NGVA Europe Position Paper on LNG

Head Office Brussels Office Tel: +34 91 325 2836

Av. de Aragn 402 Av. de Cortenbergh 172 www.ngvaeurope.eu

ES - 28022 Madrid B - 1000 Brussels [email protected]

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January 2013

Position Paper: LNG, a Sustainable Fuel for all

Transport Modes

NGVA Europe

A Position Paper of NGVA Europe prepared by:

Dr. Antonio Nicotra, General Manager Gasfin Investment S.A., Managing Director Air-

LNG GmbH

Table of Contents 1. Scope of the Position Paper ............................................................................................................ 2

2. Definitions & Characteristics ........................................................................................................... 2

3. Why LNG ? ....................................................................................................................................... 3

3.1 Because it is compact: ............................................................................................................. 3

3.2 Because it is clean & safe: ....................................................................................................... 3

3.3 Because it is economic: ........................................................................................................... 4

3.4 Because it is (becoming) available at petrol filling stations: ................................................... 5

4. Brief History of LNG ......................................................................................................................... 5

5. LNG Technology, Supply Chain & Markets Safety & Security....................................................... 6

6. LNG Business Scope and boil-off//venting management ............................................................ 8

7. LNG Design Standards ..................................................................................................................... 9

8. LNG Quality Standards .................................................................................................................. 11

8.1 Standards for Heat & Power Pipeline Applications ............................................................ 11

8.2 Standards for NGV Internal Combustion Engines Mobile Applications ............................. 13

LD NGVs - UNECE R83 ........................................................................................................... 15

HD NGVs - UNECE R49 .......................................................................................................... 15

Correlation between NGV Test Reference Gases and LNG/Gas Market Fuel

Specifications ............................................................................................................................... 17

9. GHG Emissions from LNG - Carbon Footprint on Life Cycle Assessment ...................................... 18




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1. SCOPE OF THE POSITION PAPER

The scope of this Position Paper is to provide relevant information on Liquefied Natural Gas

(LNG) as most sustainable fuel for mobility for all kind of transport vehicles (by land, water

and air), describing its characteristics & quality standards (depending on its sourcing from

fossil natural-gas or renewable bio-gas), its production technologies & safety aspects, trading

availability & prices, distribution and application technologies & efficiencies, its

environmental impact on GHG emissions & carbon footprint on Life Cycle Assessment, as

fuel for mobile internal combustion engines (PISI/DISI, DICI, jet-engines & gasturbines).

NGVA Europes Position Paper aims at remaining objective and concise, without specific

references to business operators.

2. DEFINITIONS & CHARACTERISTICS

LNG is Natural Gas that has been cooled and cryogenically condensed to a liquid form at

nearly atmospheric pressure and a temperature of about - 162C.

LNG is generically produced from fossil gas sources; should renewable bio-gas sources be

utilized the relevant liquid gas is called LBG or LBM or bio-LNG (Liquid-Bio-Gas or Liquid-Bio-

Methane).

LNG composition when produced from fossil gas sources varies and typically contains

between 81-99% of methane (C1), 0-13% of ethane (C2), 0-4% of propane (C3), 0-1% of

heavier hydrocarbons gas (C3+) and 0-1% of nitrogen (N2); sulphur & mercury compounds

and carbon dioxide & water must be entirely removed to avoid damaging the liquefaction

process. Liquid-Bio-Gas (after treatment) is >97% methane with minimal N2 residues.

LNG may be defined Lean-LNG when it has a methane-content >95%, or Rich-LNG when

methane is 89%, C2+ 8%, Inert




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by the wide tolerance of the European grid requirements (45-54 for H-Gas, 39-44 for L-Gas);

the generally high WI of LNG vapours is usually and more economically reduced by adding N2

instead of removing C2+ .

The Methane Number (MN) of a gas indicates its knocking resistance. A MN of 80 means that

the gas anti-knocking behaviour is the same as a mixture of 80% methane with 20 %

Hydrogen (anti-detonation: correlated to gasoline MON & RON: example: MN of 60 to 100

[from L-gas to CH4100%] gives a MON of 113-140.

LNG is colourless, odourless, non-corrosive and non-toxic; its direct contact with human body

parts will cause severe cold-burns and the inhalation of its vapours may cause suffocation

due to oxygen displacement.

