Fossil Fuels

Introduction
Fossil fuels, coal, oil and natural gas, are a non-renewable source of energy. Formed from plants and animals that lived up to 300 million years ago, fossil fuels are found in deposits beneath the earth. The fuels are burned to release the chemical energy that is stored within this resource. Energy is essential to moden society as we know it. Over 85% of our energy demands are met by the combustion of fossil fuels. These two pie charts show exactly how vital fossil fuels are to our society by showing how much of each energy resource is consumed.

Formation
Going back to the earlier days of Earth, the plants and animals that lived then eventually died and decomposed. The majority of these life forms were phytoplankton and zooplankton. When these ancient ocean dwellers died, they accumulated on the bottom of a seabed; this is how a good portion of our fossil fuel reserves began. The actual transformation process of these prehistoric creatures is not known, but scientists do know that the pressure, heat, and a great deal of time go into the making of fossil fuels.
Geologists are fairly certain that the beds of organic remains mixed with silt and mud to form layers. Over time, mineral sedimentation formed on top of the organisms, effectively entombing them in rock. As this occurred, pressure and temperature increased. These conditions, and possibly other unknown factors, caused organic material to break down into the simpler form of hydrocarbons: chains of carbon and hydrogen ranging from simple configuration to complex compounds. Another affect of extreme pressure is that the oil and gas which are various mixtures of hydrocarbons, migrate upwards to the surface. Exactly when in the conversion process and the nature of this migration is not known and is subject to conjecture.
Oil and gas are found in the ground, not freely drifting up through the earth. This is because the hydrocarbons come across rock formations that they are unable to penetrate. Complex rock structures that effectively trap gas and oil are formed by tectonic plate activity, the same forces that shift continents. The most common formation that accomplishes this is called an anticline, a dome or arched layer of rock that is impermeable by oil and gas. Underneath this barrier, a reservoir builds up. An oil reservoir is not some vast underground lake, but rather a seemingly solid layer of rock that is porous. Oil fields have been found everywhere on the planet except for the continent of Antarctica.
These fields always contain some gas, but this natural gas, methane, does not take nearly as long to form. Natural gas is also found in independent deposits within the ground as well as from others sources too. Methane is a common gas found in swamps and is also the byproduct of animals' digestive system. Incidentally, Methane is also a greenhouse gas.
Coal is formed in a similar to the other fossil fuels, though it goes through a different process, coalification. Coal is made of decomposed plant matter in conditions of high temperature and pressure, though it takes a relatively shorter amount of time to form. Coal is not a uniform substance either, it's composition varies from deposit to deposit. Factors that cause this deviation are the types of original plant matter, and the extent the plant matter decomposed. There are over 1200 distinguishable types of coal. Coal begins as peat, a mass of dead and decomposing plant matter. Peat itself has been used as fuel in the past, as an alternative to wood. Next, the peat becomes lignite, a brownish rock that contains recognizable plant matter and has a relatively low heating value. Lignite is the halfway point from peat to coal. The next phase is subbituminous. A shade of dull black, showing very little plant matter, this type of coal has a less than ideal heating value. Bituminous coal is jet black, very dense, and brittle. This type of coal has high heating value.
The main point of this is that all of these fossil fuels are made of hydrocarbons. It may come as a surprise that these two elements, hydrogen and carbon, can create many, many different compounds with unique characteristics. What makes hydrocarbons valuable to our society is the stored energy stored within them. This energy is contained in the atomic bonds. The original source of this energy is all the solar energy the prehistoric organisms trapped in their bodies eons ago. How do we make use of this bond energy then? We burn them.
