Concrete or iron, a pound is a pound. The concrete would be cheaper.
The standard life of a power plant is calculated on a 40 year span. The component manufacturers guarantee that their components, Pulverizers, feeders/ fans, boilers, turbogeerators etc will last 40 years with the specified maintenance.
The problem is that it is impossible. To deliver the claimed 668 MW ALL 140 trains have to be in downhill motion at the same time producing almost 7000 HP each. IF that could happen, (and it can't) you would only have that power for 19 minutes. A farce and a way to scam the Government, which is us, out of a fortune. Can you say "Solyndra"?
(Note: This piece-of-crap interface is starting to really bother me. Can't Kalmbach hire some high-school kids in an advanced STEM program to fix the few things that need to be modified to make the italics work correctly and the 'wrong' arrow keys disabled or subject to warning message if inadvertently pressed? UI and IxD on that level are not rocket science, and haven't been difficult to code for many years...)
I think the "40 years" is a financial life, for purposes of capital allocation and opportunity cost. The usual-suspects accountants on here might comment on the depreciation rules that would apply to this specialized equipment, what its fair market value ought to be, and other considerations that apply.
Likewise, general rules for AC motor maintenance, electronics servicing, etc. are pretty well established, and I'm sure were defined in the business plan long before the company applied to the BLM for the lease. I only see two major areas that might have been missed. One is wheel wear, and the other is the specialized turning mechanism for the weights.
Switches are an integral part of operation, and so hollow tread becomes a complication that a pure dedicated shuttle operation might not be as concerned with. There is plenty of 'slack' in the operating critical path of any given consist in this system, so it would not be difficult to machine the wheels on either a fixed or portable underfloor wheel lathe when necessary, or perhaps to swap out wheelsets on an expedient basis in a fixed facility or 'jig'. I presume that the 'best' bainite head-hardened rail would be used in a facility of this size, and dressing or grinding of the railhead profile ought to be fairly simple to conduct (again at the required scale and relatively small footprint of the facility)
The turning mechanism is more complicated, has more points of potential failure, and (as designed) may hang up both a consist and the entire stock of gravitational potential above the point of failure. Most of this is amenable to emergency procedures, provided the need is recognized and the procedures and equipment provided ahead of time. Since I do not think the ARES proponents are fools, I think they have ways to deal with the different types of extraordinary maintenance/repair or failure management, and would design the equipment both for maintenance and ease of emergency response.
Concerning iron weights: It does not appear to me that size reduction of the weights gives any advantage here, and the cost both to acquire and ship very large castings or fabrications would be greater than for the concrete ones. I was assuming the use of 'loaded' or heavy aggregate in the concrete or the embedding of heavy materials in the reinforcement to get the system to the desired weight.
Implicitly, the mass of the weights would be chosen to optimize the various components and operational scheduling to give lowest overall cost. That involves the required structure in the consists, the strength of the lift and turntable that handles the weights, the speed and grade involved, and the anticipated duration and rate required for actual peak power generation from the facility. Heaven knows there's enough space there for slightly larger weights!
There's also the implicit temptation to use the greatest possible mass that fits ... or use denser material to shrink the lateral measurement and thereby allow more gravitational potential per foot of K-rail. Some of this involves more than just economics -- structural safety both in operations or anomalous conditions/accidents would be important. I suspect for example that the weights as designed are provided with corner castings that allow them to be lifted and handled with slings or stretchers from above, for emergency situations and for loading; it's also possible that the external 'boxes' of the weights are designed to suit ISO dimensions that allow them to be handled in well cars for shipping. (I would certainly consider doing it that way!)
This Ares concept is unlike anything ever suggested here before. In the cost/benefit analysis for Ares, cost does not matter because the presumed benefit is practically infinite. What is it worth to save the planet and everything living on it? It is easy to think outside the box if cost doesn’t matter.
I'm just sitting here chuckling. Seems the loudest opponents on this thread are the same people that always promoted wild-pie-out-of-the-sky RR ideas/technology (like thoseintermodal self-unloading things), and accused anyone who questioned them as not being able to think "outside the box".
Apparently the box got bigger.
Back to your normally scheduled discussion.
It's been fun. But it isn't much fun anymore. Signing off for now.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.t fun any
They say that this system has a life of 40 years. Assuming that the need continues indefinitely, what happens after 40 years? It sounds as if everything wears out after 40 years and must be completely replaced with a new plant. But surely something this complex does not just arrive at a point where it is uniformly worn out.
