As we all know USA is a G12 (super power) nation who's power is supplied approximately 50% by the Coal Power Industry. take a look in this site to see the air quality by states..

I wish the same could be done all over the globe, but I guess the means for that isn't available yet.

follow this link!
======= http://www.weather.com/outlook/health/airquality/?state=AL#AL

Wind power is the fastest-growing form of electricity generation in the United States, accounting for 42 percent of all new generation in 2008. Solar energy employs more than 20,000 Americans in high-tech, high-paying jobs. And millions of Americans are now powering their homes with clean electricity that doesn't produce any global warming pollution.

A recent economic analysis shows that investing $100 billion in clean energy would create two million new jobs nationwide over two years -- four times as many as the same investment in traditional fuels.

In fact, investing in energy efficiency makes far more economic sense than building new power plants. Making just 5 percent of American homes twice as energy efficient per year would eliminate the need for almost 300 power plants by 2030 and save American consumers billions in energy costs.

========my own personal note^_^

Clearly renewable energy is on it's way... But we have to put into consideration that wind and solar energy are "intermittent power sources" indicating that power can be harnessed under conditions. Take for wind power as example, it will require to build 3 times more to generate power equal to the fossil fuel power plants. Solar also takes up approx. 2hectares of land to produce 1MW... But with further research hopefully it would make wind or solar power a reliable power source.

PROBLEM:

The negative side of energy use—pollution of the environment—is not a recent problem. In 1306 King Edward I of England so objected to the noxious smoke from London's coal-burning fires that he banned coal's use by everyone except blacksmiths. The enormous scale of today's energy use has increased environmental concerns.

Coal-fired electric power plants emit gases that are harmful to the environment. Scientists believe that burning huge quantities of fossil fuels causes the "greenhouse effect," in which gases from the fuels trap heat in the earth's atmosphere and cause increased warming, which threatens the environment. Burning coal also contributes to the formation of acid rain and to public health concerns. Sulfur dioxide, for instance, has been shown to cause respiratory problems.

Carbon dioxide accounts for the largest share of greenhouse gas emissions. In 2002 the combustion of coal in the United States produced 2.1 billion metric tons of carbon dioxide, or 36% of total carbon dioxide emissions from all fossil fuels used in the United States.

ACID RAIN. Acid rain is any form of precipitation that contains a greater-than-normal amount of acid. Even nonpolluted rain is slightly acidic (with a pH of about 5.6) because rainwater combines with the carbon dioxide normally found in the air to produce a weak acid called carbonic acid. But pollutants in the air can increase the acidity of rain and other forms of precipitation, such as snow and fog.

Chemicals such as oxides of sulfur and nitrogen, which are given off during the combustion of fossil fuels, are pollutants that combine with precipitation to form acids. These oxides increase in the air because of automobile exhaust, industrial and power plant emissions, and other fossil fuel combustion processes. In many parts of the world acid rain has caused significant damage to forests, lakes, and other ecosystems.

HEALTH ISSUE:

Emissions from coal-fired power plants include mercury, sulfur oxides, and nitrogen oxides. Mercury reaches humans when they eat fish contaminated by airborne mercury that settles in lakes and streams. Scientific data have not yet determined a significant link between mercury that originates from coal-fired power plants and significant health effects in humans. However, sulfur oxides and nitrogen oxides contribute to air pollution, which can cause upper respiratory conditions

SOLUTION:

THE CLEAN COAL TECHNOLOGY LAW. In 1984 Congress established the DOE's Clean Coal Technology (CCT) program (PL 98–473). Congress directed the DOE to administer cost-shared projects (financed by both industry and government) to demonstrate clean coal technologies. The demonstration projects had the goal ofusing coal in more environmentally and economically efficient ways.

CLEAN COAL TECHNOLOGY AND THE CLEAN AIR ACT. The stated goal of both Congress and the DOE has been to develop cost-effective ways to burn coal more cleanly, both to control acid rain and to improve the nation's energy security by reducing dependence on imported fuels. One strategy is a slow, phased-in approach in which utility companies and states reduce their emissions in stages.