Combustion, Drilling, and Refining
Combustion is the process of breaking atomic bonds to release energy in the form of light and heat. Fossil fuels have many hydrocarbons, each with numerous bonds. When they undergo combustion, they release a great deal of heat. This is the main reason why natural gas and heating oils are used extensively in the world today. However, energy in the form of heat is by nature very chaotic and disorganized. Simply burning fossil fuels is wonderful for keeping the winter chill at bay, but setting oil on fire in your washing machine won't get your clothes clean. Likewise, we can't put petroleum directly out of the ground into our cars and expect them to operate. To make use of the resource of fossil fuels, humans have developed drilling, refining, and methods to harness fossil fuel energy.
Early oil explorers relied heavily on intuition and guesswork to find the precious 'black gold.' These daring entrepreneurs were known as 'wildcatters.' A fabled technique used by the wildcatters is the 'old hat.' They would basically toss their hat up in the air and wherever it landed, they drilled. When the wildcatters got lucky, and struck oil, it would typically gush up the drill pipe, hence, a gusher. Because gushers are a safety hazard and environmental concern, oil companies today contain them. After discovering an oil field, it is the task of the oil company's engineers and technicians to get it out. Not all oil fields turn out to be gushers and even the ones that are eventually loose pressure, leaving a lot of untapped fossil fuel resource in the reservoir. Even with modern extraction techniques, 100% of the oil in any given field is still not yet recoverable.
One thing an oil company does to facilitate the extraction process is setting up what is known as a 'Christmas tree,' a system of valves and pipes that regulate oil flow and pressure. Another system used in much smaller reservoirs not worth the expense of manning with technicians is the setup of a beam pump These are also known as 'nodding donkeys;' they extract oil from small oil pools that do not contain much resource. In large oil fields, techniques such as water and gas injection are employed to maximize return of the investment. By pumping water and gas into the wells, the pressure increases allowing oil to flow upwards once more Large oil fields can be found under the sea floor as well. To exploit these fields, vast oil drilling stations, which are marvels of modern engineering, tap into these underwater deposits and bring them to the surface.

Although fossil fuels have been around long before humans even discovered fire, our prehistoric ancestors had no use for them. In the late 1800's, coal and gas were used as heat and light sources, steam locomotives as well. There were early automobiles too, but these vehicles were more of a novelty than a way of life. It wasn't until the 1940's did things change. Why the 1940's? The answer is that engineers and inventors had government support and extra incentive to develop fossil fuel technologies, war. World War II was the catalyst and not World War I because 'The War to End All Wars' was fought by men in trenches and mechanized warfare had only been developed late in the conflict. World War II had the German Blitzkrieg, or 'Lightning War.' This tactic utilized Shtuka dive bombers and Panzer tanks; German engineers enabled this, and was eventually countered by Allied technological advancements. From then on, usage and development of fossil fuels steadily rose.
The primary refining technique used to separate hydrocarbons and provide the ingredients for modern fuels is called fractional distillation. Hydrocarbons of different size and configuration usually have differences in boiling points that are large enough to use as a method of separation. By vaporizing them, they tend to float upwards until the hydrocarbons condense, which is where they are collected. Hydrocarbons as simple as butane and alcohols with few carbons are sorted along with more complex ones such as aromatics with 9 carbons. The fuels we commonly use today are a mixture of these hydrocarbons distilled from the petroleum extracted from the earth.
Fuel types and Engines
Gasoline is a highly specialized fuel that contains hydrocarbons ranging from butane to C10. It is designed for the Otto-cycle engine, also known as spark ignition or 4-stroke engine. This engine as well as others will be described in more detail later on. Some characteristics of gasoline enable the following:
1. Quick start at low temperatures
2. Fast acceleration
3. Low occurrence of stalling
4. Relatively quiet and low tendency to knock
5. Good combustion efficiencyThe next classification of fuels is the distillate fuels. They are kerosene, turbo-jet fuel, diesel, and heating oil. Kerosene was the first petroleum fuel oil to be widely used; this was before electric lights and after the days of animal and vegetable oil. Kerosene has become less popular and is no longer produced in the quantities it once was. Countries with limited access to electricity and outdoors enthusiasts still have a use for this fuel.
