I realize that it's probably been a while since anyone built a new coal fired power plant in North America. Presumably, it will probably be quite a while until someone builds another one. In 2005(?) Trains Magazine ran some maps of the month that showed power plants of the U.S. and where their coal originated. A lot of PRB coal seems to go south, east, and southeast. It also seems like a fair amount of power plants haul their coal a long way, yet another plant 100 miles away will be using coal from mines that are a lot closer. What goes into siting a coal fired power plant? Obviously, the plant is usually situated near a good supply of water, for cooling needs. Unless it's sited right next to the mine, it seems like 99% of the time, it would be on a rail line. How do they determine what type of coal they plan to burn? Does the type of coal used determine which railroad to site a plant on, or does the railroad chosen to serve the plant lead them toward the type of coal to design for? Since the PRB coal became popular in the early 70's due to environmental laws, were those plants burning PRB coal built in that era, or just converted in that era from a different type of coal?
Thanks to Chris / CopCarSS for my avatar.
Murphy —
Actually, Luminant (successor to TXU) just opened the first of two units at its Oak Grove plant near Kosse, Texas, and will open the second unit this year: http://www.luminant.com/plants/pdf/OakGrove_Facts.pdf. Meanwhile, Great River Energy will be opening a new plant at Spiritwood, N.D., this spring: http://www.greatriverenergy.com/makingelectricity/newprojects/spiritwoodstation.html. I also stumbled across this: the Dry Fork Station near Gillette, Wyo.: http://www.basinelectric.com/Projects/Dry_Fork_Station/index.html. Anybody know of other projects currently going on out there?
I'll leave the economics to those who've got a better grasp of this whole question. But I would note there seems to be two philosophies: build close to your fuel source, or build close to your consumers. In the first category, you have North Dakota's power plants adjacent to the lignite fields. In the second, you have the major plants in the Great Lakes states that burn PRB coal. Of course, there are many other examples of both; these are just a couple that come to mind. The fuel source model has the advantage of low transportation costs, but you experience "line loss" as the power travels to market over high tension wires. With the population center model, it's vice-versa.
Best,
We are still building coal fired generting stations. The location of the plant can vary. If you built it close to the PRB, you have long transmission lines and a lot of power loss getting it east. If you build it by the consumer, you have to haul the PRB coal there.
The EPA emissions standards were phased in on a time schedule. Power plants that burned high sulpher eastern coal could 'blend' in more low sulpher coal to meet the emission standard. At some point they had to go to 'pure' low sulpher coal - hence the PRB trains across the country.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
Andy Cummings Murphy — I'll leave the economics to those who've got a better grasp of this whole question. But I would note there seems to be two philosophies: build close to your fuel source, or build close to your consumers. In the first category, you have North Dakota's power plants adjacent to the lignite fields. In the second, you have the major plants in the Great Lakes states that burn PRB coal. Of course, there are many other examples of both; these are just a couple that come to mind. The fuel source model has the advantage of low transportation costs, but you experience "line loss" as the power travels to market over high tension wires. With the population center model, it's vice-versa. Best,
There's a 3rd factor at work here, Andy: politics.
For decades the State of Illinois obligated Chicagoland's big electric utility, The Commonwealth Edison Company, to burn Illinois coal. This requirement may have been modified or overridden when the E.P.A. clamped down on sulfur dioxide emissions during the mid-to-late 1970s.
I'm not sure, but I think the same kind of politics played out between the state government in Denver and Public Service of Colorado plus the Colorado Springs electric utility. Today Xcel Energy, the successor to Public Service of Colorado, does burn Powder River Basin coal as required.
As noted by the Trains Editor, my former employer TXU - I am retired - now Energy Future Holdings has opened a new coal fired power plant. It burns lignite coal, which is a low grade coal that is found in abundant supply in Texas. Lignite coal is a dirty fuel that is blended with low sulfur coal to produce a better outcome.
