Fuel Efficiency in Conversion to Energy

[jebatty]

Thought some info on the conversion efficiency of coal to electrical energy might be interesting with regard to nofossil's research which indicates a possible 56% efficiency for a home wood gasification boiler. https://www.hearth.com/econtent/index.php/forums/viewthread/13805/

Let me state my conclusion first: Overall efficiency from coal injected into the boiler to the end user's consumption of electricity likely is about 22%. This efficiency level does not take into account the losses involved in the mining, processing, transporting and handling of coal between the ground and injection into the boilers. In the final analysis, the electrical generating system efficiency based on coal is exceptionally low. When this overall very low efficiency is compared to the exceptionally high level of CO2 emissions from coal, one has to very seriously ask: "Why should not every effort be made as soon as possible to eliminate use of coal as an energy source for generation of electricity."

Without having the knowledge to critique nofossil's research, there is a lot of industry research on the efficiency of converting coal to electrical energy. Consider the following:

A. Much research shows that the average thermal efficiency of coal fired electric generating plants is only about 33%. That means that only 1/3 of the energy value of the coal ends up being generated electricity at the generating plant. The rest is wasted heat.
http://www.fossil.energy.gov/programs/powersystems/gasification/index.html
http://www.energetics.com/gridworks/grid.html

B. Technology apparently exists to raise this efficiency level to about 48%, which probably is close to the maximum possible real-world thermal dynamic efficiency using the limits of current technology. Nofossil's research needs to be evaluated in view of the outstanding research on thermal dynamic efficiency.
http://en.wikipedia.org/wiki/Fossil_fuel_power_plant
http://www.newton.dep.anl.gov/askasci/eng99/eng99187.htm

C. Overall transmission line losses between the generating plant and the user are estimated to range between 8% and 15%.
http://www.energetics.com/gridworks/grid.html

In Europe this number averages 7%, probably mostly due to the shorter transmission line distances.
http://www.groupsrv.com/science/about326877.html

D. None of these efficiency numbers take into account the losses involved in the mining, processing, transporting and handling of coal between the ground and injection into the boilers.

E. None of these efficiency numbers take into account end user efficiency in converting the delivered electrical energy into something useful. If power factor (PF) is useful in estimating end use efficiency, my estimate is that average home PF = 0.75, which means only 75% of the electrical energy delivered to the home ends up as something useful, the rest being wasted.

F. In the United States, about 40.5 percent CO2 emissions was attributed to the combustion of fossil fuels for the generation of electricity in 1998, the latest year for which all data are available.

Coal has the highest carbon intensity among fossil fuels, resulting in coal-fired plants having the highest output rate of CO2 per kilowatthour.

CO2 emissions from coal-fired electricity generation comprise nearly 80 percent of the total CO2 emissions produced by the generation of electricity in the United States, while the share of electricity generation from coal was 51.0 percent in 1999.

http://www.eia.doe.gov/cneaf/electricity/page/co2_report/co2report.html

Conclusion: as stated above.

 

[wdc1160]

Je, where did you get 33% from? I read the sources that you posted and they gave different numbers.

 

[TMonter]

Who says CO2 is an issue? Based on current evidence in peer reviewed literature it very well may not be.

On a per megawatt basis even accounting for externalities coal is by far the cheapest fuel.

 

[jebatty]

Je, where did you get 33% from? I read the sources that you posted and they gave different numbers.

Look at the second source, the heading titled "Electric Generation," first line: "The average thermal efficiency is around 33%."
http://www.energetics.com/gridworks/grid.html

The first source, at the link specified below, about half way down the page, "... (the average efficiency of today's coal-burning power plant typically is around 33-35%)."
http://www.fossil.energy.gov/programs/powersystems/combustion/index.html

The about 33% efficiency factor for today's coal-fired electric generating plants seems to be pretty common knowledge across the board.

 

[jebatty]

Who says CO2 is an issue? Based on current evidence in peer reviewed literature it very well may not be.

On a per megawatt basis even accounting for externalities coal is by far the cheapest fuel.