Under the Clean Air Act of 1990 (PL 101–549), restrictions on sulfur dioxide and nitrogen oxide emissions took effect in 1995 and tightened in 2000. Each round of regulation requires coal-burning utilities to find lower-sulfur coal or to install cleaner technology, such as "scrubbers" that reduce smokestack emissions that contribute heavily to air pollution. When the first Clean Air Act was passed in 1970, it was aimed at changing the air-quality standards at new generating stations, and older coal-using plants were exempt. Under the 1990 act, older plants are also covered by the regulations.

In January 2004 the Environmental Protection Agency (EPA) proposed new regulations for reducing emissions of sulfur dioxide, nitrogen oxides, and mercury from coal-burning power plants. The Interstate Air Quality Rule focuses on twenty-nine eastern states whose sulfur dioxide and nitrogen oxide emissions are significantly contributing to fine particle and ozone pollution problems. The Utility Mercury Reductions Rule focuses on controlling mercury emissions from power plants. (When taken into the body, mercury can result in serious health effects in children.) These proposed actions strengthen Clean Air Act regulations and standards but are not specifically mandated by the Congress. When implemented, the EPA expects them to result in rapid and significant air quality improvement.

CLEANER COAL USE. The coal-burning process can be cleaned by physical or chemical methods. Scrubbers, which are a physical method commonly used to reduce sulfur dioxide emissions, filter coal emissions by spraying lime or a calcium compound and water across the emission stream before it leaves the smokestack. The sulfur dioxide bonds to the spray and settles as a mudlike substance that can be pumped out for disposal. Scrubbers, however, are expensive to operate, so particulate collectors are the most common emissions cleaners for coal. While they are cheaper to operate than scrubbers, they are less effective. Cooling towers reduce heat released into the atmosphere and reduce some pollutants. Chemical cleaning, a relatively new technology not yet in widespread use, involves the use of biological or chemical agents to clean emissions.

Read more: Coal - Environmental And Health Concerns About Coal - Air, Plants, Emissions, Sulfur, R11, and Dioxide http://www.libraryindex.com/pages/1519/Coal-ENVIRONMENTAL-HEALTH-CONCERNS-ABOUT-COAL.html#ixzz0xhZXMjIl

Greenhouse emissions
>Obama wants Congress to set a cap on greenhouse emissions such as carbon dioxide. That would require companies to buy permits to emit greenhouse pollution.

Clean coal technology
>There is $3.4 billion in the stimulus bill for fossil-fuel research, including for technology that would allow coal-plant operators to bury carbon dioxide from the plant.

Upgrading the power grid
>There is more than $10 billion in the budget for improvements to power lines that transmit electricity. The existing network does not have enough capacity.

Nuclear waste
>Obama's budget cuts off funding for the Energy Department's plans to bury nuclear waste at Yucca Mountain. There's an estimated 63,529 tons of nuclear waste in temporary storage.

Oil and gas drilling
>Interior Secretary Ken Salazar has canceled drilling plans for public lands in Utah and Wyoming. He's also re-evaluating President Bush's offshore drilling plan.

Air pollution
>The Obama administration dropped a legal defense of Bush-era limits on mercury emitted by power plants. The Bush plan would not have required mercury cuts at every plant.

Endangered species
>Obama directed federal agencies to consult with environmental and scientific experts before undertaking construction projects that may threaten endangered species.

=====taken from USA today.
USA TODAY'S Traci Watson takes a look at the actions President Obama has taken on key environmental and energy issues
article updated 3/9/2009

Learn more from the Center for Media and Democracy's portal on climate change.

This article is part of the Coal Issues portal on SourceWatch, a project of CoalSwarm and the Center for Media and Democracy.

