Ultra-Low EmissionTransit Buses

April 27, 2010

Presented by Richard Thompson

• Heavy Vehicles – Transit Buses

• Hybridized Hydrogen

– Fuel cell dominant

– Battery dominant (plug-ins)

• All-Electric

Transit Agencies are Looking for a Change

• Clean (tighter emission standards) and Quiet (public acceptance)

• Well-publicized challenges have slowed fuel cell passenger vehicle development

• However, USDOD and USDOT have maintained (and in some cases accelerated) hydrogen research and deployment

• Number of commercial-ready products in the area of buses and industrial trucks (forklifts) has grown in recent years

• Over 300 hydrogen fuel cell forklifts to be deployed in Texas in the next two years

Transit Bus Architectures of Interest

Prime Mover Technology

Prime Mover Efficiency

Comments

Diesel ICE (ref) 35 to 40%

Hydrogen ICE (ref) 35 to 40% • Never gained the attention of fuel cells• Low emissions, Lower cost than fuel cells

Prime Mover Technology

Prime Mover Efficiency

Comments

Fuel cell dominant 45 to 55% • Zero emissions at the vehicle• Costs are high, pre-production stage

Battery dominant with fuel cell for range extender

75 to 95%(Efficiency is

power dependent)

• Zero emissions at the vehicle• Costs can be lower with proper balance of fuel

cell and battery sizing• Higher efficiency yields better fuel economy

All-electric 75 to 95%(Efficiency is

power dependent)

• Zero emissions at the vehicle• Very limited range (~ 20 miles)• Requires expensive rapid re-charge

infrastructure along the bus route

Comparison of Energy Storagefor Vehicles

Recent developmentsare suggestingimprovedperformance

Flywheels Ultracapacitors Batteries

High power

High energy

High efficiency

Long cycle life

Degradation free

Temperature invariant

Design independence

Opportunities exist to blend energy of batteries with power of flywheels or capacitors

What We are Doing?

Where are We Going?

Hydrogen infrastructure

• Skid-mounted hydrogen fueling station for vehicles

• Generates hydrogen from natural gas

• Integrated system includes– fuel processor, which converts natural

gas to hydrogen gas,– pressure swing absorption unit, which

purifies the hydrogen– hydrogen compressor– storage tanks– hydrogen dispensing system

• First permanent fueling station in Texas

– Completed February 2010– Production is 40 kg/day

• Submitted proposal to TCEQ in April 2010 to:

– Assess fueling station’s performance, reliability

– Verify production cost of $2 to $3/kg– Public outreach and education

Pure H2

Integrated Hydrogen Supply System

Reformer

PressureSwing

Absorption

Compressor

High PressureStorage

Dispenser

Utility Water

Methane

H2-rich gas

Pure H2WaterShift

Reactor

Pure H2

Integrated Hydrogen Supply System

Reformer

PressureSwing

Absorption

Compressor

High PressureStorage

Dispenser

Utility Water

Methane

H2-rich gas

Pure H2WaterShift

ReactorReformer

PressureSwing

Absorption

Compressor

High PressureStorage

Dispenser

Utility Water

Methane

H2-rich gas

Pure H2WaterShift

Reactor

Field Validation of a Hydrogen Plug-in Hybrid bus in Austin, TX

• Seed money from FTA (through CTE)

• TCEQ Proposal - April 2010– NOx reduction– Further commercial acceptance of

hydrogen bus and fueling station

• Twelve month revenue service demo operated by Capital Metro

• Proterra’s hydrogen hybrid bus– Combines hydrogen fuel cells with a

“plug-in hybrid” feature using advanced Li-Ion batteries

– Increases fuel economy by 2 to 3 over conventional diesel buses.

