands. Relatively new technologies (such as fuel cells) can be used to efficiently harness the chemical energy stored in diatomic hydrogen (H₂). However, there is no accessible natural reserve of uncombined hydrogen, since what little there is resides in Earth's outer atmosphere (exosphere). Hydrogen for use as fuel must first be produced using another energy source; hydrogen would thus actually be a means to transport energy, rather than an energy source, just as common rechargeable batteries are. One existing method of hydrogen production is steam methane reformation; however, the most common source of methane is natural gas, which is in short supply. Another method of hydrogen production is through electrolysis of water which uses electricity generated from any source, or a combination of: fossil fuels, nuclear, and/or renewable energy sources. Biomass or coal gasification, photoelectrolysis, and genetically modified organisms have also been proposed as means to produce hydrogen.

According to the majority of energy experts and researchers, hydrogen is currently impractical as an alternative to fossil-based liquid fuels. It is inefficient to produce, has low energy density (hydrogen gas tanks would need to be 2-3 times as large as conventional gasoline tanks), and is expensive to transport and convert back to electricity. Also hydrogen fuel cells are still prohibitively expensive as a prime mover of transportation. However, theoretically it is more efficient to burn fossil fuels to produce hydrogen than burning oil directly in car engines (due to efficiencies of scale). Unfortunately, this does not take into consideration the significant energy cost of having to build hundreds of millions of new hydrogen powered vehicles plus hydrogen fuel distribution infrastructure. Research on the feasibility of hydrogen as a fuel is still underway, and the outcome is, at best, uncertain.

[edit] Air engine

The Air engine is an emission-free piston engine using compressed air as fuel.

[edit] Liquid nitrogen

A liquid nitrogen would extract energy from the temperature difference between air and liquid nitrogen. The Stirling engine or cryogenic heat engine offers a way to power such vehicles. A means to generate liquid nitrogen, which is only an energy storage medium, is needed.