Coal, Return of the King?

Coal is a combustible, sedimentary, organic rock formed from ancient organic matter, which has been consolidated between other rock strata and transformed by the combined effects of microbial action, pressure and heat over a considerable time period. This process is referred to as 'coalification'.

Initially peat, the precursor of coal, was converted into lignite or brown coal - coal types with low organic 'maturity'. Over many more millions of years, the continuing effects of temperature and pressure produced additional changes in the lignite, progressively increasing its maturity and transforming it into the range known as sub-bituminous coals.

Coal Formation

As this process continued, further chemical and physical changes occurred until these coals became harder and more mature, at which point they are classified as bituminous or hard coals. Under the right conditions, the progressive increase in the organic maturity continued, ultimately to form anthracite.

The degree of 'metamorphism' or coalification undergone by a coal, as it matures from peat to anthracite, has an important bearing on its physical and chemical properties, and is referred to as the 'rank' of the coal.

Coal Types

Low rank coals, such as lignite and sub-bituminous coals, are typically softer, friable materials with a dull, earthy appearance; they are characterized by high moisture levels and a low carbon content, and hence a low energy content.

Higher rank coals are typically harder and stronger and often have a black vitreous luster. Increasing rank is accompanied by a rise in the carbon and energy contents and a decrease in the moisture content of the coal. Anthracite is at the top of the rank scale and has a correspondingly higher carbon and energy content and a lower level of moisture.

Anthracite: Anthracite is coal with the highest carbon content, between 86 and 98 percent, and a heat value of nearly 15,000 BTUs-per-pound. Most frequently associated with home heating, anthracite is a very small segment of the U.S. coal market. There are 7.3 billion tons of anthracite reserves in the United States, found mostly in 11 northeastern counties in Pennsylvania.

Bituminous: The most plentiful form of coal in the United States, bituminous coal is used primarily to generate electricity and make coke for the steel industry. The fastest growing market for coal, though still a small one, is supplying heat for industrial processes. Bituminous coal has a carbon content ranging from 45 to 86 percent carbon and a heat value of 10,500 to 15,500 BTUs-per-pound.

Sub-bituminous: Ranking below bituminous is sub-bituminous coal with 35-45 percent carbon content and a heat value between 8,300 and 13,000 BTUs-per-pound. Reserves are located mainly in a half-dozen Western states and Alaska. Although its heat value is lower, this coal generally has a lower sulfur content than other types, which makes it attractive for use because it is cleaner burning.

Lignite: Lignite is a geologically young coal which has the lowest carbon content, 25-35 percent, and a heat value ranging between 4,000 and 8,300 BTUs-per-pound. Sometimes called brown coal, it is mainly used for electric power generation.

Large coal deposits only started to be formed after the evolution of land plants in the Devonian period, some 400 million years ago. Significant accumulations of coal occurred during the Carboniferous period (350-280 million years ago) in the Northern Hemisphere, the Carboniferous/Permian period (350-225 million years ago) in the Southern Hemisphere and, more recently, the late Cretaceous period to early Tertiary era (approximately 100- 15 million years ago) in areas as diverse as the USA, South America, Indonesia and New Zealand.

Worldwide, coal is the most abundant of the hydrocarbons, and its reserves are also the most widely distributed. Estimates of total recoverable reserves of coal worldwide in 2002 were about 1,081 billion short tons. The resulting ratio of coal reserves to production exceeds 200 years, meaning that at "current rates of production" (and no change in reserves), coal reserves could in theory last for another two centuries. But the projected levels of consumption is on an upward trajectory, without factoring in a declining availability of petroleum. So a projection based on current levels of consumption becomes irrelevant.

As per International Energy Outlook (IEO) 2006:

In 2003, the United States consumed 1.1 billion tons of coal, accounting for 92 percent of total coal consumption in North America and 44 percent of the OECD total. U.S. coal consumption rises to 1.8 billion tons in 2030 in the IEO reference case.

• In Canada, coal consumption increases from 69 million tons in 2003 to 123 million tons in 2030.
• Coal consumption in OECD Europe increases by only 40 million tons (5 percent) in the IEO2006 reference case.
• In the IEO2006 reference case, coal consumption in OECD Asia increases by 156 million tons, to 560 million tons in 2030. With little change projected for Japan’s coal consumption, South Korea and Australia/New Zealand account for virtually all of the increase in the region.
• Coal consumption in non-OECD countries increases by 140 percent in the IEO2006 reference case, from 3.0 billion tons in 2003 to 7.1 billion tons in 2030, led by strong economic growth and rising demand for energy in China and India.
• Coal consumption in non-OECD Europe and Eurasia is projected to increase at an average rate of 1.7 percent per year, from 543 million tons in 2003 to 856 million tons in 2030.

