Instead of heat dissipating dynamic braking...

[Anonymous]

Larry and Paul,

 

I agree that this would ultimately be a tax on the consumer.  As to the fairness between different modes of transportation, the paper addresses that issue in the section on pages 51-54 where the pros and cons of various methods of collection are discussed.

 

Overall, this seems very similar to a cap and trade system except that, so far, it lacks the “trade” component or anything similar.  So far, it is just a cap and fill-in-the-blank system, so it seems to be a work in progress.  And while the second component has not yet been decided, but it seems likely to be a tax or fee collected by the government. 

 

Furthermore, the cap component is not really a cap, but rather sliding scale of restrictiveness, which would correspond to a sliding scale of fees.  

 

And still furthermore, unlike a cap and trade system, which would only apply to the emission of CO2, this system of charging taxes or fees for environmental impact would apply to many facets of supposed pollution, including noise and visual impact.

 

Look at it this way:  Prior to this new system, laws simply limited the amount of noise and vibration that a train could make.  So, trains could vibrate and make noise with impunity as long as they did not exceed the legal limit.  Now with this new system, the societal harm of a train’s noise and vibration at all levels of intensity is calculated, and the railroad operating the train is charged a sliding fee that corresponds to the amount of noise and vibration they produce, even if the noise and vibration is very small.  I suppose they would say that no amount of noise and vibration is 100% safe.

[Paul_D_North_Jr]

Most importantly, any such scheme needs to be assessed equally and even-handedly on all modes of transport - rail, truck, barge, ship, bus, car, etc. - and/ or power generation or whatever else it is that produces the environmental effect that is of concern  

Otherwise, ther's a considerable risk that we'll be right back where we were in the 1950s - 1970s, with an uneven playing field that disadvantages the railroads, because they don't vote as much as truckers and consumers, etc.  I'm not much interested in that kind of a rigged game. 

- Paul North.

[tree68]

Bucyrus

If this type of environmental tax were to come to the U.S. in order force railroads to pay for their environmental damage, we could be in for big changes.  Investment in new technology to save fuel and reduce noise would suddenly be cost effective as a way to offset the new taxes.  Recovering dynamic brake energy might be just one of a host of related new ideas that will come to fruition.  The bottom line will be a more environmentally friendly rail transport, albeit at higher cost to shippers.

And at a higher cost to the consumer - to whom the higher costs shippers pay will be passed on.

Consider, too, the possibility that XYZ railroad (perhaps a regional or shortline) may decide it just ain't worth it and throw in the towel.  Assuming the worst - no one steps in to take over and the ROW becomes a rail trail - those final miles must now be served by trucks, which will certainly also be tagged for environmental costs.  How many of them will survive?

Mind you, I'm not against improving our impact on the environment, but we have to consider all of the potential costs involved - something some environmentalists seem to forget.

[Anonymous]

In the piece linked by Paul North at the top of this page about recovering dynamic brake energy, it mentioned that such recovery might be cost effective if you factor in the reduction in environmental costs.  Linked below is a comprehensive paper dealing with the environmental costs of rail transport in the UK.  I assume that the “environmental costs” mentioned in the dynamic brake article are the same type of environmental costs that are described in great detail in the paper linked below.  Perhaps it is just confined to the E.U., but if so, I wonder if it will come to the U.S.  There does seem to be a strong sentiment that we should be more like Europe.   

 

I get the impression that this identifying and placing a dollar cost on environmental impact is cutting edge stuff, but I am not exactly sure what it is the cutting edge of.  It reminds me of my phone bill that tells me what to pay and all the reasons why.  It is easy to understand the former, but impossible to understand the latter. 

 

The profoundly complex analysis that is going into calculating environmental costs seem like they will show up as gibberish on a bill with the dollar amount clearly shown.  Take a look, for example, at the environmental cost of railroad noise and vibration as it is quantified in the bewildering analysis starting on page 21.  I would sure hate to have to prove that the noise bill was incorrect. 

 

Page 51 begins a discussion about the possible means of charging for environmental costs.  The following is a quote from the discussion on page 51:  

 

 

“In terms of industry and wider social acceptability, the introduction of these charges will need careful handling.  Whatever the mechanism, such a charge is likely to be seen as a tax.”   