Turbo-jet fuel was first developed in WWII for use in airplane engines. Because of constraints on petroleum products, namely gasoline for tanks and other ground vehicles, this fuel was designed to make use of compounds not vital to gasoline production whenever possible. The result was a highly volatile fuel that led to many accidents in handling. Modern aviation fuel is still more volatile than gasoline, though it has become much safer than it previously was.
Diesel fuel and domestic heating oil are similar in composition. Domestic heating oils are not widely used in the US, though they still have limited application in underdeveloped countries. Diesel fuels are used frequently in the world today; transport vehicles such as trains, boats, trucks, and busses use diesel fuel.
Fuel oils are mainly residuals from the fractional distillation process. They are more or less the leftovers from production of other fuels. They have been and are still used in power generation plants. Because of the low quality and high pollution content fuel oils are being used less often.
Of the fuels previously listed, gasoline, turbo-jet fuel, and diesel fuel were designed for usage in engines. A fairly good, simple definition of an engine is a device that converts chemical or heat energy into mechanical energy. Engines convert fossil fuel energy into a form that we can more readily use.
The majority of engines in the world today are internal combustion engines. This type of engine is found in most machines and vehicles that run on fossil fuels. The first internal combustion engine was invented by Nicolaus August Otto. There are 4 general types of internal combustion engines that will be discussed here briefly. The first is the type designed by Mr. Otto himself, the Otto-cycle engine. These are the engines you typically find in cars. These are 4-stroke engines, named thus because it goes through 4 phases during operation: intake, compression, expansion, and exhaust. The parts of the engine directly involved in this cycle are the cylinder, the piston, the valves, and the spark plug.
· Intake-- Intake valve opesns allowing fuel/air mixture into the cylinder
· Compression-- The piston rises, reducing volume and increasing pressure
· Expansion (power stroke)-- Spark plug ignites, fuel expands pushing piston
· Exhaust-- Exhaust valve opens expelling spent fuel from cylinder
The second type of engine is known as a 2-stroke engine. These are usually placed in lawn mowers, outboard motors, and high performance recreational vehicles. There are two main differences between 4 and 2-stroke engines A 4-stroke engine causes two revolutions in one cycle whereas the 2-stroke only takes one revolution to complete its cycle. The other major difference between them is that 2-strokes require a gasoline/oil mixture as fuel. This is because the cylinder must be kept completely bathed in lubricants to prevent damage. Due to these attributes, these engines are much more compact and can generate higher revolutions per minutes and more acceleration. The problem with this design is that it is not at all fuel efficient and burning motor oil causes a lot of pollution.
Diesel engines, as you might know, require no spark plugs in the combustion process. Otherwise, the design of the diesel engine is not much different than an Otto-cycle engine. Instead of spark plugs, the diesel engine relies on compression and the heating of air in the fuel mixture to cause ignition. To achieve this, diesel fuel has a lower boiling point and does not require much heat. Diesel fuel is cheaper to make than gasoline, though its high level of pollutants require it to undergo further filtration; this drives the fuel price up.
The last type of conventional engine discussed here is the wankel rotary combustion engine, named after its inventor, Felix Wankel. Out of the engines discussed, this one is the most 'revolutionary' (excuse the pun). The wankel engine does not use pistons, instead it uses a rotor. The rotor spins and drives the shaft by expanding fuel in the housing on the sides of the rotor. The results of this engine type are as follows:
· Light weight and compact
· Smooth: no reciprocating motion
· Extended power stroke rotation: 270 degrees vs. 180 degrees of a piston
· Fewer moving parts
· Cooler combustion means fewer oxides of nitrogenThe wankel engine was used in the Mazda motorcars RX series of cars. For all the advantages of this engine, it had one major drawback, it was extremely inefficient in fuel consumption. The oil crisis in 1973 caused this engine to loose support and funding for further development to improve consumption. Currently the RX series of Mazda cars is no longer in production, however Mazda has made a RX-01 concept car. Wankel rotary engines can also be found in porches and other powerful sports cars.