Everyone has a right to an opinion. But opinions to me have little worth. That is why I cited reputable, credible, generally respected data sources for all of my facts. I did state my opinion based on those facts. That's fair. You also may state your opinion based on those facts. That's fair. We all then can evaluate the merits of the opinions expressed.

So, it is fair for me to ask you to please cite your reputable, credible, and generally respected data sources on which you base each of your opinion statements so that I and others can evaluate the merit of your opinions.

 

[wdc1160]

JE,

how does Nofo's heating effciency relate?

 

[jebatty]

Didn't give it too much thought, but if thermal dynamic efficiency of electrical generation plants is only about 33%, and if under current technology the probably maximum efficiency which can be attained is about 50%, and the 50% involving a very high degree of heat recovery (I saw one source that mentioned flue temp of 120), my thought was for a home boiler system reaching a higher efficiency level might be looked at to see how or why these numbers might differ from what nofossil calculated. That's all. Hope this makes sense.

 

[Nofossil]

One major difference - the 33% that might be raised to a maximum of 48% is the conversion of the original chemical energy to electricity after passing through the intermediate step of converting it to heat.

I'm only converting it to heat - a much more efficient process. Careful independent tests have shown that gasification boilers can achieve a 90% efficiency - that is, 90% of the chemical energy in the fuel is converted to heat extracted from the boiler via the water circulated through the boiler.

 

[jebatty]

You're probably right -- the number and explanation that seemed to ask for more thought was that 50% number. That number was based on recovery of the heat that normally is wasted up the stack or through the cooling towers. the recovered heat being fed to a central heating system, for example, just like our boilers feeding the hot water through a our heating systems.

It didn't seem logical, but maybe it is, that another, say 40%, is lost in the steam-turbine-electric generation process.

I'm no engineer and know just about nothing about thermo dynamics, so an amateur mind is at work here.

 

[Nofossil]

It's well worth reviewing the numbers and doing a sanity check. We need more people doing that in every area of life. It's amazing how often common practices make no sense when you look at the actual data.

 

[jebatty]

Who says CO2 is an issue? Based on current evidence in peer reviewed literature it very well may not be.

A rational person would weigh the evidence, consider the disagreement, and reach a conclusion based on the weight of the evidence. So, that process should be applied to CO2's role as a greenhouse gas, global warming, agent. Following are a few of many reputable, credible, and generally respected data sources which evidence the greenhouse gas, global warming, effect of CO2. The data sources in support of the material role of CO2 as a global warming, greenhouse gas are so numerous that in my opinion, coming to a contrary conclusion regarding the role of CO2 as a global warming, greenhouse gas, is irrational. Following are a few sources.

http://www.umich.edu/~gs265/society/greenhouse.htm
http://www.eia.doe.gov/oiaf/1605/ggccebro/chapter1.html

"Scarcely any reputable expert now doubted that CO2 and other greenhouse gases were at least partly responsible for the unprecedented warming all around the world since the 1980s. A final nail in the skeptics' coffin came in 2005, when a team compared computer calculations with long-term measurements of temperatures in the world's ocean basins (it was not in the air but the massive oceans, after all, that most of any heat added soon wound up). In each separate ocean basin, they showed a close match between observations of rising temperatures at particular depths, and calculations of where the greenhouse effect should appear. This was telling evidence that the computer models were on the right track. Nothing but greenhouse gases could produce the observed ocean warming — and other changes that were now showing up in many parts of the world, as predicted." http://www.aip.org/history/climate/co2.htm

"Although emissions of CO2 are the largest anthropogenic contributor to the risks of climate change, other
substances are important in the formulation of a cost-effective response.' [quoted as to the comment of CO2 as the largest contributor] http://web.mit.edu/globalchange/www/MITJPSPGC_Rpt94.pdf

CO2 is the largest contributor to greenhouse gas climate change, but other pollutants also have a role.
http://science.nasa.gov/headlines/y2000/ast29aug_1.htm

 

[jebatty]

[quote author="TMonter" date="1203994450]On a per megawatt basis even accounting for externalities coal is by far the cheapest fuel.[/quote]

This unsupported comment caused me to look further into the "real cost" of coal. Following is an article which I site not so much as to its pure factual content, but for the purpose of putting a perspective on this issue and providing "fuel" for conversation about coal's real cost.

http://www.huffingtonpost.com/robert-f-kennedy-jr/coals-true-cost_b_74738.html

If you *oogle "real cost of coal" you will find some light in seeing the real cost of electricity from coal fired electric generating plants. De-light yourself in the results.