 

 

http://www.rail-reg.gov.uk/upload/pdf/aea_enviro_rep.pdf

 

If this type of environmental tax were to come to the U.S. in order force railroads to pay for their environmental damage, we could be in for big changes.  Investment in new technology to save fuel and reduce noise would suddenly be cost effective as a way to offset the new taxes.  Recovering dynamic brake energy might be just one of a host of related new ideas that will come to fruition.  The bottom line will be a more environmentally friendly rail transport, albeit at higher cost to shippers.

[Anonymous]

Apparently the concept and practice of monetizing the cost of certain detrimental consequences of societal functions is relatively new.  As I understand it, the process might be used to place a dollar cost on something such as the effect of a certain type of pollution that is generated by a road.  The cost would be extrapolated from all of the negative impact on the group of people who are affected by the pollution, taking into account such things as average medical costs imposed on those people by the pollution.  The process might be extended to account for the costs that are imposed on the owners of livestock due to the effect of the pollution on the animals.  The process could also calculate the cost of impacts other than pollution such as noise or stress, for instance.

 

I get the impression that this new science is just now learning to discover the monetized costs, which are presently borne by rather large groups of people who may affected by the costs without their knowledge in many cases.  However, the ultimate purpose and goal has got to be to rightfully assign monetary accountability for these costs to the responsible entity, company, group, person, etc. 

 

So, in the example of capturing dynamic brake energy being made economically feasible by the so-called environment cost savings, I suspect that those costs are presently being calculated, but have not yet been charged to the railroad companies.  And when they are charged, railroads will have a larger monetary incentive to invest in fuel saving measures.

 

The link below gives a staggering explanation of the concept, which it characterizes as being as much art as it is science.  I can see why.  Like what RWM posted, it too gives monetized costs of various types of pollution.  Somehow it strikes me as regulators mining for justifications, but I can’t say for sure until I digest the whole thing.    

 

http://us.geocities.com/davefergus/Transportation/0ExecutiveSummary.htm

[Railway Man]

Bucyrus

Railway Man

Bucyrus

In the last sentence, what do they mean by “environmental cost savings”?

 

Monetized cost of pollutants as established by law.  Currently, these are (for pollutants emitted in year 2010):

1. CO2, $30.77/ton
2. Particulate Matter, $192,697.05/ton
3. Volatile Organic Compounds, $1,747.53/ton
4. NOX (nitrogen oxides), $4,112.00/ton

A system or practice that reduces emissions of pollutants avoids cost of pollutants,

RWM

So, are these “monetized costs of pollutants as established by law” fines or fees levied by state or federal government?  Who are they paid to?  If these costs are established and known, why does the article speculate as to whether or not the savings from recovery of dynamic braking energy would offset those costs?

 

I am not aware that these monetized costs relate to any fines or fees, or any laws that say so.  I'd need to consult an environmental attorney or permitting expert to know that.

I do not know why the article speculates.  I could guess, if you do not mind.  If one is doing a cost-benefit analysis of a system that costs money to build, one has to know the quantity of inputs (capital cost, maintenance cost, fuel), and outputs (work, emissions).  Usually that requires some field testing.  I do not know if that has been done.  Perhaps that is why the article does not assume it knows the answer.

RWM

[Paul_D_North_Jr]

That's close reading for you !     But I don't know what the abstract intended to mean by ''environmental cost savings'' - I haven't accessed any more than what you see here.  I took it to mean possible subsidies for avoiding air pollution, but that's just my quick 'on-the-fly' interpretation - I was more interested in other aspects of the abstract.

I suspect the reason for the speculation is that the report was written for an April 2006 conference, and published in May 2006.  However, I am inclined to believe that the figures* provided by RWM were most likely established or set more recently than that, esp. for C-O2 - the ''cap-and-trade'' scheme has not gotten much traction or attention until the last year or two, as I understand it. 

* Source, citation, or reference, please ?  Feel free to disguise it as much as possible if that's appropriate.  I looked at http://www.cantorco2e.com but can't access anything without registering, etc., and that's too much trouble for this ancillary purpose.  Thanks.

- Paul North.

[Anonymous]

Railway Man

Bucyrus

In the last sentence, what do they mean by “environmental cost savings”?

 

Monetized cost of pollutants as established by law.  Currently, these are (for pollutants emitted in year 2010):

1. CO2, $30.77/ton
2. Particulate Matter, $192,697.05/ton
3. Volatile Organic Compounds, $1,747.53/ton
4. NOX (nitrogen oxides), $4,112.00/ton

A system or practice that reduces emissions of pollutants avoids cost of pollutants,

RWM

So, are these “monetized costs of pollutants as established by law” fines or fees levied by state or federal government?  Who are they paid to?  If these costs are established and known, why does the article speculate as to whether or not the savings from recovery of dynamic braking energy would offset those costs?

