AARHUS UNIVERSITY
DEPARTMENT OF ENVIRONMENTAL SCIENCE
20 October 2015
DCE – DANISH CENTRE for ENVIRONMENT and ENERGY
Emissions from heavy duty vehicles using
upgraded biogas as a fuel
Senior adviser Morten Winther
UNI
VERSITET
AARHUS UNIVERSITY
DEPARTMENT OF ENVIRONMENTAL SCIENCE
Introduction
− The project “Biogas for transport - resources, environment
and welfare economics” is carried out at DCE from 20142016 (Jensen et al., 2015)
− The project is an internal project under the Science
Program for Sustainable Energy and Environment
Internal DCE seminar 2015
20 October 2015
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
Introduction
› The project examines the following questions:
› Is potential biogas production sufficient to fulfil the transport
energy demand in a future perspective. What are the
emission consequences, and health related and social costs
› Important to understand, in order to create a qualified basis
for prioritisation of biogas resources
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20 October 2015
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
Disposition
− This presentation explains the work made so far in WP3 and
4, dealing with fuel and emission estimates in the project
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20 October 2015
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
Disposition
− Fuel consumption for trucks and buses in a diesel reference
scenario up to 2035
− Some notes on CNG (Compressed Natural Gas) and LNG
(Liquefied Natural Gas) vehicles in a biogas scenario
− CH4 emission sources critical for CNG/LNG vehicles
− Calculated GHG (Greenhouse Gas) emission savings in 2035
− Some conclusions
Internal DCE seminar 2015
20 October 2015
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
Diesel reference scenario
− HDV’s are grouped into rigid trucks, trucktrailers, articulated trucks and buses
− FC = Nveh x Milann (km) x EFC (MJ/km)
− Fleet, mileage and speed data: DTU
Transport and Danish Road Directorate
− Fuel factors also split into e.g. EU emission
legislation levels: Conv. and Euro I-VI
Type/size
RT 3,5 - 7,5t
RT 7,5 - 12t
RT 12 - 14 t
RT 14 - 20t
RT 20 - 26t
RT 26 - 28t
RT 28 - 32t
RT >32t
TT/AT 28 - 34t
TT/AT 34 - 40t
TT/AT 40 - 50t
TT/AT 50 - 60t
TT/AT >60t
Urban Buses <15t
Urban Buses 15 - 18t
Urban Buses >18t
Coaches <15t
Coaches 15 - 18t
Coaches >18t
RT: rigid trucks
TT/AT: Truck-trailers, artic. trucks
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
− Euro VI enters the fleet and old emission technologies are phased out
− Euro VI dominates fuel totals; 81 %, 95 %, 99 % in 2020, 2025 and 2030,
20 October 2015
Internal DCE seminar 2015
respectively
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
Euro VI in closer details
− Euro VI vehicles are relevant for
natural gas substitution.
− Most fuel expected for 40-50t and
34-40t trucks; 46 % and 21 %,
respectively (note the axis scaling!).
− 2035: 45 PJ diesel in total. A full
substitution requires 51 PJ of natural
gas
Internal DCE seminar 2015
20 October 2015
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
CNG vehicles – short description
− CNG: Compressed Natural Gas
− On board storage: Pressure bottles (200-260 bar)
− SI (spark ignition) engine, operates similarly to a gasoline engine
− Euro VI, equipped with a three-way catalyst
− CNG has smaller km range between fuel stops compared to diesel
Internal DCE seminar 2015
20 October 2015
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
CNG vehicles – short description
− CNG fuel economy vs diesel: Big variations.
− An average of 19 % more MJ/km was found in recent national work1
1COWI/Energistyrelsen: Framework conditions for using
natural gas in heavy duty road transport, 150 pp., December
2014 (in Danish: Rammevilkår for gas til tung vejtransport)
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20 October 2015
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
CNG vehicles – short description
− NOx and PM (Particulate Matter): No significant emission differences
between natural gas and diesel Euro VI, based on the limited
measurement data assessed so far1
1COWI/Energistyrelsen: Framework conditions for using
natural gas in heavy duty road transport, 150 pp., December
2014 (in Danish: Rammevilkår for gas til tung vejtransport)
Internal DCE seminar 2015
20 October 2015
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
CNG vehicles – substitution
− CNG Substitution is made for rigid trucks
 Demand for long range is less critical for smaller trucks
 Some CNG trucks already for sale in Denmark (up to 320 hp)1, a good precondition
1www.gasbiler.info: Natural gas fueled vehicles for sale in
Denmark, Danish Gas Technology Centre
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20 October 2015
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
LNG vehicles – short description
− LNG: Liquefied Natural Gas
− On board storage: Vacuum insulated storage tanks (3-10 bar, -160 oC)
− Dual fuel engine (using 5 % diesel to pilot ignition); operates similarly to a
diesel engine
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20 October 2015
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
LNG vehicles – short description
− Emission performance similar to Euro VI, equipped with SCR and DPF
− Longer km range than CNG, due to more fuel stored
− Fuel economy: Same drawback as for CNG, compared to diesel (ICCT,
2015)