All of our lignite power plants are built next to the coal sources. Otherwise, it would not be feasible to mine the coal and transport it long distances, as is the case with PRB coal. In fact, it costs more to get the lignite out of the ground at most of our locations than it costs to mine the PRB coals. But the transport costs, which can easily equal the per ton cost of mining the coal, makes the lignite coal cheaper than the PRB coal in Texas. However, because of environmental concerns, we blend PRB coal with the lignite coal to help reduce air pollution.
The wide spread use of lignite coal in Texas power plants has helped rein in the cost of electric energy in the Lone Star state. However, the cost advantage has been eroded by the need to install expensive pollution control equipment to control the pollution outputs created by the burning of lignite.
Prior to the development of coal plants in Texas, the state was dependent on natural gas for most of its electricl power plant boiler fuel. And it became or has become very expensive. At the time I went to work for the company, we had some gas contracts for nine cents a BTU. Now the cost is in the neighborhood of $5.70 a BTU, but it has been close to $15 a BTU during the past decade. Had it not been for the coal, the cost of electric energy in Texas, as well as many other parts of the U.S., would have had a dampening impact on the U.S. economy.
At the time that I retired from the company, we operated approximately 56 miles of rail devoted to getting the coal from the mines - open pit - to the power plants. The railroad was a neat little operation.
Sam1The wide spread use of lignite coal in Texas power plants has helped rein in the cost of electric energy in the Lone Star state. However, the cost advantage has been eroded by the need to install expensive pollution control equipment to control the pollution outputs created by the burning of lignite.
The pollution control equipment also makes an impact on thermal efficiency, I seem to recall that coal fired plants now average about 33%, where an oil or gas fired plant with the same steam conditions would be around 40%. The flip side of lower thermal efficiency is a potentially higher demand for cooling water, not good in the PRB.
Natural gas is also getting a boost from improvements in combustion turbines - combined cycle plants are approaching 60% thermal efficiency. A integrated coal gasification plant would likely have a lower thermal efficiency, but could be easily better than for a straight steam plant.
- Erik
Murphy Siding [snip] In 2005(?) Trains Magazine ran some maps of the month that showed power plants of the U.S. and where their coal originated. A lot of PRB coal seems to go south, east, and southeast. It also seems like a fair amount of power plants haul their coal a long way, yet another plant 100 miles away will be using coal from mines that are a lot closer. [snip]
Back in the day - before electricity deregulation, consolidation/ mergers, and the rise of independently owned 'merchant' generating plants - coal plants were almost always located with a utility's service area.
Another consideration is access/ distance to its high-tension transmission grid, all other factors being equal - though the utility can and often did acquire R-O-W and build new lines when necessary.
A curious exception to the rule of building near a water supply and an existing rail line is PP&L's Montour Steam Electric Station at Strawberry Ridge about 15 miles northeast of Northumberland, PA, which is at the confluence of the North and West Branches of the Susquehanna River. PP&L built a dam to impound the cooling water - I'm not sure of the source, but I believe it is the West Branch - in a substantial lake known as Montour Lake. A fairly lengthy spur was also built from the then-PRR's Buffalo line just north of Milton, PA. I believe this plant was the destination of the coal in that segment of the History Channel's Extreme Trains series a year ago.
For a long while, the coal plants here in the East that I worked at were 'grandfathered' - the gradually tighter air emissions limits either didn't apply to them, or only partially so. So they continued to burn the coal they were originally designed for - mostly from western Pennsylvania, in my experience. As the regulations got tighter, more scrubbers were added, and PRB coal started showing up in some places. I believe there are a couple of plants up in New Hampshire - the one at Bow comes to mind - that seem to have occasional cross-country moves of it.
Other than Montour SES, all of the coal plants that I can think of - and the lands that I know of which were acquired for new plants that were never built - were all next to good-sized rivers or bays off the Atlantic Ocean, and adjacent to at least 1 and sometimes 2 rail lines - PRR and RDG most often.
- Paul North.
