Alternative fuel
From Free net encyclopedia
Alternative fuel is any energy source for powering an engine that does not involve petroleum (oil). Some alternative fuels are biodiesel, ethanol, electricity, hydrogen, methane, natural gas, wood, and vegetable oil. The need for the development of alternative fuel sources has been growing due to concerns that the production of oil will no longer supply the demand. See Future energy development for a general discussion.
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Categorization
Some of these come into the category of renewable energy. Renewable energy includes electricity generation for the home, while the term "alternative fuels" tends to refer to mobile energy. Some alternative fuels and the cars they power are:
Gasoline type biofuels
- ethanol or mixtures with gasoline E85,
- 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
- propane (aka LPG, LP gas)
- synfuel synthetic fuels
- sunfuel synthetic fuels out of biogen ressources
- oil shale,
- Hybrid electric vehicle
External combustion
- steam engine cars (like the Stanley Steamer),
- coal-oven steam cars,
- organic waste fuel,
- gas vaporizing carburetor,
- 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,
- water fuel cell,
- Star Fuel,
- magnet car, MAGLEV
- air car working on compressed air.
Some less conventional alternative fueled cars are:
- wind-up car,
- nuclear powered,
- compressed air (stored energy),
- rubber band (stored energy),
- spring power (stored energy), and
- wind-powered sail cars.
Most alternative fuels are designed to be cheap, non-polluting, non-finite sources of energy.
Renewable energy
Main article: Renewable energy
Another 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, ethanol and biodiesel, 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.
Biodiesel has some potential advantages because it could replace petroleum diesel without engine modification, and could reuse existing fuel distribution infrastructure. Hydroelectric power currently produces electricity more cheaply than natural-gas turbines; as a result, nearly every river in North America that can be dammed has been. Gigantic hydropower projects have recently been built all around the world (see Itaipu and Three Gorges Dam). Another promising renewable energy source may be wind power (currently over four times as efficient as solar PV power systems). Concentrating Solar Power (CSP) Plants are economic in arid and semiarid regions today. This is particularly true if these solar power plants are designed to take full advantage of the combined heat and power potential outputs. These solar facilities can produce not only electricity, but also steam, hot water, chilled water, and ice using absorption refrigeration cycle equipment. Thermal depolymerization, like biodiesel, has significant current interest and investment because of the potential to replace or gradually replace oil based transportation fuels.
One factor potentially in renewable energy's favor is its much smaller environmental impact. Renewable energy sources may have a significantly smaller total "cost" compared to fossil fuel production after factoring in pollution - in other words, oil production is likely more expensive (compared to renewable energy) than the initial price seems to indicate, if you factor in the cost of pollution on our public health programs.
Alternatives to oil
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. Potentially significant deposits of non-conventional oil include the Athabasca Oil Sands site in northwestern 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, but they are not yet considered proven reserves of oil. Extracting a significant percentage of world oil production from tar sands may not be feasible. The extraction process takes a great deal of energy for heat and electrical power, presently coming from natural gas (itself in short supply). There are proposals to build a series of nuclear reactors to supply this energy. Non-conventional oil production is currently less efficient, and has a larger environmental impact than conventional oil production.
Other fossil fuels and the Fischer-Tropsch process
It is 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, and methane into liquid hydrocarbons (Gas To Liquid GTL) of various forms. The carbon dioxide and carbon monoxide are generated by partial oxidation of coal and wood-based fuels (Biomass To Liquid BTL). This process was developed and used extensively in World War II by Germany, which had limited access to crude oil supplies. It is today used 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.
Methanol 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 share of Ethanol (up to 85% Ethanol and 15% fossil gasoline for lubrification).
However methanol or ethanol is not in itself a source of energy, but a way to obtain oil with a net loss of energy which has to come from a source like fossil fuel planetary reserves, solar radiation (either through photosynthesis, photovoltaic panels or some other undiscovered way), or others. New processes are set up to use not only crops but the whole plant to generate alcohol.
Another potential source of fossil energy 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.
Nuclear power
The U.S. would require at least an eightfold increase in nuclear power production, from 10% of all energy supplied to about 90%, to replace both the current amount of electricity generated from fossil fuels and gasoline usage. Nuclear engineers estimate that the world can derive 400,000 quads of energy (1000 years at current levels of consumption) 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.
Fast breeder reactors are another possibility. As opposed to current LWR (light water reactors) which burn the rare isotope of uranium U-235, fast breeder reactors produce plutonium from U-238, and then fission that to produce electricity and thermal heat. It has been estimated that there is anywhere from 10,000 to five billion years' worth 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. There are a few such research projects working on fast breeders - Lawrence Livermore National Laboratory being one, currently working on the small, sealed, transportable, autonomous reactor (SSTAR).
The long-term radioactive waste storage problems of nuclear power have not been solved, although onsite spent fuel storage in casks has allowed power plants to make room in their spent fuel pools. One possible solution several countries are considering is using underground repositories. The U.S nuclear waste from various locations is planned to be entombed inside Yucca Mountain, Nevada.
Because 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 heat to these vehicles. The most simple 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 would be produced by electrolysis, either conventionally or at high temperatures supplied by reactor heat.
Fusion power
Main article: Fusion power
It is relatively easy to start nuclear fusion reactions, which generate lots of energy (cf. nuclear weapons). However, the energy input needed in achieving the necessary temperature and electromagnetic confinement for controlled and sustained fusion is much too vast to maintain a significant energy gain.
Electricity produced in a typical fusion facility would not involve the creation of millenary radioactive waste, neither would it involve a risk of nuclear meltdown[1]. 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. [2].
The research to make fusion power possible started in 1950, and has made remarkable progress since then [3]. ITER will be the first fusion reactor which reaches ignition, will cost 10 billion dollars and its construction will start in 2006, while in 2015 it should be ready[4]. The European Union, Japan, Russia, the USA, South Korea, India and China are jointly participating in ITER.
However, ITER is only a scientific project. It will not generate electricity. If the current rate of research is maintained, fusion power may become a viable economic alternative to oil around 2050 [5].
Another problem regarding fusion power is that fusion might be an alternative to oil only in generating electricity. However, a great portion of oil consumption is related to transportation and production of oil derivates (plastics, fertilizers, etc.). Hydrogen fuel cells are a potential solution to the transportation problem, but the technology is still being developed.
Hydrogen
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 (what there is resides in Earth's outer exosphere) and thus 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 do. The most immediately feasible hydrogen mass production method is steam methane reformation, which requires natural gas, itself potentially in increasingly short supply. Another method of hydrogen production is through water electrolysis which can use electricity generated from any 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, insufficiently energy dense (hydrogen gas tanks would need to be 2-3 times as large as conventional gas tanks), and expensive to transport and convert back to electricity. 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.
External links
- U.S. DOE Clean Cities Program Program that focuses on putting alternative fuels into use across the United States (with much success to show for it); there are approximately 90 coalitions across the U.S. that work in areas ranging in size from small cities to entire states
- Sustainable Green Fleets EU-sponsored Dissemination project for alternative propelled cars and alternative fuels
- Alternative Fuel Vehicle Training National Alternative Fuels Training Consortium, West Virginia University U.S.