[Railway Man]

Bucyrus

In the last sentence, what do they mean by “environmental cost savings”?

 

Monetized cost of pollutants as established by law.  Currently, these are (for pollutants emitted in year 2010):

1. CO2, $30.77/ton
2. Particulate Matter, $192,697.05/ton
3. Volatile Organic Compounds, $1,747.53/ton
4. NOX (nitrogen oxides), $4,112.00/ton

A system or practice that reduces emissions of pollutants avoids cost of pollutants,

RWM

[Anonymous]

Paul_D_North_Jr

It was found that the total dynamic brake energy potential was over 1,200 kilowatt-hours per train. Depending on the efficiency of the storage system, as much as 70 gallons of diesel fuel could be saved per train.  This equates to 2,800 gallons of fuel a day and a corresponding reduction in emissions. Nevertheless, fuel savings themselves do not provide enough incentive to warrant implementation of dynamic brake energy recovery, but with the addition of environmental cost savings financial benefits may be seen.''

 

In the last sentence, what do they mean by “environmental cost savings”?

[Paul_D_North_Jr]

The Original Post:

Ulrich

Why not have the electricity generated by the traction motors stored in batteries on the locomotive or on a tender behind the locomotive? Instead of dissipating the energy as heat it could then be used later. The energy savings might be significant and I'm sure the engineers have thought this through...but what is the holdup on making this happen or why is it not feasible?

The following abstract appears to be relevant to the question [emphasis added - PDN]:

Prospects for dynamic brake energy recovery on North American freight locomotives Painter, T.D.   Barkan, C.P.L.   Illinois Univ., Urbana-Champaign, IL; This paper appears in: Rail Conference, 2006. Proceedings of the 2006 IEEE/ASME Joint Publication Date: 4-6 April 2006 On page(s): 181-188 Location: Atlanta, GA, ISBN: 0-7918-4203-7 INSPEC Accession Number: 8968290 Digital Object Identifier: 10.1109/RRCON.2006.215308 Current Version Published: 2006-05-22

Abstract ''As fuel costs and environmental impacts assume greater importance to railways, so does the importance of options for increased energy efficiency and emissions reduction.  A study was conducted on the potential recovery of dynamic brake energy from diesel-electric locomotives in North American freight service.  Using computer simulations (Train Energy Model) and locomotive event recorder data, estimations were made of the energy that could be recovered from dynamic brake use.  In addition, the differences between the results of the computer simulations with respect to the actual events recorded were examined in order to evaluate how well the model simulates an engineer's operation of locomotives and provide guidance for future improvements to the simulation model.  A case study of the energy recovery potential for a Class 1 railroad operating on a major mountain pass in North America was conducted.  The route analyzed has two characteristics that make it a good candidate for studying energy recovery potential.  First, there is an extended down grade approximately 25 miles long, and second, it has heavy traffic with about 80 trains a day traversing it.  Both of these factors enhance the likelihood that investment in energy recovery technology will be economically viable.  It was found that the total dynamic brake energy potential was over 1,200 kilowatt-hours per train. Depending on the efficiency of the storage system, as much as 70 gallons of diesel fuel could be saved per train.  This equates to 2,800 gallons of fuel a day and a corresponding reduction in emissions. Nevertheless, fuel savings themselves do not provide enough incentive to warrant implementation of dynamic brake energy recovery, but with the addition of environmental cost savings financial benefits may be seen.'' From: http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?isnumber=34260&arnumber=1634073&count=45&index=25

- Paul North.

[CSSHEGEWISCH]

Boyd

How about using the 3rd rail or overhead wire idea and use the electricity generated going down hill and put it into the power grid for the surrounding homes and businesses? I know with most engines it would have to be converted from DC to AC but power is power. This idea would be great for a RR hill nearest Al Gores home because his home sure uses a lot of electricity.

Do the dynamic brakes on the hood of a GP or SD get hot enough to roast some weenies or marshmallows?

I only read about half of the first page so my apologies to anyone if I repeated their idea. 

