Electric Buses. Mark Poulton, Vehicle Technology Manager Surface Strategy & Planning

Transcription

1 Electric Buses Mark Poulton, Vehicle Technology Manager Surface Strategy & Planning London Electric Vehicle Partnership meeting City Hall, 7 July 2014

2 Contents TfL s electric bus research priorities Trials of pure electric buses Routes 507 & 521 Route H98 Route 312 Early results and feedback CO 2 impacts Issues / challenges Advanced technology demonstration Range-extended diesel-electric (plug-in) hybrid buses High-power wireless charging

3 Research priorities for e-buses Pure electric buses: to understand operational viability & durability of battery technology realistic vehicle range recharging times charging strategies passenger / weight trade-off battery degradation Plug-in hybrid or range-extended diesel-electric hybrid buses: to investigate practicality & operational benefits and to quantify potential CO 2 savings over existing hybrid technology Opportunity charging: investigate the potential of wireless charging systems and fast / rapid charging for extending range and maximising availability

4 Electric bus trials in London TfL, via bus operators, is undertaking a number of electric bus trials during 2014 and beyond These will involve 8 single deck pure electric buses on four routes in both central London and outer suburbs

5 Routes 507 & 521 BYD ebus Two 12-m BYD ebuses operating alongside conventional diesel buses (Mercedes-Benz Citaro), since December service runs between Victoria and Waterloo stations: route length 2.24km; running time ~ 20 minutes 521 service runs between London Bridge and Waterloo stations: route length 3.50km; running time ~ 35 minutes

6 Vehicle requirements routes 507 & 521 Route: 507 Ref: MF Early MF MF 50 Morning Morning Morning Peak 45 05:30-07:30-10:00-07:30 09:30 12: MF Afternoon MF Evening Peak 16:30-19:00 MF Early Evening MF Late evening 13:00-19:30-15:30 21: :00-23: :30-07:30 07:30-09:30 10:00-12:00 13:00-15:30 16:30-19:00 19:30-21:00 21:00-23:00 MF Early Morning MF Morning Peak MF Morning MF Afternoon MF Evening Peak MF Early Evening MF Late evening

7 BYD ebus monitoring & performance data A snapshot of typical average daily charging, operational hours and performance monitoring data for two periods since February 2014: Charge duration Daily operating hours (on road) Daily battery SOC used % Daily energy consumption kwh Daily mileage Specific energy consumption kwh per mile 5hrs 9hrs Some Examples of Longer Operating Hours 7hrs 13hrs Aim of this trial is to: gain experience, knowledge and build confidence to plan the optimised deployment of electric buses in London monitor performance to validate the manufacturer s claims of an urban operating range of 250 km (156 miles) on a single charge evaluate the potential fuel cost savings (75% claimed)

8 BYD ebus - London specifications Dimensions & Masses Length mm Width 2550 mm Kerb Weight kg Range Urban Conditions 250 km Battery Voltage 540 V 600 Ah Capacity 324 kwh Charging System Standard Charge 5 (60kW) h Passenger Carrying Capacity Comparisons Make/Model Seated Standing Wheelchair Total Citaro BYD

9 Route H98 Optare MetroCity Four 10.6-m Optare MetroCity pure electric buses entered service on route H98 (Hayes- Houlslow) on 31 May 2014, alongside conventional diesel ADL Enviro200 buses Vehicles are initially being deployed in a varied operational pattern to gain experience of capabilities Recharging by both rapid DC (~ 1 hour) and slower (overnight 6-8 hours) techniques

10 CO 2 impacts* BYD ebus (vs 12-m Euro V Citaro) Average energy consumption: 1.8 kwh/mile (1.12 kwh/km) Average specific CO 2 emissions: 528 g/km Optare MetroCity (vs 10.2-m Euro V Enviro200) Average energy consumption: 1.2 kwh/mile (0.75 kwh/km) Average specific CO 2 emissions: 352 g/km TfL Euro V single deck diesel bus fleet average specific CO 2 emissions: 938 g/km (tailpipe; WTW + c.15%) Pure electric single deck bus CO 2 saving potential > 50% * preliminary data; subject to verification & audit and based on 2012 UK grid carbon intensity factor, including upstream emissions from production of fuels used in electricity generation, and for efficiency losses during electric vehicle charging and from electricity transmission and distribution (472.4 g/kwh)

11 Challenges for electric buses 1. Impact of ancillary loads (lights, HEVAC, air compressor, power steering, battery conditioning) reduces available range. During extreme weather these loads can be as much as the energy needed to propel the vehicle 2. Key to successful operation of electric buses is maximising utilisation and hours in operation and benefiting from reduced running costs. These can be achieved by: Recharging during inter-peak period(s), but this can impact on TVR / PVR ratio, or Opportunity (rapid) charging, either through DC chargers (plug-in charge points, overhead catenary or underground contactors) or by wireless chargers embedded in the road

12 Wireless energy transfer (Induction Charging) High power wireless charging at strategic transport interchanges could be a key enabling technology for bus electrification (and other fleet applications, such as taxis) This technology is not yet fully commercialised and is being trialled by TfL as part of an 8-city European demonstration project ( ZeEUS )

13 TfL s wireless charging bus demonstration project TfL is to demonstrate plug-in series hybrid (or rangeextended electric) buses Induction charging or Inductive Power Transfer used to provide opportunity charging Infrastructure is to be installed in TfL bus stations at either end of demonstration route(s) Objective is to operate on grid electricity as much as possible; battery will provide a significant amount of the energy required Flexibility of hybrid power-train retained

14 London ZeEUS demonstration route 69

15 Route km (~ (7 7 miles) in length Running miles) long time ~40-50 minutes Layover Running time up to 15 minutes PVR ~ minutes vehicles Busy, Layover congested time up bus stations to 14 minutes PVR vehicles TfL will set a route-specific performance target (EV / grid energy %, fuel saving )

16 Induction charging infrastructure Ground stations are solid state; no moving parts Inductive power transfer is initiated automatically when the vehicle is correctly aligned Infrastructure is waterproof, vandal-resistant and able to be remotely monitored External requirements are a control unit and cooling system

17 Conclusions Mayor s climate change targets are driving TfL s CO 2 emissions reduction strategies In addition to trialling new technology, TfL has already achieved operational improvments and retrofitted vehicles to reduce CO 2 and improve air quality Electric buses offer the potential to move towards zero emissions operation in future, in conjunction with policy levers such as the proposed ULEZ Trials and demonstrations are to gain experience, knowledge and build confidence to plan the optimised deployment of electric buses in London Infrastructure requirements (& investment) key to many future solutions electric vehicles, range-extended/plug-in hybrids, hydrogen fuel cells...