Aviation fuel, the turbo-jet fuel, is used by both jet and propeller aircraft today. Prop engines are designed similar to the 4-stroke engines of cars, though the demands on these two varieties of engines are quite different. To accommodate this, prop engines are much larger and have higher power output. The distillate fuel they use is ideal for this purpose. With the inception of jet propulsion the fuels used did not change all that much. Even though it may seem that the jet engine is very different, it is still considered to be an internal combustion engine. The main components of a jet engine are the compressor, combustion chamber, and the turbine. Air flows into the compressor where it is pressurized and forced into the combustion chamber There, inside the chamber, fuel is constantly flowing in, and ignited causing an expansion of the fuel The turbine's purpose is to provide enough energy from the expelled gasses to the compressor in order to operate at peak performance. Jet engine technology has advanced greatly and there are many different types of them. Just to list a few, there are turbojet, turbofan, turboprop, turboshaft, and ramjet designs. Each have specialized uses, mostly in aviation technology.
Coal and Electricity
Fossil fuels are excellent sources of energy for out transportation needs; however they are also the primary source of electrical energy in the world today. Coal power plants account for at least 60% of our national energy and 52% of the world's demand. We, as a world, burn approximately 1.9 billion tons of coal a year to generate electricity.
How we get electrical energy from coal is by means of coal power plants. These power plants first combust the coal in large furnaces creating tremendous amounts of heat. This heat is used to evaporate water in boilers so they convert to steam. The steam expands, causing pressure to increase in the boiler. A steam turbine is placed at the exit of the boiler where it converts energy from the moving steam into mechanical energy. The rotation of this turbine is used to spin a magnet inside a power generator. This generator is a large electromagnet that encases the spinning magnet. Instead of putting electricity into the electromagnet to cause the coil to magnetize, electrons are captured from the spinning magnet and collected. The electrons are then sent to the national power grid where they are distributed as needed.
Health Impacts
Air particles are deadly. The byproducts that form from the burning of fossil fuels are very dangerous. These small particles can exist in the air for indefinate periods of time, up to several weeks and can travel for miles. The particles, sometimes smaller than 10 microns in diameter, can reach deep within the lungs. Particles that are smaller than this can enter the blood stream, irritating the lungs and carry with them toxic substances such as heavy metals and pollutants. Over a lifetime of continued exposure, a person's ability to transfer oxygen and rid pollutants is impeded. Those affected could become afflicted with fatal asthma attacks and other serious lung conditions. the World Resources Institute reports that between the years of 2000 and 2020, 8 million deaths worldwide could possibly occur without changing present conditions. In 1990 alone, respiratory diseases were a leading cause of disabilities and illnesses worldwide. This is a global problem and requires a global solution. Because the contamination is growing at an exponential rate, minor reductions now will greatly reduce the number of lives lost in the future.
How Much is left?
So far the United States has produced the most oil at 171 billion barrels. Followed by the former Soviet Union with 125 billion and Saudi Arabia far behind in third place with 74 billion barrels. this illustrates the maturity of the United States which for many years was the world's most important producer.
The term reserves means the amounts yet to produce from known discoveried resources as of today, however it is difficult to estimate the actual amount. The country with the most reserves is Saudia Arabia with 189 Gb. This is followed by the former Soviet Union with 84 Gb. Note that the whole Middle East region has more than half of the world's oil reserves with 439 of the possible 800 billion barrels in the world.
Discovered to date is the sum of the cumulative production and the reserves. Again, see that the Middle East Gulf is in first place with 625 Gb followed by Eurasia, 267 Gb, and North America, 225 Gb. For singular countries, the order holds true with Saudi Arabia in first with the former Soviet Union and the United States rounding out the top three.