Regenerative braking is an old idea that dates back some of the earliest main line electrifications, "electricity keeping its own books".  GE promoted this concept heavily with the MILW electrification.  Since rotary converters or motor-generator sets were in use in the substations at the time,  conversion of DC power to AC power was not an issue.

I have heard of dynamic brake grids glowing like toaster elements on long downgrades.

[Boyd]

How about using the 3rd rail or overhead wire idea and use the electricity generated going down hill and put it into the power grid for the surrounding homes and businesses? I know with most engines it would have to be converted from DC to AC but power is power. This idea would be great for a RR hill nearest Al Gores home because his home sure uses a lot of electricity.

Do the dynamic brakes on the hood of a GP or SD get hot enough to roast some weenies or marshmallows?

I only read about half of the first page so my apologies to anyone if I repeated their idea. 

[carnej1]

Paul_D_North_Jr

 The Original Post -

Ulrich

Why not have the electricity generated by the traction motors stored in batteries on the locomotive or on a tender behind the locomotive? Instead of dissipating the energy as heat it could then be used later. The energy savings might be significant and I'm sure the engineers have thought this through...but what is the holdup on making this happen or why is it not feasible? 

Well, it now appears that it is feasible.  See the thread "Re: NS and Brookville Equipment building a Battery Electric Locomotive" at -  http://cs.trains.com/trccs/forums/t/156966.aspx - esp. the Norfolk Southern newsletter referenced therein, at - http://www.nscorp.com/nscorphtml/bizns/bizNS1-2.pdf - from which the following quote was taken [pg. 7; emphasis added - PDN]:

 ''The project team is designing and building an energy-storage system that for the first time would recover energy discharged by a locomotive’s traction motors during braking. The concept is similar to hybrid automobile technology, with expectations that 25 to 30 percent of the locomotive’s battery power can be recharged during operation. In diesel locomotives, by contrast, the dynamic energy generated by the traction motors is blown off as heat and goes unused.

“We are pioneering the use of batteries and recovering this traction motor braking energy,” Barbee said.''

 Ulrich ol' buddy, for an apparent 'shot in the dark' you really nailed this one.      Let me know if you're going to a casino or buying a Powerball lottery ticket anytime soon, OK ? 

- Paul North.

 Hopefully Brookville's system improves on the state of the art (I refer to Railpower's spate of Battery fires) but this is hardly a first. The Railpower Green Goats and General Electric's prototype Hybrid EVOLUTION series locomotive use regenerative braking. In fact Railpower built some Hybrid Slugs (for BNSF, IIRC) that were essentially cabless battery electric locomotives, although in this case designed to operate mated (and electrically connected) to a modified Geep rather than a "plug in" hybrid like the new Brookville project. Brookville itself has built a number of Genset units that use regenerative braking to power the auxiliaries. If you do a patent search (via Google or FreePatent.com) you will find that both GE and Railpower hold patents for an "Energy storage Tender"(GE) and a "Cabless Booster Locomotive with Energy Storage"(Railpower) which are identical to the system you are discussing....

 It seems to me that the key to this is advancing Battery technology.......

[Paul_D_North_Jr]

 The Original Post -

Ulrich

Why not have the electricity generated by the traction motors stored in batteries on the locomotive or on a tender behind the locomotive? Instead of dissipating the energy as heat it could then be used later. The energy savings might be significant and I'm sure the engineers have thought this through...but what is the holdup on making this happen or why is it not feasible? 

Well, it now appears that it is feasible.  See the thread "Re: NS and Brookville Equipment building a Battery Electric Locomotive" at -  http://cs.trains.com/trccs/forums/t/156966.aspx - esp. the Norfolk Southern newsletter referenced therein, at - http://www.nscorp.com/nscorphtml/bizns/bizNS1-2.pdf - from which the following quote was taken [pg. 7; emphasis added - PDN]:

 ''The project team is designing and building an energy-storage system that for the first time would recover energy discharged by a locomotive’s traction motors during braking. The concept is similar to hybrid automobile technology, with expectations that 25 to 30 percent of the locomotive’s battery power can be recharged during operation. In diesel locomotives, by contrast, the dynamic energy generated by the traction motors is blown off as heat and goes unused.

“We are pioneering the use of batteries and recovering this traction motor braking energy,” Barbee said.''

 Ulrich ol' buddy, for an apparent 'shot in the dark' you really nailed this one.      Let me know if you're going to a casino or buying a Powerball lottery ticket anytime soon, OK ? 