LNG, as such, cannot burn nor explode: its gas vapours have a flammability range between 5-

15% volume concentration in air at >540 C auto-ignition temperature; below this

temperature & within this range, an ignition source is needed for LNG gas vapours to burn or

explode in confined places.

The combustion of LNG gas vapours release the cleanest exhaust gas with the lowest

CO2/GHG emissions of all combustion fuels (including hydrogen and electricity on Life Cycle

basis); exhaust gases from LNG vapours do not contain measurable quantities of PM or SOx

and release about 85% less NOx and 25% less CO2 than oil derivate fuels (emissions HCs

depend on the engine technology/efficiency). LNG gas vapours are cleaner than pipeline-

CNG and bio-methane from bio-gas provides the best quality. The Carbon Footprint Life Cycle

Assessment of LNG and LBG provide best performances compared to any other fossil-fuel or

bio-fuel.

3. WHY LNG ?

3.1 Because it is compact:

1 m3 of LNG corresponds to about 600

m3 of gas (Standard state), 3 m3 of CNG

at 200bar and 0.65 m3 of oil (energy

equivalence),

1 Kg of LNG has the energy content of

1.14 Kg diesel-oil and 1.12 Kg gasoline,

In volume: 1L of LNG has the same

energy density as 0.6 L of diesel-oil,

0.7 L of gasoline, and 3.1 L of CNG.

3.2 Because it is clean & safe:

LNG density (0.42-0.48 Kg/L) is lower than water (1 Kg/L), and its vapour density (0.7-0.8) is

lower than air (1); it does not mix nor sink in water, therefore not polluting it, and it rapidly

disperses into high atmosphere, reducing the risk of flame-injection. If inhaled, gas vapours

are non-carcinogenic & non-toxic, however they may suffocate due to oxygen displacement;

direct human body contact with extreme low temperature of LNG causes severe cold-burns.




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The combustion of LNG gas vapours

releases the lowest emissions of CO2

because LNG contains the highest

concentration of methane (C:H4), having the

highest C:H ratio, compared to any other

hydrocarbon (C:H3, C:H2, C:H, ratios); this

condition requires to feed a higher specific

amount of combustion-oxygen, determining

a higher specific amount of water in the

exhaust gases.

The presence of more water has a beneficial

effect in quenching the combustion

temperatures, reducing NOx emissions.

Uncontrolled LNG vapours dispersed into

the atmosphere have a GHG effect 21-25

times more detrimental than CO2 (according

to IPCC 100-year cycle, and it is 72 times

more detrimental than CO2 over a 20-year

period); it requires the industry to maximize

its efforts to avoid uncontrolled release of

vaporized LNG into the atmosphere (LNG

venting).

3.3 Because it is economic:

The modern LNG industry is still relatively young and constantly achieving cost reductions

(also related to economy of scale in sizes and volumes) while the oil refining industry is facing

cost increases due to the reducing availability & quality of oil feedstock and to the more

sophisticated refining procedures needed to fulfil more severe requirements of oil-products

specifications.

As a result of this trend, LNG prices have moved away from oil parity in the early 2000s, to

currently being below 50% of oil prices in Europe, while the economic recovery of shale gas

in the US has dropped their gas prices below 20% of oil, stopping LNG imports into the US

and favouring LNG exports.




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3.4 Because it is (becoming) available at petrol filling stations:

LNG was first developed as buffer-storage of peak-shaving power units, to liquefy and

store natural gas during off-times, to be re-gasified for peak demand that could not be met

by pipeline volume capacity; these units are small/mid-size with about 1-2t/h capacity (1400-

2800 Sm3/h) and about 20,000m3 storage tank.

Subsequently, the LNG technology has been

used to compact gas to its minimal volume for

more economic transportation over long

distances, because less energy (and consequent

less GHG emissions) is needed to liquefy gas and

transport it liquid over long distances, instead of

repeatedly re-compressing the gas for pipeline

transmission over thousands of kilometres; for

this application plant sizes grew to large single-

trains of 500-1000t/h, storage tanks of 120,000-

180,000m3 and ships of 120,000-266,000m3.

Ultimately, the LNG technology is returning to small and very-small size units to allow natural

gas to be conveniently and efficiently used also for all mobile applications, where a gas

pipeline-network is not available and where the necessity to carry the fuel tank on-board the

vehicle requires the fuel-tanks system to be compact, light, efficient and safe. For mobile

applications tanks size vary from 60-600L (car/truck) to 3,000-9,000L (train/ship/aircrafts),

25-50m3/120m3 (road/rail tanker). LNG refuelling at the dispenser station is becoming user-

friendly as for petrol.

