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The Coal Question

With the price of oil rising to $130/bbl, the consequences of global climate change becoming ever clearer, air pollution in our cities being an ongoing problem, and the security of energy supplies coming into question, the question of alternative sources of energy and ways of using energy has never been more important. When most of us think of "alternative" energy, we think of wind energy or solar energy, or maybe geothermal and hydro. Whatever we think of when we think of alternative energy, there is a powerful movement in the United States to include COAL as an alternative source of energy. Led by fossil fuel corporations and their advocacy groups, the "coal rush" is pushing for the construction of new coal-fired power stations, which already supply half of the electricity we use, facilities for the conversion of coal into diesel fuel and natural gas, and the expansion of mining operations across the country. The economic and political clout carried by the coal industry in coal-rich states has often lead to difficulty in passing any type of legislation that would restrict or regulate the use of coal.

Should we base our future upon another fossil fuel, one that has the power to be much more destructive than the ones [oil and gas] we are using right now? That is the question - the "COAL QUESTION".

The State of Coal

Fifty-percent of the electrical energy that is produced in the United States of America has its roots in coal, the nice black rocks which are all that's left of vast ancient forests. These forests were where now-extinct species of exotic plants and trees died and were buried in swamps, and over the millennia compressed until nearly everything that was not carbon was forced out. Millions of years later, in a whole new world, these vast deposits of carbon were discovered by humans, who realized that this stuff will burn, and yield large amounts of something that we value very highly - energy.

Coal is the rock that built the industrialized world, and no one is doubting that it is what brought us to where we are today. While most coal use today is completely hidden from our view, we use more now that we have ever used in the past.

I wake up in the morning to the sound of a coal-fired alarm clock, and walk into a bathroom and flip on a coal-fired light and fire up a coal-powered shaver. I then usually heat up tea in a coal-burning microwave oven, and go to class or work which is lighted by coal. I come home and get on my computer, which also burns coal, and check my web site, whose server is coal-fueled. I listen to music, via my coal-powered stereo system. I take a shower in warm water which is heated by coal and eat food which has been cooked with it.

Of course, none of these devices actually have a coal burner inside of them which requires the continuous feeding of black rocks (imagine!). They are all powered by electricity, and the workhorse of our electricity system is currently coal. We burn coal every time we turn on an electrical appliance.

It takes nearly one billion tons of coal per year to fuel America's coal-fired power stations, which collectively produce over 1.5 trillion kilowatt-hours of electrical energy from those one billion tons. We use many of those kilowatt-hours to improve our quality of life and make for a more comfortable, more enjoyable world. We must, however, investigate how our use of fossil fuels such as coal impacts our world in ways that are not always visible. It is easy to see the benefits of electricity, though it is not always easy to see the consequences of producing it from coal or any other resource. I will attempt to discuss some of those consequences, how they affect you and I, and how we may be able to manage them.

The Coal Issues

I see five basic technical issues which are unique to coal/fossil fuels. The fifth (Power Plant Inefficiency) is not unique to coal but to the centralized power generation architecture which we currently use for electricity production. This is a thermodynamic limitation which can be overcome by downsizing power plants - difficult to do with coal, especially with carbon sequestration added in.

• Carbon Dioxide (Climate Change/Global Warming)
• Air/Water Pollution
• Mining Issues
• Power Plant Inefficiency
• Sustainability

Carbon Dioxide (Climate Change/Global Warming)

The greatest and most controversial issue surrounding coal use today is its production of carbon dioxide (CO₂) when combusted.

The fact that coal is mostly carbon means that it should be no surprise that it produces a very large amount of carbon dioxide. There is no way to overcome this fact - when we burn coal in air (oxygen), carbon dioxide is formed and this reaction is intrinsic to the process of getting energy from the coal, as it is the combination of the carbon atoms with oxygen which results in the energy (heat) being released.

COAL PRODUCES MORE CO₂ PER UNIT OF ENERGY RELEASED THAN ANY OTHER FUEL.

The basic concept of climate change is that through the use of fossil fuels, by burning them at a rate thousands of times faster than they were formed, we are throwing the Earth's carbon cycle out of balance by dumping millions of years worth of carbon into the atmosphere in less than two hundred years. There is not much to be debated about this part of the problem, as we know that it is happening and that fossil energy is the cause. Fooling with the biogeochemical cycles is not to be taken lightly, as these cycles are what keep every ecological system in operation and keep the raw materials of life in check.

