SHELL LPG STUDYLPG as energy carrier and fuel English summary

LIQUEFIED PETROLEUM GAS

Volume of both gases in liquid state

PROPANE266:1

BUTANE228:1

Volume in gaseous state

In the past few years, Shell has produced a number of scenario studies (see below). Some have examined the passenger car and goods vehicle sectors as energy consumers, plus domestic heating of private households (Shell/BDH 2013; Shell 2014). Other Shell studies have analysed the present situation and prospects for certain energy sources and fuels, especially biofuels and natural gas (Shell 2012; Shell 2013).

One energy source which has hitherto received little attention is Liquefied Petroleum Gas (LPG). It is used in nearly all sectors of consumption, for a wide variety of applications – as a source of energy, but also as a base material for other products. In the more recent past, use and con-sumption of LPG have increased steadily. At the same time, global supply and thus availability of LPG are improving as well.

The Shell LPG study therefore deals with the current state of LPG use and LPG application tech-nologies. It also considers the question of what potential and perspectives exist for LPG, especially as an energy source. Apart from non-automotive applications, the focus is on the use of LPG in road transport, especially as an automotive fuel in passenger cars.

WHAT IS LIQUEFIED PETROLEUM GAS?

The term Liquefied Petroleum Gas (LPG)

comprises mainly the two gases propane and butane, and mixtures of the two, because of their properties and characteristics. Both gases exist in the liquid state under relatively low pressure, of less than 9 bar, at room temperature. That is why they are also known as liquefied petroleum gases. Liquefaction reduces the volume of LP gases by a factor of approximately 250 (Hempel 2007).

Propane and butane are both short-chain saturated hydrocarbons (alkanes). Propane is a molecule with three carbon and eight hydrogen atoms (C3H8). Butane consists of four carbon and ten hydrogen atoms and has two isomers, normal butane and isobutane; n-butane and isobutane share the same chemical formula (C4H10), but display different spatial arrangements of their atoms and also have different properties, for example a boiling point at –0.5°C for n-butane vs. –12.8°C for isobutane. Due to their material and combustion properties, both liquefied petroleum gases suit many possible applica-tions. When being used as a fuel in vehicles with an internal combustion engine, LPG is also called autogas.

Liquefied Petroleum Gas (LPG) should not be confused with Liquefied Natural Gas (LNG) or Compressed Natural Gas (CNG), both of which consist mainly of the natural gas methane (CH4). LNG is stored as a cryogenic liquid cooled at –161°C; CNG is kept under high pressure of at least 200 bar (Shell 2013).

SHELL LPG STUDYShell Deutschland, HamburgDr. Jörg Adolf (project lead); Dr. Christoph Balzer; Dipl.-Ing. Arndt Joedicke; Dipl.-Ing. Uwe Schabla

Prognos AG, BaselDipl.-Physiker Samuel Straßburg

OWI, AachenDip.-Soz. Michael Ehring; Winfried Koch, M.Sc.; Dr. Klaus Lucka

fka mbH, AachenDr. Bruno Gnörich; Dipl.-Ing. Markus Thoennes

PROPANE C3H8

BOILING POINT –42.1 ºC

n-BUTANE C4H10

BOILING POINT –0.5 ºC

VOLUME REDUCTION THROUGH LIQUEFACTION

iso-BUTANE C4H10

BOILING POINT –12,8 ºC

32

Other Prod. 10.4

Diesel 39.0

Petrol 19.2

Naphtha 5.7

Refinery Gas 3.4

Kerosene 6.8

Fuel Oil 13.0

LPG 2.5

Fuel

sEur

ope

2014

Top 5 LPG Producer

Top 5 LPG Consumer

USA 59.4

SAR 24.7

CHI 24.6

RUS 14.2

UAE 12.2

USA 52.8

CHI 27.6

SAR 17.6

JAP 16.9

IND 16.3WLPGA/Argus 2014

Top 5 LPG Producer

Top 5 LPG Consumer

USA 59.4

SAR 24.7

CHI 24.6

RUS 14.2

UAE 12.2

USA 52.8

CHI 27.6

SAR 17.6

JAP 16.9

IND 16.3WLPGA/Argus 2014

and additional information of commercial propane and commercial butane. ISO LPG standards are mainly meant for international trade and not specifically for product use. The American standard for Liquefied Petroleum Gases ASTM D1835 covers liquefied petroleum gases that are intended for use as domestic, commercial and industrial heating, and engine fuels (IEA/AMF 2008).