- Paul North.

[Paul_D_North_Jr]

Ulrich

Why not have the electricity generated by the traction motors stored in batteries on the locomotive or on a tender behind the locomotive? Instead of dissipating the energy as heat it could then be used later. The energy savings might be significant and I'm sure the engineers have thought this through...but what is the holdup on making this happen or why is it not feasible?

From the May 13, 2009 Wall Street Journal, the Trains "Newswire" for May 14th, and many other sources:

 "GE to Build Locomotive-Battery Plant" at:

http://online.wsj.com/article/SB124215410749511683.html?mod=googlenews_wsj 

- PDN.

[favuprailroadfan]

 Only thing that I have to say is. Yes they do take the electricity produced by the dynamics and put it into storage batteries, these are located under the walkway of the units. If you can find it, I believe GE has numbered it. GE 2010. It is a hybrid. It is green in color last thing I knew. If I'm not mistaken, they are part of the GEVO line. But that is the way they are taking the energy from the DB's and saving what it makes. Who needs calculations.

[carnej1]

Paul_D_North_Jr

lonewoof

1: 208 ampere-hours for 1 hour = 208 amperes, constantly, for 1 hour. That's about what your car's starter draws (continuous cranking amperes), only it draws it for 5 or 10 SECONDS. It's gonna take a MUCH healthier battery than you have under your hood, to supply 208 amps for a solid hour.

2: Recharge rate is more likely to be something like  1/10 of the maximum discharge rate; you'd likely want to recharge that 208 ampere-hours at something more like 28 amps for 10 hours.

3. Batteries are going to require maintenance, especially if they are being worked that hard. Somebody is going to have to keep an eye on them, and add water (distilled) as required.

Electrifying the grades, and feeding power back into the grid MIGHT be practical, aside from initial costs and continuing maintenance.

/Lone

Well, I was prepared to "eat crow" on this one for shooting it off my keyboard without researching it further - and taking cold comfort and refuge in the disclaimers that I included with what I wrote above.  I thought about this a little more - esp. point 1. - in the context of, "Could a car battery run my whole 200-Amp service house for 1 hour ?"  (I know, that's 12 v. vs. 120 volt, which is another matter) - and came up with, "Probably not - might take about 10 batteries to do that, at 20 amps each for an hour" (plus the voltage differential).

However, this past weekend I attended a local electric vehicle show ("Electric Vehicle EV-ent" - see: http://sites.google.com/site/wwweveventcom/ ).  One of the technical people there - in response to someone else's question - recommended Trojan Batteries, and said that one model designed for a floor machine had something like a 408 Amp-Hour capacity.  So I looked on their website, and under the Technical Information for marine batteries at:

http://www.trojanbattery.com/ProductLiterature/documents/SellSheet-Marine_000.pdf

are a couple of candidates.  Specifically, the T-145 has a 215 Amp-Hour capacity if it is drawn down over 5 hours (42 Amps), and is of a size and weight consistent with my calcs above (0.50 cu. ft., 72 lbs.).  Likewise, the L16H-AC has a 357 A-H capacity over 5 hrs. (71.4 Amps, or about 1/3 of what I was basing my calcs. on), though it is a little heavier (125 lbs.) and about twice as large (1.02 cu. ft.) as what I had figured. 

So it still seems to be preliminarily technically feasible - which is all I was trying to get a handle on - though perhaps it might take a pair of B-units to hold all the batteries to equal a 4,400 HP diesel.  One of the other posts above mentioned that the GE locomotive is 2,000 HP - this might well be why.  Of course, the financial aspects would need to be looked into further - I understand that these batteries are several hundred dollars each. 

2.  Recharging rates- I express no opinion on this - way beyond my expertise.  That would need to be looked into, though, no doubt about it.

3.  Watering the batteries is the major maintenance chore for electric vehicles, too - the panelists at the display made that clear.  Coincidentally, today Trojan Batteries announced their system to do that automatically for golf carts - see: 

http://www.trojanbattery.com/About-Us/MediaPR/documents/HydroLinkPressRelease_FINAL.doc 

and

http://www.trojanbattery.com/pdf/HydroLink_Brochure_LowRes.pdf 

So who's going to build one as a test bed to acquire real-world data and to demonstrate and de-bug the concept ?

- Paul North.