The October 2003 map of Western power plants was a bit misleading. It implied it was showing what were described as "Significant Coal Routes," but in fact it was little more than a color-coded (by company) general map of most Western routes. Many of the routes it showed handle little if any coal, and certainly not unit coal moving to power plants. And there was no indication of which mines shipped to which power plants via which routes. (I realize mine sources can vary for a single plant, but this too could have been represented.) But I give them high marks for showing us where the mines and power plants are, especially the two plants in the Northwest which most rail observers don't realize even exist.
A coal-fire co-generation plant was built at Fort Drum, NY when the installation expanded to house the 10th Mountain Division (Light Infantry). The intent was to heat the new buildings with steam from the plant and use the excess capacity to generate electricity to sell on the grid.
It was found that the local soils were corroding the steam pipes (rather quickly) so all of the buildings were converted to natural gas and the plant now only generates electricity.
Based on the cars I've seen coming in to the plant, I'm guessing that it gets a mix of Appalachin, possibly Illinois, and likely Power River coal.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
Sam1 Prior to the development of coal plants in Texas, the state was dependent on natural gas for most of its electricl power plant boiler fuel. And it became or has become very expensive. At the time I went to work for the company, we had some gas contracts for nine cents a BTU. Now the cost is in the neighborhood of $5.70 a BTU, but it has been close to $15 a BTU during the past decade. Had it not been for the coal, the cost of electric energy in Texas, as well as many other parts of the U.S., would have had a dampening impact on the U.S. economy.
At the risk of sounding "nit picky," shouldn't the natural gas prices you're quoting here be expressed in terms of dollars per million BTUs? Today's Wall Street Journal quotes a natural gas settlement price for February delivery of $5.691 per MMBTUs (million BTUs).
Here are some figures I remember from decades ago.
7,000-8,000 BTUs/pound for Powder River Basin coal.
10,000-12,000 BTUs/pound for Hanna, Wyo Basin coal.
I wonder what Routt County, Colorado and Texas lignite average in terms of BTUs per pound? Anyone know?
Murphy,
Consumers Power Company here in Michigan has secured the necessary state and federal permits to build a new coal fired plant in Essexville on the Saginaw Bay. Construction should begin soon unless "the greenies" manage to tie it up in court.
To comply with emissions regulations, virtually all the plants here are using a mix of PRB and Appalachian coal and scrubbers. The larger plants are situated on or near the Great Lakes, and can get coal either by rail or lake freighter.
Norm
I am surprised that there are still coal burning plants being built. Recently, a plan to build a second plant at Big Stone Lake, on the ex-Milwaukee Road line at the S.D./MN line was shot down in flames. I was even more surprised to see a mine-mouth power plant being built north of Gillette, in the Powder River basin of Wyoming. I lived in Gillette for a couple of years. There is a Wyodak power plant that has been on the outskirts of town for maybe 40 years. It is almost a desert. In an area that dry, how do they deal with a lack of cooling water?
Bob-FrymlHere are some figures I remember from decades ago. 7,000-8,000 BTUs/pound for Powder River Basin coal. 10,000-12,000 BTUs/pound for Hanna, Wyo Basin coal. I wonder what Routt County, Colorado and Texas lignite average in terms of BTUs per pound? Anyone know?
Bob, I think you are a little low on the PRB ratings and high on those for Hanna Basin. IIRC Coal Creek which produced the lowest rated coal in the PRB produced 8,200 BTU/lb, and most of the rest were in the 8,700 BTU/lb to 8,800 BTU/lb range. The low rating for coal from the area where Coal Creek mine is located is why it has only operated sporadically and why no other PRB mines were opened in that part of the Basin. I think the Hanna Basin coal was just slightly higher rated than PRB coal. I thought that the better coal that the UP hauled in the earlier times came from the Colowyo branch. There were also mines around Kemmerer, ID on the OSL.
Before it is too late, contact the BNSF investors relation department and request one of their outstanding "Coal Maps". Even tho it is a bit dated (July, 1998) the map details on line coal mines.