James Hansen, director of NASA's Goddard Space Institute, has recommended that no further coal plants be built that do not capture their carbon dioxide emissions, and has further recommended that all coal emissions be phased out by 2025 in the developed world and by 2030 in the developing world.[1] According to Hansen, the consequence of emissions continuing beyond that time is increasing risk of passing "tipping points" and "points of no return."[2]

Hansen's recommendation consists of two parts:

* Moratorium on new non-sequestering plants.
* Phase-out of existing plants.

The first recommendation, a coal moratorium, has been the subject of widespread citizen organizing, state-level legislation, and proposed national legislation.

The second recommendation, a phase-out of existing plants, has received less attention. To date, no scenarios have been published recommending specific steps to implement the recommendation of a coal plant phase-out.

MAJOR CONSIDERATION IN COAL PHASE OUT

Phasing out existing coal plants will require consideration of a number of issues:

* Age of existing coal plants
* Timeline and comparative costs for alternatives to replace existing coal-fired generation
* Timeline for efficiency and conservation to offset existing coal plant power production
* Land requirements of alternative sources such as concentrating solar power
* Job losses in coal plants and coal mines; policy options for offsetting such losses
* Effect of pending policy proposals such as carbon trading or carbon taxes on the existing coal fleet
* Policy options for scheduling and enforcing coal plant shut-downs
* Requirements and for new transmission lines
* Secondary environmental and health benefits from phasing out coal plants, such as reductions in mercury and sulfur dioxide emissions, and ending mountaintop removal mining

Retrofitting Existing Coal Plants for Carbon Capture

According to the U.S. Department of Energy, it is not economical to retrofit existing coal plants with carbon capture technology:

Existing CO2 capture technologies are not cost-effective when considered in the context of large power plants. Economic studies indicate that carbon capture will add over 30 percent to the cost of electricity for new integrated gasification combined cycle (IGCC) units and over 80 percent to the cost of electricity if retrofitted to existing pulverized coal (PC) units. A recent study from the National Energy Technology Laboratory (NETL) confirms that additional alternatives need to be pursued to bring the cost of carbon capture down. In addition, the net electricity produced from existing plants would be significantly reduced - often referred to as parasitic loss - since 20 to 30 percent of the power generated by the plant would have to be used to capture and compress the CO2.[8]

This figure shows the relative fraction of man-made greenhouse gases coming from each of eight categories of sources, as estimated by the Emission Database for Global Atmospheric Research version 3.2. These values are intended to provide a snapshot of global annual greenhouse gas emissions



*Power station are divided amongst Coal, Nuclear,and Geothermal.
*Since Coal PP makes up to 40%-50% of total Power Station, it can only be accounted for 14.75 percent of Co2 gas.

=============as of June 19 2006
source: Global warming art

I will post updates on the GHG inventory if and when I can stumble upon another reliable source.. since most of the other sites doesn't allow hosting of their results and/or charts.[u]

[size=18]Comparison of Growth Areas and Emissions, 1980-2008
The graph shows that between 1980 and 2008, gross domestic product increased 126 percent, vehicle miles traveled increased 91 percent, energy consumption increased 29 percent, and U.S. population grew by 34 percent. During the same time period, total emissions of the six principal air pollutants dropped by 54 percent.
[/size]
This will be updated at 2011, since Air pollution Emission changes is updated every 3 years.

Source: 2009 US Greenhouse Gas inventory Report
Taken From: Environmental Protection Agency (US)

The pie chart shown below demonstrates how Carbon is emitted per sector

At the bottom of the boiler furnace there is a bed of inert material. Bed is where the coal or fuel spreads. Air supply is from under the bed at high pressure. This lifts the bed material and the coal particles and keeps it in suspension. The coal combustion takes place in this suspended condition. This is the Fluidized bed.

Special design of the air nozzles at the bottom of the bed allows air flow without clogging. Primary air fans provide the preheated Fluidizing air. Secondary air fans provide pre-heated Combustion air. Nozzles in the furnace walls at various levels distribute the Combustion air in the furnace.

