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How energy efficient really israilway transportation?Stefan FassbinderDeutsches KupferinstitutAm Bonneshof 5D-40474 DüsseldorfTel.: +49 211 4796-323Fax: +49 211 4796-310sfassbinder@kupferinstitut.destf@eurocopper.orgwww.kupferinstitut.dewww.leonardo-energy.org The German Copper Institute, DKI, is the central information and advisory service dealing with all uses of copper and copper alloys. We offer our services to: Commercial companies We can be contacted by: The skilled trades post Industry phone R & D institutes fax Universities e-mail Artists and craftsmen internet Students online database, or Private individuals personally 1
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Electricity boosts mobilityElectric motors• have their highest torque at standstill: No disengaging, no gearchange, no torque converter required,• provide a considerable short-term overload capability: Higher acceleration than the power rating would let you suppose,• do not have any no-load consumption during standstill, rolling or braking,• offer the opportunity to feed back energy during braking! Motor = Generator,• and their primary fuel is totally flexible (fossil, nuclear, hydro, wind – just mix as you like!).So it is not a miracleif railway companies preferelectric traction! Characteristic data of 16.7 Hz railways Electricity system of DB AG in D-A-CH Installed EnergyType of power plant DB AG ÖBB SBB capacity productionVapour 42.2% 66.0% Employees 240242 42893 27822Hydro 11.0% 10.0% Passengers 1919Mio. 200Mio. 332Mio. Railway gridRotating convertor 34.3% 14.6% total 33862km 11000km 3011kmElectronic convertor 11.9% 9.4% electrified 19300km 8200km 3011km shareTotal 3.2GW 11.0TWh/a of lines 57% 75% 100%Sum of all electric vehicles 22.4GW (700%) of transport 85% 100% volume 56% of DB lines are … since the energy electrified. These 56% carry“consumption” of an electric 85% of all traffic.locomotive can be negative! However … 2
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…what about the other 15%? e. g. the 612 series?• Engine power rating: 2*560 kW = 1120 kW• Smart and convenient: Tilting technique, air conditioning• Maximum permissible speed: 160 km/h• Fuel consumption: 1.7 l/km (for one, not 100 km!)What about diesel locomotives?• On a series 232 diesel locomotive (6 axles, 120 t, 2,200 kW, max. 120 km/h) at a constant speed of 120 km/h a consumption of 3 l/km was measured.• (for good resons railway companies reference the fuel consumptions to one kilometre, not to 100 kilometres!)• There are no new diesel locomotives.• There are old diesel locomotives with new engines.•“Ludmilla” efficiency is then >40%. The engine “Taiga Drum”• But what„s the use of this if the engine is idling over 90% of its operating time?• And if a DB technician explains: “Diesel locomotives hamper the traffic when circulating on an electrified line!” …• …and if a railway trade journal reports the electrification of a line no longer than 22 km had already cut the circulation time by 5 minutes?„Elektrischer Betrieb bei der Deutschen Bahn im Jahre 2009“. „eb“ Elektrische Bahnen & Verkehrssysteme 1-2/2010, p.19 3
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However, the 101 series electric loco(4 axles, 84 t, 220 km/h) provides amotor power rating of 6,600 kW!Note: It„s electricity that wakes trains up!The parameters responsible forthe energy demand are(at ≈200 km/h): of a car of a train factor (4…5 seats) (450 seats) 100Mass 1.5 t 450 t 300 Note:of staticare a means of ≈55% transportation! 0.6Coefficient Trains friction mass 28…35%Coefficient of rolling friction ≈2% <2‰! 0.1Resulting: some good reasons railwaykNNote: For Rolling friction force 0.3 companies give rolling 9 kN 30Power demand resulting from as per kW figures! friction coefficients this 15 mille 450 kW 30as a share of power rating 15% 7% 0.5Air friction force 1.5 kN 30 kN 20Power demand resulting from this 85 kW 1550 kW 18as a share of power rating 85% 23% 0.27Total power demand 100 kW 2000 kW 20as a share of power rating 100% 30%! 3.3 4
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Now what are the other70% of power good for?Compared to a car, a train has:- A very great mass.- Significantly less static friction (steel on steel rather than rubber on asphalt).+ Significantly less rolling friction (steel on steel rather than rubber on asphalt).+ Significantly less air friction (since the train travels in its own windshade!).Worth noting:The top speedof a car is usually of a railway vehiclethe highest is usually thepossible speed, highestlimited by the permissibleavailable engine speed.power. 5
