Natural Gas Principles

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NATURAL GASNatural Gas is a vital component of the world's supply of energy. Itis one of the cleanest, safest, and most useful of all energysources. Despite its importance, however, there are manymisconceptions about natural gas. For instance, the word 'gas'itself has a variety of different uses, and meanings. When we fuel

our car, we put 'gas' in it. However, the gasoline that goes into yourvehicle, while a fossil fuel itself, is very different from natural gas.The 'gas' in the common barbecue is actually propane, which, whileclosely associated and commonly found in natural gas, is not reallynatural gas itself. While commonly grouped in with other fossil fuelsand sources of energy, there are many characteristics of natural gas that make it unique. Below is abit of background information about natural gas, what exactly it is, how it is formed, and how it isfound in nature.

What is Natural Gas?Natural gas, in itself, might be considered a very uninteresting gas - it is colorless,

shapeless, and odorless in its pure form. Quite uninteresting - except that naturalgas is combustible, and when burned it gives off a great deal of energy. Unlike otherfossil fuels, however, natural gas is clean burning and emits lower levels ofpotentially harmful byproducts into the air. We require energy constantly, to heat ourhomes, cook our food, and generate our electricity. It is this need for energy thathas elevated natural gas to such a level of importance in our society, and in ourlives.Natural gas is a combustible mixture of hydrocarbon gases. While natural gas isformed primarily of methane, it can also include ethane, propane, butane andpentane. The composition of natural gas can vary widely, but below is a chart outlining the typicalmakeup of natural gas before it is refined.

Typical Composition of Natural Gas

Methane CH4 70-90%

Ethane C2H6

0-20%Propane C3H8

Butane C4H10

Carbon Dioxide CO2 0-8%

Oxygen O2 0-0.2%

Nitrogen N2 0-5%

Hydrogen sulphide H2S 0-5%Rare gases A, He, Ne, Xe trace

In its purest form, such as the natural gas that is delivered to your home, it is almost pure methane.Methane is a molecule made up of one carbon atom and four hydrogen atoms, and is referred to asCH4.Ethane, propane, and the other hydrocarbons commonly associated with natural gas have slightlydifferent chemical formulas, which can be seen.

A Natural GasWellhead


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Natural gas is considered 'dry' when it is almost pure methane, havinghad most of the other commonly associated hydrocarbons removed.When other hydrocarbons are present, the natural gas is 'wet'.Natural gas has many uses, residentially, commercially, andindustrially. Found in reservoirs underneath the earth, natural gas iscommonly associated with oil deposits. Production companies searchfor evidence of these reservoirs by using sophisticated technology thathelps to find the location of the natural gas, and drill wells in the earth

where it is likely to be found. Once brought from underground, thenatural gas is refined to remove impurities like water, other gases,sand, and other compounds. Some hydrocarbons are removed and

sold separately, including propane and butane. Other impurities are also removed, like hydrogensulfide (the refining of which can produce sulfur, which is then also sold separately). After refining, theclean natural gas is transmitted through a network of pipelines.Natural gas can be measured in a number of different ways. As a gas, it can be measured bythe volume it takes up at normal temperatures and pressures, commonly expressed in cubicfeet.Production and distribution companies commonly measure natural gas in thousands of cubicfeet (Mcf), millions of cubic feet (MMcf), or trillions of cubic feet (Tcf). While measuring by

volume is useful, natural gas can also be measured as a source of energy. Like other forms ofenergy, natural gas is commonly measured and expressed in British thermal units (Btu). OneBtu is the amount of natural gas that will produce enough energy to heat one pound of waterby one degree at normal pressure. To give an idea, one cubic foot of natural gas containsabout 1,027 Btus. When natural gas is delivered to a residence, it is measured by the gasutility in 'therms' for billing purposes. A therm is equivalent to 100,000 Btu's, or just over 97cubic feet, of natural gas.

The Formation of Natural GasNatural gas is a fossil fuel Like oil and coal, this means that it is, essentially, the remains of plants andanimals and micro-organisms that lived millions and millions of years ago. But how do these once

living organisms become an inanimate mixture of gases?There are many different theories as to the origins of fossil fuels. The most widely accepted theorysays that fossil fuels are formed when organic matter (such as the remains of a plant or animal) iscompressed under the earth, at very high pressure for a very long time. This is referred to asthermo-genic methane. Similar to the formation of oil, thermogenic methane is formed from organicparticles that are covered in mud and other sediment. Over time, more and more sediment and mudand other debris are piled on top of the organic matter. This sediment and debris puts a great deal ofpressure on the organic matter, which compresses it. This compression, combined with hightemperatures found deep underneath the earth, break down the carbon bonds in the organic matter.