Instead, it will require constant maintenance and repair; and probably a lot of performance upgrades as well. It will have a daily operating cost besides the 15-20% net loss in the transaction of using energy to lift the weights and then recovering part of that energy.
I think they exaggerate the simplicity of using off the shelf components. They distinguish between that approach and one needing a "break through" development of technology as though it is one or the other. In reality, there is a lot of ground between those two extremes.
In the grand scheme of things, wouldn't it work out better if the weights were made out of iron because it's much denser than concrete? Think of ore jennys being short.
Thanks to Chris / CopCarSS for my avatar.
tdmidgetIt's pure hokum. For 668 megawatts and 140 trains that means that each is simultaneausly developing 6396 HP and that does not include electrical , mechanical, and operational losses. B.S.
I'm somewhat on the same page. At this point there is not enough reliable information to make a judgement, but history has shown most of these schemes to be nothing more than a means of obtaining federal subsidies followed by bankruptcy and absconding with the money. Taxpayers get fleeced.
Color me cynical.
Norm
It's pure hokum. For 668 megawatts and 140 trains that means that each is simultaneausly developing 6396 HP and that does not include electrical , mechanical, and operational losses. B.S.
RME rotated to maximize gravitational potential
rotated to maximize gravitational potential
I thought they were rotated to conserve space, to minimize ugly footprint on beautiful hill.
https://books.google.com/books?id=TPReBwAAQBAJ&pg=PA76&dq=%22regenerative+braking+coming+downhill%22&hl=en&sa=X&ved=0ahUKEwjf56ePz8jMAhXFHxoKHVXqAgMQ6AEIHTAA#v=onepage&q=%22regenerative%20braking%20coming%20downhill%22&f=false
http://www.google.com/patents/US8593012
wanswheel http://www.amusingplanet.com/2015/03/gravity-train-as-energy-storage.html https://www.youtube.com/watch?v=2dyJDIP0Udo&t=26m36s
http://www.amusingplanet.com/2015/03/gravity-train-as-energy-storage.html
https://www.youtube.com/watch?v=2dyJDIP0Udo&t=26m36s
I took a look a the video provided above, in which they discuss a 668 MW system. Based on a 7.5% grade and 19 mph, I estimated that about 500 weights (at 234 tons each) decending simultaneously are needed to generate that much power. (For simplicity, I excluded the weight of the cars and any frictional losses.)
Do these numbers make sense or am I way off?
Anthony V.
RME,
Okay, I can see the need for that strategy. You don’t want to be investing in lifting the weights during the phase calling for generation, considering the fact that there is ample time during the sun/wind phase to do the lifting of weights; and that is the phase with the cheapest available power to do the lifting. If you left the weights on the cars, it would require a lot more cars. Since the generation is delivered over an extended period, it makes sense to use fewer cars and load/unload the weights. Thanks for the explanation.
EuclidI don't follow your explanation. Why is there a need to remove the weight boxes from their cars and store them until they are needed again?
If you look at the video that goes with the promotion, this will become clearer. In fact, you need to handle the boxes both at 'top' and 'bottom' to get best utilization out of the expensive capital.
First, you won't have enough "trains" to serve the demand for a whole 'peak' period. The under-18-minute "best speed for generating efficiency" establishes this. Instead of filling the whole upper yard with standing motored consists, what they propose is to use a more limited number of them, and ferry the dead weight up the hill with repeated trips. Each time they go up, four weights are 'disconnected' at the top, rotated to maximize gravitational potential, and rested on the concrete side rails. The trainset then descends (recapturing a reasonable percentage of the electricity used to raise it in so doing, so the multiple trips are more of a 'wash') and loads more weight. Eventually all the great many weights -- much more, as noted, than a 'single' train, or all the provided "4-car consists", could hold directly are up at the top of the grade.
Now comes generation time. Each consist ascends (consuming whatever electricity is needed to get it as quickly as 'reasonable and prudent' to its loading point) and is then loaded with weight. It travels down at whatever best generating speed is moment to moment, and eventually arrives (in about 18 minutes) to the end of the forming weight stack on one track in the lower yard. Here, as quickly as practically needed, it offloads the four weights (perhaps not needing to rotate them other than as needed for the concrete-support-rail holding system) and then goes up light -- and in minimum time consistent with other efficiency factors -- to where it can be loaded to keep the power generation going. I expect in fact that the consists would run very closely spaced or even 'touching' ... perhaps in both directions where possible.
