Rail Traction: The economics of transiting towards Hybrid & Hydrail
- Tarun Huria PhD Student, University of Pisa • Why hybridise ? • University of Pisa & Hybrid Technologies • Economics of Hybridisation • Towards Hydrail Conventional Rail Traction Technologies
• Electric Traction (1881): • Expensive infrastructure, Lower operating cost, renewable energy (?), regenerative braking (?) – DC Electric Traction » 1.5kV / 3kV DC supply to railway locos. – AC Electric Traction » Predominantly 25 kV AC supply; Regenerative braking possible; Presently most efficient mode. » Upper-bound of the regenerated voltage is restricted by the catenary voltage – at higher speeds, leads to inability of the regenerated power to be fed to the grid. Conventional Rail Traction Technologies
• Diesel Traction (1893): – Oil-dependent, emissions, Flexibility of operations, – Diesel-electric traction » Diesel engine + alternator/generator produces onboard electricity. » Dynamic braking possible; more effective than regenerative braking (of electric traction) - avoids wear & tear of wheels & brake- blocks » Can be most easily hybridised – Diesel-mechanical & diesel hydraulic traction » Use mechanical or hydraulic transmission to power the wheels Hybrid Rail Traction
• Hybrid : with more than one source of on-board power … » ICE + batteries, ICE + batteries + supercaps, fuel cells + batteries, fuel cells + batteries + supercaps » First used by Greeks/Romans/Vikings on oar & sail powered boats • Series / parallel architectures Hybrid Traction Power
RESS ED EGS AUX 0 50 100 Time 150 Key drivers for hybridisation
• Energy costs escalating rapidly » Train energy consumption dependent on gradients, maximum speeds & stopping patterns » Typically constitute around 15-20% of total expenses; and growing » Varies 19 - 33 kWh/1000 (German ICE, MEET project) » Ʃ lifecycle energy costs >> original investment costs
• Reduce carbon footprint • Economic sense Hybrid Rail Traction
• Advantages over conventional technologies » Regenerative braking (savings: from 10 to 25%) » Prime mover operates at efficient zone of fuel maps » Energy booster for achieving higher acceleration » Can be run as ZEV • Is most advantageous when the load varies considerably e.g. passenger services • Hybridisation degree dependent upon duty cycle » Benefits from downsizing prime mover negate weight of additional components » Fuel savings >> 15 - 20%, emission reduction > 50% • Why hybridise ? • Hybrid Vehicles & University of Pisa • Economics of Hybridisation • Towards Hydrail Parallel-Hybrid scooter Prototype HYS - Università di Pisa & Piaggio Vehicle Prototype
Hybrid drive-train FC-based hydrogen Vehicle (in the framework of EU funded FRESCO Project) 1- Layout study
Batteries for auxiliaries
H2 tank
Supercapacitor
Air compressor
Electric Radiator Engine Fuel cell ECUs Engine crankcase FC-based hydrogen Vehicle (in the framework of EU funded FRESCO Project) 2- vehicle under test at DSEA Labs FC-based hydrogen Vehicle (in the framework of EU funded FRESCO Project) 3 - vehicle being prepared for on-track tests ENFICA-FC Project 1) Technical specifications/acquisition: - Chopper - Inverter - Motor - Battery 2) Design and realisation of AMU 3) Power-train integration 4) Lab tests: • Of the electricity generation system loaded with resistors • Of the whole power train loaded with artificial mechanical load ENFICA-FC Project
• On 26th May 2010, a new world record of 135 km/h for 45 minutes established, overcoming Boeing’s 2009 record of 120 km/h for 20 minutes.