As one gets deeper and deeper under the earths crust, the temperature gets higher and higher. Atlow temperatures (shallower deposits), more oil is produced relative to natural gas. At higher

temperatures, however, more natural gas is created, as opposed to oil. That is why natural gasis usually associated with oil in deposits that are 1 to 2 miles below the earth's crust. Deeperdeposits, very far underground, usually contain primarily natural gas, and in many cases, puremethane.Natural gas can also be formed through the transformation of organic matter by tiny micro-organisms.This type of methane is referred to as biogenic methane. Methanogens, tiny methane producingmicroorganisms, chemically break down organic matter to produce methane. These microorganismsare commonly found in areas near the surface of the earth that are void of oxygen. Thesemicroorganisms also live in the intestines of most animals, including humans. Formation of methanein this manner usually takes place close to the surface of the earth, and the methane produced isusually lost into the atmosphere. In certain circumstances, however, this methane can be trapped

A Methane molecule, CH4


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underground, recoverable as natural gas. An example of biogenic methane is landfill gas. Waste-containing landfills produce a relatively large amount of natural gas, from the decomposition of thewaste materials that they contain. New technologies are allowing this gas to be harvested and used toadd to the supply of natural gas.

A third way in which methane (and natural gas) may be formed is through biogenic processes.Extremely deep under the earth's crust, there exist hydrogen-rich gases and carbon molecules. Asthese gases gradually rise towards the surface of the earth, they may interact with minerals that alsoexist underground, in the absence of oxygen. This interaction may result in a reaction, forming

elements and compounds that are found in the atmosphere (including nitrogen, oxygen, carbondioxide, argon, and water). If these gases are under very high pressure as they move towards thesurface of the earth, they are likely to form methane deposits, similar tothermogenic methane.

Natural Gas Under the EarthAlthough there are several ways that methane, and thus natural gas, may beformed, it is usually found underneath the surface of the earth. As naturalgas has a low density, once formed it will rise towards the surface of theearth through loose, shale type rock and other material. Most of thismethane will simply rise to the surface and dissipate into the air. However, a

great deal of this methane will rise up into geological formations that 'trap'the gas under the ground. These formations are made up of layers ofporous, sedimentary rock (kind of like a sponge, that soaks up and contains

the gas), with a denser, impermeable layer of rock on top. This impermeablerock traps the natural gas under the ground. If these formations are largeenough, they can trap a great deal of natural gas underground, in what isknown as a reservoir. There are a number of different types of theseformations, but the most common is created when the impermeablesedimentary rock forms a 'dome' shape, like an umbrella that catches all of the natural gas that isfloating to the surface.There are a number of ways that this sort of 'dome' may be formed. For instance, faults are acommon location for oil and natural gas deposits to exist. A fault occurs when the normalsedimentary layers sort of 'split' vertically, so that impermeable rock shifts down to trapnatural gas in the more permeable limestone or sandstone layers. Essentially, the geologicalformation which layers impermeable rock over more porous, oil and gas rich sediment has thepotential to form a reservoir. The picture above shows how natural gas and oil can be trapped underimpermeable sedimentary rock, in what is known as an anticlinal formation. To successfully bringthese fossil fuels to the surface, a hole must be drilled through the impermeable rock to release thefossil fuels under pressure. Note that in reservoirs that contain oil and gas, the gas, being the leastdense, is found closest to the surface, with the oil beneath it, typically followed by a certain amount ofwater.With natural gas trapped under the earth in this fashion, it can be recovered by drilling a hole throughthe impermeable rock. Gas in these reservoirs is typically under pressure, allowing it to escape fromthe reservoir on its own.In addition to being found in a traditional reservoir such as the one shown above, natural gas mayalso be found in other 'unconventional' formations.

History Of Natural GasNatural gas is nothing new. In fact, most of the natural gas that is brought out from under the groundis millions and millions of years old. However, it was not until recently that methods for obtaining thisgas, bringing it to the surface, and putting it to use were developed.Before there was an understanding of what natural gas was, it posed somewhat of a mystery to man.


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Sometimes, such things as lightning strikes would ignite natural gas that was escaping from under theearth's crust. This would create a fire coming from the earth, burning the natural gas as it seeped outfrom underground. These fires puzzled most early civilizations, and were the root of much myth andsuperstition. One of the most famous of these types of flames was found in ancient Greece, on MountParnassus approximately 1,000 B.C. A goat herdsman came across what looked like a 'burningspring', a flame rising from a fissure in the rock. The Greeks, believing it to be of divine origin, built atemple on the flame. This temple housed a priestess who was known as the Oracle of Delphi, givingout prophecies she claimed were inspired by the flame.

These types of springs became prominent in the religions ofIndia, Greece, and Persia. Unable to explain where these firescame from, they were often regarded as divine, or supernatural. Itwasn't until about 500 B.C. that the Chinese discovered thepotential to use these fires to their advantage. Finding placeswhere gas was seeping to the surface, the Chinese formed crudepipelines out of bamboo shoots to transport the gas, where it wasused to boil sea water, separating the salt and making itdrinkable.Britain was the first country to commercializethe use of natural gas. Around 1785, natural

gas produced from coal was used to light houses, as well as streetlights.Manufactured natural gas of this type (as opposed to naturally occurring gas) wasfirst brought to the United States in 1816, when it was used to light the streets ofBaltimore, Maryland. However, this manufactured gas was much less efficient, andless environmentally friendly, than modern natural gas that comes from underground.Naturally occurring natural gas was discovered and identified in America as early as1626, when French explorers discovered natives igniting gases that were seepinginto and around Lake Erie. The American natural gas industry got its beginnings inthis area. In 1859, Colonel Edwin Drake (a former railroad conductor who adoptedthe title 'Colonel' to impress the townspeople) dug the first well. Drake hit oil and natural gas at 69feet below the surface of the earth.