There are no global standards for gaseous fuels, only for liquid ones (WFCC 2013). However, there is a European LPG automotive fuel standard: ‘EN 589: Automotive fuels –

LPG – Requirements and test methods’. For non-automotive applications, only national product standards have hitherto been valid. Moreover, when liquefied petroleum gases are used in public gas networks, certain quality requirements for combustible gases must be fulfilled.

Product standards directly determine the com- position of liquefied petroleum gases. One way they do this is by prescribing maximum and minimum proportions of individual com- ponents, in particular respective shares of pro-pane and butane as well as the shares of the alkenes propene (C3H6) and butene (C4H8).

Emirates), China and Russia. The largest con-sumers of LPG are the USA, China and Saudi Arabia, and other mainly Asian countries such as Japan, India, Thailand and South Korea (WLPGA/Argus 2014).

Nearly half the world’s supply of LPG is con-sumed by the domestic sector, in heating and cooking. Another major customer for liquefied petroleum gases is the petrochemical industry. By contrast, the transport sector accounts for only about one-tenth of world LPG consump-tion. Main centres for LPG applications to transport are Asia and Europe.

LPG STANDARDS & REGULATIONS

Liquefied petroleum gases do not occur in pure form, neither in oil and gas production nor in refineries. They generally contain other hydrocarbons, accompanying substances and also impurities. Therefore, as for other products, there are standards and technical rules which set requirements for LPG and how to handle it.

The International Standardisation Organisation (ISO) has developed two standards for LPG: ISO 8216 contains a classification of petroleum fuels including light distillates (Part 3), whereas ISO 9162 specifies required characteristics

is also obtainable from biomass, though biogenic LPG has hitherto played no role on the market.

The largest producer of liquefied petro-

leum gases is by far the USA, at around 60 million tonnes per year. In the USA, substantial quantities of LPG are released in the extraction of unconventional natural gases. The USA are followed by the oil and gas producers of the Middle East (Saudi Arabia, United Arab

LPG: ORIGIN AND MARKETS

A fundamental feature of liquefied petroleum gases is that they are not main products, but mostly occur as by-products or joint

products in combination with other hydro-carbons (gases or liquids). They accrue from crude oil and natural gas extraction and from processing of the crude oil into petroleum products in refineries. Worldwide, around 60 % of LPG derive from crude oil and natural gas extraction and around 40 % from refinery production. Whereas refining dominates in Western Europe, gas processing is the main source of LPG in North America and in the Middle East.

Gases occurring in crude oil extraction are also known as Associated Petroleum Gas (APG). In natural gas production, liquid hydrocarbon components are often extracted together with the natural gas. These compo-nents are known as Natural Gas Liquids (NGLs). Liquefied petroleum gases are obtainable both from APGs and NGLs. NGLs are increasingly important in global oil and gas supply. They currently represent 15 % of global crude oil and 20 % of global natural gas production (IEA 2010; IEA 2014b).

The other main source of LPG is crude oil processing. Using temperature and pressure, oil refineries convert crude oil into useful oil products. LPG is one of the lightest petroleum products (light distillate), boiling off at low temperatures. Its share in the range of oil products depends on the type of the refinery; on average LPG accounts for 2.5 to 3 % of refinery output (FE 2014). In principle, LPG

EUROPEAN REFINING OUTPUT STRUCTURE 2013, IN %

TOP-5 LPG PRODUCER, mln t TOP-5 LPG CONSUMER, mln t

54

Naphtha 4.94 mb/d = 51%

Other 0.78 mb/d = 8%

LPG 1.26 mb/d = 13%

Ethane 2.71 mb/d = 28%

Total9.7 mb/d

Total9.7 mb/d

Naphtha 51%4.9 mb/d

Other 8%0.8 mb/d

LPG 13%1.3 mb/d

Ethane 28% 2.7 mb/d

IEA 2014b

1.0

2.0

3.0

4.0TUR

RUSPL

KORIND IT

THAUSA DE AUS

mln

WLP

GA

/Arg

us 2

014

LPG vehicles offered in Europe are technically bi-fuel capable, i.e. they normally run on LPG, but can also be fuelled with petrol from a smaller fuel tank. LPG systems for passenger cars, ex-works or as retrofits, are available in various technical configurations. So far, LPG systems have used LPG port injection in gaseous or sometimes liquid phase. More recently, LPG direct injection in liquid phase has entered the market; these systems use the existing petrol injectors also for LPG. Today’s LPG vehicles comply with the Euro 5 exhaust emission standard, and some even with Euro 6.