More importantly, the map lists coal fired power plants (with and without scrubbers) plus marine terminals. Pretty neat map.
ed
Murphy Siding I am surprised that there are still coal burning plants being built. Recently, a plan to build a second plant at Big Stone Lake, on the ex-Milwaukee Road line at the S.D./MN line was shot down in flames.
I am surprised that there are still coal burning plants being built. Recently, a plan to build a second plant at Big Stone Lake, on the ex-Milwaukee Road line at the S.D./MN line was shot down in flames.
beaulieu Bob-Fryml Here are some figures I remember from decades ago. 7,000-8,000 BTUs/pound for Powder River Basin coal. 10,000-12,000 BTUs/pound for Hanna, Wyo Basin coal. I wonder what Routt County, Colorado and Texas lignite average in terms of BTUs per pound? Anyone know? Bob, I think you are a little low on the PRB ratings and high on those for Hanna Basin. IIRC Coal Creek which produced the lowest rated coal in the PRB produced 8,200 BTU/lb, and most of the rest were in the 8,700 BTU/lb to 8,800 BTU/lb range. The low rating for coal from the area where Coal Creek mine is located is why it has only operated sporadically and why no other PRB mines were opened in that part of the Basin. I think the Hanna Basin coal was just slightly higher rated than PRB coal. I thought that the better coal that the UP hauled in the earlier times came from the Colowyo branch. There were also mines around Kemmerer, ID on the OSL.
Bob-Fryml Here are some figures I remember from decades ago. 7,000-8,000 BTUs/pound for Powder River Basin coal. 10,000-12,000 BTUs/pound for Hanna, Wyo Basin coal. I wonder what Routt County, Colorado and Texas lignite average in terms of BTUs per pound? Anyone know?
The heat content figures I quoted came from someone I know who used to work for Arch Minteral at Hanna. Those were the numbers he supplied 20-to-25 years ago. Perhaps the heat content of PRB coal mined today is higher versus what it was then.
Jackson County, Colorado did have some coal mines that produced some decent quality coal, but the costs of extraction plus transportation charges did not make the coal competitive. The coal that did move out of there by rail moved over Union Pacific's Coalmont Branch, but due to grades and sharp curves coal shipments were restricted to 35-cars per train. For awhile business along that branchline was good, and U.P. spent a lot of money for ditch work, new crossties, a lengthened siding near the Wyoming-Colorado border, and heavy 2nd-hand mainline rail. But when the CNW-UP joint venture into the PRB opened in 1984, the Coalmont business declined.
In November 1987 the Wyoming-Colorado (WYCO) Railroad tried to make a go of the Coalmont Branch, but after a few years of operation they were ultimately unsuccessful. Today, only about the first mile out of Laramie is all that's left. The rest has been sold for scrap.
Murphy Siding I realize that it's probably been a while since anyone built a new coal fired power plant in North America. Presumably, it will probably be quite a while until someone builds another one.
I realize that it's probably been a while since anyone built a new coal fired power plant in North America. Presumably, it will probably be quite a while until someone builds another one.
(To put those numbers into perspective, the U.S. has 351,831 MW of production capacity from coal as of 2005, so the new plants represent an increase of about 6%, which is not inconsequential! Moreover, the U.S. drives its coal-plants harder than its natural-gas and oil-fired plants for technical/economic reasons, so that while coal plants represent 32.2% of U.S. generation potential capacity, they account for 48.5% of all electricity actually generated.)
However, there are many cancellations or delays in new-start capacity during the last 2 years, partially due to permitting issues, partially due to cost estimates that came in to high, and partially due to inability of some projects to demonstrate purpose-and-need to state or federal regulators, but most of all because the economic downturn has caused a severe decline in electric consumption. In fact, there are some in the industry who are predicting the decline might be permanent, that the U.S. will never need as much power as it can generate right now.
Again, quoting Coal Power, "Regardless of these constraints, beyond 2008, 116 new U.S. coal-fired units—representing 41,000 MW—have been proposed. In fact there are still 34 units and nearly 11,000 MW of new coal-fired capacity that have a possible construction start scheduled for 2009. It is widely expected that the majority of these units and associated projects will, in the best of circumstances, be delayed beyond 2009."