• Fueled at UT-CEM’s onsite station

• UT-CEM is the prime– Evaluate both the bus and station– Evaluate

• Performance and reliability• Cost effectiveness

10.4 mpg (diesel energy equivalent) measured at the 2010 Winter Olympics demo (1000 miles)

All-Electric Fuel Economy

Hybrid Fuel Economy in Charge Sustaining Mode

All-Electric Transit Bus Demonstration in San Antonio, TX

• Several transit agencies beginning demonstrations of all-electric transit buses

• USDOT/FTA Program

• UT-CEM is a sub to Center for Transportation and the Environment

• UT-CEM’s role is– Acquisition of the bus’s

battery data

– Modeling of the batteries

– Goal is to characterize any degradation due to effects of rapid re-charge

• All-electric derivative of the Proterra fuel cell transit bus

• 70 kWh of li-ion batteries

• Rapid charge in about 8 minutes (or less), 60% to 70% SOC swing

• Gives about 20 mile range

• Requires on-route charging infrastructure

Phase I Program – Assess Flywheel Technology Emerging from the Formula One Racing Community and

its Benefits to the US Transit Bus Market

• Current Phase I program , under USDOT/FTA with Center for Transportation and the Environment

• Goal - determine if this flywheel technology presents a lower-cost alternative for hybridized transit buses in the US

• If Phase I answer is yes, Phase II proposal to FTA to– Select mid-size transit bus for retrofit with Williams

technology

– UT-CEM will complete the control algorithms and flywheel integration

– UT-CEM will evaluate vehicle during an extended demonstration in the US

• Williams Hybrid Power Ltd, located in England, is commercializing flywheel energy storage for passenger vehicles

• Developed in the demanding and harsh environment of Formula One racing

• Company is now making the technology available to meet the demands of the wider transport and mobile energy storage market.

Energy Source/Storage Type Cost per Wh Cost per kW

Fuel Cell n/a $4000

WHP Flywheel (costs for prototype) $284 $1067

WHP Flywheel (1/11/2010 estimate for >1000 production cost)

$44 $167

WHP Flywheel (March 2010 estimate for >>1000 production cost)

$11 $42

Li-Ion Batteries $4 $500

Porsche 911 GT3 R Hybrid with Williams Flywheel System (Feb 11,2010)

• After its debut in Geneva the 911 GT3 R Hybrid will be tested in long-distance races on the Nürburgring

• The highlight of this test programme will be the 24 Hours on the Nordschleife of Nürburgring on May 15th and 16th (2010)

• The focus is not on the 911 GT3 R Hybrid winning the race, but rather serving as a spearhead in technology and a “racing laboratory” providing know-how on the subsequent use of hybrid technology in road-going sports cars.

DOD Program on Extended Range Hydrogen Fuel Cell Utility Vehicle

• Phase II program by Defense Logistics Agency

– Prime - Center for Transportation and the Environment

• DOD Program Goals– Convert all-electric utility vehicle

to hydrogen fuel cell power– Must provide extended range

compared to all-electric versionUltracapacitor

Modules4X 16V 500F

Boost Converter(to 48Vdc Motor)

Controller/Data Acquisition

NI Compact Rio

Fuel Cell Module

8kW20-40Vdc

Hydrogen Storage3.73 Kg

• Design has been finalized• Using a NI Compact RIO to control

– 8.5 kW fuel cell– 28 Whr ultracap bank– Boost/buck converter– 12.9 kW traction motor (peak)

• Beginning in October 2010– Vehicles begin a 12 month demo at Warner

Robins AFB– UT-CEM collects data and evaluates

vehicle performance• 3.7 kg tank provides estimated 300 mile range

What About CNG?

• Direct CNG vehicles (ICE) are again gaining popularity– Lower emissions (NOx is lower, but still significant)– Low fuel cost– Heavy hybrids – buses, sanitary, etc.

• Main problem for CNG is onboard storage and limited range

• Here comes UT-CEM and GTI– Submitted a joint proposal to evaluate the benefits of hybridized

CNG for heavy hybrids• CNG gen set• Energy storage for regenerative braking

• Main emphasis is:– Extended range through increased vehicle efficiency– Assess benefits of battery dominant approach (plug-in hybrid)– Also, attempt to lower NOx emissions

Questions?

Richard Thompson

UT - Center for Electromechanics

PRC Mail Code #R7000

Austin, TX 78712

Phone:  (512) 232-1615

r.thompson@cem.utexas.edu