For heavy lorries, dual fuel systems based on diesel drivetrains have been developed. Dual fuel vehicles replace some of the diesel fuel with an air/LPG mixture. However, so far, they have been almost unknown in road haulage (trans aktuell 2013).

In emerging and developing economies, LPG vehicles are used for passenger and goods transport in the form of three-wheelers such as motor rickshaws and tuk-tuks (ICCT 2012). LPG is also of some importance as a

the application of LPG to rail transport and shipping is technically feasible, it has been used little (if at all) in practice. By far the most important application of LPG as a transport fuel are road transport vehicles with internal combustion engines.

There are estimated to be 16.7 million vehicles driven by LPG worldwide. Most LPG vehicles run in Europe and Asia. The main autogas fleets in the European region can be found in Turkey, Russia, Poland and Italy, while in Asia LPG vehicles are most numerous in South Korea, India and Thailand. In many of these countries, LPG cars are the most important alternative drivetrain, second to petrol and diesel cars, and ahead of e-mobility. In Turkey, the LPG consumption for road transport is even higher than the petrol consumption (IEA 2014a).

LPG vehicles are typically passenger cars. Apart from passenger cars, LPG is only used in significant volume in light commercial vehicles using powertrains similar to passenger cars. The LPG systems applied to passenger cars are all based on spark ignition engines. All

Liquefied under pressure, propane and butane are also used as propellants in spray and aerosol cans.

Finally, as an alternative to or substitute for naphtha, ethane and others, LPG can be used as a feedstock in the production of intermediate petrochemicals, such as ethylene and propylene. Intermediate petrochemicals such as olefins and aromatic hydrocarbons are used to produce all kinds of plastic and other materials. Today (2013), petrochemical industry uses approximately 1.3 million barrels of LPG per day i.e. 60 million tonnes of LPG per year. As world demand for petro-

chemicals is growing, rising demand for

LPG can be expected from the petro-

chemical industry (IEA 2013; IEA 2014b).

LPG IN TRANSPORT

After technical modifications, it is possible to use LPG (autogas) as a fuel and propellant in combustion drive systems (combustion engines and turbines). However, its suitability for use in individual means of transport varies. Though

The standards also specify certain characteris- tics such as density, vapour pressure or volatility. The aim is to assist trade in the product and facilitate the safe, technically reliable and environmentally friendly handling of LPG.

NON-AUTOMOTIVE APPLICATIONS

Liquefied petroleum gases are used in nearly all sectors of consumption, in almost all regions of the world, for a wide variety of applications. A distinction should be made between energy and non-energy (material) applications.

Apart from road transport, LPG is used as an energy source in cooking, domestic heating, hot water supply and heat generation for work pro- cesses. Flexibility of energy supply often plays a key role. As LPG is easy to store and carry, it can be deployed even at locations unconnected to public energy networks. LPG is therefore also known as a ‘mobile energy source’.

In industrialised countries, LPG plays only a subordinate role in heating and hot water for private households, while it is used for cooking primarily in the leisure sector. The situation is the opposite in many emerging and developing economies, where LPG offers an alternative to traditional biomass and open fireplaces. In these countries, LPG is widely viewed as a transition fuel pending a more

sustainable energy future (IEA 2006; World Bank 2011; UN 2015).

For non-energy purposes, liquefied petro-leum gases are used as coolants with low greenhouse and ozone depletion potential, in refrigerators and air conditioning systems.