The issue of anthropogenic climate change/global warming (AGW) is very complicated and sensitive; even today it is highly debated. There are serious economic interests at stake if we were to embark upon the task of cutting carbon dioxide emissions, mostly in powerful corporations which produce and use fossil fuel products. Unfortunately, this has immensely hindered the development of alternatives, which will be necessary even if the AGW issue were to disappear tomorrow.

Dealing with CO₂ (or not...)

There are two ways to approach the CO₂ issue...

The first is to not approach it at all, and continue emitting carbon dioxide just as we do today - freely and uncontrolled. Dealing with CO₂ is a serious undertaking, and it is easy to see why carbon-intensive industries and their advocacy groups might be interested in funding research to attempt to debunk anthropogenic global warming theory or to block legislation which may limit the amounts of carbon dioxide which can be released to the atmosphere or hold industries accountable for the CO₂ that they do emit.

Carbon dioxide, unlike other pollutants, produces effects which are neither directly nor immediately felt. Therefore it is easier to convince people that the continuation of its emission is harmless and will not have any effect on them. It is also easy to pass the problem on to future generations for the sake of making an extra buck today.

Most industries have finally agreed that greenhouse gas emissions must be cut. Now the battles rage over how it is to be done and who is to be responsible. Coal-fired utilities, as the nation's single largest source of greenhouse gas emissions, are in the thick of this debate, and much lip-service is given by everyone about cutting emission but no one seems to want to be the one to take the first step, as it has become a blame-game of the United States-versus-China and industry-versus-industry over who should be responsible. I think that it really is easy - everyone should be responsible for taking care of their own emissions. For coal, this is difficult to swallow because coal has the highest carbon intensity of any energy source. Utility companies which rely more heavily on coal have more work cut out for them.

While it is certainly disheartening that these industries continue even to this day to fight emissions caps, they are only following the basic rules of capitalism - get the government, etc. off of our backs so that we can pursue our purpose in life: to make money.

There is no way to burn coal without producing CO₂, so we must either release it, or capture it.

Carbon Sequestration

"Carbon Sequestration" is the process whereby carbon dioxide is captured and theoretically stored permanently or temporarily in geologic media, biological media, or soil.

• Biological Carbon Sequestration - trees, other biomass
• Soil carbon Sequestration - enrichment of the soil to encourage storage of organic compounds.
• Geologic Carbon Sequestration - storage of CO₂ in underground rock strata.

The holy grail for the coal-fired utility sector is to find a way to economically capture the carbon dioxide arising from coal combustion and pipe it into underground rock strata where it can be stored for a long period of time, out of the atmosphere.

While it has been calculated that there should be enough volume in the world's geologic strata to hold the carbon dioxide arising from nearly all of the known reserves of coal on the planet, there are limits to how much of these reservoirs can actually be filled with CO₂. A careful selection process by which reservoirs are singled out on account of stability, geology, size, proximity to energy demand centers, and possibilities for leakage must take place before carbon dioxide can be injected. This process results in a great reduction in the number of available storage sites.

When suitable storage sites are found, the actual drilling of the injection well and injection of CO₂ are processes which have been proven effective and are taking place at several sites in the world today, notably in the North and Barents seas off the coast of Norway. Associated CO₂ from the Sleipner and Snohvit gas fields is injected into saline aquifer formations at the rate of 1.0 and 0.7 million metric tonnes per year, the equivalent of a 400-500 MW coal-fired power plant. The Sleipner sequestration has been operating since 1996 as is a result of high Norwegian CO₂ taxes which make it more economically feasible for Statoil to inject the gas underground rather than release it to the atmosphere.

Economic Challenges

The technology required for carbon sequestration is quite mature and is available today. There are few things which can be done to improve its efficiency, as the process of capturing and controlling CO₂ will, by nature of the second law of thermodynamics, rob energy from the plant which otherwise would be exported to the grid. For carbon sequestration to be successful at all, power plants must be configured differently in how they burn the coal, which makes it nearly impossible to simply retrofit existing plants with carbon sequestration systems.