All the little consists keep doing this for the length of time peaking power is necessary; expansion of the system would involve multiple mains with at least one 'dedicated' up-track that keeps ascending traffic strictly separated from downcomers.
If all you did was to run trains up and down with weights fixed on them, like winding a giant grandfather clock, all you'd be doing was timeshifting the demand with an enormous capital expense and sunk/stranded cost. In addition you'd be using a substantial amount of the developed power merely to lift the upgoing trains -- if the losses 'scale', as I'm certain they do, you're throwing away some of the on-peak benefit just in toting the tare weight.
That doesn't happen with the multiple offloading -- you recursively lift short segments with cheap power, and minimize the cost of recursive trains, while maintaining an enormous net source of potential energy 'in the aggregate' represented by all the weights sitting on their supports, packed as close together and close to the 'top' of the gravity well as manageable.
I have an idea. Instead of building new isolated track out in the dessert, and haul the same rotating weights up and down-- use an existing grade, like Cima, or better yet Cajon. Install catenary over the track, and construct a motor track at Summit and San Bernardino. Rent the motors to BNSF on an incentivised "power-by-the-hour" basis as helper engines during utility power surplus, and as brake motors during high power demand. The railroad would use their own engineers, save diesel fuel and ware and tare on their engines, and could earn carbon credits.
Euclid ... I don't follow your explanation. Why is there a need to remove the weight boxes from their cars and store them until they are needed again?
...
I don't follow your explanation. Why is there a need to remove the weight boxes from their cars and store them until they are needed again?
During a power serge, the motors will make multiple trips: attach a weight, loaded trip down, drop off weight at bottom, light trip back up, repeat as needed. The opposite would happen during power surplus.
RME Euclid I do not understand the need for unloading and storing the weight boxes, and then taking them out of storage and reloading them on the cars. IF that is really necessary for some unexplained reason, building a reliable, trouble-free, automatic system for accomplishing that task will be an enormous exercise in engineering, design, testing, and development. It's actually pretty trivial. Methods like those used for roller table sideloading alone would do it, at a measurable but not particularly high cost per unit. What they seem to be proposing is to have no 'superstructure' on the cars, rotate the boxes 90 degrees, and slide them off on holding rails adjacent to the running rails (which minimizes length of storage while permitting greater load within limited track or loading gauge). This is a bit more complex, but not rocket science.
Euclid I do not understand the need for unloading and storing the weight boxes, and then taking them out of storage and reloading them on the cars. IF that is really necessary for some unexplained reason, building a reliable, trouble-free, automatic system for accomplishing that task will be an enormous exercise in engineering, design, testing, and development.
It's actually pretty trivial. Methods like those used for roller table sideloading alone would do it, at a measurable but not particularly high cost per unit. What they seem to be proposing is to have no 'superstructure' on the cars, rotate the boxes 90 degrees, and slide them off on holding rails adjacent to the running rails (which minimizes length of storage while permitting greater load within limited track or loading gauge). This is a bit more complex, but not rocket science.
EuclidI do not understand the need for unloading and storing the weight boxes, and then taking them out of storage and reloading them on the cars. IF that is really necessary for some unexplained reason, building a reliable, trouble-free, automatic system for accomplishing that task will be an enormous exercise in engineering, design, testing, and development.
It begins to be clear that if running speed of 19mph is to be used on the hills, you need to decouple the actual number of expensive and fairly sophisticated running 'platforms' or consists from the actual dead storage of gravitational potential energy (thought of, here, as the concrete-block equivalent of water in a pumped-storage reservoir). There are a LOT of trips going up and down with the limited number of trainsets, which may not be clear from the description given but will show up in the physics.
Remember that 'peak' requirement is more than that roughly 18-minute transit time, so it would be logical to assume that minimizing the cost of the repeated vertical trips to 'reload' the consists doing the on-peak generation -- for example, by absolutely minimizing their tare weight going up -- is a sensible part of the long-term economics. At least this is obvious to me. Even transporting safety frames or cages for the masses is going to consume additional electrical energy at a time when 'every kwh counts'.