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20 October 2015
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
LNG vehicles – substitution
− LNG substitution for large trucks (TT/AT trucks)
− LNG fulfills demand for longer km range by large trucks
− Suitable engine capacities already on the market in e.g. the US
− EU directive 2014/94 places on member countries to establish LNG
fueling stations along main arterial roads by 2025
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20 October 2015
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
CH4 loss from CNG/LNG vehicles1
− CNG sources:
− CH4 from exhaust (tail pipe)
− CH4 from the crankcase (So-called ”blow by emissions”, leaks
between piston rings and cylinder walls, vented to the atmosphere)
1Delgado, O., Muncrief, R.: Assessment of heavy-duty natural gas
vehicle emissions: Implications and policy recommendations,
The International Council on Clean Transportation (ICCT), White
Paper, 34 pp., July 2015
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20 October 2015
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
CH4 loss from CNG/LNG vehicles1
− LNG sources:
− CH4 from exhaust (tail pipe)
− CH4 from dynamic venting in the fuel injection system
− CH4 from the fuel tank (”boil off” pressure release for safety reasons)
1Delgado, O., Muncrief, R.: Assessment of heavy-duty natural gas
vehicle emissions: Implications and policy recommendations,
The International Council on Clean Transportation (ICCT), White
Paper, 34 pp., July 2015
Internal DCE seminar 2015
20 October 2015
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AARHUS UNIVERSITY
DEPARTMENT OF ENVIRONMENTAL SCIENCE
CH4 loss from the fueling station1
− CNG fueling stations
 CH4 leaks from pipes and fittings
 CH4 escape during nozzle connection and disconnection
 Compressor loss
− LNG fueling stations
 Methane boil-off in storage tanks
 Manual venting of vehicle fuel tanks prior to refueling
 Spills and escape during nozzle connection/disconnection
1Delgado, O., Muncrief, R.: Assessment of heavy-duty natural gas
vehicle emissions: Implications and policy recommendations,
The International Council on Clean Transportation (ICCT), White
Paper, 34 pp., July 2015
Internal DCE seminar 2015
20 October 2015
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AARHUS UNIVERSITY
DEPARTMENT OF ENVIRONMENTAL SCIENCE
− Calculation for 2035: All heavy duty Euro VI vehicles use CNG/LNG
− Tank-to-wheel greenhouse gas emissions:
 For low/high CH4 loss, estimates range between 12 - 22 % of diesel reference case
 CO2 originates from the ”5 %” diesel pilot fuel
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
− Pump-to-wheel greenhouse gas emissions:
 Using low/high CH4 loss, estimates range between 14-25 % of diesel reference case
 CO2 originates from the ”5 %” diesel pilot fuel
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AARHUS UNIVERSITY
DEPARTMENT OF ENVIRONMENTAL SCIENCE
Conclusions
− For CNG/LNG vehicles there a several emission sources of CH4, on board
the vehicles as well as at the gas fueling station
− NOx and PM (Particulate Matter): The (scarce) literature data reveals no
significant emission differences between natural gas and diesel vehicles for
Euro VI
Internal DCE seminar 2015
20 October 2015
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AARHUS UNIVERSITY
DEPARTMENT OF ENVIRONMENTAL SCIENCE
Conclusions
− Estimated tank-to-wheel GHG emissions from CNG/LNG vehicles are in the
range of 12-22 %, of the diesel reference case
− Including fueling station losses of CH4, estimated ”pump-to-wheel”
emissions increase to 14-25 % compared to diesel
Internal DCE seminar 2015
20 October 2015
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
Conclusions
− Additional CH4 loss is expected during the production of biogas and during
distribution
− On the other hand, the CH4 emission savings from manure will be very big
− Both sources are being assessed in the current project; no results yet.
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20 October 2015
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
Thank you for your attention!
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DEPARTMENT OF ENVIRONMENTAL SCIENCE
Summary of CH4 loss
− Conclusions from ICCT (2015) survey:
 CH4 from exhaust is the same for CNG and LNG
 CNG crankcase ~ LNG dynamic venting + fuel tank venting
 Fueling station loss, CNG ~ LNG
CH4 loss (% of fuel delivered)
Pump-to-tank
Tank-to-wheel
Total Pump-to-Wheel
Source: ICCT (2015)
Fueling station
Exhaust
Crankcase ~ dynamic
venting/tank boil off
low estimate high estimate
0,3
0,3
0,1
0,9
0,4
0,8
Internal DCE seminar 2015
0,8
2,0
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AARHUS UNIVERSITY
DEPARTMENT OF ENVIRONMENTAL SCIENCE
Introduction
− For overview’s sake, the project consist of 8 WP’s:
› WP1, WP2: Biomass resources and potential biogas production (Jørgensen,
Møller)
› WP3: Future energy demand of the transport sector with a focus on road
transport heavy duty vehicles (HDV); (Jensen)
› WP4: Energy consumption and emissions of different HDV’s powered by
upgraded biogas (Winther)
› WP5: Health-related external costs of air pollution (Brandt)
› WP6, WP7: Life-cycle Analysis and Cost-Benefit Analysis (Thomsen, Cong)
› WP8: Stakeholder involvement and dissemination of results (Jensen)
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20 October 2015
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