• Capture of CO₂ from dilute flue gases at existing plants. Because the air used to combust the coal contains nearly 78% nitrogen which passes through the furnace unreacted, carbon dioxide makes up only a small portion of the gases that must be handled.
• Oxyfuel combustion - burning the coal in an atmosphere of oxygen and recirculated flue gases rather than air in order to prevent dilution of the flue gases with nitrogen.
• Integrated Gasification Combined Cycle (IGCC) - gasifying the coal with steam, thereby performing the Water Gas Shift Reaction, separating the hydrogen and CO₂, using the hydrogen as fuel for a gas turbine/steam turbine combination, and further processing the CO₂ for underground injection.
• Carbon Fuel Cells - Fuel cell technology which can use the carbon-oxygen reaction to directly produce electricity. The carbon from coal would have to be purified as to remove all sulfur and metals to avoid poisoning the fuel cells. Fuel cells have the potential to produce small-scale, localized energy from coal, provided that the cost and carbon sequestration options would be viable.

There are trade-offs in every one of these processes. Currently, retrofitting existing plants is estimated to be the most expensive, producing electricity at 8-9 cents per kilowatt-hour. Oxyfuel combustion and IGCC would likely be somewhat similar in cost, as IGCC is a completely different plant design and oxyfuel would require the addition of a facility for the distillation of oxygen from liquid air and an extraction and compression unit for the carbon dioxide.

DIAGRAM OF A BASIC INTEGRATED GASIFICATION COMBINED CYCLE (IGCC) FACILITY

Such technology will never show up on any power plant as long as the coal industry continues to contribute more money to political lobbying than to research and development. It would be nice if the promise of "clean coal" were actually fulfilled and not used as something to get the public warmed up to coal so they will support the building of a traditional power plant.

Converting a gas to a pressurized gas, liquid, or solid requires energy. Pumping these substances to the site of disposal requires energy. And there is always the risk of leakage once the gas is in place. Power stations will need to be located close to the point of disposal, unlike the existing setup where they are placed near electrical demand centers.

What about Skyonic et. al.?

Processes such as Skyonic SkyMine claim to be able to sequester CO₂ as a solid, such as calcium carbonate or sodium hydrogen carbonate (baking soda).

It may be possible to chemically react the gas to form stable solids which can be disposed of with decreased risk of reentry to the atmosphere. The problem is that these reactions tend to be very slow and are not thermodynamically favorable (they require energy to come from somewhere). The rate of production of carbon dioxide by fossil fuel combustion far outstrips even the natural carbonate deposition processes. The amounts of solid product produced would equate to billions of tons per year, exceeding such things as the amount of rock quarried in the United States each year or the amount of cement produced in the world each year. Where on earth would we go with that much soluble baking soda! Sounds like an environmental nightmare waiting to happen.

I have no doubt that the developers of SkyMine had success in the laboratory, but when the process is applied to a large industrial scale, the volumes become unmanageable let alone the increases in entropy which come along with the process (though we have little idea on how it actually works, as Skyonic is an "intellectual property" corporation designed to hide the details.)

Where are we going with Carbon Sequestration?

All of the coal plants that are currently going online are pulverized coal steam plants - the same basic technology that has been used for 120 years and the same technology which currently produces 40% of the world's electrical power. They've added flue gas desulfurization (not without a fight) and supercritical boilers to increase the efficiency a bit, but the basic principles remain the same. Capture of greenhouse gases from such plants' dilute flue gases would likely be completely unfeasible from an economic and thermodynamic standpoint. It is foolish to allow for the construction of such facilities, as they would negate any and all efforts to reduce greenhouse gas emissions. Climatologist James Hansen at NASA along with many others have on several occasions recommended a moratorium be placed on the construction of coal-fired power stations unless they have carbon sequestration included.

If carbon sequestration can get off the ground and perform well, it may be a feasible option to allow the continued use of fossil fuels. We should not, however, allow carbon sequestration to become a money pit into which we dump the bulk of our research and development funds, leaving truly renewable technologies which have the capacity to produce energy WITHOUT CO₂ and sustainability issues out in the cold. I have my own personal doubts about large-scale carbon sequestration, but like anyone I cannot predict the future and cannot rule out the possibility that it may be a viable technology. It is in no way, however, the most sustainable solution (as it uses fossil fuels, and is not very energy efficient to boot - especially when most coal-fired power stations throw away 2/3 of the heat of combustion to begin with).