I had not thought about this before, but distributing power across a relatively large number of axles on a very light consist is a means of controlling aggregate wheelslip. So there is another reason why you'd have them. (In practice, I'd expect the number of actual 'powered' axles to be titrated, in a sense, until you have just the right cost-to-benefit ratio justified for practical operation... again, don't look for that in promotional documentation because it just gives those who are likely to be the target audience MEGO syndrome, and those who understand the physics or operations will think about it anyway.)
AnthonyVIf the train is lowered at a constant speed regardless of the number of cars attached to the locomotive, then the retarding force produced by the regenerative braking (i.e., the dynamics) would have to be proportional to the number of cars. This requires adjusting the brake so that the electric motor torque (and the power generated) increases in the same proportion. I am not an electrical engineer so I cannot comment how this is accomplished in practice. Maybe Erik or others can weigh in on this.
The situation is a little complicated by the (almost certain) use of AC motors, but not enough to keep this question from having some common-sense answers.
There is no need for 'constant-speed' braking, and the only operational consideration of speed vs. torque that I can see is that for economic reasons you want to keep the train 'up the grade' (to maximize the remaining gravitational potential energy as much as possible at any time) so you would operate it as slowly as needed to produce the demanded power. With AC there is little or no effective rotational speed consideration or hourly/instantaneous analogue for temperature rise in motor windings.
Slide control (the DB analogue of wheelslip) is easily handled in most situations where it might occur, and I would presume that any 'spots' of low adhesion would be flagged in the 'computer' system for attention.
There are several reasons why "powered cars" might be used other than the obvious (the advantages of slugs/MATEs without the drawback of changing adhesive load). One is to change the effective train resistance more quickly or 'steplessly' by using a larger number of motors, although the economics here would require the equivalent of an inverter setup for each axle. With the loads being discussed, I'd much rather use "MU" distributed powered axles for dynamic rather than concentrating the load on a few expensive wheels, particularly since there is much more opportunity for high peak loading of the electrical gear in generation than in motoring, particularly if there are any 'anomalous conditions'. (Not to make a direct comparison, but it should be remembered that the other direct reason the N&W TE-1 turbine was retired was that its motors ... Westinghouse hexapole motors ... were essentially burned out in just those several years of service. It takes a special kind of trying to do that to those. This application promises to stress electrical components in some very interesting ways when, not if, something in the control system or its software is 'misconfigured', and some discussions of this, while obviously not revealed in promotional pieces, have no doubt been conducted.)
Murphy Siding AnthonyV Euclid Why would they want any powered cars? The non-powered cars will produce power by exerting their gravitational force on the locomotive. In re-reading the article, I am not sure I understand their description of this. The energy stored is proportional to the total mass times the change in elevation. How would the number of powered cars affect this? Anthony V. Help me out with the physics please. I understand that a locomotive rolling down the hill can use regenetive braking to send power back into the grid. If the locomotive is coupled to a car that is the same weight, does that double the amount of juice being sent to the grid?
AnthonyV Euclid Why would they want any powered cars? The non-powered cars will produce power by exerting their gravitational force on the locomotive. In re-reading the article, I am not sure I understand their description of this. The energy stored is proportional to the total mass times the change in elevation. How would the number of powered cars affect this? Anthony V.
Euclid Why would they want any powered cars? The non-powered cars will produce power by exerting their gravitational force on the locomotive. In re-reading the article, I am not sure I understand their description of this.
Why would they want any powered cars? The non-powered cars will produce power by exerting their gravitational force on the locomotive.
In re-reading the article, I am not sure I understand their description of this.
The energy stored is proportional to the total mass times the change in elevation. How would the number of powered cars affect this?
Help me out with the physics please. I understand that a locomotive rolling down the hill can use regenetive braking to send power back into the grid. If the locomotive is coupled to a car that is the same weight, does that double the amount of juice being sent to the grid?
I am not an electrical engineer so I cannot comment how this is accomplished in practice. Maybe Erik or others can weigh in on this.
Yes I understand that fossil fuel power plants are complex and expensive. Both fossil fuel plants and solar/wind plants benefit from storage, which is also complex and expensive. However solar/wind plants fundamentally require more storage than fossil fuel plants. I do find the railroad based storage idea interesting and would love to be involved with the development work on it.
I suspect that the ultimate embodiment will be quite different than the prototype concept presented at this time. Right now, they have a business and a design concept that is valid, but I don’t think the execution is ready for prime time. There is a huge amount of engineering and design that has yet to be done. This plant will operate like a giant vending machine. I doubt that it will be made from “off the shelf” components to the extent that they currently expect.