 

 The General Electric locomotive is 4,400HP from the engine IN ADDITION TO 2,000HP from the batteries. According to GE's website it can operate as a 6,000HP unit for short periods of time. Everything I have read indicates that it is NOT designed to operate on battery power only like a Railpower Green Goat. The system will allow the Engine(prime mover) to operate at lower RPM's for a given throttle setting with the batteries "making up the difference"..

[Paul_D_North_Jr]

lonewoof

1: 208 ampere-hours for 1 hour = 208 amperes, constantly, for 1 hour. That's about what your car's starter draws (continuous cranking amperes), only it draws it for 5 or 10 SECONDS. It's gonna take a MUCH healthier battery than you have under your hood, to supply 208 amps for a solid hour.

2: Recharge rate is more likely to be something like  1/10 of the maximum discharge rate; you'd likely want to recharge that 208 ampere-hours at something more like 28 amps for 10 hours.

3. Batteries are going to require maintenance, especially if they are being worked that hard. Somebody is going to have to keep an eye on them, and add water (distilled) as required.

Electrifying the grades, and feeding power back into the grid MIGHT be practical, aside from initial costs and continuing maintenance.

/Lone

Well, I was prepared to "eat crow" on this one for shooting it off my keyboard without researching it further - and taking cold comfort and refuge in the disclaimers that I included with what I wrote above.  I thought about this a little more - esp. point 1. - in the context of, "Could a car battery run my whole 200-Amp service house for 1 hour ?"  (I know, that's 12 v. vs. 120 volt, which is another matter) - and came up with, "Probably not - might take about 10 batteries to do that, at 20 amps each for an hour" (plus the voltage differential).

However, this past weekend I attended a local electric vehicle show ("Electric Vehicle EV-ent" - see: http://sites.google.com/site/wwweveventcom/ ).  One of the technical people there - in response to someone else's question - recommended Trojan Batteries, and said that one model designed for a floor machine had something like a 408 Amp-Hour capacity.  So I looked on their website, and under the Technical Information for marine batteries at:

http://www.trojanbattery.com/ProductLiterature/documents/SellSheet-Marine_000.pdf

are a couple of candidates.  Specifically, the T-145 has a 215 Amp-Hour capacity if it is drawn down over 5 hours (42 Amps), and is of a size and weight consistent with my calcs above (0.50 cu. ft., 72 lbs.).  Likewise, the L16H-AC has a 357 A-H capacity over 5 hrs. (71.4 Amps, or about 1/3 of what I was basing my calcs. on), though it is a little heavier (125 lbs.) and about twice as large (1.02 cu. ft.) as what I had figured. 

So it still seems to be preliminarily technically feasible - which is all I was trying to get a handle on - though perhaps it might take a pair of B-units to hold all the batteries to equal a 4,400 HP diesel.  One of the other posts above mentioned that the GE locomotive is 2,000 HP - this might well be why.  Of course, the financial aspects would need to be looked into further - I understand that these batteries are several hundred dollars each. 

2.  Recharging rates- I express no opinion on this - way beyond my expertise.  That would need to be looked into, though, no doubt about it.

3.  Watering the batteries is the major maintenance chore for electric vehicles, too - the panelists at the display made that clear.  Coincidentally, today Trojan Batteries announced their system to do that automatically for golf carts - see: 

http://www.trojanbattery.com/About-Us/MediaPR/documents/HydroLinkPressRelease_FINAL.doc 

and

http://www.trojanbattery.com/pdf/HydroLink_Brochure_LowRes.pdf 

So who's going to build one as a test bed to acquire real-world data and to demonstrate and de-bug the concept ?

- Paul North.

 

[NP Red]

chad thomas

 Then when they are set out at the bottom of the grade they could be pluged into a inverter or motor / alternator built to take the stored charge and feed the grid. Then the sleds would be returned to the top of the hill. 

Interesting idea but returning the sled to the top would use some additional power. At that point it might not be worth the trouble.

[JonathanS]

Building on some of the ideas in this thread what might be the most likely to work in the short term would be to put third rail on the significant grades and equip the diesel fleet with retractable third rail shoes.  When decending a third rail grade the shoes would be extended and the dynamic braking current would be diverted from the resistor grids to the third rail where it would be converted to 60 Hz AC and sold to the grid.  This would eliminate the dedicated electric locomotives or regenerative sled and would also eliminate the battery problem.  As a plus the railroads would have another revenue source to partially offset the fuel cost.