• Flew on fuel cells powered by H2 gas @ 350 bar ! • Why hybridise ? • Hybrid Vehicles & University of Pisa • Economics of Hybridisation • Towards Hydrail Economics of hybridisation: Case studies
• Scenarios » Existing railway planning to switch to hybrid locos » New railway, planning traction mode between electric, diesel & hybrid • Case A – To determine the break-even traffic of an existing railway, planning to switch to hybrid traction » electric vs. diesel vs. hybrid • Case B – To determine the break-even traffic for a new railway » electric vs. diesel vs. hybrid Economics of hybridisation: Case A
Economics of Hybrid Traction
700.00
690.00
680.00
670.00
660.00 Cost ($ million) 650.00
640.00 1234 Passenger - km (million)
Electric Traction Diesel Traction Hybrid Traction Economics of hybridisation: Case B
Economics of Hybrid Traction 37500 37000 36500 36000 35500 35000 34500 34000 33500 33000 Cost of Traction ($ million) ($ Traction of Cost 32500 1300 1310 1320 1330 1340 1350 Passenger - km (million)
Electrical Traction Diesel Traction Hybrid Traction Examples of hybrid locomotives/trains
• America » Rail Power (2004) » GE (2008) » BNSF (2009) • Asia » JR East (2007): Orders for 10 more this year » RTRI (2007) » JR Freight (Toshiba, 2010) • Europe: » France (Bombardier, 2007) Ten French regions ordered 144 hybrid trains » UK » Holland (Alstom, 2009) Transiting to hybrids
• Increasing number of railways are switching to hybrid powered trains • Manufacturers » Bombardier » Hitachi » Toshiba » Mitsubishi » Alstom » Siemens » ABB • Why hybridise ? • University of Pisa & Hybrid Technologies • Economics of Hybridisation • Towards Hydrail How to kickstart Hydrail ? • Costly FC-based generation system (approx 5000 €/ kW vs. 50 $/kW for ICEs) • FC stack life is still well behind that of ICEs • Some technical issues still to be solved (low temp storage, system reliability etc.) • Inadequate hydrogen production & infrastructure • Too many standards and regulations So what can we do today? • Build prototypes and demonstrators • Make people realise that it’s a safe technology • Adopt technologies that can be adapted to hydrail later, with the minimal inputs • This could be possible by adopting hybrid propulsion
23 Series-hybrid trains
DC Mech. power Bus to Wheels Pf (t) Pu(t) EG PC PC EM Fuel Ps(t)
fuel converter ES Electric Drive Ps* ON/ OFF Driver inputs Energy Management System (EMS) Other signals
24 A FC-based drive train
DC Mech. power Bus to Wheels Pf (t) Pu(t) EG PC PC EM Fuel Ps(t)
fuel converter ES Electric Drive Ps* ON/ OFF A FC-based drive train Driver inputs Energy Management System (EMS) is just another series-hybrid drive train, Other signals in which: - the fuel is hydrogen - the EG is based on fuel-cells
25 Pure FC-based propulsion or hybrid solution?
DC Mech. power Bus to Wheels Pf (t) Pu(t) FCGS PC PC EM H2 Ps(t)
fuel converter ES Electric Drive
Pure FC-loco Hybrid FC-loco solution • Avoids additional cost & • Reduced size of FC (reduction weight of energy storage increases with variation in duty cycle) • Lower costs, higher life Hybridisation works better when the duty cycles and load fluctuates more: best solution for suburban or intercity trains or shunters.
26 Hydrogen Fuel-cell based propulsion general scheme FCGS ES ED HSS H2 supply system ON/OFF Fuel DC-DC Electric Cell Conv. Drive Auxiliaries Stack ES
LP
HP Interface Int. Interface
p,θ Int erface
EMS H2 tank H2 tank HSS: Hydrogen Subsystem FCGS: Fuel-cell based generation Driver Other system (fuel converter) inputs signals ES: Energy Storage ED: Electric Drive
27 Electro-mechanical hybrid trains may be already competitive (1) Track FAENTINA (Firenze-Faenza) 100km – 17 intermediate stops Comparison of Hybrid and conventional vehicles in terms of consumption and emissions
150 600 Vehicle Altitude Reference 100 300 ELref = 0,75 50 0
speed [km/h] -300
0 [m] altitude relative 0 1000 2000 pure3000 electric4000 5000 6000 7000 8000 pure electrictempotime [s] [s]
(due to optimisation) 800 (due to track) EL 0,75
600 0,65
400 0,55
200 0,45
power [kW] power 0 0,35 Ped
[pu] ES Energy Level -200 Pgen 0,25
0 1000 2000 3000 4000 5000 6000 7000 tempotime [s][s]
28 “Vettore Idrogeno” Project: FC-based Vehicle – Preliminary layout
FC-Ba sed Braking Electricity Rehostat Generator Auxiliary Load Filters Electronic Converter Hydrogen Tanks
Electrochemical Electric converter for Battery propulsion motors 3) FC-based hydrogen Locomotive (study) 2 – Performance analysis in comparison with electromechanical hybrid 1000 relative altitude [m ] Simulation Results 750 Complex Cycle (auxiliaries enclosed) 500 +24% o -24% o 250 +5% o -5% o 0 ICE-based [kg/km] 0 1000 2000 3000 4000 5000 6000 7000 time [s ] 9000 120 Fuel Consumption 0.48 Reference 100 speed [km/h] CO2 1.5 80 [g/km] 60 40 NOx 10.8 20
HC 0.02 0 0 1000 2000 3000 4000 5000 6000 7000 time [s ] 9000 CO 0.3 0,9 Battery E nerg y Le vel [p u.] PM 0.02 0,8 FC-based
0,7
FC-based [kg/km] 0,6 ICE based
Fuel Consumption 0.18 0,5 0 1000 2000 3000 4000 5000 6000 7000 time [s ] 9000
Cycle step: E H H H H E E = pure electric mode (only for the ICE-based) H = hybrid mode Hydrogen Fuel-cell based propulsion An evolutionary approach
Introduction of Hybrid propulsion in railway DC DC ICE G M may: AC AC Tractor Wheels DC Generator electric drive - give immediate advantages in terms of fuel consumption
- give some zero-
DC DC emission range FC stack M and auxil. DC AC Tractor Wheels - pave the way towards DC Generator electric drive FC-based hybrid propulsion
31 Questions?