In 2005(?) Trains Magazine ran some maps of the month that showed power plants of the U.S. and where their coal originated. A lot of PRB coal seems to go south, east, and southeast. It also seems like a fair amount of power plants haul their coal a long way, yet another plant 100 miles away will be using coal from mines that are a lot closer.
The reason for the first sentence is two-fold: First, "that is where the people are;" there is relatively thin population and thus relatively thin demand west of the PRB until one reaches the Pacific Coast. Second, there are substantial coal resources in the Rocky Mountain states in western Wyoming, Colorado, Utah, and the four-corners area of Arizona and New Mexico, and to haul PRB coal west is trying to leapfrog it over local sources. Transportation costs for a ton of coal are not related to the quality of the coal or the value of the coal, so PRB coal quickly prices itself out of the market as it moves west compared to sources further west. That said, there are several power plants in the West that do burn PRB coal, such as PGE at Boardman, Oregon, Trans-Alta at Centralia, Washington, Colorado Springs Department of Utilities Ray Nixon plant south of Colorado Springs, Excel Energy Pawnee and Comanche plants at Brush and Minnequa, Colorado, and Platte River Power Authority's Rawhide Station near Wellington, Colorado. Nevada Power's and LS Energy's proposed adjacent stations near Ely, Nevada, 1,500 MW and 3,000 MW, respectively, were planned for PRB coal, as was a 1,500 MW plant near Mesquite, Nevada. These latter three proposals are now moribund. In general, the reason for the new-build plants being designed for PRB coal, as well as conversion of several such as Ray Nixon that were previously burning high-BTU Yampa Field coal, is that the PRB has a relatively long-term viability compared to Rocky Mountain fields that may only have 10-20 years remaining. Large power stations are 50-year investments; one does not build one unless there is very high assurance that the coal around which the plant is designed will be in economically affordable supply 50 years hence.
The reason for your second sentence has a great deal to do with when the power plant was built, and that power plants are designed for a specific coal and often cannot be converted to burn a different coal without enormous costs. Combustion machinery is sophisticated and if you try to burn an inappropriate coal in it you will destroy it -- literally. For example, the ash in coal has a fusion temperature -- the temperature at which it melts. Some coal plants are "wet" meaning their boilers intend for the ash to melt in the firebox, and others are "dry," meaning the ash emerges out the other side of the tubes as a very hot powder suspended in the combustion gas stream. If you insert a coal with a lower ash fusion temperature into a firebox than it is designed for, you risk slagging the tubes, melting the tubes, and destroying the boiler. That could be a $100,000,000 mistake, not even including the cost of purchasing merchant power to replace your coal plant or employing all your idel hands while the plant is down for a year for repairs.
Accordingly, coal plants designed in the mid-1960s were aware the PRB might come on line, but there was no guarantee, and were also designed before the Clean Air Act. Accordingly, most of those in the midwest were built to burn Illinois Basin coal which is much higher in both BTU and sulfur, and much lower in ash and water content, than PRB coal. Post CAA, power plant designers had to decide to either install scubbers or burn PRB coal, or blend with low-sulfur Appalachian coal, or low-sulfur Colorado coal. There are many choices and the economic tradeoffs are complicated.
What goes into siting a coal fired power plant? Obviously, the plant is usually situated near a good supply of water, for cooling needs. Unless it's sited right next to the mine, it seems like 99% of the time, it would be on a rail line. How do they determine what type of coal they plan to burn? Does the type of coal used determine which railroad to site a plant on, or does the railroad chosen to serve the plant lead them toward the type of coal to design for?
The most important factor, by far, is air quality of the location proposed for the plant. A plant cannot be permitted in a "non-attainment" area where air quality already does not meet current federal standards, unless it will be a zero emitter, or the power plant will pay others in the non-attainment area to reduce or remove pollutants equal to the amount the power plant will emit. That usually prices the cost of construction and operation out of non-attainment and into attainment areas.
