Coal is a “DIRTY” Business

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Coal is a “DIRTY” Business

Postby WalkerARCHITECTS » Sat Mar 29, 2008 3:40 am

Coal is a “DIRTY” Business


Although Walker Architects does advocate cleaning up the existing coal plants we are annoyed with a mentality that continues to promote fossil fuels for new power plants that produce more carbon dioxide. We already have too much of it in our atmospere. Building power plants that produce any quantity of CO2 beyond the current level is increasing the size of the problem.

The problem is that we already generate ten billion tons of CO2 per year that the planet cannot digest. The surplus CO2 is acting as an insulating blanket and trapping heat in our atmosphere that would otherwise be shed to outer space, thus driving the global warming trend. The consensus of science worldwide is that global climate is changing because of human activity that produces excessive quantities of carbon dioxide. We need to reduce carbon dioxide emissions over what is currently produced so building any kind of power plants that produce more is simply not part of the solution. It is in fact contributing to the problem.

Public Citizen is an environmental group. They hired a scientist to examine 18 proposed new COAL plants that use a new gasification technology. This technology reduces the emissions generated by a typical coal power plant by 70 to 90 percent. Many advocates of coal are promoting the building of these new coal gasification power plants because they are reducing the really bad pollution you would usually get if you built a typical coal power plant. They can make it sound like a desirable solution when in fact it is contributing to the problem.

If I had a process that would reduce the radioactive poisons produced as waste by a breeder nuclear power plant by 70 to 90 percent is it suddenly a good idea to build them? Obviously more poison is simply more poison and such poison in any quantity is a bad idea.

Photo-voltaic power plants would ELIMINATE the Emissions! Whats wrong with that alternative in Texas?


“New Study Shows Coal Gasification Could Eliminate 70 to 90 Percent of Air Pollution From 18 Proposed Coal Plants in Texas
Major Utilities Across Country Choosing the Technology to Lower Emissions.

AUSTIN – A Public Citizen study released today shows that emissions from 18 proposed coal plants in Texas could be reduced by 70-90 percent if modern coal gasification technologies are used.
Richard Furman, an MIT-trained scientist who has worked for three electric utilities and now volunteers for environmental groups, performed the analysis for Public Citizen. He compared the total emissions from the 18 traditional pulverized coal plants to the emissions that would result if the same amount of power were to be produced by modern coal gasification plants.

The analysis showed that over a one year period, coal gasification could provide electricity for Texans with dramatically less pollution – 86 percent less NOx, a smog-forming gas; 93 percent less SO2, an acid rain-causing gas; 87 percent fewer soot or fine particles; 73 percent less brain-damaging mercury; and 92 percent less CO2, a global warming-causing gas.

The 18 proposed coal fired power plants for Texas would emit more than 30,000 tons of smog-forming gas each year – more than that caused by one million cars. The analysis shows that if modern coal gasification was used, smog emissions could be cut to just 4,500 pounds a year. Gasification also more easily sequesters carbon dioxide, reducing the emissions of global warming gases by more than 90 percent a year.

“These significant emission reductions would increase the cost of electricity less than half a cent per kilowatt hour,” said Furman. “That adds up to less than 60 cents per meter per month, or less than a bottle of water.”

Coal gasification works by breaking down coal into its chemical parts rather than burning it directly. New gasification plants have demonstrated that they are a dependable way to produce energy and much cleaner than traditional coal burning plants. Gasification can operate with the types of coal commonly used in Texas and would use 60 to 70 percent of the water of a conventional plant.

“This is good news for Texas’ most polluted cities like Austin and Waco that are close to violating federal clean air standards,” said Tom “Smitty” Smith, director of Public Citizen’s Texas office. “The bad news is that the state’s environmental agency isn’t requiring generating companies to even look at this type of coal plant. While Public Citizen doesn’t support the use of coal for power generation, this study shows that gasification would be a far less polluting way to produce power than traditional dirty coal plants.”

Questions we would like to have answered below:

Where do they put the CO2 after they have sequestered it?

Why not build solar driven power plants instead?

If we do build the new better Coal plants then shouldn’t we decommission and tear down the old dirty plants so we have a net contribution to reducing CO2 emissions?

Does the article about Public Citizen and coal plants above seem to be worded in such a way that it promotes building more coal power plants while ignoring disclosure of the reasons that Public Citizen does not support the use of coal for power generation?