 

[jebatty]

On a per megawatt basis even accounting for externalities coal is by far the cheapest fuel.

I apologize for messing up the quote.

 

[FishHawk 210CC]

No fossils efficiency is from converting energy to heat only.

The conversion to electricity is where the efficiency is lost as the turbine can not convert the heat of vaporization of the water (approx 970 btu/lb) only the super heat portion of the steam (approx 1 BTU / deg / lb). To increase the electricity generating efficiency, you increase the pressure and degree of superheat of the steam.

If you loooked at the efficiency of a coal plant converting coal to heated water/steam it would be much, much higher than nofossils 56%.

To truly get efficient power production you should tie together a manufacturing process that uses/requires low pressure saturated steam and can return clean condensate to utilize the energy in the water needed to vaporize it to make steam. That allows the energy to be used productively not just disposed of in a cooling tower.

The CO2 issue a completely different discussion than the cost efficiency coal fired plants.

 

[Nofossil]

If you loooked at the efficiency of a coal plant converting coal to heated water/steam it would be much, much higher than nofossils 56%.

Probably not more than 44% higher, though.

 

[Ken45]

Burning one fossil fuel or another isn't going to solve very much. Coal is good because it is plentiful and we have it in this country. When you consider the alternative fossil fuels (oil, gas) don't forget to figure in the cost of war that they entail. How much pollution did the First Gulf War create (remember the burning oil wells?)

The real answer, I believe, is that we need to figure out nuclear power. How come France has been safely generating most of it's power from nukes for decades, but we can't?

Ken

 

[pbvermont]

With nuclear power there is always the issue of spent fuel. Where do you store it...safely?

 

[Ken45]

With nuclear power there is always the issue of spent fuel. Where do you store it...safely?

I agree that is the hardest problem. But I also believe that there are nuclear power technologies that do not have that problem, but the U.S. refuses to consider them.

Ken

 

[jebatty]

Ken, I think you're right. I *-oogled nuclear waste, and didn't quickly find what I understand is available, which is I think is reprocessing, recovering and reusing the material in the spent fuel rods. What I wonder though, and this has not a lot to do with nuclear energy, is "normal" industrial pollution, chemicals, etc. now is everywhere, with health effects largely unknown. What about the "normal" industrial waste in the mining, processing and reprocessing of uranium and nuclear material? Where is it going? The big government sites I understand to be wastelands.

Is there a story here the media is not reporting because it is "owned" by the money interests?

 

[Nofossil]

Couple of thoughts on nuclear.

First, waste disposal is technically easy and safe, just politically difficult. One good option is to encase it in glass and drop it into ocean floor subduction zones, where it will be drawn into the magma under the tectonic plates and not re-emerge for many millions of years.

Second, the reactors in use in the US are ancient technology. Newer designs extract far more energy per pound of fuel (current designs are 1% efficient) and produce drastically less waste.

Third, the dangers of radiation are significantly overstated by the media as well as the scientific community. which ought to know better. While it's certainly true that large doses of radiation are bad for you, there are significant studies and data that suggest that small doses are actually beneficial at levels well above what are considered acceptable under current standards. Google 'hormesis' and 'Linear No Threshold' for more insight.

I hope that we get past the fear and hysteria before we suffer needless hardships. Nuclear is the cleanest, least intrusive, and least expensive option that we have to generate the quantities of electricity that we need if we are to move away from fossil fuels.

 

[Ken45]

I hope that we get past the fear and hysteria before we suffer needless hardships. Nuclear is the cleanest, least intrusive, and least expensive option that we have to generate the quantities of electricity that we need if we are to move away from fossil fuels.