4. BRIEF HISTORY OF LNG

Natural gas liquefaction dates back to the 19th century when British chemist and physicist

Michael Faraday experimented with liquefying different types of gases, including natural

gas. German engineer Karl von Linde built the first practical compressor refrigeration

machine in Munich in 1873.

The first LNG plant was built in West Virginia in 1912 and began operation in 1917. The

first commercial liquefaction plant was built in Cleveland, Ohio in 1941; LNG was stored

in atmospheric pressure tanks. The liquefaction of natural gas raised the possibility of its

transportation to distant destinations.

In January 1959, the world's first LNG tanker, the Methane Pioneer (a converted World

War ll liberty freighter containing five 7,000 barrel equivalent aluminium prismatic tanks

with balsa wood supports and insulation of plywood/urethane) carried an LNG cargo

from Lake Charles, Louisiana to Canvey Island, United Kingdom. This event demonstrated

that large quantities of liquefied natural gas could be transported safely across the ocean.

Over the next 14 months, seven additional cargoes were delivered with only minor

problems. Subsequently, the British Gas Council proceeded with plans to implement a

commercial project to import LNG from Venezuela. However, before the commercial

agreements were finalized, large quantities of natural gas were discovered in Libya and




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in the gigantic Hassi R' Mel field in Algeria, which are only half the distance to England as

Venezuela.

In 1964, with the start-up of the 1st 0.9 bcm (billion cubic meters per year) Arzew GL4Z

plant, Algeria became the world's first LNG exporter and the United Kingdom the first

LNG importer. Since then Algeria has become a major world supplier of natural gas as

LNG to Europe and worldwide. In 1969 the US started exporting LNG from Alaska to

Japan.

In 1970 the Libyan/Marsa El Brega plant started exporting; in 1972 the Brunei/Lumut

plant, followed in 1977 by the Indonesian/Botang A and UAE/Das Island plants, in 1983

the Malaysian/Bintulu plant and in 1989 by Australian/Karratha plant; Qatar started

exporting in 1996, Trinidad-Tobago and Nigeria in 1999, followed by Oman 2000, Egypt

2004, Equatorial Guinea & Norway 2007, Yemen 2008, Russia/ Sakhalin 2009. With

capacity expanding from 42 to 77 Mtpy (million tons per year), Qatar is the world largest

LNG exporter today.

Over a period of 40 years, from 1960 to 2000, the LNG industry steadily grew from zero

to a global supply of 100,000 Mtpy, primarily as project-financing of point-to-point

delivery contracts (from liquefaction plant to regasification plant) for injection into the

national gas grids and main use for heat & power. Additional capacity of 100,000 Mtpy

has entered into operation in the last 10 years.

Until the early 2000s, natural gas was trading at prices comparable to oil (oil-parity).

Since 2003, oil has moved up and away from the previous levels of 20-30 $/barrel (bl), with

nervous fluctuations related to global economy & politics, with peaks & trends over $100-

140/bl.

On the contrary, in the last 10 year, LNG and gas prices showed moderate seasonal

fluctuations in ranges corresponding to $40-50/bl of oil equivalent in Europe and $15-25/bl

of oil equivalent in the US. These values may be assumed as industry bench-mark prices for

LNG imports and exports.

In the last 40 years, the demand-supply of LNG has constantly doubled (1980=25Mtpy,

1990=50Mtpy, 2000=100Mtpy, 2010=200Mtpy), and it is expected that it will double

again between 2010 and 2020, because of the significant price advantages compared to

oil, combined with environmental advantages.

LNG price & cleanness, combined with compactness and efficiency, raised the interest

for using LNG also as fuel for transports with dedicated and dual-fuel engine

technologies: in 2000 the Glutra (a Norvegian ferry) was the 1st ship propelled with LNG;

already in the mid-1990s busses and heavy duty (HD) trucks were converted to use LNG

in California; while even before, in 1989, the Russian Tupolev cryogenic TU155 aircrafts

made several commercial flights also to Europe, using LNG as fuel.

