rail traction: the economics of transiting towards hybrid & hydrail
TRANSCRIPT
Rail Traction: The economics of transiting towards
Hybrid & Hydrail
- Tarun HuriaPhD 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
0 50 100 150
RESS ED EGS AUX
Pow
er
Time
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 PrototypeHYS - Università di Pisa & Piaggio
Vehicle Prototype
Hybrid drive-train
ECUs
H2 tank
Supercapacitor
RadiatorFuel cell
Air compressor
Engine crankcase
Batteries for auxiliaries
Electric Engine
FC-based hydrogen Vehicle(in the framework of EU funded FRESCO Project)
1- Layout study
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 AEconomics of Hybrid Traction
640.00
650.00
660.00
670.00
680.00
690.00
700.00
1 2 3 4
Passenger - km (million)
Cos
t ($
mill
ion)
Electric Traction Diesel Traction Hybrid Traction
Economics of hybridisation: Case B
Economics of Hybrid Traction
3250033000335003400034500350003550036000365003700037500
1300 1310 1320 1330 1340 1350
Passenger - km (million)
Cos
t of T
ract
ion
($ m
illio
n)
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
23
• 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
• 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
So what can we do today?
How to kickstart Hydrail ?
24
Series-hybrid trains
ES
DC Bus
PC PC
fuel converter Electric Drive
Fuel EG EM
Energy Management System (EMS) Driver inputs Other signals
Mech. powerto Wheels
Ps* ON/OFF
Pu(t) Pf (t)
Ps(t)
25
A FC-based drive train
ES
DC Bus
PC PC
fuel converter Electric Drive
Fuel EG EM
Energy Management System (EMS) Driver inputs Other signals
Mech. powerto Wheels
Ps* ON/OFF
Pu(t) Pf (t)
Ps(t)
A FC-based drive train is just another series-hybrid drive train,
in which:- the fuel is hydrogen - the EG is based on fuel-cells
26
Pure FC-based propulsion or hybrid solution?
ES
DC Bus
PC PC
fuel converter Electric Drive
H2 FCGS EM
Mech. powerto Wheels Pu(t) Pf (t)
Ps(t)
Pure FC-loco• Avoids additional cost &
weight of energy storage
Hybrid FC-loco solution• Reduced size of FC (reduction
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.
27
Hydrogen Fuel-cell based propulsion general scheme
ES
Interface
DC-DC Conv.
Fuel Cell
Stack Auxiliaries
FCGS ED
Electric Drive
Interface
H2
tank
LP HP
HSS H2 supply
system
p,θ
ON/OFF
Inte
rface
Int.
ES
HSS: Hydrogen Subsystem FCGS: Fuel-cell based generation system (fuel converter) ES: Energy Storage ED: Electric Drive
Driver inputs
Other signals
EMS
28
Track FAENTINA (Firenze-Faenza) 100km – 17 intermediate stopsComparison of Hybrid and conventional vehicles in terms of consumption and emissions
0 1000 2000 3000 4000 5000 6000 7000 80000
50
100
150
tempo [s ]
600
300
0 -300
rela
tive
altit
ude
[m]
spee
d [k
m/h
] Vehicle Reference Altitude
0 1000 2000 3000 4000 5000 6000 7000
-200
0
200
400
600
800
tem po [s ]
pow
er [k
W]
0,75 0,65 0,55 0,45 0,35 0,25
ES
Ene
rgy
Leve
l [p
u]
EL
Ped Pgen
time [s]
time [s]
pure electric(due to track)
pure electric(due to optimisation)
ELref = 0,75
Electro-mechanical hybrid trains may be already competitive (1)
“Vettore Idrogeno” Project: FC-based Vehicle – Preliminary layout
Braking Rehostat
Electric converter for propulsion motors
FC-Based Electricity Generator
Electrochemical Battery
Hydrogen Tanks Auxiliary Load
Electronic Converter Filters
3) FC-based hydrogen Locomotive (study)2 – Performance analysis in comparison with
electromechanical hybrid
ICE-based [kg/km]
Fuel Consumption 0.48
CO2 1.5
[g/km]
NOx 10.8
HC 0.02
CO 0.3
PM 0.02
FC-based [kg/km]
Fuel Consumption 0.18
Simulation Results(auxiliaries enclosed)
0 10 00 2 000 30 00 4 000 50 00 6 000 700 0 90 00 0
20
40
60
80
100
120
time [s ]
Refere nce speed [km /h]
Cyc le s tep: E H H H H E
B attery E nerg y Le vel [p u.]
0 ,5
0 ,6
0 ,7
0 ,8
0 ,9
0 4 000 50 00 6 000 700 0 90 00 time [s ] 2 000 30 00 10 00
re lati ve a ltitude [m ]
+5% o
+24% o -24% o
-5% o 0 40 00 5000 60 00 7 000 9000time [s ] 20 00 3 000 1000
25 0 50 0 75 0
100 0
0
E = pu re e lectric m ode (on ly fo r th e IC E-ba s ed ) H = hyb rid m ode
FC -based
IC E based
Complex Cycle
31
Hydrogen Fuel-cell based propulsionAn evolutionary approach
DC
AC
electric d rive
ICE M DC
AC G
Tracto r W heels
DC Generator
DC
AC
electric d rive
M DC
DC Tractor W heels
DC Generator
FC stack and auxi l.
Introduction of Hybrid propulsion in railway may:
- give immediate advantages in terms of fuel consumption
- give some zero-emission range
- pave the way towards FC-based hybrid propulsion