Fine particles of partly burned coal, ash and bed material are carried along with the flue gases to the upper areas of the furnace and then into a cyclone. In the cyclone the heavier particles separate from the gas and falls to the hopper of the cyclone. This returns to the furnace for recirculation. Hence the name Circulating Fluidized Bed combustion. The hot gases from the cyclone pass to the heat transfer surfaces and go out of the boiler.

As for the carbon in the coal that produces the Carbon gas, you can burn it and uses the hot combustion gases to spin a gas turbine to generate electricity. The exhaust gases coming out of the gas turbine are hot enough to boil water to make steam that can spin another type of turbine to generate even more electricity. But why go to all the trouble to turn the coal into gas if all you are going to do is burn it?

A major reason is that the impurities in coal — like sulfur, nitrogen and many other trace elements — can be almost entirely filtered out when coal is changed into a gas (a process called gasification). In fact, scientists have ways to remove 99.9% of the sulfur and small dirt particles from the coal gas. Gasifying coal is one of the best ways to clean pollutants out of coal.

Another reason is that the coal gases — carbon monoxide and hydrogen — don't have to be burned. They can also be used as valuable chemicals. Scientists have developed chemical reactions that turn carbon monoxide and hydrogen into everything from liquid fuels for cars and trucks to plastic toothbrushes!

Sulfur is a yellowish substance found in coal. A way of removing sulfur particles from coal is to break it in small chunks then wash it.
Sulfur exist in specks called "pyritic sulfur" that of which can be washed out in large water filled tanks. Coal floats while sulfur sinks (due to it's dense properties). This is done in "coal preparation plants", which is a requisite for Coal Fired/Steam Power Plant.

Nitrogen Oxide or NOx is formed when nitrogen combines with oxygen. NOx is a pollutant, which is mostly responsible to occurrences of smog.
The best way to prevent Nox is to prevent Nitrogen from combining with Oxygen. When there are more fuel than air in the combustion chamber NOx aren't formed. It is in these set condition that oxygen combines with the fuel itself rather than the Nitrogen.

Mercury is minutely found in coal. With the presence of the so called "scrubbers" Mercury is reduced to a level that isn't fatal to health or the environment.

Scrubbers have been present in most CFPP since 1978. But with newer innovations & enhancements Scrubbers are so effective that 90% of pollutants are reduced. The key is lime or limestones. They are crushed to powder like substances. Sulfur, Nitrogen, and Mercury are acid base, while Lime are alkaline. Alkalines are effective in absorbing acids.
Now the approach in using limestones varies, some technologies introduced limestone in the combustion process, therefore upon burning the fuel hazardous chemicals are gravely reduced and at the same limestones are also present in "scrubbers". The presence of limestones in both process ensures optimum reduction of Sulfur, NOx and Mercury.

Coal plays a major role in energy generation. But with the past environmental hazards that it had brought us, the "world" now is more environmentally sensitive. As more and more the populace is experiencing the effects of climate change.
This brought about the changes in the "Coal power Plant Industries", researches and technologies have been made to effectively lessen the impact of Coal Power Plants.

"Among the key options under development for use alone or in combination are:

* Optimizing existing plants so they reduce emissions and increase the amount of electricity produced with the same amount of coal.
* Continuing to develop and refine best-available combustion technology, including circulating fluidized-bed (CFB) technology, which includes supercritical and ultra supercritical combustion. This option may also include burning biomass as a fuel, thus reducing the level of CO2 emissions, and oxy-combustion for collecting CO2-rich flue gas.
* Gasification — turning coal into a gas and removing impurities from the coal gas before it is combusted.
* Carbon capture and storage (CCS) — capturing the carbon dioxide from the flue gas and storing it underground or reusing it."

=======this is part of an article found @ http://www.plantservices.com/articles/2009/213.html?page=1
Please take note that this has been acknowledge by the Department of Energy (USA)

The "Proposed Coal fired Power Plant in the Zamnoanga City" utilizes the Circulation Fluidized-bed Technology.