Most in the industry characterizes this well as the beginning of thenatural gas industry in America. A two-inch diameter pipeline wasbuilt, running 5 and miles from the well to the village ofTitusville, Pennsylvania. The construction of this pipeline provedthat natural gas could be brought safely and relatively easily fromits underground source to be used for practical purposes.In 1821, the first well specifically intended to obtain natural gaswas dug in Fredonia, New York, by William Hart. After noticinggas bubbles rising to the surface of a creek, Hart dug a 27 footwell to try and obtain a larger flow of gas to the surface. Hart isregarded by many as the 'father of natural gas' in America.

Expanding on Hart's work, the Fredonia Gas Light Company waseventually formed, becoming being the first American natural gas company.During most of the 19th century, natural gas was used almost exclusively as a source of light. Withouta pipeline infrastructure, it was difficult to transport the gas very far, or into homes to be used forheating or cooking. Most of the natural gas produced in this era was manufactured from coal, asopposed to transport from a well. Near the end of the 19th century, with the rise of electricity, naturalgas lights were converted to electric lights. This led producers of natural gas to look for new uses fortheir product.In 1885, Robert Bunsen invented what is now known as the Bunsen burner. He managed to create adevice that mixed natural gas with air in the right proportions, creating a flame that could be safelyused for cooking and heating. The invention of the Bunsen burner opened up new opportunities for

The Oracle at Delphi, Greece

A Natural GasStreetlight

A Reconstruction of 'Colonel'Drake's First Well in Titusville,

Pa


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the use of natural gas in America, and throughout the world. The invention oftemperature-regulating thermostatic devices allowed for better use of the heatingpotential of natural gas, allowing the temperature of the flame to be adjusted andmonitored.Without any way to transport it effectively, natural gas discovered pre-WWII wasusually just allowed to vent into the atmosphere, or burnt, when found alongsidecoal and oil, or simply left in the ground when found alone.One of the first lengthy pipelines was constructed in 1891. This pipeline was 120

miles long, and carried natural gas from wells in central Indiana to the city ofChicago. However, this early pipeline was very rudimentary, and was not veryefficient at transporting natural gas. It wasn't until the 1920's that any significanteffort was put into building a pipeline infrastructure. However, it wasn't until afterthe World War II that welding techniques, pipe rolling, and metallurgical advances allowed forthe construction of reliable pipelines. This post-war pipeline construction boom lasted well into the60's, and allowed for the construction of thousands of miles of pipeline in America.Once the transportation of natural gas was possible, new uses for natural gas were discovered.These included using natural gas to heat homes and operate appliances such as water heaters andoven ranges. Industry began to use natural gas in manufacturing and processing plants. Also, naturalgas was used to heat boilers used to generate electricity. The transportation infrastructure had made

natural gas easy to obtain, and it was becoming an increasingly popular form of energy.

A Brief History of RegulationIn 1938, the U.S. government first regulated the natural gas industry. At the time, members of thegovernment believed the natural gas industry to be a 'natural monopoly'. Because of the fear ofpossible abuses, like charging unreasonably high prices, and given the rising importance of naturalgas to all consumers, the Natural Gas Act was passed. This Act imposed regulations and restrictionson the price of natural gas to protect consumers. In the 1970's and 1980's, a number of gasshortages and price irregularities indicated that a regulated market was not best for consumers, or thenatural gas industry. Into the 1980's and early 90's, the industry gradually moved towardsderegulation, allowing for healthy competition and market based prices. These moves led to a

strengthening of the natural gas market, lowering prices for consumers and allowing for a great dealmore natural gas to be discovered.Currently, the natural gas industry is regulated to a lesser extent by the Federal Energy RegulatoryCommission (FERC). While FERC does not deal exclusively with natural gas issues, it is the primaryrule making body with respect to the minimal regulation of the natural gas industry.Competition characterizes the natural gas industry as it is known today. The opening up of theindustry, and the move away from strict regulation, has allowed for increased efficiency andtechnological improvements. Natural gas is now being obtained more efficiently, cheaply, and easilythan ever before. However, the search for more natural gas to serve our ever growing demandrequires new techniques and knowledge to obtain it from hard-to-reach places.Today, the natural gas industry has existed in this country for over 100 years, and it continues to

grow. Deregulation and the move towards cleaner burning fuels have created an enormous marketfor natural gas across the country. New technologies are continually developed that allow Americansto use natural gas in new and exciting ways. With all of the advantages of natural gas, it is no wonderthat it has become the fuel of choice in this country, and throughout the world.

NATURAL GAS RESOURCES

A TypicalBunsen Burner


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How Much Natural Gas is there?

There is an abundance of natural gas in earth crust, but it is a non-renewable resource, the formation of whichtakes thousands and possibly millions of years. Therefore, understanding the availability of our supply of

natural gas is important as we increase our use of this fossil fuel.

