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Energy Resources

matter most because energy
 

Not surprisingly, therefore, the relation between energy consumption and economic prosperity is direct, as can be seen from the bottom graph on the right.

The energy resources of direct geological interest can be broadly grouped into three classes:

ancient rain forests ® peats
and bogs ® lignite ® coal

where coal itself implies increasing grade from subbituminous to bituminous to anthracite, the most prized of all.

The U.S. coal deposits 

Coal naturally occurs in sedimentary layers and the act that the large land plants did not evolve until well into the Paleozoic too makes the exploration for coal a relatively simple matter. In the U.S., for instance, extensive beds of bituminous coal occur in the late Paleozoic (Pennsylvanian to Mississippian and Permian), over a vast region that stretches from Pennsylvania to Alabama. Appalachian folding has also produced anthracite beds in northeastern Pennsylvania. The interior fields, covering the region from Michigan through Illinois to Texas, too carry bituminous coal and belong to the same geological horizons. As against these, coal beds of the far western fields that extend from New Mexico to Montana, North Dakota and Canada, are of Cretaceous to Eocene age and often tend to be either lignite or subbituminous coal.

 

The U.S. is particularly rich in coal, with about 290 billion tons of recoverable reserves. World reserves of coal are estimated at about one trillion tons, and the total resources about ten times as much.

The world economy continues to depend heavily on the fossil fuels (which accounted for 85% of the energy source in 2000 and may command a higher proportion in 2020, according to the U.S. Department of Energy). The growth is likely to be much faster for oil, of which our supplies are limited, than for coal, whose supplies are abundant but utilization carries a greater risk of environmental degradation.

The USGS estimates total U.S. reserves of discovered oil at 279 BBO (billion barrels of oil), for instance, 61% of which has been already used up. Likewise, about 62% of the discovered 230 BBOE (billion barrels of oil equivalent) U.S. gas reserves too have been used up. While much of recent exploration and drilling has therefore shifted off-shore, mainly to the Gulf of Mexico, focus is also shifting to the debate on Alaska's North Slope (the map on the bottom left) and to tapping the extensive Athabasca tar sand in Canada, with estimated reserves of about 1.25 trillion barrels of oil. Similar oil sands also occur elsewhere in North America (see the map on the bottom right), the richest of the U.S. occurrences being the Green River formation.

The U.S. economy has become particularly vulnerable to the imminent paucity of oil, nonetheless, more so because the actual practice in the U.S. is to abandon an oil well when less than 40% of the oil remains! Does this mean that the end of oil is in sight, as the geophysicist King Hubbert had argued in a Scientific American article in 1971 by predicting that 80% of the world's oil endowment will get exhausted by 2929-25 (the seeds of this idea can be found in Hubbert's article in Feb 4, 1949 issue of Science), or that it is only the cheap oil that we are worried about?

The key to Hubbert's prophecy (the critics would call him an alarmist, though) lies in estimating the dynamic depletion time for a resource which he defined as the time when 80% of it has been used up. As can be surmised from the box alongside, while Hubbert's strategy incorporates the past pattern, the inference based on it needs to be continually updated.

The graph on the bottom left compares the cumulative world oil production through history for different assumptions about the world's total endowment. Notice how the model mimics the observed data reasonably well if the geological estimation of world's total petroleum availability is 1.4 billion barrels. Recently, though, the USGS has revised this estimate upwards, as is shown in the table presented below, to about 3 BBO for oil and about 5.6 BBOE for oil and natural gas combined.

That technology has stayed abreast of the demand is precisely what the worldwide data on consumption and reserve estimates since 1971 clearly suggest (the data tabulated alongside are from British Petroleum's 2003 statistical review of world energy).

Notice that world's total proved oil reserves were estimated at 641.8 billion barrels in 1971. For the 1971 annual oil production (and consumption) of 18.4 billion barrels, this implied an estimate of 34.9 (= proved reserves/annual production) as the number of years this supply would last. By 2001, a full 30 years later, this estimate increased to 38.6 years (= 1050 billion barrels proved estimates/27.2 billion barrels 2001 production), even though production now was about one and a half times that in 1971!

Nuclear Energy
 

Click below to browse Nuclear Energy Institute’s website

Three types of nuclear technology exist:

Unlike ²³⁵U which undergoes slow neutron fission, ²³⁸U does not (it undergoes fission on bombarding with fast neutrons in reactions that are hard to control). The simplest way to extract nuclear energy, therefore, is to use ²³⁵U, as the conventional 'burning' type reactors do. An alternative is to breed ²³⁹Pu⁹⁴ (plutonium) from ²³⁸U, by neutron capture and electron emission, because ²³⁹Pu⁹⁴ is fissionable by slow neutrons. Actually, the radioactive decay series of interest to nuclear power generation are three:

These three radioactive decay series are shown below (numbers on the vertical axes here denote atomic mass, those on the horizontal axes the atomic number) while the box alongside explains where the energy in radioactivity comes from.

2400 billion kWh each year, as much as from all sources of electricity worldwide in 1960. In a current perspective, it is twelve times Australia's or South Africa's total electricity production, five times India's, twice China's and 500 times Kenya's total. It comes from over 430 nuclear reactors with a total output capacity of more than 350 000 megawatts (MWe) operating in 31 countries. A further thirty reactors are under construction, and another 70 are on the drawing board.

"The oceans cover a little more than 70 percent of the Earth's surface. This makes them the world's largest solar energy collector and energy storage system. On an average day, 60 million square kilometers (23 million square miles) of tropical seas absorb an amount of solar radiation equal in heat content to about 250 billion barrels of oil. If less than one-tenth of one percent of this stored solar energy could be converted into electric power, it would supply more than 20 times the total amount of electricity consumed in the United States on any given day."

(from NREL's OTEC Home Page: Click on the image below to visit this site and learn more about the possibilities of using this energy source)

While NREL is no longer active in OTEC research, these two links will give you some interesting information:

NREL's Introduction to Ocean Energy

U.S. Department of Energy's Ocean Thermal Energy Conversion Systems

Look into these references

OCEAN DRILLING PROGRAM LEG 164 PRELIMINARY REPORT GAS HYDRATE ...