GLOBAL DEMAND FOR PETRO- CHEMICAL FEEDSTOCK 2013

LARGEST LPG FLEETS BY COUNTRY 2013

76

6750

3250

1750

1850

725

17115520

1185

4096

12

5

WLPGA /Argus 2014, mylpg.eu 2015

574280

75324

330

207

2750

2970

1205

700

590

440

480

205

4400

33

10,089

57

20

40

60

80

100

120

JEC

201

4c

CO2 emissions per 1MJ Petrol E0 = 100

PetrolE5

PetrolE10

DieselB7

LPG

Biofuel advantage

A state of the art compact passenger car fuelled by petrol directly emits around 120 g CO2/km vs. 105 g CO2/km for an LPG vehicle, as shown in the figure on the next page. An LPG vehicle offers similar CO2 advantages in relation to mileage as in relation to energy content, because petrol and LPG vehicles operate nearly equally efficient. However, LPG vehicles offer no greenhouse gas advantages over diesel cars, as the diesel engine is much more efficient and thus over-compensates the greenhouse gas advantage of the LPG fuel.

Around 15 to 20 % of total or Well-to-Wheels greenhouse gas emissions originate from the Well-to-Tank part. As there is little difference in the Well-to-Tank emissions of LPG vs. fossil petrol and diesel fuel, LPG cars retain their advantage over petrol fuelled vehicles – 125 vs. 140 g CO2/km. LPG vehicles emit even less

However, there are some fuel-specific differences: The octane number of LPG is higher than for petrol, which can result in efficiency benefits at high engine loads. On the other hand, the additional LPG components (especially the LPG fuel tank) add weight to the vehicle which can lead to increased fuel consumption. Overall, the specific energy consumption of similar cars per kilometer (megajoule per km) is roughly the same. However, because LPG has a lower volumetric energy density, about 25 % more LPG fuel is used, in litres per 100 km, than petrol.

Diesel vehicles are up to 20 % more efficient than cars with spark-ignition engine. Only dual fuel lorries based on the diesel principle can approximate to the efficiency of a diesel lorry.

With regard to greenhouse gas emissions, a distinction must be made between direct emissions (Tank-to-Wheels) from fuel combustion, and upstream emissions from the production of the fuel (Well-to-Tank) (JEC 2014b; JEC 2014c).

In terms of direct greenhouse gas emissions, LPG generates about 10 % less CO2 per

unit of energy (1 megajoule, MJ) than

pure fossil petrol (E0) or diesel fuel (B0), due to its lower carbon content. Even when compared with petrol containing 10 % bio- ethanol (E10) or diesel with 7 % biodiesel (B7), fossil LPG shows lower direct greenhouse gas emissions per 1 megajoule (see graph above, biofuel advantage from biomass capturing CO2 while growing allocated to direct greenhouse gas emissions).

ENVIRONMENTAL BENEFITS OF AUTOGAS

For a long time, LPG was thought to have positive effects on the environmental impact of road traffic. To some extent, this view is still held. The environmental impacts of LPG fuelled passenger cars are largely determined by their energy consumption and emissions of greenhouse gases and air pollutants.

As engines for LPG vehicles are based on spark ignition engines, there is little difference in engine efficiency between LPG and petrol powertrains (DLR 2013; JEC 2014a).

low-emission fuel for industrial lift trucks (fork-lift trucks).

In many European states, the LPG infrastructure is well developed, in particular in Central and Eastern Europe. A total of around 25,000 to 30,000 filling points exists in wider Europe.

In countries with larger LPG vehicle fleets, the number of LPG vehicles per LPG filling point ranges from about one hundred to several hundred vehicles per LPG filling point. However, there are some countries, where LPG filling stations are few and far between, e.g. in Scandinavia, Austria or Switzerland.

LPG FILLING POINTS IN EUROPE

TANK-TO-WHEELS GREENHOUSE GAS EMISSIONS OF FUELS

98

0

20

40

60

80

100

120

140

0

20

40

60

80

100

120

140

Petrol E5 Petrol E10 Diesel B7Petrol DieselLPG

Tank-to-Wheels

LIQUEFIED PETROLEUM GAS

PURE FOSSIL FUELS

FOSSIL FUELS WITH BIOFUEL SHARE

Well-to-Tank

g CO2eq/km

JEC

201

4b, 2

014c

; ba

sed

on th

e N

ew E

urop

ean

Driv

ing

Cyc

le (N

EDC

)

GREENHOUSE GAS EMISSIONS OF COMPACT VEHICLES BY DRIVETRAIN

–5,000

0

5,000

10,000

15,000

20,000

20,000 40,000 60,000 80,000 100,000 120,000 140,000 160,000 180,000 200,000

Total mileage, kms

Amortisation LPG vs. Petrol

Operating costs in €

PetrolLPG

x-axis. Depending on the LPG vehicle’s annual mileage, amortisation times range from three to seven years.