This section will provide a framework for understanding just how much natural gas there is in the groundavailable for our use, as well as links to the most recent statistics concerning the available supply of natural gas.

As natural gas is essentially irreplaceable (at least with current technology), it is important to have an idea of

how much natural gas is left in the ground for us to use. However, this becomes complicated by the fact that no

one really knows exactly how much natural gas exists until it is extracted. Measuring natural gas in the groundis no easy job, and it involves a great deal of inference and estimation. With new technologies, these estimates

are becoming more and more reliable; however, they are still subject to revision.

A common misconception about natural gas is that we are running out, and quickly. However, this couldn't befurther from the truth. Many people believe that price spikes, such as were seen in the 1970's, and more recently

in the winter of 2000, indicate that we are running out of natural gas. The two aforementioned periods of high

prices were not caused by waning natural gas resources - rather, there were other forces at work in themarketplace. In fact, there is a vast amount of natural gas estimated to still be in the ground. In order to

understand exactly what these estimates mean, and their importance, it is useful first to learn a bit of industry

terminology for the different types of estimates.Unconventional natural gas reservoirs are also extremely important to the nation's supply of natural gas. U.S.

Natural Gas Resource EstimatesBelow are three estimates of natural gas reserves in the United States. The first, compiled by the Energy

Information Administration (referred to as the EIA), estimates that there are 1,190.62 Tcf of technicallyrecoverable natural gas in the United States. This includes undiscovered, unproved, and unconventional natural

gas. As can be seen from the table, proved reserves make up a very small proportion of the total recoverable

natural gas resources in the U.S. The most recent EIA data on proved reserves in the U.S. can be found here.

Natural Gas Technically Recoverable Resources

Natural Gas Resource Category

(Trillion Cubic Feet)As of January 1, 2000

Non-associated Gas

Undiscovered 247.71

Onshore 121.61

Offshore 126.1

Deep 81.56

Shallow 44.52

Inferred Reserves 232.7

Onshore 183.03

Offshore 47.68

Deep 7.72

Shallow 39.96

Unconventional Gas Recovery 369.59

Tight Gas 253.83

Shale Gas 55.42

Coal bed Methane 60.35

Associated-Dissolved Gas 140.89

Total Lower 48 Unproved 990.89

Alaska 32.32
http://www.eia.doe.gov/http://www.eia.doe.gov/http://www.eia.doe.gov/oil_gas/natural_gas/data_publications/crude_oil_natural_gas_reserves/cr.htmlhttp://www.eia.doe.gov/http://www.eia.doe.gov/http://www.eia.doe.gov/oil_gas/natural_gas/data_publications/crude_oil_natural_gas_reserves/cr.html


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Uses Of Natural Gas

For hundreds of years, natural gas has been known as avery useful substance. The Chinese discovered a very

long time ago that the energy in natural gas could be

harnessed, and used to heat water. In the early days ofthe natural gas industry, the gas was mainly used to

light streetlamps, and the occasional house. However,

with much improved distribution channels and

technological advancements, natural gas is being usedin ways never thought possible.

There are so many different applications for this fossil

fuel that it is hard to provide an exhaustive list ofeverything it is used for. And no doubt, new uses are

being discovered all the time. Natural gas has many

applications, commercially, in your home, in industry,and even in the transportation sector! While the uses

described here are not exhaustive, they may help to

show just how many things natural gas can do.According to theEnergy Information

Administration, energy from natural gas accountsfor 24 percent of total energy consumed in the

United States, making it a vital component of thenation's energy supply. For more detailed

information on the demand for and supply of energy,

and natural gas, including forecasts and outlooks,clickhere.

Natural gas is used across all sectors, in varying

amounts. The graph below gives an idea of theproportion of natural gas use per sector. The

industrial sector accounts for the greatest proportion

of natural gas use in the United States, with theresidential sector consuming the second greatest

quantity of natural gas.

Residential Uses

Commercial Uses

Uses in Industry

Natural Gas in the Transportation Sector

Electric Generation Using Natural Gas

RESIDENTIAL USES

Total Energy Consumed in the U.S. 2000

Source: EIA - Annual Energy Outlook 2002

Natural Gas Use By Sector
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Natural gas is one of the cheapest forms of energy

available to the residential consumer. In fact, naturalgas has historically been much cheaper than

electricity as a source of energy. The Department of

Energy (DOE) estimates that in 2002, natural gas isthe lowest cost conventional energy source available

for residential use. According to the DOE natural gas

costs less than 30 percent of the cost of electricity,

per Btu (British thermal unit).This not only holds for residential heating, but for

other uses of energy around the home as well.

According to the American Gas Association(AGA), a natural gas water heater could heat two

bathtubs full of water for the same cost as it would

take an electric water heater to heat only one bathtub full of water (AGA - PR-18 May 1, 2002).Not only is natural gas cheap for the residential consumer, it also has a number of varied uses. The best known

uses for natural gas around the home are natural gas heating and cooking. Cooking with a natural gas range or

oven can provide many benefits, including easy temperature control, self ignition and self cleaning, as well asbeing approximately one-half the cost of cooking with an electric range. Many of the top chefs prefer natural

gas ranges for their quick heating ability and temperature control. Gone are the days of temperamental naturalgas ranges, the newer generations of natural gas ranges allow for some of the most efficient, economical, and

versatile cooking appliances ever.