That leaves us with a 90-100 year supply. Now, when you superimpose declining supplies of oil to the scenario described, picture becomes bleak. Just like oil, it is not important when the coal runs out. More significant is the date when coal production peaks. In fact, according to a detailed analysis by Gregson Vaux, coal production usually follow its own bell shaped curve. Mr. Vaux projects that Coal production in the US would peak around mid-twenty first century. Most of the coal produced so far has been the easiest to mine and the highest quality black coal. That leaves the remaining reserves, substantial as they are, with a higher fraction of lower quality coal at deeper depths.

Coal is the dirtiest of all fuels. From mining to coal cleaning, from transportation to electricity generation to disposal, coal releases numerous toxic pollutants into the air, water and land. These disrupt ecosystems and endanger human health. Some cause cancer, others damage the nervous and immune systems, and some impede reproduction and development. The environmental effects of coal use range from the poisoning of local rivers by acid mine drainage to the global problem of climate change caused by CO2 (carbon dioxide) emissions. ‘Clean coal’ technologies are expensive and are still unable to completely remove harmful emissions from coal-fired power plants.ii Figure 1 illustrates the various impacts of coal-use on land water and air.

Mine wastes are generated in huge quantities and must be disposed of. The wastes are flammable and prone to spontaneous combustion. They also contain heavy metals capable of leaching out into local rivers, streams and groundwater. Coal washing generates similar waste problems.

Acid mine drainage (AMD):
Sulphuric acid is created when exposed coal gets wet and dissolves toxic metals.v The resulting run-off is directly toxic to aquatic life and renders the water unfit for use. Furthermore, some of the metals bioaccumulate (i.e. build up in living things) along the aquatic food chain. Solid Energy’s Stockton mine alone produces some 30,000 million liters of AMD annually. AMD can contaminate drinking water sources and plague nearby communities for centuries, or even longer.

Synthetic fuel derived from coal is gaining popularity. The technology for converting coal to synthetic liquid fuel is not new. Oil starved Germans used it during WWII and the South African's used it during the apartheid. But if it was a cheap and convenient way to may transportation fuel, why didn't the world use it on a large scale ? Making synthetic fuel from Coal is very expensive and the net energy gain is minuscule compared to conventional oil.

For instance, Sasol has made 1.5 billion barrels of synthetic fuel from 800 million tonnes of coal over 50 years. The U.S. alone consumes more than 7 billion barrels of oil on an yearly basis and the world consumes a staggering 30 billion barrels of oil annually. Converting just the U.S fraction of global oil consumption to synthetic fuel from coal, would require enormous 3.75 billion tonnes of coal annually. That is truly a implausible task, when you consider the fact that current world coal production stand at 4.6 billion tonnes. The projected annual production in 2030 is only 7 billion tonnes. This estimate from World Coal Institute fails to include any such surge in demand due to synthetic fuels.

All said and done, coal will play a bigger role in the energy mix of the post Peak Oil world, it will come at a big environmental cost and it will not come close to filling the gap of declining petroleum supply.

A nuclear economy ?

Nuclear power plants do not emit any greenhouse gases or other pollutants. All the nuclear leak risks attributed to nuclear power plants are usually blown out of proportions. But the nuclear waste disposal presents a problem. By mass, the most significant of these is depleted uranium. This has been created in both military and civil uranium enrichment programs, with around 1.2 million tonnes currently stored at enrichment plants throughout the world. There are only minor non-nuclear uses for this material and it has historically been regarded as a waste with little potential economic value.

Nuclear energy will not drive our cars or fly our aircrafts. But it can definitely power our homes. Public aversion to nuclear power is a big hurdle to overcome and there is very little political will to promote and build nuclear power plants, because of NIMBY( Not In My Back Yard ) issues. Nearly all the 1.8 million tonnes of uranium mined since 1945 can still be identified in one form or other today. Unlike fossil fuels, uranium has not been burnt, giving off gases which may cause the greenhouse effect, acid rain and ozone depletion. This provides the nuclear industry with the opportunity of suggesting the inclusion of such external costs of alternative generation options in decision making. The downside is that the residual materials from the fuel cycle are generally perceived by the general public (but not by the industry) as a significant hazard. Although there are also certain public concerns on reactor safety and non-proliferation, the popular perception is that the residual materials are probably the true Achilles heel of the nuclear industry.