At present, a new LPG compact car also requires an extra outlay of around 2,000 to 2,500 € compared to a similar petrol vehicle. A diesel car costs roughly the same as an LPG car. With fuel prices for LPG and petrol at 0.75 and 1.55 € per litre, the higher procurement costs of an LPG in comparison to a petrol car are again written off at a total of around 55,000 to 60,000 km driven.

Compared with a new diesel car, for a roughly similar procurement price and a diesel fuel price at 1.40 € per litre, LPG offers a slight energy cost advantage per kilometre. Despite the diesel engine’s greater efficiency, it is not competitive under these energy cost structures from the beginning.

The economic viability of LPG in road transport depends on the fuel price level and the

allows an approximation. It compares only the most important cost items. One is the one-off LPG retrofit cost, or the cost differential of a new LPG car vs. a reference vehicle. The other are running costs, consisting largely of fuel cost per kilometre.

A suitable vehicle to use as a reference is a C-segment or compact car like the VW Golf, which is the most common class in many European countries. Its base version’s price is around 20,000 Euro. A compact car uses 5 litre of diesel, 6.3 litre of petrol and nearly 8 litre of LPG per 100 km under real driving conditions.

A retrofit of a petrol car to LPG costs between 2,000 and 2,500 € nowadays. With LPG retail prices at 0.75 € and petrol prices at 1.55 € per litre, the retrofitting costs are written off after just under a total of 60,000 km on the road; here LPG and petrol vehicle operating cost curves (including retrofit expenses) intersect each other and the amortisation curve crosses the

In summary, regarding energy and the environ-ment, LPG vehicles offer two advantages: LPG vehicles may help to diversify the energy mix in road transport and LPG will reduce greenhouse gas emissions of road transport, if LPG vehicles replace petrol cars.

OPERATING COST OF AUTOGAS VEHICLES

An important criterion, though not the only one, for retrofitting a petrol car or buying a new car powered by LPG is an economic advantage over similar reference vehicles. The cost-effectiveness of LPG vehicles depends on the added costs of LPG engineering, on engine efficiency, fuel prices, and vehicle mileage (Wietschel et al. 2013, ADAC 2015).

A total cost of ownership analysis can help to calculate the economic advantage of a vehicle engine type. However, often a simplified ownership or operating cost comparison

greenhouse gas per kilometre than a petrol vehicle operated with E10. In total, an LPG vehicle still emits slightly more greenhouse gas per km than a more efficient diesel vehicle (100 g CO2/km).

With regard to local air quality, burning LPG (without exhaust cleaning technology) in principle generates fewer air pollutants than liquid fuels. In addition, stricter exhaust emission standards have been implemented. Exhaust gas cleaning systems for vehicles have become much more advanced and diesel and petrol fuels have been reformulated to burn cleaner.

Hence LPG vehicles in road transport offer hardly any advantages in terms of air pollutant emissions when compared to new state of the art petrol and diesel cars. Only the particulate emissions are significantly lower for LPG than for liquid fuels if no particulate trap is applied.

ECONOMICS OF AN LPG VEHICLE RETROFIT

10 11

–30

–20

–10

0

10

20

30

40

50

–250

–200

–150

–100

–50

0

50

100petajoule (PJ) thsd t CO2

2014 2030 Pro LPG

2030 Contra LPG

2014 2030 Pro LPG

2030 Contra LPG

CO2-REDUCTION: WtT TtW WtWLPG SUBSTITUTION OF DIESEL PETROL

0

20

40

60

80

100

120

0.0

0.2

0.4

0.6

0.8

1.0

1.2

2014 2030 Pro LPG

2030 Contra LPG

2014 2030 Pro LPG

2030 Contra LPG

NEW REGISTRATIONS & RETROFITS FLEET

thsd vehicles mln vehiclesData 2014: KBA 2015

possible repercussions on the sustainability of car transport in Germany, measured in terms of energy consumption and greenhouse gas emissions, can be explored. Based on the trend scenario for auto-mobility in Germany of the 26th Shell Passenger Car Study (Shell 2014), two mini-scenarios were considered up to 2030: a Pro LPG and a Contra LPG Scenario.