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With a great deal of good will 66kW 6,6MWwe will now requirement car anda train Power let a car with IC•55kW kW engine and (very tight) space for 66 P (car) 5,5MW P (IC train) •44kW 4 passengers travel at 4,4MW•33kW km/h, P (car) 200 3,3MW P (IC train)while a train with a drive power rating of 22kW 2,2MW• 6,600 kW offers plenty of space to•11kW passengers (including toilets, a 400 1,1MW bistro, …). At a travelling speed of 0,0MW 0kW v • 200 km/h50km/h requires: 150km/h 200km/h 0km/h this 100km/hBut a car accelerates faster?100% v/vmax 90% 80% 70% Well, initially yes, but the Acceleration process 60% car and trainlot … 200 km/h) train has a (0 of reserves! 50% 40% 30% 20% v/vmax Car 10% v/vmax IC train s 0% 0km 1km 2km 3km 4km 5km 6km 7km 8km 6
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Quiz question 1:How far will an ICE2 expresstrain of the 402 series continue to rollunbraked in a flat area when suddenlythe power fails at a speed of 230 km/h?Answer 1:The test was not carried out all throughto the end. After 32 km the train was stillrolling at 120 km/h!Quiz question 2:How fast will a railway carriagebecome when you let it roll down adecline of 5‰ (just 0.5%!)?Answer 2:Note: For some good reasons railwaycompaniesto technical documents by asAccording give inclines and declinesper mille Bahn AGDeutsche figures! it will (finally) reacha speed of 44 m/s ≈ 160 km/h (after1 hour of rolling)!A street car would simply just stall and not roll at all! 7
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Quiz question 3:Why is it that in a train repairhall which can be opened at both endsit is not allowed to leave both gatesopen at the same time?Answer 3:Because the wind might blow thelocomotoves out of the hall!So let’s just accelerate a200km/hfully occupied street car v to 200 km/h, disengage150km/hand see what willhappen…100km/hMass: Train rolls kg 2000 Train rolls Train brakes Car rolling outRolling friction coefficient: Car rolling out 50km/h 2% Car rolling outFront surface area: 2 m²cx value: 0km/h 0.37 2km s Engine power: 1km 0km 105 kW 3km 8
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Hauling force and power IC fast train with DBs 101300kN series locomotive and 6MW 9 carriages250kN 5MW Hauling force Power 200kN 4MW150kN 3MW Required hauling force Required power100kN 2MW50kN 1MW Speed 0kN 0MW 0km/h 50km/h 100km/h 150km/h 200km/hHauling force – 80% left? IC fast train with DBs 101300kN series locomotive and 6MW 9 carriages250kN 5MW Hauling force Power 200kN 4MW150kN 3MW Required hauling force Available hauling force100kN 2MW Required power50kN 1MW Speed 0kN 0MW 0km/h 50km/h 100km/h 150km/h 200km/h 9
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Power – 70% left? IC fast train with DBs 101300kN series locomotive and Power limit 6MW 9 carriages250kN 5MW Static friction limit Hauling force Power 200kN 4MW150kN 3MW Required hauling force Available hauling force100kN 2MW Required power Available power50kN 1MW Speed 0kN 0MW 0km/h 50km/h 100km/h 150km/h 200km/hAt 300 km/h, however …300kN 8MW ICE3 high speed railcar of DBs 403 series 7MW250kN … the demand does 6MW F 200kN increase rapidly 5MW150kN 4MW P Required hauling force 3MW100kN Available hauling force Required power 2MW50kN Available power 1MW v 0kN 0MW 0km/h 100km/h 200km/h 300km/h 10
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The ultimate train concept330km/h ICE3 high speed railcar 0,75m/s² a 300km/h of DBs 403 series270km/h 0,60m/s²240km/h210km/h 16 out of 32 axles driven 0,45m/s²180km/h v by a 500 kW motor each150km/h provide optimal 0,30m/s²120km/h acceleration and 90km/h energy recovery 60km/h 0,15m/s² Speed 30km/h Acceleration s 0km/h 0,00m/s² 0km 5km 10km 15km 20km 25kmThe ultimate train concept330km/h ICE3 high speed railcar 0,75m/s² a 300km/h of DBs 403 series270km/h 0,60m/s²240km/h210km/h 16 out of 32 axles driven 0,45m/s²180km/h v by a 500 kW motor each150km/h provide optimal 0,30m/s²120km/h acceleration and 90km/h energy recovery 60km/h 0,15m/s² Speed 30km/h Acceleration t 0km/h 0,00m/s² 0s 60s 120s 180s 240s 300s 360s 11