Air/Water Pollution

Aside from carbon dioxide, Coal-fired power stations are major sources of the following air pollutants:

• Sulfur Dioxide
• Nitrogen Oxides
• Particulate Matter
• Mercury

Sulfur Dioxide

Sulfur dioxide, which CAUSES (yes, CAUSES, not "thought to cause") acid precipitation, has always been a major pollutant produced by coal-fired plants. Regulations require that all new coal units be built with "scrubbers" to remove the sulfur dioxide by washing the flue gases with limestone slurry, but there are still hundreds which fall under a "grandfather" loophole in the Clean Air Act which allows them to continue operating unscrubbed on account of their age

Some grandfathered plants have voluntarily added or are adding scrubbers which will reduce their emissions. I know of at least three power plants in Pennsylvania which have pursued this option.

Nitrogen Oxides

Nitrogen oxides are a byproduct of high-temperature combustion and are one of the components responsible for the formation of smog. Although automobiles are a much greater source for noxious NO_x emissions, coal-fired power stations continue to be a major source. Over the years, many plants have installed low-NO_x burners and/or S[N]CR (selective [non] catalytic reduction) systems to cut down their nitrogen oxide emissions. Many others, however, do not have these features.

Particulate Matter

Particulate matter consists of soot and ash particles. Modern coal-fired boilers combust the coal under conditions not conducive to the production of large amounts of soot. Ash particles are captured in electrostatic precipitators with quite high effectiveness. These pollutants are of the visible variety which can be seen by the public, and therefore they are generally kept under control.

"Ultrafine Particles" are a class of particulate matter with extremely small particle sizes (less than 0.1 micrometers in size) and these can pass through most pollution control equipment. These particles are easily created by the combustion of coal and other fuels (such as diesel fuel in truck engines). The presence of high levels of ultrafine particles is believed to be linked to certain cardiovascular conditions.

Mercury

Mercury, a KNOWN bioaccumulative neurotoxin, is emitted from coal-fired power stations as a result of the mercury which occurs naturally in coal. Coal-fired power plants are the largest source of mercury emissions in the United States. Mercury is emitted from the stack in vapor form and eventually is converted to organomercury compounds (such as methyl mercury) in the environment which are quite hazardous and build up quickly in aquatic organisms, many of which are eaten by humans. Mercury also precipitates onto the land and can find its way into our bodies though other routes. Mercury emissions to the air can be controlled, but mercury itself cannot be destroyed or made nontoxic as it is a chemical element.

Other Pollutants

The ash leftover from coal combustion, along with the by-products of the various flue gas cleaning process, present challenges as well. Elements such as mercury and lead are never destroyed and are simply concentrated in the coal ash after combustion. Human activity excels is distributing these materials quite evenly around the planet (again, in accordance with the second law of thermodynamics!).

We are often concerned about emissions of radioactive material from nuclear power stations. The fact is, however, that coal-fired plants emit amounts of radioactivity that would be considered a serious emergency if they were emitted at nuclear plants. Just like mercury and lead, radioactive uranium and thorium in coal is concentrated in the coal ash.

It is said that the nuclear fission of the uranium component of coal would yield more energy than the combustion of the organic component of the coal.

There should not be cause for concern over these substances, as the radionuclides in coal ash are in very low concentration. It is worthy to note, however, that coal-fired power plants emit much greater quantities of radioactive material to the environment during normal operation than do actual nuclear power plants. It also should not be taken lightly that coal ash may be a viable source of nuclear fuel.

Mining Issues

Even if the coal-to-electricity process could be made emission-free, the coal still has to be mined. The coal industry has increased the use of highly controversial mountaintop removal mining in order to extract coal more efficiently (efficiently as in with less people and less money) in Appalachia. The introduction of explosives and new power equipment has greatly reduced the role of the miner, as the coal industry is producing more and more coal with fewer and fewer people. The industry is no longer the massive employer which it used to be, and its employment and labor relations continue to be controversial even to this day.