Agree, nothing is totally safe, not even corn/ethanol ;-) I believe our national approach to nuclear power is irrational, emotional, and political. Besides, there is BIG MONEY to be made by ignoring nuclear power (e.g. coal, oil, natural gas, corn, etc.)

I also believe that our excessive gov't bureaucracy has hobbled the industry and probably made it less safe, rather than more safe. As I mentioned earlier, France gets most of it's electricity from nuclear power with a great safety record. Why can't we? Is it because boondoggles like corn/ethanol (and wind farms) buy more votes and campaign contributions? Is it because "big oil" has more friends in Washington?

I realize that we haven't selected good waste disposal approaches (although I don't see anything wrong with the sequestering/ocean subduction approach), but let's face it, if this country was generating most of it's electricty from nuclear power, oil prices would be a lot lower and we might have avoided a couple of nasty wars and horrendous deficits.

Ken

 

[Ken45]

Ken, I think you're right. I *-oogled nuclear waste, and didn't quickly find what I understand is available, which is I think is reprocessing, recovering and reusing the material in the spent fuel rods. What I wonder though, and this has not a lot to do with nuclear energy, is "normal" industrial pollution, chemicals, etc. now is everywhere, with health effects largely unknown. What about the "normal" industrial waste in the mining, processing and reprocessing of uranium and nuclear material? Where is it going? The big government sites I understand to be wastelands.

Is there a story here the media is not reporting because it is "owned" by the money interests?

Jim,

Fast Breeder Reactors can be designed to produce very little waste. France has a big one. The U.S., in 1977, decided to prohibit such reactors. It would appear that we did so for unsound reasons. See
http://argee.net/DefenseWatch/Nuclear Waste and Breeder Reactors.htm

for more information.

Ken

 

[TMonter]

A rational person would weigh the evidence, consider the disagreement, and reach a conclusion based on the weight of the evidence. So, that process should be applied to CO2’s role as a greenhouse gas, global warming, agent. Following are a few of many reputable, credible, and generally respected data sources which evidence the greenhouse gas, global warming, effect of CO2. The data sources in support of the material role of CO2 as a global warming, greenhouse gas are so numerous that in my opinion, coming to a contrary conclusion regarding the role of CO2 as a global warming, greenhouse gas, is irrational. Following are a few sources.

You'd think so wouldn't you. Perhaps you should read the peer reviewed literature and not the short politicized versions off of websites:

I’ll state it for advocates here that this “consensus” in the science field does not exist---and it surely doesn’t exist in the scientific literature. The National Academies all defer to the IPCC, not their own judgment of the work found in the peer-reviewed journals. What I’m about to do is provide some of the references found in the scientific journals, organized by subject (and why the particular subject is important to the debate).
First thing I’m going to reference here is the references of the technical debunking of that ancient sacred cow (advocates get touchy over this one), the Mann (or “hockey stick") graph. This thing is important in that the graph was used by the IPCC in it’s third assessment report, and it’s still used by advocates like Al Gore, to show that the planet had stable temperatures while we had stable greenhouse gas levels.

Well, here are those papers that show that the graph is based on flimsy methodology:

Von Storch, Science, 2004
McIntyre & McKitrick, Geophysical Research Letters, 2005 (it should be noted that many scientists dispute this paper, but enough of the research has been proven valid to list it)
Mangini et al, Earth and Planetary Science Letters, 2005.

Plus there are two other reports that vastly condemn the graph, commonly known as the “North” report, and the Wegman report. The first was done by an arm of the National Academy of Sciences, the second was done by a panel of statisticians and others for a Congressional committee. This graph needs to be put to rest, and the next set of references I’ll provide should put the last nail in the coffin of the idea that the IPCC and advocates keep repeating.

That idea is that greenhouse is a key driver of climate change, hence that human industry is the primary cause of climate change---being as it’s supposedly (without any scientific proof of it) the chief contributor to the rise in greenhouse gas levels. What this section has is references to temperature reconstructions that show us that pre-industrial temperatures (hence, climate) was much more variable than advocates like to admit, because it would undo everything they claim, basically it proves that greenhouse isn’t the key factor that they claim, as pre-industrial temperatures were varied despite relatively low and stable greenhouse gas levels.