Natural gas is one of the most popular fuels for residential

heating. According to the AGA, 51 percent of heated homes inthe U.S. (or 49.1 million households), used natural gas heating in

2000. This popularity is also shown through the high proportion

of new homes built with natural gas heating. According to the

U.S. Census Bureauin their report Characteristics of New

Housing, 2003, 70 percent of single family homes completed in

2003 use natural gas heating, followed by 27 percent that useelectric heat, and 2percent that use heating oil. This represents

the sixth consecutive year that natural gas has heated 70 percent

of new homes. This is compared with 47 percent of new homes

using natural gas in 1986. The number of homes heated withnatural gas increased 16 percent between 1990 and 2000; 52% of

all U.S. homes today are heated and/or cooled with natural gas.

To learn more about recent trends in natural gas use, clickhere to view the Energy InformationAdministration's (EIA's) report, Natural Gas Markets: Recent Trends and Prospects for the Future, which

outlines significant historical trends and their implications for the future of natural gas use.

Despite this massive increase in the proportion of homes using natural gas the actual volume of natural gas

consumed has not increased to the same degree due to increased efficiency of natural gas appliances. Moderntop of the line gas furnaces can achieve efficiencies of over 90 percent (meaning that only 10 percent of the

energy contained in the natural gas is lost as waste heat). Even low-end natural gas furnaces achieve high

efficiencies, around 78 percent.

Residential Energy Costs per Btu

Installing Residential Natural Gas Distribution
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In addition to heating homes, natural gas can also be used to help cool houses,

through natural gas powered air conditioning. Natural gas air conditioning isnothing new, in fact, it provided most of the air conditioning requirements of the

1940's and 50's. However, due to new advancements in technology and

efficiency, natural gas air conditioning is experiencing resurgence in popularity.Although natural gas air conditioner units are initially more expensive than a

comparable electric unit, they are considerably more efficient and require less

maintenance. Modern residential air conditioner units use close to 30 percent

less energy than in years past, and have an expected working life of 20 yearswith very little maintenance.

Natural gas appliances are also rising in popularity due to their efficiency and

cost effectiveness. Although many gas powered appliances are initially moreexpensive than their electric counterparts, they are commonly much cheaper to

operate, have a longer expected life, and require relatively low maintenance.

Some examples of other natural gas appliances include space heaters, clothes dryers, pool and Jacuzzi heaters,fireplaces, barbecues, garage heaters, and outdoor lights. All of these appliances offer a safe, efficient, and

economical alternative to electricity or other fuel sources. Almost 70 percent of new homes use natural gas for

space heating, meaning that a large portion of new homes already have the natural gas delivery infrastructure inplace. The same natural gas pipes that supply gas to a furnace can be used to supply energy for all of the

appliances listed above, making installation simple and easy.Although natural gas has many uses, and can supply energy to a vast number of residential appliances, there are

some energy requirements around the house which cannot be satisfied by natural gas. A television, or blender,or microwave, for instance, will likely never be powered directly by natural gas, but will instead require

electricity. However, natural gas can still provide energy for these appliances at the home, by what is known as

'distributed generation'.Distributed generation refers to using natural gas to generate electricity right on the doorstep. Natural gas fuel

cells and micro-turbines both offer the residential consumer the capacity to disconnect from their local electric

distributor, and generate just enough electricity to meet their needs. Although this technology is still in itsinfancy, it is very promising in being able to offer independent, reliable, efficient, environmentally friendly

electricity for residential needs.

The very first natural gas fuel cell was installed in a house in Latham, New York, in July 1998. The system wasplugged into the home's natural gas line as the fuel supply, and is now completely independent of any outside

electricity. Because a significant amount of electricity is wasted when it is distributed through power lines from

a central power plant to the home, on-site electric generation could lead to significantly higher energy

efficiency, which translates to cost savings for the residential consumer.

COMMERCIAL USES

A Residential Natural Gas

Furnace - Efficiency with aPlain Exterior


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Commercial uses of natural gas are very similar to residential uses. The

commercial sector includes public and private enterprises, like officebuildings, schools, churches, hotels, restaurants, and government

buildings. The main uses of natural gas in this sector include space

heating, water heating, and cooling. For restaurants and other

establishments that require cooking facilities, natural gas is a

popular choice to fulfill these needs.

According to the Energy Information Administration(EIA), as of

the year 2003, the commercial sector consumes about 8,368 trillionBtu's of energy a year (aside from electrical system losses), most of

which is required for space heating, lighting, and cooling.

Of this 8,368 trillion Btu's, about 3,233 trillion Btu's (or 39 percent) aresupplied by natural gas. Natural gas is the primary energy source for

space and water heating, cooking, and drying, and also accounts for

about 13 percent of energy used in commercial cooling.Natural gas space and water heating for commercial buildings is very similar to that found in residential houses.