5. LNG TECHNOLOGY, SUPPLY CHAIN & MARKETS SAFETY & SECURITY

A good description of the LNG world industry, trade routes & contracts, exports sources &

imports terminals, quantities & qualities is reported in the LNG Industry 2010 Report of the

GIIGNL (The International Group of LNG Importers), publically available at:




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http://www.giignl.org/fileadmin/user_upload/pdf/A_PUBLIC_INFORMATION/LNG_Industry/

GNL_2010.pdf

A good description of LNG processes & technologies along its value chain, with particular

focus on safety & security regulations, is well described in the LNG Safety and Security 2006

Report of the CEE (Centre for Energy Economics of the University of Texas at Austin), publicly

available at:

http://www.beg.utexas.edu/energyecon/lng/documents/CEE_LNG_Safety_and_Security.

pdf

Technologies related to the production of Bio-LNG (LBM/LBG) from bio-gas, transportation of

LNG by road, design, storage & handling in L-CNG satellite stations and application as fuels in

dedicated (spark-ignited) and dual-fuel (compressed ignition) engines are the business scope

of several NGVA Members.




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6. LNG BUSINESS SCOPE AND BOIL-OFF//VENTING MANAGEMENT

The liquefaction of NG has the main clear purpose of increasing the energy density of the

fuel: 36.5 MJ/M

3 (0.036 MJ/L) of gas @ standard ISO conditions of 20 C and 1 bar

7.3 MJ/L of gas @ 20 C and 200 bar

21.9 MJ/L in liquid form @ -162 C and 1 bar

In order to condense NG into a liquid, it must be cooled to approximately -162 0C at 1 bar. It

is then obvious that the isolation mechanisms are critically important to minimize the heat

exchange and dispersion losses with the environment because, inevitably and as a matter of

thermodynamics, a cryogenic fluid losing heat to the ambient modify its status in either of

the following two effects: If stored at constant volume: its inner pressure increases,

If stored at constant pressure: the cryogenic fluid boils (boil-off) and vapours have to

be released (venting).

LNG on-board storage tanks are typically designed to take LNG at higher pressures than the

ambient. Due to the inherent behaviour of LNG cryogenic vessels, the release of NG boil-off

(mainly CH4) could happen under different circumstances.

There are different systems allowing the proper functioning of the vehicle and of the

refuelling infrastructure. LNG vehicle delivery systems can be classified as follows:

- Vapour collapse system: in this system, the delivery pressure is lower than the tank maximum

working pressure. The tank is equipped with an economizer capable of drawing the vapour

phase from the tank, keeping its pressure at a constant rate. Cold LNG is usually sprayed at the

top of the tank during refuelling so as to collapse the vapour phase (if any) contained within it.

This system reduces the pressure in the tank, allowing it to be refuelled.

- Vapour return system: in this system, the delivery pressure is higher than the tank maximum

working pressure. For this, the tank is equipped with a pump that pressurizes the LNG to the

appropriate level for the engine. The pressure in the tank can therefore vary depending on the

rate the fuel being consumed. Similar spraying is done when refuelling, but total amount of

vapours contained within the tank may or may not collapse. If a significant amount of vapour is




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contained in it, the tank can be connected to the refuelling station in order to return the

vapours.

Some considerations concerning the use of LNG for mobile applications:

a) The use of LNG as fuel for mobile applications has an inherent time factor associated,

making it ideal for commercial applications (having intensive and constant use, with

limited periods of inactivities) and less attractive to private cars with occasional use and

long periods of parking time (where boil-off vapours would inevitably form and require

to be disposed).

b) The time during which a cryogenic tank can maintain the LNG content with no gas

release (venting) is known as holding time. In North America, holding time of LNG tanks

is regulated, having to be greater than 5 days, according to SAE J 2343. The same

approach is being followed within the UNECE LNG Task Force, prescription which will be

adopted in Europe per ECE R110 when and if approved.

c) Due to the above mentioned reasoning (different existing LNG delivery systems), LNG

fuelling and on-board usage systems are vent-free under normal operation of the

vehicle. The technology to prevent venting in case of low LNG consumption at the

station or on-board the vehicle is available. Vapour transfer to the station or on-board

processing of vapours reduce the tank pressure and resets the clock on holding time.

d) Nevertheless, if a cryogenic LNG tank is left unused (i.e. situation of an LNG vehicle left

parked and filled-up for a long time), it will vent sooner or later. According to technology

and the data applied by the US operator Chart Industries: when a typical 437 litre

vehicle fuel tank with relief pressure of 15,9 bar is filled to normal filling so that the initial

saturation of LNG in the tank is 8,3 bar, and the vehicle is left unused in stationary

situation, the holding time (non-venting time) is five days. Smaller initial saturation

would result in longer holding time. After this holding time, relief valve would open and

the content of the tank would be vented within 35 days at an average flow rate of 0.19

kg/hour. Different technologies applied by other LNG operators would have longer or

shorter holding times.

e) This venting behaviour could also be controlled by different systems:

Storage of the vented gas into a high pressure CNG cylinder.