I do not understand the need for unloading and storing the weight boxes, and then taking them out of storage and reloading them on the cars. IF that is really necessary for some unexplained reason, building a reliable, trouble-free, automatic system for accomplishing that task will be an enormous exercise in engineering, design, testing, and development.
Inventors often embellish their inventions with unnecessary features in an attempt to enhance the credibility of the invention. It is a natural inclination. The first thing that is needed is a clearly explained operational concept. On the face of it, I would expect semi-permanently connected trainsets with rolling stock that permanently carries the load boxes. So I don’t understand the need for all the yard trackage, switches, etc.
The operation will have to contend with the effects of wind force advancing or retarding the downhill run. It will also have to be able to extract all of the energy out of that run before the run ends. There will have to be full control of the automatic air brake system, and some type of detectors to make sure that the system is operating properly.
Rain and snow will decrease adhesion for both the uphill pull and the downhill dynamic braking. These variations imply the need to reduce the train tonnage and/or increase the motive power accordingly. It might be more cost effective to just roof over the entire trackwork. Perhaps complete enclosure in a building might be the most practical approach.
My take is that the closer you look the more confusing this is. My major problem is that they describe at least three systems and show three 'pictures'.
The 50 MW 'starter set', my term obviously, is described in the first part of the article. Its AVERAGE grade is 10.48%, 3000 foot rise over 5.5 miles. I did not get a train configuration. I am confident they could get a workable power to weight ratio to get up the hill, and am confident that they can hold 19 MPH coming down, but I strongly question their ability to stop on that grade with any locational precision. If I were doing this I would have a flat spot to stop at least at the bottom.
The larger set, 333 MW, has the three track main line plus storage for 5700 concrete blocks in yards at both the top and bottom. Clearly they plan to load and unload a lot of blocks. The company video show loading and unloading being done magically as the train is moving. They are going to have to invent a way to do that, including getting the 'locomotives' past the blocks which end up at 90 degree angle to the track and over the track.
Another artist's rendition shows two electric locos pulling what appear to be covered hopper cars filled with rock and dirt. That would work with existing technology, unlike the magic blocks, but storing the cars at the top and running back lite would require a relatively complex yard and a switcher at each end.
They need a practical railroader to help design this thing. Hope they get one!
Mac
I would say the answer to your question is that an unpowered car that also has no onboard ability to generate power from dynamic braking against the downhill load;—that car will generate its full potential of power as a falling weight simply by being coupled to the locomotive. So the locomotive and all of the non-dynamic- braking cars will channel all of their kinetic energy to the locomotive, which will use its dynamic braking to convert the total combined energy back into electricity to add to the grid.
Your question also raises this point. As these falling trains reach the bottom, do they simply stop because their locomotives have converted all of the kinetic energy into electricity as the train enters flat terminal region? I would think that the answer to that is no. It seems that one would want to extract just the right amount of the available kinetic energy of the falling train, and then bring the train to a stop with its conventional air brakes. The effectiveness of dynamic brakes fall off at the slower speeds.
One thing to consider is that the purpose of this system is to capture all of the kinetic energy available in the raised mass. Whereas with dynamic braking, the purpose is to only capture some of it to produce a certain amount of slowdown or retardation.
So with this storage system, one would want to make sure that the braking effort is applied hard enough to capture all of the energy before the train stops at the bottom.
EuclidAre these really 24,300-ton trains being pulled up a 7.5% grade with two locomotives?
In other versions of this idea, the locomotives pull some of the available mass in 'trips', essentially parking the gravitational potential energy of each cut at the top and then descending (with appropriate dynamic-braking recovery) to get the next one. The practical 'train' size limit going down is of course not the same as that going up...
In re-reading the article, I am not sure I understand their description of this. These are two bullet points from the article:
That amounts to 81 concrete masses per train. Does this mean that each train is composed of two locomotives, two braking slugs, and 81 cars?
Are these really 24,300-ton trains being pulled up a 7.5% grade with two locomotives?
Logic question: The article says that each of the 70 trainsets would be made of of two powered and two non-powered cars. Why would you want non-powered cars in the mix? They're not producing power to put back in the grid. Wouldn't having 4 powered cars be exactly twice as efficent? (And twice the cost?)
Near as I can tell, it's to make the animation look more interesting than just rail cars rolling down a hill and coming to a stop.
What is the purpose of removing the weight boxes from their cars and storing them in that rack?
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