After you sort out all the non-attainment areas that the plant can't be built in, then it becomes a complicated economic tradeoff between cost of construction of transmission lines, ability to permit transmission lines, availability of water, ability to permit the water extraction, cost of transportation, reliability of coal supply, duration of coal supply, characteristics of coal supply, cost of coal supply, and price that you think you can put the power into the market in competition with other power sources, particularly these days merchant natural gas plants. Also, laws about renewable energy, local environmental impacts, local community impacts, and so forth, matter. Virtually every location in the U.S., regardless of which party they vote for, has strong opposition to a power plant, including communities that haven't voted for a Democrat in 150 years, don't own a single Prius, and don't have any stores that sell half-fat double-shot soy lattes. The jobs and economic growth that a power plant represents are actually not desired by most rural states or communities, as far as I can tell, from my attending public hearings, because it (1) changes their existing social power structure and might bring in people who aren't like them, and (2) might possibly benefit someone in a city.
Since the PRB coal became popular in the early 70's due to environmental laws, were those plants burning PRB coal built in that era, or just converted in that era from a different type of coal?
At first the PRB-consuming plants were all new-build. Many plants were later converted, mostly because CAA amendments steadily made it more and more costly to continue burning Illinois Basin or an Illinois Basin-Colorado or Illinois Basin-eastern Appalachian blend. In other words, the cost of conversion plus the higher cost of coal transportation and the lower cost per BTU more than offset the cost of emissions equipment construction, operation, and maintenance. Some plants such as Mississippi Power's Daniel Station were conversions simply to obtain lower cost per BTU (at least as far I understand it in that case.)
RWM
Is there some sort of formula or rule of thumb for the size (output) of a coal burning plant vs the amount of coal it consumes in a year? Does it vary on the BTU value of the coal?I am looking for a frequency of unit train model (from PRB) based on the size of the plant. For instance, appx how many tons of PRB coal will a 1.5MW plant use. I can convert the tons to trains per year.
Thanks,
Ed
Yes, there's a series of formulas, but there are a lot of variables that you have to determine in order to have a meaningful answer. There's no single formula, and no two people will ever calculate the number quite the same because there are still assumptions involved.
Some of the important variables are the load factor of the plant, the efficiency of the boiler, the amount of power drawn off for "house" use (particularly important depending upon the type and energy consumption of the emissions controls equipment, if any), and the BTU content of the coal. Not all PRB coal is alike -- the northern PRB coal has significantly less heating value than southern PRB coal.
For a round number, let's assume a brand-new 1,500 MW plant with two 750 MW units, supercritical boilers, baghouse, ammonia injection, 85% load factor, southern PRB coal averaging 8,800 BTU/lb. and 25% moisture content, 135-car trains, and 120 tons per car. For those inputs, a ballpark tons per hour per unit is 400 and the number of 16,200-ton (net) trains per day is 19,200/16,200 = 1.185
"In fact, there are some in the industry who are predicting the decline might be permanent, that the U.S. will never need as much power as it can generate right now."
In view of some prospects for more use of electricity for primary transportation power and other trends that impact electric power consumption at the residential level, I find that prediction quite remarkable. Do you see the prediction based on the assumption that general economic activity will not return to previous highs or is it other factors such as improved energy efficiency and conservation, i.e., turning off the lights?
"We have met the enemy and he is us." Pogo Possum "We have met the anemone... and he is Russ." Bucky Katt "Prediction is very difficult, especially if it's about the future." Niels Bohr, Nobel laureate in physics
Both, plus certain economic activities that surrounded the real-estate bubble that will be a long time, if ever, coming back.
The WSJ had a very good article last Thursday on this subject.
GP40-2 This is a temporary situation. I know this forum doesn't like to bring in politics, but it is impossible to separate politics from both the railroad and coal industries. They have been intertwined historically, and will continue to be linked. That being said, you will see an uptick in new coal plant construction after the mid term elections, and the 2012 Presidential elections (with the ensuing shake up at the EPA). You can infer from that what political party is going to lose power in the next two years. Regardless of what the EPA thinks, eastern coal will be used for power generation until there is no more coal that can be economically mined. The powerful eastern congressional members will see to that to protect their local economies. Coal is dirty, but politics is even dirtier.