Burning of the vented gas to produce CO2 and H2O.

Mandatory obligation for LNG vehicle operators to de-fuel their systems

when parking for a period longer than the given holding time.

7. LNG DESIGN STANDARDS

The LNG industry is still relatively young and it is one of the worlds safest industries: it has

consolidated its large scale technologies & operating systems (primarily for heat & power

application) during 1995-2005, and the relevant design standards have been issued and

regularly revised to improve operability/safety:

Large LNG facilities with storage capacities in excess of 200 tons (about 450 m3) are primarily

regulated by the EN 1160:1996 and EN 1473:1997 standards.




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Instead, small scale applications for mobile transports only started developments in the

1990s and, consequently, the relevant technologies & operating systems are still at

optimization development stage and appropriate design/safety standards are still in

progress:

Smaller LNG satellite plants and stations with storage capacity between 5 and 200 tons are

covered by EN 13645:2001, and more specifically regulated by national and regional

authorities.

A specific CEN standard for NGV refuelling infrastructure (pr-EN 13638:2007) was cancelled

for exceeding the permitted time for balloting. A New TC within ISO (TC 252) has been

created for working on an international standard for NGV fuelling stations. The Working

Group 1 is dealing with the CNG standard, and the Working Group 2 with the LNG & L-CNG

standards. Target date to deliver is mid-2015.

Also in progress are: CEN/TC 265 and TC 282 referring to installations of tanks and

equipment for flammable liquids including LNG, ISO/CD 12617 for LNG connectors and

ISO/CD 12614 & ISO/CD 12991 for LNG vehicles components. Additionally, the UNECE LNG

Task Force is preparing all the necessary requirements to permit the approval of LNG

systems to be installed on-board the vehicles, and to be inserted within ECE Regulation 110.

The NFPA 57 and NFPA 59A (US National Fire Protection Association) codes are in place and

applicable to LNG vehicles fuels systems, production, storage, and handling of LNG, providing

relevant recommendations with regards to safety and security aspects.

The NGVA Europe is committed to favouring the harmonization of the current national

differences with regards to LNG design standards.

Many natural gas vehicles still have typical engines designed for gasoline or diesel that have

been adapted to use natural gas; only recently engine manufacturers have started designing

engines dedicated & optimized to the use of gas.

At the same time, the distribution & refuelling equipment is being improved and optimized

to adopt user-friendly solutions similar to petrol.

These processes are still progressing and causing variations of the operating conditions and

of the relevant requirements and, consequently, the release of relevant design standards

need to refer to this evolution.




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8. LNG QUALITY STANDARDS

8.1 Standards for Heat & Power Pipeline Applications

The quality of the LNG traded worldwide (except LBG) refers to the specification of the

product shipped in bulk from the producers to the various receiving terminals. Currently, this

LNG is sold at prices in US$/MMBTU, related to its HHV (High Heating Value) and not

specifically referring to other chemical or physical specifications, on condition that the

product satisfies the Wobbe Index (WI) accepted by the gas pipeline network linked to the

relevant receiving terminal.

The typical average composition of various LNG received by different receiving terminals is

indicated in the LNG Industry 2010 Report of the GIIGNL mentioned in paragraph 5; a similar

table provided by the IGU (International Gas Union) gives typical LNG compositions as

follows:

Worldwide average LNG compositions

Nitrogen Methane Ethane Propane Higher HC

Gross/High

Heath

Value

Wobbe

Index

% % % % C4 + % MJ/Sm3 MJ/Sm3

Algeria-Arzew 0,56 87,98 9 1,99 0,47 41,68 52,62

Algeria-Bethioua

1 1,2 87,59 8,39 2,12 0,7 41,01 51,96

Algeria-Bethioua

2 0,92 91,39 7,17 0,52 0 39,78 51,41

Algeria-Skikda 1,02 91,19 7,02 0,66 0,11 39,87 51,42

Egypt-Damietta 0,08 97,7 1,8 0,22 0,2 38,39 51,03

Egypt-Idku 0 97,2 2,3 0,3 0,2 38,61 51,19

Libya 0,69 81,57 13,38 3,67 0,69 44,02 53,82

Nigeria 0,08 91,28 4,62 2,62 1,4 41,76 52,87

Abu Dhabi 0,29 84,77 13,22 1,63 0,09 42,45 53,16

Oman 0,35 87,89 7,27 2,92 1,57 42,73 53,27

Qatar 0,36 90,1 6,23 2,32 0,99 41,58 52,65

Trinidad 0,03 96,82 2,74 0,31 0,1 38,82 51,29

USA-Alaska 0,17 99,73 0,08 0,01 0 37,75 50,62

Australia-NWS 0,09 87,39 8,33 3,35 0,84 42,74 53,4

Brunei 0,05 90,61 4,97 2,89 1,48 42,09 53,06

Indonesia-Arun 0,06 91,16 6,01 1,84 0,93 41,32 52,64

Indonesia-Badak 0,02 89,76 5,06 3,54 1,62 42,61 53,34

Malaysia 0,16 91,15 4,96 2,79 0,94 41,52 52,7




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It is worth mentioning that LNG producers/distributors sell the LNG based on its Gross

Calorific/ Higher Heating Value, while users would mainly benefit from the Net

Calorific/Lower Heating Value.

The Wobbe Index (of a Gas or LNG vapours) is defined as HHV in Mega Joule per normal

cubic meter (MJ/Nm3) of the vapours divided by the square root of the vapour density

relative to air and it is regulated by ISO 13443:1996.

The figures below, prepared by the Programme Committee D.1 Study Group of the IGU

during the 2003-2006 triennium, show how widely tolerant is the EU gas network, with Japan

desiring higher ranges and UK-US preferring lower ranges.

The LNG producers adjust the quality specification of their product according to their

(tolerant) contractual obligations. A table with the specifications of all LNG traded worldwide

is reported in the LNG Industry 2010 Report of the GIIGNL publically available from their

web page (ref: prg.5).

The LNG receivers adjust/lower the high WI of LNG to gas-pipe requirements by adding

nitrogen.




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8.2 Standards for NGV Internal Combustion Engines Mobile Applications Fuels used in the internal combustion engines of vehicles need more stringent specifications

than just calorific value, to satisfy the increasingly efficient engine technologies and the constantly more demanding restrictions for the exhaust gases. All transportation fuels already have well specified standards for market fuel specifications: EN 228 for gasoline, EN 589 for LPG, EN 590 for diesel-oil, EN 14214 for FAME-methyl-ester and other relevant standards for marine and aircraft applications.

Also natural gas (including re-gasified LNG) to be used as fuel in NGVs requires more stringent conditions than just LHV and WI, also depending on the type of engine:

o The Methane Number (MN) related to knocking resistance/anti-detonation capabilities (correspondent to MON/RON indexes for gasoline) is important to PISI/DISI Otto-engines and new Dual-Fuel C.I. engines using a mixture of NG and diesel. The higher the




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value, the more efficient the engine can result, as the compression ratio could be raised without damaging the engine. Additionally, the more stable this property is, the easier for the engine design process to achieve good results.

Methane Number (MN) vs Motor Octane Number (MON)

o The Lambda Shift Factor indicates how much the Air/Fuel-ratio (lambda) will shift when any engine is operated not on pure methane, but on different gas-fuel compositions.

o The Subsonic Bievo Index is defined as the required metering area (or injector opening duration for the same Air/Fuel-ratio), compared to the 100% methane situation.

Lamba Shift Factor and Bievo Index affect A/F-ratios and engine performances

ISO 15403:2006 defines natural gas as a gas with more than 70%volume/mole of methane and a higher caloric value of 30-45 MJ/m3. EN 437 presents Wobbe ranges of Test Reference Gases. The ISO 15403 also recommends limits for moisture, dust, 3%vol for both CO2 and O2 and a H2S limit of




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LD NGVs - UNECE R83

The UNECE R83 Regulation defines the emissions standards for Light-Duty-Vehicle fuels

including NGVs. As for gasoline or diesel, the regulation defines the reference gas

specifications to be used during the testing, and which are supposed to be representative of

the different existing market qualities (G20 and G25). Those can be found in annex 10A of R83

Rev4, figure below:

HD NGVs - UNECE R49

The UNECE R49 Regulation defines the Type Approval procedure for HD engines and, as

ECE R 83, provides reference fuel specifications for heavy-duty NGVs . In order to cover the

expected variability of NG quality across Europe, the regulation presents relevant

differences/performances for gases deviating from pure methane (G-20) to specified GR -

G23 (for H-gas range) and G23 - G25 (for L-range).