[Paul_D_North_Jr]

A key to understanding this is that the typical "duty cycle" of power output for locomotives (except helpers for steep grades) and hybrid cars is similar in that:

There are usually short periods only of max. power output, a fair amount of time at partial power output, and a lot of time at idlng, coasting, or braking.  A graph of the power output over time would look like a couple of mountain ranges sitting on a flat plain, with a couple of plateaus here and there in between. 

As I understand it (which could be mistaken):  The design goal that is common to both kinds of hybrids - Engine Dominant and Battery Dominant - is to size the combination of Engine + Battery outputs to meet the max. instantaneous power demands; the difference is how the lesser needs for power are met in between those peaks.  In the Engine Dominant mode, the engine (alone) does that - pretty much like engines in conventional cars and locos do today - and just relies on the battery to boost the power output only when needed for the peaks.  Note that in this design the engine output varies greatly throughout the duty cycle and usually has to be sized to provide a significant fraction of the peak power output.  However, in the Battery Dominant mode, the battery supplies the lower power outputs, and the engine just recharges the battery at a more or less constant rate and speed.  The key here is to size the battery output to provide a significant fraction of the peak power output, the engine to provide the rest of the peak and the "average" power output that is needed during the duty cycle, and the battery capacity to provide the make-up power needed during the times when the power demands are "above average"  That battery capacity can be thought of as the depiction on the graph described above as the area between the engine's average power output and the power demand, until another longer time of low power demand is encountered during which the batteries can be recharged again. 

- Paul North.

[carnej1]

erikem

Ulrich

Why not have the electricity generated by the traction motors stored in batteries on the locomotive or on a tender behind the locomotive? Instead of dissipating the energy as heat it could then be used later. The energy savings might be significant and I'm sure the engineers have thought this through...but what is the holdup on making this happen or why is it not feasible?

 

As other people have mentioned, GE has been working on a hybrid locomotive for several years now. The battery technology, IIRC, is a nickel halide sulfur chemistry, not as high specific energy as Li-ion, but presumably cheaper than Li-ion. My recollection is that the battery is good for 1.5 MWH (2,000 hp-hr), and supplies 1.5 MW at max discharge rate.

The electrical system on the GE AC locomotives revolves around ~800VDC bus, so adding a battery is relatively straightforward. 

 The GE hybrid propulsion system is Engine Dominant meaning that the energy stored in the battery is used to supplement the traction current from the Alternator (unlike a Railpower Green Goat where the engine/alternator just recharges the batteries) thus allowing the unit to run in a lower power setting for a given output....

[erikem]

Ulrich

Why not have the electricity generated by the traction motors stored in batteries on the locomotive or on a tender behind the locomotive? Instead of dissipating the energy as heat it could then be used later. The energy savings might be significant and I'm sure the engineers have thought this through...but what is the holdup on making this happen or why is it not feasible?

 

[Edited to include information from GE's announcement to build a battery plant near Albany.] 

As other people have mentioned, GE has been working on a hybrid locomotive for several years now. The battery technology, IIRC, is a nickel halide sulfur chemistry [correction Sodium nickel chloride], not as high specific energy as Li-ion, but presumably cheaper than Li-ion. My recollection is that the battery is good for 1.5 MWH (2,000 hp-hr), and supplies 1.5 MW at max discharge rate. [Each cell is good for 90 watt hours, so there are a lot of cells in the battery.]

The electrical system on the GE AC locomotives revolves around ~800VDC bus, so adding a battery is relatively straightforward. 

[blue streak 1]

Paul_D_North_Jr

Around now someone ought to be thinking about the "perpetual motion machine" / energy recovery aspects of this, as follows:  If we start at the bottom of a grade with a fully-charged set of batteries in the loco; then go up that grade and use a significant portion of the batteries' charge to do that; then come back down that same grade again with a train in dynamic braking and (in a theoretically perfect world with no friction and no electrical resistance) so that the energy that was expended in going uphill is completely recovered and used to fully recharge the batteries; then what's to stop us from repeating that cycle many

PDN::  OOPS I thought the best regenerative energy recovery into a 60Hz AC Cat system was about 31% (somewhat better if the regenerative is going for coach electrics (HEP or EMUs). Now if the regenerative system went into batterys then the power into the batterys might be 40 - 50% (not having to go through an inverter). Isn't that the battery recovery on our present automobiles about 50 - 70% ( not equivalent because traction motors are acting as a generator and not an alternator)? Isn"t the difference not having to put the regenerative braking back through an inverter?