In the Pro LPG Scenario, supported by an LPG-favourable economic and fiscal environ-ment, it is possible to double the stock of LPG cars to over a million vehicles by 2030, in particular through increasing the number of LPG vehicles entering the LPG fleet to more than 100,000 per year. By 2030, LPG would replace 40 petajoules or 1.3 billion litres of petrol equivalent of petrol and diesel. Annual Well-to-Wheels greenhouse gas emissions would be reduced by around 250,000 tonnes.

In the Contra LPG Scenario, the economic situation for LPG worsens significantly. This brings LPG retrofits and new registrations down to almost zero by 2020. As a result, the stock of LPG vehicles would be almost halved, to just 250,000 by 2030. Largely due to the high age of the vehicles and correspondingly lower LPG mileage, the savings of greenhouse gas from LPG vehicles compared with petrol and diesel cars would be reduced substantially.

Thus, LPG vehicles can contribute to the diversi-fication of fuel supplies and to the reduction of greenhouse gas emissions of passenger car transport. Nevertheless, to achieve a substantial impact, the stock of LPG cars would have to grow considerably, even beyond the Pro LPG Scenario.

relative fuel prices. With lower petrol and diesel prices, running an LPG vehicle becomes less attractive and vice versa. A further key factor for the economic attractiveness of LPG is the national energy tax on transport fuels; throughout Europe, there is a wide range of energy tax rates on road transport fuels. Often governments grant energy tax relief for LPG as a fuel. Mostly, some economic incentive such as an LPG tax rebate remains necessary to sustain a critical mass of LPG vehicles and LPG fuelling infrastructure (WLPGA 2014).

AUTOGAS SCENARIOS (FOR GERMANY)

After a sharp upturn in the past decade, the German LPG passenger car fleet has grown from approximately 20,000 units in 2005 to 500,000 vehicles today. With a share of 1.1 % in the German passenger car fleet of more than 44 million, LPG vehicles are the most important alternative drivetrain to petrol and diesel cars. In fact, Germany owns one of Europe’s largest LPG fleets. However, the number of licensed LPG cars in Germany has recently recorded a slight decline.

95 % of German LPG car registrations are private. Most are converted petrol vehicles. In the frequency distribution according to vehicle age, cars of ‘middle age’ predominate the LPG fleet. With an average age of just under ten years, the LPG vehicle fleet is therefore rather older than the fleet of cars as a whole (approximately nine years on average).

With a cohort model of passenger cars and scenario technique, future development paths for LPG vehicles in the German car fleet and

LPG VEHICLES: RETROFITS, NEW REGISTRATIONS AND FLEET

LPG: FUEL SUBSTITUTION AND GREENHOUSE GAS SAVINGS

1312

Liquefied petroleum gas (LPG) belongs to the family of hydrocarbons and consists mainly of the two gases propane and butane, which are easy to liquefy. Liquefied petroleum gases occur in crude oil and natural gas extraction and are produced in refineries during crude oil processing. LPG has versatile applications in all sectors of consumption and is used in nearly every area of daily life today.

LPG is used for non-energy or material purposes: as a propellant or coolant, or as a feedstock in the petrochemical industry. LPG often offers technical, ecological or economic advantages over alternative substances.

As an energy source, LPG has flexible applications and offers emission advantages over liquid and solid energy sources. In many emerging and developing economies, LPG is a transition fuel on the way to a more sustainable energy future.

In road transport, LPG cars are the most prevalent alternative type of drivetrain second only to petrol- and diesel-engined vehicles in many countries. Most of the LPG vehicles are retrofitted petrol vehicles. New LPG vehicles represent the latest state of the automotive art.

LPG can help to diversify the energy mix of road transport and reduce its greenhouse gas emissions. In leading LPG mobility markets, LPG cars offer an economic advantage over petrol-powered vehicles.

LITERATURE

SUMMARY AND CONCLUSIONS

ADAC 2015: ADAC Fahrzeugtechnik, Autokosten – Berechnungsgrundlagen für die standardisierte Kostenberechnung, München 2015.

DLR 2013: Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Institut für Verkehrsforschung, CNG und LPG – Potenziale dieser Energieträger auf dem Weg zu einer nachhaltigeren Energieversorgung des Straßenverkehrs, Berlin u.a.O. 2013.

FE 2014: Fuels Europe (FE), Statistical Report 2014, Brus-sels 2014.