Is the article misleading?
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Postby Richard Haut » Sat Mar 29, 2008 3:03 pm

If I understand correctly, the Texas coal is Lignite - known generally as "brown coal". Its high moisture content gives very high quantities of ash.

Mr. Furman (who I believe describes himself as a "retired engineer" who advises government, utilities and others) appears to be something of a fanatic for coal gasification.

I in no way pretend to have expertise in this matter, but one of the problems is Mercury:

“No technology designed specifically to control mercury in coal plants is in use anywhere in the world, or has even undergone long term testing.” - EPRI Journal article “Mercury Control for Coal-Fired Power Plants”, Summer 2005, page 19 (and, to be fair, quoted by Richard Furman).

Are there photovoltaic power plants ? Can it produce sufficient power, compared to main power plants ? Why does nobody mention hydroelectric any more ?

Is nuclear inherently dangerous ? Will a fusion power nuclear reactor like the one at Cadarache up the way here in France help ?
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Postby Antisthenes » Mon Mar 31, 2008 12:26 pm

meanwhile a the Navajo put up 700 megawatts of solar and wind

while coal remains the only fuel source that could lead to catastrophic ocean rises.

i think people should be demanding the shut down of all coal fired plants worldwide

clean coal is a myth and propaganda, if we let one positive note on coal pass by us we are committing life on earth to extinction

just say NO to coal!
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Postby TJCaine » Mon Mar 31, 2008 1:32 pm

A great debate...

I have come to be convinced that coal is not an answer in general. It is true that it is by far the single largest contributer to CO2 content in the atmosphere. I would encourage everyone to try and listen to a lecture by Ed Mazria, founder of Architecture2030 ( who targets coal power and its replacement in the US. He lists 600 existing coal plants in the US with 151 in various stages of development. His lectures are illuminating. Here are some surprising stats that stuck out in my mind last time I heard him speak. There are more on the website:

- Wal-Mart is investing a half billion dollars to reduce the energy consumption and CO2 emissions of their existing buildings by 20% over the next seven years. If every Wal-Mart Supercenter met this target...
The CO2 emissions from only one medium-sized coal-fired power plant, in just one month of operation each year, would negate this entire effort.

- California passed legislation to cut CO2 emissions in new cars by 25% and in SUVs by 18%, starting in 2009.If every car and SUV sold in California in 2009 met this standard...
The CO2 emissions from only one medium-sized coal-fired power plant, in just eight months of operation each year, would negate this entire effort.

- If every household in the US changed a 60-watt incandescent light bulb to a compact fluorescent...The CO2 emissions from just two medium-sized coal-fired power plants each year would negate this entire effort.

To the question of solar, can we produce enough solar to fill our nation's need? The answer is absolutely, but there is a catch. We have all seen photos of America at night. The trick becomes what method do you use to store enough power during the day so you can power the country at night? There are numerous suggestions: heat production and storage, giant salt-based batteries...

Kind of puts things in perspective. After the lecture, I was curious as to the size and cost of the solar cells needed to power the whole country. My extremely rough calculations put the size at bit larger than the size of Massachusetts and at a cost of around $13 trillion. Keep in mind... that's a lot of infrastructure one is replacing.
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Postby Antisthenes » Mon Mar 31, 2008 2:31 pm

wind is cheaper

and imagine how much wave power there is...
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Postby csintexas » Wed Apr 02, 2008 10:34 am

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Postby csintexas » Wed Apr 16, 2008 3:38 pm

From this website:

I'm afraid that the logic here is probably correct.
I think it is self evident that modern society is a product of vast quantities of cheap energy. When this supply is exhausted modern civilization (as we know it) will no longer be possible.


ENVIRONMENTAL ACCOUNTING: Emergy and Environmental Decision Making
by Howard T. Odum; Wiley, 1996 ;

From page 314, we find that in 1993 total USA fuel use was 4.78 x 10e24 sej (increasing about 2% per year ever since). From page 187 we find that total net solar radiation absorption for Alaska and the lower 48 was 4.48 x 10e22 sej. In other words, the USA is presently using fossil fuels more than 100 times greater than the total absorption of solar radiation across the entire USA!

So-called "renewable" energy systems are evaluated differently than "non-renewable" energy systems. In order to be "renewable", an energy system must produce enough net energy to reproduce itself.