The ultimate is cumulative production when production ends. It is important to realize that there is an ultimate even if it is difficult to determine the number exactly. The Middle East region has the largest endowment with 687 Gb, followed by Eurasia with 295 Gb, and North America with 238 Gb. Saudi Arabia, 280 Gb, the FSU 230 Gb, and the United States, 210 Gb, are the three most richly endowed countries.
The undiscovered is the ultimate less the discovered. In terms of individual counrtires, the former Soviet Union (21 Gb), Iraq (19 Gb), Iran (17 Gb), and Saudi Arabia (16 Gb) have the greatest promise. Discovery rates have been falling with it currently standing at about 7 Gb a year. Most of what remains will likely be found within 10-20 years.
The remaining is the reserves plus the undiscovered. The middle east gulf continues to dominate with about half of the total, followed by Eurasia, and Latin America.
Now it is important to see which countries are close to running out of oil. This graph shows how close some countries are to the midpoint of what they can produce.
It is difficult to know the future, but these facts can put things in perspective:
Known US reserves as of 1990: 36 Gb.
The total population is about 250 million, which yields 144 barrels per person.
The consumption rate is 3 billion barrels of oil per year, which gives 12 barrels per year, per person.
144/12 is approximately 12 more years left.
In 1995, the reserve estimate dwindled to 22.5 Gb and the consumption rate remained the same.
22.5/3 means that 7.5 years remain which corresponds to the earlier prediction. On a worldwide basis, there are 400 Gb per person. The timescale when this resource is used up is dependent on the world consumption rate, a figure difficult to estimate. A worst case scenario is the "Third World" scenario which has the third world nations aspire to the US consumption rate causing the world rate to double: there would be only 400/24, meaning 17 years left. Although this is a worst case, most best case scenarios offer a resource exhaustion timescale which is at most 3-4 times this value which is 50-70 years.
Note that Saudi Arabia produces the same as the US. The US needs 600,000 wells for its production and Saudi Arabia, only 860 wells. This is because the US sits on an old oil field while Saudi Arabia is located over a very young and rich one.
Oil Spills
With the United States importing 55% of its oil, oil spills are a serious problem. The Exxon Valdez oil spill awakened the nation as we saw its effects on television. To this day there still exsists measurable differences in the environment. Some species have not been able to recover.

Resources Effected By The Exxon Valdez Oil Spill

Resource
Description Of Injury
Status Of Recovery
Comments / Discussion
Oil Spill Morality (est.)
Measured Decline
Sublethal / Chronic Effects
Current Population Status
Continuing Effects
MARINE ANIMALS
Harbor Seals
Yes (300)
Yes
Yes
Stable
Unknown
Many seals were directly oiled. There was a greater decline in population in oiled vs. unoiled areas in 1989 and 1990. Population was in decline prior to the spill and recovery has still not begun possibly due to lack of preferred diet. Current population decline is 6% per year.
Killer Whales
Yes (13)
Yes
Unknown
Deteriorating
Unknown
13 adult whales of the AB pod were missing and presumed dead in 1990 and no young were produced in 1990 or 1991. The pod gained 4 members in the following two years but since then there have been more losses than births. Some experts think that the loss of 13 whales is not related to the spill.
Sea Lions
Unknown
Yes
No
Continuing Decline
No
Several sea lions were observed with oiled pelts and oil residues were found in some tissues. It was not possible to determine population effects or cause of death of carcasses recovered. Sea lions were already in decline prior to the spill.
Sea Otters
Yes (3,500 to 5,500)
Yes
Yes
Stable
Yes, Possibly
Survival differences between oiled and unoiled areas have been noticed since the spill. Sea Otters feed in the lower intertidal zones and may still be effected by hydrocarbons in the environment.
TERRESTRIAL MAMMALS
River Otter
Yes (total unknown)
No
Yes, Possibly
Unknown
Unknown
Exposure to hydrocarbons and possible sublethal effects were determined, but no effects were established on population. In 1991 studies showed that exposure to hydrocarbons still remained probably from exposure through diet.