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Also you have to accelerate the train tothe desired travelling speed of 300 km/h(83.3 m/s) first in order to run that fastWith a 4% supplement for rotating masses and an efficiencyof 87%, measured at the pantograph, this makes about520 kWh for one single acceleration from 0 to 300 km/h.With the DB tariff of 9 c/kWh this costs approximately 47 €!It would be pretty sad to get nothing of this back at all.Counted with an efficiency of 87% again, you can retrieve75% during brakage – if all goes well. 2 m 450 ,000 kg mWkin * v² * 83.3 1.56 *10 9 Nm 1.56GJ 434 kWh 2 2 sBad outlook for the dieselElectric traction turns out to be far superior:• Power density and dynamic behaviour are outstanding.• 8% of all electricity consumed by locomotives in Germany has been used once before by another locomotive and fed back again into the supply system.• Usually this works only with water (or e. g. copper!) but never ever with coal, gas and oil.• The share will continue to grow, since by and large more and more old electric locos without feedback capability are being replaced with modern power electronic ones.• But we will still have to wait for a long time to see a diesel engine coming around that, when braking, sucks up fumes and converts them back into fresh air and fuel. 12
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Electric power speeds us up!• For 2009, DB„s department for Energy Cost Management gives an average circulation of 347,620 km for each of their 145 locomotives of the 101 series.• The average consumption is ≈17 kWh/km (including electricity the locomotive has fed into the train for heating the carriages and for ancillary supplies).• This yields an electricity cost of half a million Euros per year.• The purchase price of the 101 series is around 3 million Euros.• So for the power consumption of a locomotive„s 30-year- long life you could buy in 5 complete locomotives!• 8% of energy fed back saves 1.2 million Euros per loco during 30 years! Or let’s have a look at suburban transportation The regional train from Aachen to Dortmund travels about 160 km far, calling 22 times. Its top speed is 140 km/h. If it went all through non-stop, it would consume only 800 kWh for overcoming the friction. But accelerating 22 times costs 1600 kWh! So this is 2/3 of the overall energy consumption! Hence, in theory about 3/4 out of 2/3, say half of the energy, could be recovered, but unfortunately … 13
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Or let’s have a look atsuburban transportation… according to DB Regio the real rate of recoveryis only 10% in this business unit!And now what to do? What’s the deficiency?Hence DB’s plans for thecoming decades are:• Increase the share of inverter 10% → 20% locos from 47% (2009) to 100%• Improve control infrastructure – 20% → 50% no more odour of hot brakes• Replace all Loco-and-carriage 50% → 60% trains with railcars, since:• Railcars are lighter and hence use less energy• The dispersed drive expands the opportunities for energy recuperation 14
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Now what„s up withthe 44% of lineswithout a trolley wire?• There is a diesel railcar standing at the railway station. There are 2 engines mumbling under no-load conditions inside it – and are being cooled, while an oil heater fuelled with diesel fuel at the price of diesel fuel is heating the passenger cabin.• The railcar starts. The engines raise their voices a little bit.• Only above some 30 km/h … 60 km/h the full power can be transmitted to the rails: Now the engines hum a bit more vigorously – for about one minute. Then the top speed has been reached. About 30% of the engine rating suffice to sustain a constant speed of 160 km/h.• But very soon we are approaching the next station. The railcar is kept rolling for several minutes, the engines disengage, mumbling calmly.• Then the railcar brakes. The engines rev up – just to dissipate the heat from the hydraulic braking system via the engine radiators!Is this a concept for the future? – Or rather a makeshift solution?But wasn‘t there something else?Oh, right: The 515 series!• Accumulator-operated railcars have been in use since 1907!• for 40 years, from 1955 to 1995, well over 220 motor vehicles of the 515 series have been in use:• Power rating 2*150 kW• Maximum speed 100 km/h• 10 t … 16 t of lead accumulators• Capacity 352 kWh … 602 kWh• Cruising range 300 km 15
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Mental experiment:A modern re-issue• Today„s Li ion accumulators provide 4 times the energy density of the old lead acid batteries, so:• you can double the capacity while halving the mass.• Doubling the capacity doubles the cruising range to about 600 km.• halving the weight along with the use of modern inverter technique with generative brakage im- prove the performance (min. 140 km/h) and the comfort (e. g. air conditioning).Comparing a hypothetical electricbattery railcar to a street car Tesla Electric Roadster railcarEnergy capacity 55 kWh 1100 kWhEnergy demand 200 Wh/km 2000 Wh/kmEnergy demand per seat 100 Wh/km 10 Wh/kmcruising range 350 km 600 kmBattery mass 0.45 t 9tas share of the vehicle 36% 12%Battery price 45.000 € 900.000 €as share of conv. vehicle 50% 25% 16