Hempel 2007: Peter Hempel, Flüssiggas. Mobiler, umwelt-schonender Energieträger für Haushalt, Freizeit und Ge-werbe, München 2007.

ICCT 2012: International Council on Clean Transportation (ICCT), A Technical Assessment of Emissions and Fuel Consumption Reduction Potential from Two and Three Wheelers in India, Washington 2012.

IEA 2006: International Energy Agency (IEA), World Energy Outlook 2006, Paris 2006.

IEA 2010: International Energy Agency (IEA), Natural Gas Liquids. Supply Outlook 2008-2015, Paris 2010.

IEA 2013: International Energy Agency (IEA), World Energy Outlook 2013, Paris 2013.

IEA 2014a: International Energy Agency (IEA), Oil Information 2014, Paris 2014.

IEA 2014b: International Energy Agency (IEA), World Energy Outlook 2014, Paris 2014.

IEA/AMF 2008: International Energy Agency/Advanced Motor Fuel Implementing Agreement (IEA/AMF), Out-look on standardization of Alternative Vehicle Fuels. Global, regional and national level. Annex XXVIII. Sub task Report, Stockholm 2008; http://www.iea-amf.org/content/fuel_information/lpg.

JEC 2014a: Joint Research Centre-EUCAR-Concawe collabo-ration (JEC), Well-to-Wheels Analysis of Future Automoti-ve Fuels and Powertrains in the European Context. Well-to-Wheels Report, Version 4.a, Luxemburg 2014.

JEC 2014b: Joint Research Centre-EUCAR-Concawe collabo-ration (JEC), Well-to-Tank Appendix 2. Summary of WTW Energy and GHG balances, Version 4.a, Luxem-burg 2014.

JEC 2014c: Joint Research Centre-EUCAR-Concawe collabo-ration (JEC), Well-to-Tank Appendix 1. Conversion fac-tors and fuel properties, Version 4.a, Luxemburg 2014.

KBA 2015: Kraftfahrt-Bundesamt (KBA), Individualaus-wertung „Autogas-Pkw“ des Bestands an M1-Fahr-zeugen nach Segmenten, Kraftstoff-Code, Merkmal privat/gewerblich und CO2-Angaben für den Stichtag 01.01.2014, Flensburg 2015.

Shell 2010: Shell Lkw-Studie. Fakten, Trends und Perspektiven im Straßengüterverkehr bis 2030, Hamburg 2010.

Shell 2012: After Super E10 – What role for biofuels?, Hamburg 2012.

Shell 2013: Natural Gas – A bridging technology for future mobility?, Hamburg 2013.

Shell 2014: Shell PKW-Szenarien bis 2040. Fakten, Trends und Perspektiven für Auto-Mobilität, Hamburg 2014.

Shell/BDH 2013: Shell/Bundesindustrieverband Deutsch-land Haus-, Energie- und Umwelttechnik e.V., Klima-schutz im Wohnungssektor – wie heizen wir morgen? Fakten, Trends und Perspektiven für Heiztechniken bis 2030 Hamburg 2013.

trans aktuell 2013: Die Diesel-Alternative, trans aktuell, 1.-19. Dezember 2013, S. 13.

UN 2015: United Nations (UN), Sustainable Energy for All Initiative of the United Nations, www.se4all.org.

WFCC 2013: World Fuels Charter Committee (WFCC), World Fuels Charter. 5th edition, 2013.

Wietschel et al. 2013: Patrick Plötz, Till Gnann, André Kühn, Martin Wietschel, Markthochlaufszenarien für Elektrofahrzeuge. Langfassung, Fraunhofer ISI, Kar-lsruhe 2013.

WLPGA 2014: World LP Gas Association (WLPGA), Au-togas Incentive Policies. A country-by-country analy-sis of why and how governments encourage Auto-gas and what works. Update 2014, Neuilly-sur-Seine 2014.

WLPGA/Argus 2014: World LP Gas Association (WLPGA)/Argus, Statistical Review of Global LP Gas 2014, London/Neuilly-sur-Seine 2014.

World Bank 2011: World Bank, The Role of Liquefied Petroleum Gas in Reducing Energy Poverty, Washington 2011.

14 15

Published 2015 by Shell Deutschland Oil GmbH

22284 Hamburg

The full edition of the Shell LPG Study is

available in German language.

Please send an e-mail to: shellpresse@shell.com