HD NG engines can be approved for a wide gas quality range, similar to the light-duty range,

However, it is also allowed in R49 to specify a certain limited gas quality range, e.g. L-gas or

H-gas or even only one specific fuel composition. Earlier UN-ECE R49 specified G20 - G23 for

the H-gas range and G23 - G25 for the L-range. However, in UN-ECE R49 regulations amend-1

the G20 is replaced by GR. Todays heavy-duty NGV reference gas specification (GR, G23 and

G25) can be found in Annex 6 of R49 ammend-1, relevant data in figures below:




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Correlation between NGV Test Reference Gases and LNG/Gas Market Fuel

Specifications

The quality standard for using the LNG (gas vapour) into the various NGV combustion engines

is related to more stringent characteristics that the LNG (gas source) must possess to satisfy

the requirements indicated by the NGV regulatory standards, going beyond the simple

calorific value limitation.

The following table summarizes some critical information and provides relevant correlations:

a) Bio-methane, particularly in its liquid form (LBM: entirely eliminating CO2,

sulphur and metals), is the nearest to the G20 reference test-gas (pure

methane).

b) Typical LNG (over 95% of LNG world production) has higher grades than G23

test-gas and high grade pipeline gas, primarily because LNG contains very

little nitrogen, while G23 is generated by diluting methane with about 7.5%

nitrogen.

c) G25 test-gas is generated by adding about 14% of nitrogen to methane,

simulating the high inert contents of the low grade pipeline gas; however L-

gas has higher contents of C2, giving higher WI and lower MN/MON than

G25.

d) GR test-gas is generated by adding 13% of ethane to methane, simulating

the high C2-contents of the Rich-LNG; however Rich-LNG has higher

contents of C3+, giving higher WI and lower MN/MON than GR.

Composition TEST REFERENCE GAS

G20 G23 G25 GR

Methane C1 %mol 99.5 0.5 92.5 1 86 2 87 2

Ethane C2 %mol - - - 13 2

Balance %mol Max 1 1 1 1

N2 %mol - 7.5 1 14 2 -

S mg/kg Max 10 10 10 10

W.I. Nr (LHV) 48 0.2 44 0.5 41.5 1 48.5 0.5

MN Nr 95 - 100 82 - 85 70 - 76 70 - 78

MON Nr 137-140 128-130 120-124 120-126

Composition Typical Composition: Bio-Gas/Natural-Gas/LNG/LBM

LBM High-Gas LNG- std Low-Gas Rich-LNG

Methane C1 %mol 98 1 93 4 93 5 82 3 83 2

Ethane C2 %mol - 5 3

5.5 3 5 1

13 1

C3+ %mol Max - 2 1 3 1

N2 %mol 2 1 2 1 0.5 0.5 13 2 0.5 0.5

S mg/kg Max 3 10 3 10 3

W.I. Nr (LHV) 46 1 46.2 0.6 47.5 1 43.3 0.5 49.5 0.5

MN Nr 90 - 95 75 - 90 75 - 90 60 - 70 63 - 70

MON Nr 135-137 124-134 124-134 113-120 115-120




18

A broad-preliminary conclusion is that G23, G25 & GR reference test-gases formulations are

not really representative of the actual composition available in the gas-pipeline and LNG

markets, because the test-gases consider diluting methane with either nitrogen or ethane,

while methane in actual gases is diluted by both ethane (and C3+) and inerts (N2 and CO2),

while in LNG methane is diluted only by ethane (and some small quantities of C3+).

NGVA Europe will endeavour to contribute to EU Project Committees and Working

Documents progressing on this topic.

9. GHG EMISSIONS FROM LNG - CARBON FOOTPRINT ON LIFE CYCLE ASSESSMENT

The combustion of natural gas generates the cleanest exhaust gas and releases into the

atmosphere the lowest emissions of CO2 and GHG in general, compared to any other hydro-

carbon fuel (and also compared to hydrogen and electricity on Life Cycle basis).