BIRDS
Bald Eagle
Yes (200 or more)
No
Yes
Recovered
No
Productivity was disrupted in 1989 but returned to normal in 1990. Exposure to hydrocarbons was found in 1989 and it is assumed that the source, based on visual observation, was from eating oiled carcasses.
Black Oyster- catchers
Yes (120 to 150 adults)
Yes
Yes
Recovering
Yes
Differences in egg sizes between oiled and unoiled areas were found in 1989. Populations declined more in oiled areas during 1989, 1990, 1991, 1992. Possibly due to exposure to hydrocarbons through diet.
Common Murres
Yes (170,000 to 300,000)
Yes
Yes
Varies
Yes
Measurable impacts on population were recorded in 1989, 1990, 1991, and 1992. Breeding is still reduced in some areas of the Gulf Of Alaska.
Harlequin Ducks
Yes (approx. 1,000)
Yes
Yes, Possibly
Unknown
Yes
Population declines lasted through 1992 partially due to reproductive failure. Currently studies are focusing on differences on winter survival rates between western and eastern Prince William Sound
Marbled Murrelets
Yes (8,000 to 12,000)
Yes
No
Continuing Decline
Unknown
Marbled murrelets experienced a 7% population decline due to the spill. Measurable population decline was also observed before the spill and continuing today.
Pigeon Guillemonts
Yes (1,500 to 3,000)
Yes
No
No
Unknown
Populations were in decline before the spill. The spill claimed between 10 and 15 percent of the population throughout the region. Hydrocarbon contamination is assumed based on the finding of hydrocarbons on the exterior of their eggs.
FISH
Pacific Herring
Yes, To Eggs & Larva
Yes
Yes
See Comments
No
Measurable egg counts between oiled and unoiled areas were found in 1989 and 1990. In 1989, 1990, 1991 lethal and subleathal effects on eggs and larvae were found. In 1993 the population crashed due to a viral disease and fungus. Commercial fishing seasons were closed for four years between 1993 and 1997.
Pink Salmon
Yes, to eggs
Yes
Yes
See Comments
No
Severe effects were inflicted on fry in 1989 and 1990 and continued to be high in 1991 and 1992. Fishing seasons were closed in 1989. Wide swings in returns have been documented but are more likely due to natural causes. The SEA ecosystem project is currently studying these swings.
HUMAN RESOURCES & SERVICES
Resource
Description of Injury
Status
Commercial Fishing
During 1989 emergency fishing closures were ordered in Prince William Sound, Cook Inlet, Kodiak and the Alaska Peninsula. This affected salmon, herring, crab, shrimp, rockfish, and sablefish. The 1989 closures resulted in over-escapement in the Kenai River and in the Red Lake system. Limited closures were also in effect in 1990.
Low adult sockeye returns in 1994 were a result of the over-escapement from Kenai River. Future fishing seasons may need to be closed to balance out the problem.
Recreation & Tourism
Some commercial recreation and tourism businesses were injured by the reduction in visitor spending as a result of the spill. Non-commercial recreation also decreased in some parts of the spill area. The quality of recreational experiences also decreased due to crowding, residual oil, and fewer fish and wildlife
Recreational users are benefiting from restoration projects in several ways. Habitat protection opens up land previously off limits to campers, hunters, sport fishers, and wildlife viewers while at the same time protecting the health of fish, bird and marine populations. In 1996 a 220-acre Cook Inlet bluff parcel was purchased and will be turned into a state-run campground and recreational facility. Money from the Exxon Settlement is also being used to build campgrounds, cabins, trails, bridges, buoys, food cages, fire rings, docks and interpretive signs.
*This table originated from http://library.advanced.org/10867/gather/effected_resources.shtml
Additional Energy Statistics

Natural Gas
Natural gas accounts for 24% of the energy in the United States. Domestic production of natural gas peaked in 1973; this is because we do not import due to safety problems. Consumption of natural gas is actually flat as oppsed to increasing usage of coal and oil.
