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GTL v LNG/CNG for transport applications
We are in a golden age for natural gas – should we convert it to
synthetic diesel or should we make it into LNG, ship to the EU and inject
it into gas networks. We can then make CNG and run vehicles on that.
Which is the best in CO2 terms?
2
GTL v CNG for transport• For any transport fuel the key measure is how many g of
CO2 emitted per km of travel by the vehicle– Taking into account CO2 emitted from making the fuel
• For a natural gas fuel, the CO2 emitted is at all points from ‘well to wheel’ and must also include the impact of any methane losses (21 times the global warming impact of CO2)
• So, need to look at all the CO2 and methane losses associated with GTL and CNG from the wellhead (natural) gas to the burner in the engine, taking account also of the fuel efficiency of the engine
• GTL is burnt in a compression ignition (CI) diesel engine, CNG in new purpose designed spark ignition (SI) engine.
Comparison is between 2009 models of the Passat- diesel and CNG
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• GTL well head to tank:– Energy use of around 30-40% (see next slide)– Lets take 35%– Plus a further 5% to transport the GTL to EU and blend with
diesel (it is not sold direct as 100% GTL as there is no distribution channel)
Well-head to Tank (GTL)
4
Energy Efficiency of the GTL Production Process
Natural gas input100 Btu
Fuel Losses 23 Btu
GTL Product60 Btu
Water 17 Btu
Energy Efficiency : 60%
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• LNG well head to tank:– Energy use of 10% from well head into the high pressure gas
network– Energy use for Transmission in gas network = 0.5%– Gas leakage to Medium Pressure (where filling stations are) =
0.2% = 4.6% CO2 equivalent– Compression of CNG = 3% (lower if at night time using
renewable electricity)– Total = 18.1% so 20% assumed Energy use from well head into
the high pressure gas network
Well-head to Tank (LNG)
LNG well head to tank lower if heat for regasification is provided by waste heat from
CCGTs – as at Isle of Grain
6I – P/G
Tank to Wheel CO2 emissionsVW Passat - different engine/fuel options
120
130
140
150
160
170
180
190
70 80 90 100 110 120 130 140 150
Leistung [kW]
CO
2 - E
mis
sion
en [g
/km
] (N
EFZ)
Quelle: K‐EFUP
B6 TDI 1.9 Bluemotion
B6 TDI 2.0 DPF
B6 TDI 2.0 DPF DSG6
B6 TSI 1.8 DSG7 (Prognose)
B6 TSI-CNG 1.4 DSG7)
CNG Passat = 119 g/km
Similar performance diesel Passat = 155
g/km
**
*
7
Total Well-head to Wheels
Diesel Passat gives 50% higher CO2 on a well to wheel basis than the CNG Passat. CNG is even lower if compression is done at night using renewable
energy (post 2020)
8I – P/G05.2008Seite 8
Also - Air qualityVW Passat - different engine/fuel options
For NOX and particulates, the TSI CNG is best. It is also best for CO2 even on fossil natural gas.
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• The CNG Passat can also run on 100% biomethanemade from waste:– No sustainability issues– No food issue– A great vehicle – see next slides
• Biomethane is the main 2nd Generation Biofuel that is available today
Biomethane
Biomethane offers a long term and sustainable carbon neutral option for road transportation
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The Passat CNG seems to be a fantastic vehicle…is it really available
or is it a concept car that VW are considering building?
See next slides to find out!
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Press Release – 7 Jan 09
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• engine 1.4 TSI CNGalready fulfills Euro-5
• operating mode: bivalent• performance 110 kW / 150 PS• torque 220 Nm (1.500 – 4.000 U/min)• maximum speed 210 km/h• fuel consumption 5.1 kg / 100 km• CO2-emissions 119 g/km• Range CNG/biomethane 420 km
3-underfloor gas tanks, steel135 Liter (22 kg)gasoline 400 km, 31 Liter
Passat TSI EcoFuel
820 km total operating range
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• The twincharger-technology of Volkswagen is the starting position to deliver an alternative fuel power train with very low fuel consumption and very low emissions, but very good driving performance
• The turbo lag, which is normally present in a CNG-Turbo-engine, is compensated by the mechanical compressor
• The performance of the CNG-TSI is very similar to a big bore natural aspirated engine, nevertheless the consumption and emissions are very low
TSI ® 1,4l ‐ 110 kW CNG
Advantages TSI plus CNG
DSG ® gearbox
Working with the dual clutch DSG gearbox, VW achieve additional fuel
consumption reductions and very good driver experience
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