LNG gas vapours are cleaner than pipeline-CNG (LNG contains less sulphur, less C2-C4

hydro-carbons & metals and less inert gases). Exhaust gases from combustion of LNG

vapours do not contain Particulates or SOx, releasing about 85% less NOx and 25% less CO2

than diesel oil or gasoline; CHx emissions depend on the engine technology and efficiency.

The table here below provides relevant comparisons on the thermodynamic characteristics

of most common hydrocarbon fuels, hydrogen and coal. In particular, it shows that the same

amount of 10kwh of (gross) power can be delivered with 15% less fuel-mass but 65% more

fuel-volume of LNG (liquid methane) compared to diesel-oil, releasing into the atmosphere

27% less CO2:

FUEL C:H

ratio

Fuels density Fuels LHV Energy densities

Gas

Kg/Sm3

Liquid

Kg/L

Mass

MJ/kg

Liquid

MJ/L

Gas

MJ/Sm3

Mass

MJ/kg

Liquid

MJ/L

hydrogen 0 : 1 0.090 0.071 121.07 8.57 10.88 284% 24%

methane 1 : 4 0.704 0.424 50.00 21.20 35.20 117% 61%

ethane 2 : 6 1.380 0.466 47.80 22.27 65.97 112% 64%

propane 3 : 8 2.026 0.508 46.35 23.55 93.90 109% 67%

butane

4 :

10 2.660 0.550 45.75 25.16 121.69 107% 72%

gasoline

8 :

14 4.368 0.720 43.50 31.32 190.00 102% 89%

diesel-oil

16 :

28 nd 0.820 42.70 35.01 nd 100% 100%

coke 20 : 2 nd 0.600 33.00 19.80 nd 77% 57%

anthracite 95 : 5 nd 1.300 29.00 37.70 nd 68% 108%




19

Specific Fuel & Oxygen consumptions CO2 & Water emissions - to deliver 10Kwh (gross

power)

FUEL kg/10kwh L/10kwh O2/10kwh CO2/10kwh H2O/10kwh emission

CO2ratio

weight

fuel ratio

volume

fuel ratio

hydrogen 0.30 4.20 2.38 0.00 2.68 0% 35% 408%

methane 0.72 1.70 2.88 1.98 1.62 73% 85% 165%

ethane 0.75 1.62 2.81 2.21 1.36 82% 89% 157%

propane 0.78 1.53 2.82 2.33 1.27 86% 92% 149%

butane 0.79 1.43 2.82 2.39 1.22 89% 93% 139%

gasoline 0.83 1.15 2.77 2.65 0.95 98% 98% 112%

diesel-oil 0.84 1.03 2.82 2.70 0.97 100% 100% 100%

coke 1.09 1.82 2.78 3.72 0.15 138% 129% 177%

anthracite 1.24 0.95 3.34 4.53 0.05 168% 147% 93%

Also, the 67% higher water content in the exhaust gases, from burning methane, has a

quenching effect on gas temperatures, lowering the formation of NOx.

The Carbon Footprint of the Life Cycle Assessment of LNG & LBG provides best performances

compared to any other fossil-fuel or bio-fuel.

LNG & LBG are currently not included in the EU joint study program (with Concawe and

EUCAR) concerning the overall GHG emissions analysis on Life Cycle Assessment of most

common transportation fuels, that compares the GHG performances of fossil fuels and

biofuels, with CNG and Bio-gas included and showing best results, as shown in the graph of

the publically available report, here below:




20

The main differentiation between CNG and LNG - bio-gas and LBM - concerns the differences

in the energy spent (and relevant GHG emissions) either for gas compression or for gas

liquefaction and thereafter for transporting the gas either in compressed-form or in

liquid-form, from the source to the tank of the user/vehicle (Well to Tank Assessment)

In general, it can be assumed that gas liquefaction requires costs and release GHGs about

three times more than its compression, but the transportation of compressed gas (with

recompression stations every 200-300Km along the pipeline) costs & pollutes about three

times more than transporting it liquid (by ships, road- tankers) and therefore the relevant

costs/benefits are related to the distances to be covered.

Furthermore, it should be taken into consideration that the liquefaction process determines

a higher purity (by entirely removing moisture, CO2, sulphur derivatives and heavy metals)

and does not suffer from contamination with oil leaking from compressor (Tank to Wheel

Assessment).

Also, L-CNG gas stations may be remotely located and do not need link to the gas grid.

NGVA Europe will endeavour to include LNG and LBM in LCAs to be accepted by EU

Authorities.

Date post:	01-Nov-2015
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