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How much really is theelectricity from the battery?Battery price: 900.000 €Life time: 3000 cyclesEnergy capacity: 1100 kWhSo in effect the power from the battery costs:Electricity taken from trolley wire 90 €/MWhCharge cycle / conversion losses +10 €/MWhNight tariff rebate -10 €/MWhWear of the accumulator battery +270 €/MWhElectricity cost from the battery 360 €/MWhComparison to the existingseries 612 diesel railcar Diesel railcar Batt. railcarPrimary energy demand 20 kWh/km <6 kWh/kmSecondary energy demand 17 kWh/km 2 kWh/km (1.7 l/km)Net energy price 1.03 €/l 0.09 €/kWhEnergy price from the battery – – – 0.36 €/kWhNet energy cost 1.80 €/km 0.18 €/kmEnergy cost incl. battery – – – 0.72 €/kmAt 250,000 km/a 450,000 €/a 180,000 €/aDuring a 30 years„ life 13,500,000 € 5,400,000 € 17
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Alternative 1: Accumulatorrailcar with pantographLocal trains often leavethe city centres onelectrified lines and turnoff onto the secondaylines only a bit later on.Here the vehicles could• be charged up during ride• in part be driven as conventional electric railcars with pantograph (»pop-up hybrid«)• and thus require only a fraction of the (expensive) battery capacity.Alternative 2:Hybrid diesel railcarsDo not confuse with the principle of the diesel-electric locomotive! Since this is an electric locomotive lugging aroundits own power plant• With the hybrid railcar, however, the diesel engine has only some 10% of the electric power (e. g. a 66 kW car engine instead of 2*315 kW railway engines).• For the diesel engine is always running at the optimal point of operation (rated speed and power) instead of idling ≈90% of its time.• Also the generator rating is only 10% that of the electrical traction power.• The battery provides 90% or bears 110%, respectively, of the electrical traction power during acceleration and brakage, respectively.• Continuous heat generation. Combined heat and power generation replaces the oil heater.• Facilitates combination with alternative 1. 18
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Hybrid diesel railcars – alsofor long-distance fast trains?Just take a trip from Berlin to Copenhagen!There they are using up the unfortunate series 605 now.• These railcars are equipped with diesel-electric drives, so these already avail of electric drive motors and inverters.• These trains arose on the platform of the 415 series 5- carriage electric railcar!• They had been withdrawn from service for several years.• They were offered for sale, but nobody wanted them.• One of the reasons given for the latter two points are high fuel costs.So why not convert these trains first?Series 605 – ICE without pantographJust consider:• Here the train does not run very fast and rarely stops.• Still the fuel consumption lies around 3 l/km!• This costs around 1800 € per single trip• For this alone 7 full-charge or 45 low-cost ticket passengers will have to be sitting on the total of 195 seats• Whereas the major share of the easement is electrified!• And for one hour the train is not travelling at all but is standing on a ship.So why not• remove 3 of the 4 diesel engines and generators,• replace them with accumulator batteries,• possibly add a pantograph and a transformer• but in any case reduce the fuel consumption by 1 l/km• and save about 600 € of fuel cost on one trip? 19
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Summary and conclusions• Electric railway drives clearly outperform diesel engines.• At the same time electric railway drives are way more energy efficient than diesel traction is.• SBB operate 100% electrically – nothing left to do.• E. g. DSB are 27% electrified – need for action!• DB AG operate 85% electrically – this is fine so far.• For the remaining 15% a re-introduction of battery operated railcars based on modern lithium ion cells should be considered. 40 years of good experinece even with lead acid accumulators support this idea.• The economic viability of electric cars lies about 10 times further away from reality than that of the battery operated railway vehicle! The German Department of Technology and the EU Commission should urgently take this into consideration with their energy efficiency support programmes. 20
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