Rail Traction: The economics of transiting towards Hybrid & Hydrail

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

Questions?

tarun.huria@dsea.unipi.it