Coal
Petroleum / Natural Gas will run out in the next 50 years. 97% of fossil fuel reserves are coal. 20% of the world's coal supply is located in the United States.
Energy yield depends on how much carbon is contained in the coal. Two types dominate US reserves. Anthracite is 95% carbon and is approximately 300 million years old. Lignite is 25% carbon is nearly 150 million years old.
Deposits are around 300 feet below the surface and typically 2-8 feet thick.
Coal production has increased since 1970.
At current usage, the supply will last 1500 years. However at a 5% growth rate the supply will last only 86 years. We can expect even greater usage as other fossil fuels become scarce. Shale Oil
Shale oil deposits in the US are found in southwestern Wyoming, eastern Utah, and western Colorado. Oil shale contains kerogen which, when burned, can be converted into fuel products. The amount of shale oil deposits are significantly greater than the amount of US petroleum deposits by a factor of ten. However, economic mining requires a yield of 25 gallons of oil per ton of shale. Only 30% of the known deposits meet this criteria. Of that 30%, only 15% is recoverable under present conditions. The refinement of shale is very difficult and requires large amounts of water. The bottom line is that shale oil is not economically viable at this point.
Conclusion
We are currently in an energy crisis. Fossil fuels are the lifeblood of our society and for many others around the world. Our supply has a finite end, which is why we are willing to go to war for it and make friends with those we really hate. The former Soviet Union and many of the countries in the Middle East are in our good favor strictly because of their oil reserves. Our foreign aid has a legitimate purpose. Even with our newfound friends, fossil fuels will run out and the use of them will soon take the lives of many people. These are important reasons to find other means of getting the energy we need to continue our society as we know it.
So what are our options? Alternative forms of energy are currently under development even though most of them are only in their inital stages. With increased government and public support, we may be able to speed up the development of these technologies and help free ourselves from the usage of fossil fuels. Oil companies will have to be dealt with because with the future shortages of fossil fuels, they would stand to reap enormous profits. To prevent this, oil and other energy resource providing companies should be encouraged to develop these technologies for the sake of ethics if not for long-term profit gains when all fossil fuel resources are exhausted. Here are some alternative, renewable sources of energy in various stages of development:
Nuclear Fusion: Fusion involves the extraction of "heavy" hydrogen (duterium) from water and the combination of two hydrogen atoms to form helium. Although it has long been hailed as the path to unlimited energy, scientific feasibility has yet to be established. Demonstrations of technological feasibility must then follow, with mastery of materials development and system engineering looming as major hurdles.
Hydrogen: Hydrogen may become the "energy carrier of the future." Most schemes for generating hydrogen are based on the splitting of water using solar energy directly, or indirectly via electricity. Hydrogen would then be used as a substitute for natural gas. Although the technical feasibility of water splitting on a large scale has yet to be established, a "hydrogen economy" remains at least a distant possibility.
Solar Satellites: Collecting solar energy in space and transmitting it to earth via microwave is another long-range possibility. Due to the large size of the required collector, current launch and deployment costs render this scheme economically infeasible. However, future advances in space equipment may change this assessment.
Energy Plants: Rapid improvements in bioengineering may provide the basis for improving the efficency or redirecting the end products of photosynthetic processes to produce commercial fuels such as hydrogen. At this time, scientific feasibility of developing "super species" remains to be established.
Combinations: Concepts for combining end uses and supply generation facilities to better utilize waste heat already are being employed. These include cogeneraton of steam and electricity and district heating. Future combinations may include the use of nuclear energy to generate heat for coal gasification and liquification. The requisite hydrogen for synthetic fuel production may be provided by splitting water with solar energy. Other hybrid systems may emerge as the component parts become practical.
With these options we can help phase out our dependency on fossil fuels and find clean, efficent, sources of power. Keep in mind that these are not the only options known today and that there are others that have not even been conceived. Using these other sources, we can guarantee a healthy and prosperous future.
source:http://www.umich.edu