Natural gas is an extremely efficient, economical fuel for heating in

all types of commercial buildings. Although space and water heatingaccount for a great deal of natural gas use in commercial settings,

non-space heating applications are expected to account for themajority of growth in natural gas use in those settings. Cooling and

cooking represent two major growth areas for the use of natural gasin commercial settings.

Natural gas currently accounts for 13 percent of energy used in

commercial cooling, but this percentage is expected to increase dueto technological innovations in commercial natural gas cooling

techniques. There are three types of natural gas driven cooling

processes. Engine driven chillers use a natural gas engine, instead ofan electric motor, to drive a compressor. With these systems, waste

heat from the gas engine can be used for heating applications,

increasing energy efficiency. The second category of natural gascooling devices consist of what are called absorption chillers, which

provide cool air by evaporating a refrigerant like water or ammonia.

These absorption chillers are best suited to cooling large commercial

buildings, like office towers and shopping malls. The third type of commercial cooling system consists of gas-based desiccant systems. These systems cool by reducing humidity in the air. Cooling this dry air requires much

less energy than it would to cool humid air.

Another area of growth in commercial natural gas use is in the food service industry. Natural gas is an excellentchoice for commercial cooking requirements, as it is a flexible energy source in being able to supply the food

service industry with appliances that can cook food in many different ways. Natural gas is also an economical,

efficient choice for large commercial food preparation establishments. New developments such as

Nontraditional Restaurant Systems, which provide compact, multifunctional natural gas appliances for smallersized food outlets such as those found in shopping malls and airports, are expanding the commercial use of

natural gas. These types of systems can integrate a gas-fired fryer, griddle, oven, hot and cold storage areas, and

multiple venting options in a relatively small space - providing the ease and efficiency of natural gas cookingwhile being compact enough to serve small kiosk type establishments.

In addition to traditional uses of natural gas for space heating, cooling, cooking and water heating, a number of

technological advancements have allowed natural gas to be used to increase energy efficiency in commercialsettings. Many buildings, because of their high electricity needs, have on-site generators that produce their own

electricity. Natural gas powered reciprocating engines, turbines, and fuel cells are all used in commercial

settings to generate electricity. These types of 'distributed generation' units offer commercial environmentsmore independence from power disruption, high-quality consistent electricity, and control over their own

Commercial Energy Use

A Desiccant Unit Atop the Park Hyatt

Hotel, Washington D.C.
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energy supply.

Another technological innovation brought about is combined heating andpower (CHP) and combined cooling, heating and power (CCHP) systems,

which are used in commercial settings to increase energy efficiency. These are

integrated systems that are able to use energy that is normally lost as heat. Forexample, heat that is released from natural gas powered electricity generators

can be harnessed to run space or water heaters, or commercial boilers. Using

this normally wasted energy can dramatically improve energy efficiency.

Uses In Industry

A Chef Prepares Food

At the PiedmontGas Cooking Technology Center

Source: Piedmont Natural Gas


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Natural gas has a multitude ofindustrial uses, including providingthe base ingredients for such variedproducts as plastic, fertilizer, anti-freeze, and fabrics. In fact, industryis the largest consumer of naturalgas, accounting for 43 percent ofnatural gas use across all sectors.

Natural gas is the second mostused energy source in industry,trailing only electricity. Lighting isthe main use of energy in theindustrial sector, which accounts forthe tremendous electricityrequirements of this sector. Thegraph below shows current as wellas projected energy consumptionby fuel in the industrial sector.

Although industry accounts for a great deal of natural gas consumption in the United States, this

industrial consumption is concentrated in a relatively small number of industries. Natural gas isconsumed primarily in the pulp and paper, metals, chemicals, petroleum refining, stone, clay andglass, plastic, and food processing industries. These businesses account for over 84 percent of allindustrial natural gas use.

Industrial ApplicationsIndustrial applications for natural gas are many. Industrial applications include those same uses foundin residential and commercial settings - heating, cooling, and cooking. Natural gas is also used forwaste treatment and incineration, metals preheating (particularly for iron and steel), drying anddehumidification, glass melting, food processing, and fueling industrial boilers. Natural gas may alsobe used as a feedstock for the manufacturing of a number of chemicals and products. Gases such as

butane, ethane, and propane may be extracted from natural gas to be used as a feedstock for suchproducts as fertilizers and pharmaceutical products.Natural gas as a feedstock is commonly found as a building block for methanol, which in turn hasmany industrial applications. Natural gas is converted to what is known as synthesis gas, which is amixture of hydrogen and carbon oxides formed through a process known as steam reforming. In thisprocess, natural gas is exposed to a catalyst that causes oxidization of the natural gas when broughtinto contact with steam. This synthesis gas, once formed, may be used to produce methanol (orMethyl Alcohol), which in turn is used to produce such substances as formaldehyde, acetic acid, andMTBE (methyl tertiary butyl ether) that is used as an additive for cleaner burning gasoline. Methanolmay also be used as a fuel source in fuel cells.In addition to these uses, there are a number of innovative and industry specific uses of natural gas.Natural gas desiccant systems, which are used for dehumidification, are increasingly popular in theplastics, pharmaceutical, candy, and even recycling industries. In each of these industries, moisturefilled air can lead to damage of the end product during its manufacture. For example, in the plasticsindustry, moisture can cause cracks and blemishes during the manufacture of certain types ofplastics. Adding a natural gas desiccant system to the manufacturing or drying environment allowsindustrial users to regulate more closely the amount of moisture in the air, leading to a moreconsistent and high-quality product.Natural gas absorption systems are also being used extensively in industry to heat and cool water inan efficient, economical, and environmentally sound way. These industrial absorption systems arevery similar to those used in commercial settings.Infrared Heating Units