Funny, but this comment summarizes and almost echoes exactly what was said by a Mr. Palmer, the President of the Western Fuels Association - a purchasing consortium of midwestern and western utilities with coal-burning power plants - as quoted in the 'sidebar' article on the WFA in the following main article from over 9 years ago:
Lonely railroads of the Four Corners Trains, October 2000 page 50 coal-hauling railroads in northeast Arizona and northwest New Mexico ( ARIZONA, BLKM, BNSF, COAL, "DIVEN, WILLIAM P.", EW, NEWMEXICO, TRN )
Back then the Kyoto protocols were brand-new, and when the article was written - 1999 - it was the Clinton Administration that the WFA was opposing.
Murphy Siding [snip] I was even more surprised to see a mine-mouth power plant being built north of Gillette, in the Powder River basin of Wyoming. I lived in Gillette for a couple of years. There is a Wyodak power plant that has been on the outskirts of town for maybe 40 years. It is almost a desert. In an area that dry, how do they deal with a lack of cooling water?
We need a mechanical engineer with knowledge of such things to provide an authoritative and detailed answer, but in the meantime I'll take a stab at addressing it:
Coal-fired power plants use the water - in the form of steam - mainly as a heat-transfer medium between the firebox and the turbine-generator, not for cooling per se. As such, they're not all that different in principle from the condensing steam locomotives that were used on the Australian and South African railroad systems, if I recall correctly, but which never caught on in the US desert SouthWest in contrast. Those condensing locomotives kept at least some of the exhaust steam before it went out the stack, and typically circulated it through a giant radiator on the sides of the tender, which cooled it enough to condense back into water - albeit pretty hot, pre-heated really - which was then re-injected into the boiler to be made into steam again, and that 'condensing cycle' repeated over and over, etc. I'll see if I kind find a good photo of one - I believe Victor Hand has published some over the years.
1st EDIT: Although it's hard to discern in those photo, this appears to be one of those 'condensing' tenders:
From - http://www.rrpicturearchives.net/showPicture.aspx?id=1823860
[End 1st EDIT]
2nd EDIT: From the caption and comment at -
http://www.railpictures.net/viewphoto.php?id=168761
Remarks: De Aar depot was a major steam shed for SAR, most of it's allocation was class 25 condenser locos and class 25 non condensers. This shot illustrates the front end differences between the two types of steam loco. The condenser is nearest the camera. The condensers could run for upto 600 miles without taking water, which made them ideal for the dry South African conditions. Only one condenser survives 3511, part of the national collection.
User Comments: Nice shot, Alan. It illustrates how the non-condensers were pampered by the De Aar shed staff (nameplates, regular cleaning), while the condensers were deliberately neglected because the shed foreman did not like them!
[End 2nd EDIT]
But one concern with those locomotives that I wonder about is the draft - what is done to replace or substitute when the draft-inducing, fire-exciting exhaust steam is diverted from the stack to the condenser, so that there is no more or much less of the 'chuff-chuff' sound of which we are so enamored ? I suppose that a mechanically or electrically-driven blower/ fan is used instead, and that the same is done with those coal-burning generating plants that have to conserve their water.
Also, there are principles of thermo-dynamics - which I do not claim to understand well - that basically require or strongly incentivize for maximum efficiency that heat-cycle 'engines' such as these have as much of a temperature drop as possible 'across' or through the steam-consuming device, such as the turbine or cylinders. That leads to a preference for discharging the spent steam cooled down as much as possible, but that is by no means necessary.
Also, in many locations, since the discharge steam/ water goes into a local waterway, the permit requirements are that the discharge water not warm the stream more than a certain amount, so that's why it has to be cooled - not because of any mechanical engineering or efficiency considerations.