A BTU of sunlight is fundamentally different than a BTU of fossil fuel. Directly and indirectly it takes about 1,000 kilocal of sunlight to make a kilocalorie of organic matter, about 40,000 to make a kilocalorie of coal, about 170,000 kilocal to make a kilocalorie of electrical power, and 10 million or more to support a typical kilocalorie of human service. So when renewable energy systems are evaluated, both inputs and outputs must be converted to solar eMjoules (or "sej") and compared. (There are ten different sets of equations to convert energy to sej: ) The difference between the sej input and sej output is known as the "net sej".

Calculations show that solar cells consume twice as much sej as they produce. So even if all the energy produced were put back into production, then one could build only half as many cells each generation -- they are not sustainable. Even if the sej efficiency of solar cells doubled, ALL of the energy produced would have to be used to manufacture new cells, which still leaves a zero net benefit to society!

Traditional measures of "net energy" for solar cells may be improving but "net sej" may be getting worse because there are ten different sets of equations to convert energy to sej. The only way to know is to DO THE MATH.

H.T. Odum's solar "eMergy" (eMbodied energy) measures all of the energy (adjusted for quality) that went into the production of a product. Odum's calculations show that the only forms of alternative energy that can survive the exhaustion of fossil fuel are muscle, burning biomass (wood, animal dung, or peat), hydroelectric, geothermal in volcanic areas, and some wind electrical generation. Nuclear power could be viable if one could overcome the shortage of fuel. No other alternatives (e.g., solar voltaic) produce a large enough net sej to be sustainable. In short, there is no way out.
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Re: Coal is a “DIRTY” Business

Postby WalkerARCHITECTS » Mon Jul 02, 2012 9:48 pm

So here we are and it is 2012 July 2. Sun is shining and there is much to celebrate in just a few days it will be 4th of July and Solar Cells are now at 43.5% Efficient. The latest record has been broken ....again!

Of course cost is a fact too.

The energy conversion efficiency (η) of a solar cell is the percentage of the solar energy to which the cell is exposed that is converted into electrical energy.

Several factors affect a cell's conversion efficiency value, including its reflectance efficiency, thermodynamic efficiency, charge carrier separation efficiency, and conduction efficiency values. Because these parameters can be difficult to measure directly, other parameters are measured instead, including quantum efficiency, VOC ratio, and fill factor. Reflectance losses are accounted for by the quantum efficiency value, as they affect "external quantum efficiency." Recombination losses are accounted for by the quantum efficiency, VOC ratio, and fill factor values. Resistive losses are predominantly accounted for by the fill factor value, but also contribute to the quantum efficiency and VOC ratio values.

Energy conversion efficiency can be calculated by dividing a cell's power output (in watts) at its maximum power point (Pm) by the input light (E, in W/m2) and the surface area of the solar cell (Ac in m2) under standard test conditions (STC).

n= Pm /ExAc

STC specifies a temperature of 25 °C and an irradiance of 1000 W/m2 with an air mass 1.5 (AM1.5) spectrum. These correspond to the irradiance and spectrum of sunlight incident on a clear day upon a sun-facing 37°-tilted surface with the sun at an angle of 41.81° above the horizon.[2][3] This condition approximately represents solar noon near the spring and autumn equinoxes in the continental United States with surface of the cell aimed directly at the sun. For example, under these test conditions a solar cell of 12% efficiency with a 100 cm2 (0.01 m2) surface area would produce 1.2 watts of power.
In 2006 testing at the National Renewable Energy Laboratory demonstrated an efficiency of 40.7% using triple-junction solar cells developed by Spectrolab a subsidiary of The Boeing Company, and part of Boeing Defense, Space & Security. Note the date of the post above!

The new announcement: Sharp just signaled a bright future for renewable energy as it achieved a new solar cell efficiency record of 43.5%, eclipsing its previous record of 36.9% set in November. Sharp shattered the efficiency record with its concentrator triple-junction compound solar cell, which uses a lens-based system to focus sunlight directly onto the cells in order to generate electricity. This latest breakthrough puts solar power one step closer to grid parity.

What’s a typical solar panel efficiency rating?

Most solar panels are around 11-15% efficient (check out this handy comparison table of solar panel efficiency to see the differences between brands). The efficiency rating measures what percentage of sunlight hitting a panel gets turned into electricity that you can use. The higher the efficiency, the less surface area you’ll need in your solar panels. Although the average percentage may sound a little low, you can easily outfit a typical roof with enough power to cover your energy needs.
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