Industrial Primary Energy Consumption by Fuel 1970 2020


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Infrared (IR) heating units provide an innovative and economic method ofusing natural gas to generate heat in an industrial setting. They are veryuseful in the metals industry, as they provide innovative ways to increasethe efficiency of powder-coating manufacturing processes. Infraredheaters use natural gas to more efficiently and quickly heat materialsused in this process. Natural gas is combined with a panel of ceramicfibers containing a platinum catalyst, causing a reaction with oxygen todramatically increase temperature, without even producing a flame.

Using natural gas in this manner has allowed industry members toincrease the speed of their manufacturing process, as well as providing amore economic alternative to electric heaters.

Direct Contact Water HeatersDirect contact water heating is an application that works by having theenergy from the combustion of natural gas transferred directly from theflame into the water. These systems are incredibly efficient at heatingwater. Normal industrial water heaters operate in the 60 - 70 percentenergy efficiency range. However, direct contact water heaters canachieve efficiencies up to 99.7 percent! Obviously, this leads to

tremendous cost savings in industries where hot water is essential.Industrial Combined Heat and PowerIndustrial consumers reap great benefits from operating natural gasCombined Heat and Power (CHP) and Combined Cooling, Heat, andPower (CCHP) systems, similar to those used commercial settings.For instance, natural gas may be used to generate electricity neededin a particular industrial setting. The excess heat and steamproduced from this process can be harnessed to fulfill otherindustrial applications, including space heating, water heating, andpowering industrial boilers. Since industry is such a heavy user ofenergy, and particularly electricity, providing increased efficiency can

save a great deal of money. The industrial sector is also subject toregulations regarding harmful emissions, and the burning attributesof natural gas help industry to reduce its emissions.Industrial Co-firingNatural gas co-firing technologies are also helping to increaseindustrial energy efficiency, and reduce harmful atmosphericemissions. Co-firing is the process in which natural gas is used as asupplemental fuel in the combustion of other fuels, such as coal,wood, and biomass energy. For example, a traditional industrialwood boiler would simply burn wood to generate energy. However, in this type of boiler, a significantamount of energy is lost, and harmful emissions are very high. Adding natural gas to the combustion

mix can have a two-fold effect. Natural gas emits fewer harmful substances into the air than a fuelsuch as wood. Since the energy needed to power the natural gas boiler remains constant, addingnatural gas to the combustion mix can reduce harmful emissions.In addition, the operational performance of the boiler, including its energy efficiency, can be improvedby supplementing with natural gas. For instance, in wood fueled boilers, adding natural gas cancompensate for the use of low grade, wet wood, allowing it to combust more quickly and completely.This type of co-firing can also be used in the generation of electricity, whether on-site or in acentralized power plant.Natural gas has innumerable uses in industry, and new applications are being developed every day.Natural gas, being a clean, efficient source of energy and a chemical building block, is an importantpart of successful and environmentally sound industry in the United States.

Schematic of a Natural GasCo-fired Boiler

The KemcoThermefficient-100 DirectContact Water Heater


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Natural Gas in the Transportation SectorNatural gas has long been considered an alternative fuelfor the transportation sector. In fact, natural gas has beenused to fuel vehicles since the 1930's!

According to the Natural Gas Vehicle Coalition, there arecurrently 130,000 Natural Gas Vehicles (NGVs) on theroad in the United States today, and more than 2.5 million

NGVs worldwide. In fact, the transportation sectoraccounts for 3 percent of all natural gas used in the UnitedStates. In recent years, technology has improved to allowfor a proliferation of natural gas vehicles, particularly for fuel intensive vehicle fleets, such as taxicabsand public buses. However, virtually all types of natural gas vehicles are either in production today forsale to the public or in development, from passenger cars, trucks, buses, vans, and even heavy-dutyutility vehicles. Despite these advances, a number of disadvantages of NGVs prevent their mass-production. Limited range, trunk space, higher initial cost, and lack of refueling infrastructure poseimpediments to the future spread of natural gas vehicles.Most natural gas vehicles operate using compressed natural gas (CNG). This compressed gas isstored in similar fashion to a car's gasoline tank, attached to the rear, top, or undercarriage of the

vehicle in a tube shaped storage tank. A CNG tank can be filled in a similar manner, and in a similaramount of time, to a gasoline tank.