A sampling of these papers are:

Cook et al, The Holocene, 1992
Villalba, Climate Change, 1994
Kiegwin, Science, 1996
Biondi et al, Geophysical Research Letters, 1998
DeMenocal et al, Science, 2000
Verschuren et al, Nature, 2000
Tyson et al, South African Journal of Science
Esper et al, Quarternary Science Reviews, 2002
Esper et al, EOS, 2004; Moberg et al, Nature, 2005
Cohn & Lins, Geophysical Research Letters, 2005
Esper et al, Quarternary Science Reviews, 2005
Grinsted et al, Journal of Geophysical Research, 2006
Vinther et al, Journal of Geophysical Research, 2006
Newton et al, Geophysical Research Letters, 2006.

Spanning the globe, using various proxy methods, all these papers show vastly variable temperatures/climate in times before human industry could possibly have been having any effect, when our atmosphere is claimed to have stable and low (by current standards) greenhouse gas levels. This section alone would be reason enough to seriously and gravely doubt the notion that greenhouse (hence, human industry by it’s allegedly huge contribution to them) is a key determinant in a warming that we’re observing.

Is there other reference that opposes the notion? You bet! The theory states that the polar regions should be most susceptible to greenhouse warming, yet I’ll reference 3 papers here that show a period during the current interglacial where (about 8,000-10,000 years ago) the arctic was much warmer than present, yet the CO-2 level (greenhouse gas) was roughly on par with pre-industrial CO-2.

They are:
MacDonald et al, Quarternary Research, 2000
Kaufman et al, Quarternary Science Reviews, 2004
Briner et al, Quarternary Research, 2006.

Is there, found within the peer-reviewed literature any possible alternative explanations? Yes, there is one that is being researched extensively and (for all the advocates claims to the contrary) shows stronger ties to temperature and climate than greenhouse gas does. It’s the solar/cosmic connections. These research papers continue to show a stronger correlation to climate drivers than greenhouse. As many of these papers show, the climate models used by advocates (notably, the IPCC) still can’t (and don’t) account for the effects of these forcings. This sampling is:

Reid, Space Science Reviews, 2000
Marsh & Svensmark, Physical Review Letters, 2000
Karlen, Ambio, 2001; Rind, Science, 2002
Kodera, Geophysical Research Letters, 2003
Fokul, EOS, 2003; Shaviv & Veizer, Geology Society of America, 2003
Soon, Geophysical Research Letters, 2005
Mayewski et al, Annals of Glaciology, 2005
Weng, Journal of Atmospheric and Solar Terrestrial Physics, 2005
Lean, Physics Today, 2005
Scaffetta & West, Geophysical Research Letters, 2006

 

[TMonter]

Advocates proudly tout those models (called General Climate Models, or GCM’s) that allegedly tell us what all this CO-2 and other gasses we’re “pumping” into the atmosphere will do. First, the biggest problem with them is that there is a fundamental flaw with using them as a scientific tool to begin with---the only test that counts in science is the test with reality. That’s something that a computer model simply isn’t. The other basic flaw that’s commonly hidden from the lay-public is that the models can’t even model known climate factors; as powerful as these super-computers are, they still aren’t able to model all the factors that we do know well. The IPCC, in its assessment reports, tells us that we understand only one factor all that well---greenhouse. Solar/cosmic and 7 other factors are listed as known, yet not well understood.

In fact (IPCC, 2001), of those other factors (all completely natural), 3 are listed as “poorly understood.” An excellent example of how far off the models can go is highlighted in the acknowledged fact (IPCC, 2007) that temperatures over the last century of CO-2 rise have risen much more slowly than theory would dictate if the theory were correct. So, the hypothesis says (Levitus et al, 2004; Hansen et al, 2005) that the oceans are acting as a heat sink, absorbing some of that heat. Unfortunately for that notion, there are numerous problems. Between 2003 and 2005 (at least), the upper oceans (where the heat absorption would occur) have been cooling (Lyman et al, Geophysical Research Letters, 2006; Gourestski & Koltermann, Geophysical Research Letters, 2007), and the heating and cooling of the oceans has been sub-regional in scale, not uniform (Ivchenko et al, Geophysical Research Letters, 2006; Gouretski et al, ad cit; Harrison & Carson, Journal of Physical Oceanography, 2007).