All kinds of coal mining comes with serious environmental impacts. Valley fills, acid mine drainage (AMD), erosion, habitat destruction, and impoundment dams holding back waste waters from the mining operations are just a few. Reclamation efforts vary greatly in their thouroughness and effectiveness.

The coal industry is very powerful - especially in states such as West Virginia and Kentucky where mining forms a significant part of the states' economies. This power often finds its way extending into Washington where it does not belong, putting corporate desires ahead of the welfare of the people. I am all for the reduction in the amount of worthless legislation which is passed, but the coal industry along with the oil, electricity, and automobile industries have helped to block landmark bills which would have put the United States of America on course towards long-term sustainability.

Power Plant Inefficiency

The thermodynamic efficiency of coal-fired power plants is around 33%. This means that only about one-third of the heat which is actually produced by coal combustion is converted into electrical energy. The remaining energy is either dissipated into the environment through the plant's cooling towers or it is dumped into a nearby river, lake, or ocean. There are few options available for increasing the amount of electrical energy which can be recovered from coal, as thermodynamics caps the maximum possible efficiency at around 50%. Some very new plants have managed to accomplish 45% efficiency, but these units are very expensive to build and are really only seen in countries where there is an incentive to use less coal (e.g. Denmark, with CO₂ taxes)

But, the rest of the energy is certainly not "lost forever". It is simply in the form of heat which is no longer hot enough to create steam for electricity generation. It is, however, perfectly usable for heating buildings and domestic hot water! We all need to heat our homes during winter in northern climates, and we currently do this mostly by burning precious natural gas. Why do we do this when we have hundreds of power plants simply THROWING AWAY billions of watts of heat energy?

Decentralization and Efficiency Gains

Coal-fired power stations normally must be large and powerful in order to be economical. The coal handling facilities, high-pressure supercritical boilers, turbine-generators, cooling towers, and air pollution control devices (especially any carbon sequestration systems) are all very expensive and usually must be built on a massive scale in order to be economically feasible. Coal is one of the few fuels (nuclear is the other major one) in which a centralized electricity generation and distribution architecture is the only feasible system. Other fuels, such as most of the renewables, oil, and natural gas, can easily be downsized or are naturally suited to a downsized, distributed system. Instead of generating electricity in huge power plants and then sending the electricity long distances over wires to users, it is generated in many smaller power plants placed closer to the point of demand.

The advantages of this system are numerous. If a fuel or other heat source is being used to power an engine or turbine for electricity production, the waste heat from this can be captured and easily used in an industrial process or in a district heating scheme in which heating and cooling for buildings is produced. The use of this waste heat is usually limited or impossible on large centralized power plants, despite the fact that doing it increases energy efficiency by three times. You get three times the energy from the same amount of fuel. That seems like a good deal to me.

There are also fewer losses along the transmission lines, because the electricity simply does not have to travel as far as it does in centralized generation.

A distributed system also reduces the dependence on a single plant or fuel source, and allows greater room for error if a plant were to suddenly go offline, because each individual plant is less important than in the central system.

Centralization of Wealth and Power

Continuing the tradition of centralized energy production will only lead to more concentration of wealth and power. The high capital expense of building up large-scale fossil-based infrastructure makes energy production a business for the very rich. The production of electricity, refined petroleum products, and large volumes of fossil fuels is being relegated to a shrinking group of corporations and people, with higher and higher concentrations of wealth. The power of the energy corporations will likely fight such decentralization trends, and if they try renewables they will likely develop them in a similar fashion to how they have developed coal and nuclear energy - make the power plant as big and powerful as possible, as even when that may not be the best solution.

Economics

One of the very few arguments that coal-fired power has going for it is that the fuel is cheap. Proponents of coal plants state that "coal is less vulnerable to price spikes than natural gas". Coal plants have fuel costs. Gas plants have fuel costs. Most Renewables HAVE NO FUEL COSTS! Once the plant is built, the price of the produced energy is not going to be variable and subject to the wrath of the coal or gas industry. Probably even more important than dirt-cheap electricity is electricity whose price can be counted on. For an example, people get used to the price of gasoline even if it is higher than normal. They don not start complaining until it starts fluctuating. Possibly more important than a fast-growing (and unsustainable!) economy is a stable economy; one that is not experiencing continuous "ups and downs", nerve-racking the people and scaring investors (preventing them from putting their money into possibly good projects, such as renewable energy).