Cooling water is mainly needed by nuclear power plants, which produce so much heat - sometimes even when not wanted, because they're hard to 'turn off' like a coal plant - so that something of that kind has to be provided for both the generating cycle and for emergency back-up cooling purposes.
There are at least 2 kinds of the giant hyperbolic shaped cooling towers that are often seen. One kind just basically discharges the hot water or steam from the plant, pretty much the same as a glorified locomotive smokestack. The other kind cools the water by evaporative cooling before returning most of it to the plant for re-use. This is kind of like the difference with getting rid of the heat given off by a pot of boiling water from a stove - pouring it down the drain, which also loses the water, vs. just letting it sit there and cool down, during which only a fraction of the water will be given up and condense on the nearby walls, ceiling, windows, etc.
Of course, there are trade-offs and considerations with each alternative, and so the plants in water-short areas will be much different from those in water-abundant areas. But that's not to say that it's impossible, or even uneconomic - just that they're adapted in many ways to suit their specialized operating conditions and constraints.
Perhaps an M.E. type can provide more insight and correct anything that I might have stated mistakenly above.
Railway Man [snip] Virtually every location in the U.S., regardless of which party they vote for, has strong opposition to a power plant, including communities that haven't voted for a Democrat in 150 years, don't own a single Prius, and don't have any stores that sell half-fat double-shot soy lattes.
Another contender from RWM for funniest quote of the week - my wife wanted to know what I was laughing at last night . . .
Railway Man The jobs and economic growth that a power plant represents are actually not desired by most rural states or communities, as far as I can tell, from my attending public hearings, because it (1) changes their existing social power structure and might bring in people who aren't like them, and (2) might possibly benefit someone in a city. [snip] RWM
[snip]
Or the benefit from the real estate/ property tax payments to the local governmental budgets - though that may become a little more atttractive in some places, depending on how dire their financial straits are in this economy. But that depends on each state's laws on same - Pennsylvania apparently exempts a lot of the utility facilities from such taxes. I'll see if I can fund some data to illustrate what it can mean, though.
Railway Man Both, plus certain economic activities that surrounded the real-estate bubble that will be a long time, if ever, coming back. The WSJ had a very good article last Thursday on this subject. RWM
JANUARY 14, 2010
By REBECCA SMITH
Page A-3, cols. 1- 4.
It might be accessible at - http://online.wsj.com/article/SB10001424052748704675104575001322373417024.html?mod=WSJ_Utilities_leftHeadlines
or - http://online.wsj.com/article/SB10001424052748704675104575001322373417024.html?
Right beneath it in the print version was a companion article entitled -
Pickens Shelves Texas Wind Project
By Keith Johnson
Well, maybe not quite - he cancelled half of his $2 billion order with GE for 667 wind turbines, and will use the remaining 333 turbines in Canada and Minnesota instead of Texas.
RWM:Thanks for the conversion formula. Looking at the local power plants:
Michigan City (NIPSCO) 680 MW would be about 1 per day
RM Schaeffer (NIPSCO) 2201 would be about 1.75 trains per day.
That would be if running at full capacity. No doubt production is down quite a bit these days.
My company is Ameren, we have a "fleet" of coal plants we affectionatly call 'Dirt Burners'; these plants are primarily on PRB coals but were designed and built to use Illinois high BTU as well as high sulfur coals. We see the differences every week, Illinois coal does produce some slag but not to the rate and level of PRB, it also requires less fuel for the boiler to produce the same steam load by about a quarter with PRB at near to 8500btu Illinois coals at around 11000btu. In the long run it is destroying our power plants using PRB with added maintenance, added fuel use, more refuse to store or dispose of.
We are currently getting scrubbers for CO2 and to remove more particulates, these new units will use lime slurry to pass the exhaust gas stream through and then we will have to pit the residue as the lime loads up, this stuff will not be sellable. Our chief facility of power delivery uses 12000 tons of coal per 24 hrs, the new scrubbers will use 6000 tons of lime per week.
Cooter: Is this your Adair plant?
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