The last paper also notes that a huge section of the oceans are not observed with anywhere near the frequency that other portions are (in an area shown to be cooling, as well).

The models also don’t account for other observations, as well. In one paper, Khalil et al, Environmental Science and Technology, 2007; note that methane levels have been levelling off over the last decade, as opposed to CO-2 levels. If humans were, indeed, pumping greenhouse gasses into the atmosphere, this shouldn’t be happening, according to the advocates’ theory. As well, there have been some notes on the models’ general failure to account for the deviation in (for instance) modeled projection and the reality observed in precipitation in the central Andes, as noted by Masiokas et al, Journal of Climate, 2006. Obviously, these models can’t be used as science. They are not only, not reality, they are proven failures when attempting to simulate reality.

Some of you might be inclined to ask whether I know of any peer-reviewed papers that question the “consensus” notion directly in their conclusions, and yes I do. I’ll reference them here: I’ve already referenced Esper et al (2005) and Cohn & Lins, see above, but there are more.

Khandakar et al, Pure and Applied Physics, 2005
Khilyuk & Chilingar, Environmental Geology, 2006
Zhen-Shan & Xian, Meteorology and Atmospheric Physics, 2007.

Bottom line here is that although climate change is happening (nobody says it’s not), it’s causes are far from certain.

In these next few sections, I’m going to present papers (again, peer-reviewed) that dispute the advocates’ commonly-pushed notion that immediate action is needed due to the imminent threat posed by climate changes. These papers show that there is, indeed, a huge amount of science that doesn’t think that climate change will cause anything catastrophic, or even threatening, even those who think humans are the cause.
The first such scare story that advocates repeat is that Global Warming is causing the sea levels to rise at an accelerating rate, which will supposedly cause coastal areas to erode and flood (shown in Day after Tomorrow, and An Inconvenient Truth). Some media shows covering the subject show that some islands are already feeling the effects of human-driven climate change, like Tuvalu in the Pacific (it was shown on CNN’s special, Boiling Point.) Well, it seems like a lot of research shows this to be a complete myth.

The central advocate claim is that global warming will melt glacial and sea ice (and is doing so), and raise sea levels. Several papers dispute that notion:

Wingham et al, Philisophical Transactions of the Royal Society A, 2006
Davis et al, Science, 2005
Holgate, Geophysical Research Letters, 2007.

In fact, the last reference (Holgate) says the rate of sea-level rise actually was slower over the last half of the 20th century, not faster. Other papers (Van der Veen, Global and Planetary Change, 2002; Morner et al, Global and Planetary Change, 2004; Church et al, Journal of Climate, 2004; and Larsen & Clark, Journal of Coastal Research, 2006) point out that there is no correlation between sea level change and climate change, which (in all cases) is measured in millimeters per year. Other papers disputing the “consensus” view advocates tout are:

Raper & Braithewaite, Nature, 2006
Jevrejevera et al, Journal of Geophysical Research, 2006).

If you have no idea how much 2 millimeters is, try looking at a metric ruler. The smallest measured distance is a millimeter. It’s one thousandth of a meter (or one tenth of a centimeter, and it takes 2.54 centimeters to make an inch). Considering that the Maldives (an island group in the pacific that’s supposedly going to be uninhabitable with rising oceans) have survived inhabited for over 1500 years (the oceans have been higher than now in that time), I think they’ll be just fine.

Forgive me if I base my observations on the actual science and not on the underpinnings of the IPCC's political rhetoric.

 

[TMonter]

“Why should not every effort be made as soon as possible to eliminate use of coal as an energy source for generation of electricity.”

The obvious answer being, another question: What will you replace it with?

Who is going to pay for the cost of replacement?

Are you willing to pay double or triple the current cost of power?

Do you even realize how clean modern coal plants are?

The big two answers are cost and availability. Coal is cheaper and more available than any other energy source. We have 200+ years of proven reserves.