I think your hogback example would have some merit if the batterys were installed in a road slug(s) connected to the prime mover locomotive. Under certain trailing tonages one less prime mover loco could be required.

Also a road slug set placed on the front or rear of a train on horseshoe could get quite a charge if in full regenerative and the regular locos not burning up energy being in dynamic but there if additional dynamics were needed.

 

[lonewoof]

1: 208 ampere-hours for 1 hour = 208 amperes, constantly, for 1 hour. That's about what your car's starter draws (continuous cranking amperes), only it draws it for 5 or 10 SECONDS. It's gonna take a MUCH healthier battery than you have under your hood, to supply 208 amps for a solid hour.

2: Recharge rate is more likely to be something like  1/10 of the maximum discharge rate; you'd likely want to recharge that 208 ampere-hours at something more like 28 amps for 10 hours.

3. Batteries are going to require maintenance, especially if they are being worked that hard. Somebody is going to have to keep an eye on them, and add water (distilled) as required.

Electrifying the grades, and feeding power back into the grid MIGHT be practical, aside from initial costs and continuing maintenance.

/Lone

 

[jchnhtfd]

There is a distinction between possible and practical.  Yes, it would be possible to power a road locomotive by batteries.  And, if so, it is obviously possible to power a switching locomotive by batteries.  But is it practical?  In the latter case, possibly -- and the success of various hybrid locomotives demonstrates that, to an extent.  In the former case, no.

I would like to point out that once one has a catenary in place, as Paul suggests (please no third rail; it's OK for Lionel, and maybe OK for a subway or certain mass transit operations, but the safety hazards make me blanch for anything in open country, never mind the maintenance headaches), there is no reason I can see not to use motors, such as Milwaukee or Great Northern or Pennsylvania used, on the electrified sections of the line.  You can couple as helpers (which in a sense is a powered version of the dynamic sled concept) with the advantage of using grid power but with the assorted disadvantages of having to tie in a helper or if you electrify a complete district you just use motors over that district, rather than diesel engines.  Not as much of a hassle as helpers, but you still have the delays involved in changing engines (in the days of steam, this wasn't a problem -- you often changed engines at district boundaries anyway).

There are subsidiary problems -- catenary isn't cheap, for instance, and in much of the country the commercial grid has neither the capacity nor the reliability to be usable, so you are looking at upgrading the grid as well (which needs it anyway), but...

[Paul_D_North_Jr]

zardoz - Yeah, I noted that once before - in the CN - Canadian Oil Sands thread a couple of weeks ago, I think.  But I work in an engineering office with big drawings - you know the quote: "Make no little plans - they have no power to excite men's souls !" (or similar - Daniel Burnham, architect, I believe) - so that's kind of like wondering about Eskimos having a lot of snow . . .

Larry - nice twist on the expression there !

Recharge - I think the Original Post had the idea that recharge would be accomplished by and during the downhill run in dynamic braking mode.  As such, it would be roughly equal in duration to the ascent or discharge cycle.  Someplace I got the notion that recharge can happen at up to 2 to 3 times the rate of discharge, with certain kinds of batteries - marine batteries like for electric outboard motors, maybe ?  Likewise, how do the hybrid cars do it ?  They have only from a few to maybe 20 seconds or so to recharge during their braking mode - which is about the same or even shorter than acceleration or running time, if I'm not mistaken.  As for the commuter trains - like the hybrid cars, each slow-down and arriving station stop would re-generate a certain amount of juice, which would then immediately recharge the batteries and be available for the next acceleration departing that stop, so it might not need a complete recharge at the end of each trip.  But recharge time would be a limitation as you note that would restrict this motive power configuration to certain specific applications, such as commuter trains, helper grades, switchers, etc.

Cold weather - yeah, I really don't know how to deal with that, though.  A toaster or heater for the battery room, maybe ?

Accessory/ auxilliary/ hotel/ "parasitic" loads - yep, noted some of them near the end of my "back of the envelope" post above, I think, for exactly the reason you noted - energy that isn't coming back on the downgrade.  I forgot the crew's microwave and refrigerator on that list , though . . .

Good comments and insights.  I'm hoping that one of the EE-type members will also weigh in and correct and clarify a few things, though.

- Paul.

 

[zardoz]

tree68

Z - I hit that in my last paragraph. 

I sit corrected.