It is a major challenge for the industry to remove this public perception because, unless this can be accomplished, it is unlikely that nuclear power can re-enter a strong growth phase. Although the industry's good record on safe handling, storage and disposal can be promoted, an alternative and complementary route is to emphasis the potential economic value of the residual materials, in that they may add to uranium resources as a contribution to environmentally-sound electricity generation.

Primary uranium supply remains the foundation of the nuclear fuel cycle today and also for the foreseeable future. All the various materials throughout the cycle start at a mine. It is therefore necessary to demonstrate that current and future nuclear power programs will not be constrained by the availability of uranium.

The metal Uranium is not a fossil fuel and hence it is ubiquitous on the earth. It is a metal approximately as common as tin or zinc, and it is a constituent of most rocks and even of the sea. Some typical concentrations are: (ppm = parts per million).


Current usage is about 68,000 tU/yr. Thus the world's present measured resources of uranium in the cost category of US$130 per kg (3.3 Mt Reasonably Assured Resources) and used only in conventional reactors, are enough to last for some 50 years( Price of Uranium is only 2% of the cost so higher prices has very little impact on the final cost of the generated electricity.) But then increasing usage in post peak world could reduce that by a few decades. Also, it may not be important when we run out of economically producible Uranium, more important event to consider might be a peaking of world Uranium production. Further exploration and higher prices could, on the basis of present geological knowledge, yield further resources as present ones are used up. There was very little uranium exploration between 1985 and 2005, so a significant increase in exploration effort could readily double the known economic resources.

This is in fact suggested in the IAEA-NEA figures if those covering estimates of all conventional resources are considered - 10 million tonnes (beyond the 3.3 Mt known Reasonably Assured Resources), which takes us to over 200 years' supply at today's rate of consumption. This still ignores the technological factor mentioned below. It also omits unconventional resources such as phosphate deposits (22 Mt U recoverable as by-product) and seawater (up to 4000 Mt), which would be uneconomic to extract in the foreseeable future (It might be too optimistic to expect uranium production from sea water - chances are it will be a big net energy loser. )

Widespread use of the fast breeder reactor could increase the utilization of uranium sixty-fold or more. This type of reactor can be started up on plutonium derived from conventional reactors and operated in closed circuit with its reprocessing plant. Such a reactor, supplied with natural uranium for its "fertile blanket", can be operated so that each tonne of ore yields 60 times more energy than in a conventional reactor. The technical difficulties of achieving this have, however, proved rather more challenging than expected and has delayed the switch. Other factors have also contributed to this. Commercial nuclear power growth has been much slower than was originally anticipated, thus increasing the anticipated life of proven uranium reserves. Alternative sources of supply have also become available in the form of uranium and plutonium from reprocessed spent fuel and from ex-military applications.

Today uranium is the only fuel supplied for nuclear reactors. However, thorium can also be utilized as a fuel for CANDU reactors or in reactors specially designed for this purpose. Neutron efficient reactors, such as CANDU, are capable of operating on a thorium fuel cycle, once they are started using a fissile material such as U-235 or Pu-239. Then the thorium (Th-232) atom captures a neutron in the reactor to become fissile uranium (U-233), which continues the reaction. Some advanced reactor designs are likely to be able to make use of thorium on a substantial scale.

The thorium fuel cycle has some attractive features, though it is not yet in commercial use. Thorium is reported to be about three times as abundant in the earth's crust as uranium. Commercially identified reserves of Thorium are a lot less.

Problems with Thorium include the high cost of fuel fabrication due partly to the high radioactivity of U-233 which is always contaminated with traces of U-232; the similar problems in recycling thorium due to highly radioactive Th-228, some weapons proliferation risk of U-233; and the technical problems (not yet satisfactorily solved) in reprocessing. Much development work is still required before the thorium fuel cycle can be commercialized, and the effort required seems unlikely while (or where) abundant uranium is available.

Nevertheless, the thorium fuel cycle, with its potential for breeding fuel without the need for fast-neutron reactors, holds considerable potential and whether we realize this potential or not will depend on our urgency for further development of Thorium fuel cycle technology. It is a key factor in the sustainability of nuclear energy.

In conclusion, nuclear energy will play an increasing role in our energy mix, at least for a few more decades. It is not a cure all for our energy predicament. Others are less sanguine about the future of Nuclear energy, for e.g. study by David Fleming

Map of Uranium Resources
The Economics of Reprocessing vs. Direct Disposal of Spent Nuclear Fuel
Cameco VP


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