The price of renewable energy can only come down. The price of coal and other fossil fuels will only go up.

Sustainability

They seem to have forgotten the fact that coal is a fossil fuel, and like all fossil fuels, is a LIMITED RESOURCE. Coal does not offer any hope for the future, it does not offer anything beyond short-sighted economic gain.

Some people tout coal as being a "bridge fuel" from fossil fuels to renewables. Natural gas, the original bridge fuel, would be a much better choice because it is a highly concentrated, clean, and easy-to-use fossil fuel, yet it is more expensive and much more limited, which actually provides the incentive to cross the bridge into renewables territory.

While the coal industry likes to use the number "250 years of coal" in their advertisements, this is assuming that the rate of coal consumption will not increase (and with the plans to make liquid fuels and even more electricity, it WILL increase), that every last ton of known reserves can be extracted from the ground at whatever rate we please, and that there actually is as much coal in the ground as we are lead to believe. If we were to base our society upon coal, we would have much less than "250 years of energy" available in these reserves.

Land Use

Coal-fired power plants have a relatively high land use compared with other sources of energy. Surface mining, while monetarily efficient, greatly increases the use of land by coal-fired electricity production.

• Land for surface/underground mining and associated impoundments for wastes.
• Land for the power plant itself (usually hundreds of acres of dedicated land)
• Land for fuel storage and staging (big coal piles at power plants).
• Land for new transmission rights-of-way accommodating larger and larger transmission lines running long distances.
• Land for disposition of the coal ash and scrubber residues if not reused.
• Land for carbon sequestration facilities (compressor stations, pipelines, injection wells, et cetera).

Most renewables, on the other hand, have a quite mild land use by comparison. Photovoltaics can be mounted on the otherwise wasted space of rooftops. Wind turbines can be placed on disused ridgetops or agricultural fields without greatly disrupting the local environment or hindering the use of the land below. Wind turbines can even be placed out at sea and use no land at all! Geothermal plants are among the lowest requirement of any form of power generation, as they do not require fuel and only the generation plant itself uses any land. Run-of-river hydro and smaller-scale and probably even the large hydropower reservoirs do not even come close to gobbling the amounts of land that a coal facility will use for mining and power generation purposes as it continuously consumes coal.

Nuclear generation, which requires mining, processing, generation, and disposal facilities can have a widely varying land-use impact, depending upon the type of mining, the degree of reprocessing of spent fuel (if any), power plant design, and disposal site design.

Conclusion

It does not make much sense to spend (waste) our money and time on a resource which is finite, will give us all kinds of extra trouble (we have to deal with the CO₂), will do nothing to curb air pollution and automobile mania in the cities (with coal-to-liquids fueling internal combustion vehicles), and will limit the ability to create an energy-efficient, truly sustainable society.

Coal-fired power may be here today, providing the electricity I am using to write this article, and the big energy guys may continuously say "Fossil Fuels will continue to supply the majority of our energy for the foreseeable future", but I am not buying it anymore. We have the power to control our own destiny. With all of the ingenuity and adaptiveness which is so prevalent in the world, there is no reason that we cannot stand up to Big Energy and begin producing energy from renewables right in our backyards, building independent/municipally-owned cogeneration plants in our cities and towns to actually produce heat and power efficiently, realizing how to consume less and still live an enjoyable, comfortable life. We can move towards a future-proof energy system based upon renewable and efficient technology, not one based upon yet another cruddy fossil fuel that takes all kinds of expensive technology to "clean it up".

See Also...

• William Stanley Jevons - The Coal Question
• The need for an international moratorium on coal power
• Coal Impoundment Location & Information System
• Senate Republicans block energy bill (CNBC)
• Google search - Valley Fills
• Acid Min Drainage - Wikipedia
• Google Search - Mountaintop Removal Mining
• Mercury - United States Environmental Protection Agency
• Coal Combustion: Nuclear resource or Danger?
• U.S. EPA National Center For Environmental Research - Nanotechnology: Ultrafine Particle Research

Last Modified: 06/08/2008
Created On: 11/11/2007