This natural gas fuels a combustion engine similar to enginesfueled by other sources. However, in a NGV, severalcomponents require modification to allow the engine to runefficiently on natural gas. In addition to using CNG, somenatural gas vehicles are fueled by Liquefied Natural Gas (LNG).Some natural gas vehicles that exist today are bi-fuel vehicles,meaning they can use gasoline or natural gas, allowing formore flexibility in fuel choice. Many of these vehicles, whichwere originally gasoline only, have been converted to allow the

vehicle to run on either fuel. This conversion is costly, andtypically results in less efficient use of natural gas.

Why Natural Gas Vehicles?There are many reasons why NGVs are increasing in abundance and popularity. New, stringentfederal and state emissions laws require an improvement in vehicle emissions over the foreseeablefuture. For example, the state of California has some of the most stringent environmental standards,many of which are currently unattainable with conventionally fueled vehicles. Natural gas, being thecleanest burning alternative transportation fuel available today, offers an opportunity to meet thesestringent environmental emissions standardsIn addition, natural gas is very safe. Being lighter than air, in the event of an accident natural gas

simply dissipates into the air, instead of forming a dangerous flammable pool on the ground like otherliquid fuels. This also prevents the pollution of ground water in the event of a spill. Natural gas fuelstorage tanks on current NGVs are stronger and sturdier than gasoline tanks.Natural gas is also an economic alternative to gasoline and other transportation fuels. Traditionally,natural gas vehicles have been around 30 percent cheaper than gasoline vehicles to refuel, and inmany cases the maintenance costs for NGVs is lower than traditional gasoline vehicles. In addition tobeing economic, many proponents of NGVs argue that a transportation sector more reliant ondomestically abundant natural gas will decrease the U.S. dependence on foreign oil - allowing for amore secure, safer energy supply for the country.

A Natural Gas Vehicle of the 1930's

Refueling an NGV


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The Environmental Benefits of NGVsOne of the primary reasons for pursuing alternative fueledvehicle technology is to decrease environmentally harmfulemissions. It is estimated that vehicles on the roadaccount for 60 percent of carbon monoxide pollution, 29percent of hydrocarbon emissions, and 31 percent ofnitrogen oxide (NOx) emissions in the United States. All ofthese emissions released into the atmosphere contribute

to smog pollution, and increase the levels of dangerousground level ozone. Vehicles also account for the emissionof over half of all dangerous air pollutants, and around 30percent of total carbon emissions in the U.S., contributingto the presence of 'greenhouse gases' in the atmosphere.The environmental effects of NGVs are much lessdetrimental than traditionally fueled vehicles.Natural gas vehicles, when designed to run on natural gas alone, are among the cleanest vehicles inthe world. In fact, the Honda Civic GX, released in 1997, has the cleanest internal combustion engineever commercially produced. This natural gas powered automobile emits so few pollutants that insome large cities the emissions from the car are cleaner than the air surrounding it! California, with

some of the tightest clean air standards anywhere in the United States, has recognized selectednatural gas vehicles as meeting and exceeding its most stringent standards, including low-emissionvehicle (LEV), ultra-low emission vehicle (ULEV), and super-low emission vehicle (SULEV) standards

Natural gas vehicles are much cleaner burningthan traditionally fueled vehicles due to thechemical composition of natural gas. While naturagas is primarily methane, gasoline and dieselfuels contain numerous other harmful compoundsthat are released into the environment throughvehicle exhaust. While natural gas may emit small

amounts of ethane, propane, and butane whenused as a vehicular fuel, it does not emit many ofthe other, more harmful substances emitted by the

combustion of gasoline or diesel. These compounds include volatile organic compounds, sulfurdioxide, and nitrogen oxides (which combine in the atmosphere to produce ground level ozone),benzene, arsenic, nickel, and over 40 other substances classified as toxic by the EnvironmentalProtection Agency.Dedicated NGVs also produce, on average, 70 percent less carbon monoxide, 89 percent less non-methane organic gas, and 87 percent less NOx than traditional gasoline powered vehicles.For more information on the environmental benefits of natural gas vehicles, visit the Natural GasVehicle Coalition.

Who Uses Natural Gas Vehicles?Natural gas vehicles as they exist today are best suited for large fleets of vehicles that drive manymiles a day. Taxicabs, transit and school buses, airport shuttles, construction vehicles, garbagetrucks, delivery vehicles, and public works vehicles are all well suited to natural gas fueling. Becausethese vehicles are centrally maintained and fueled, it is economical and beneficial to convert tonatural gas.The primary impediments to the public proliferation of NGVs include the high initial cost, limitedrefueling infrastructure, and automobile performance characteristics. NGVs, despite being cheaper torefuel and maintain, are more expensive initially than their gasoline powered counterparts. However,as the technology becomes more advanced, the cost of manufacturing these vehicles should drop,

A 'Clean Air' Natural Gas BusSource: Duke Energy Gas TransmissionCanada

Honda Civic GX - Super Clean NGV


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which may then be passed along to the consumers.In terms of refueling infrastructure, there are currently around 1,300 natural gas refueling stations inthe U.S., over half of which are open to the public. Although this is a small fraction of the number ofgasoline fueling stations in the country, as environmentalstandards and government incentives for NGVs increase,supplying natural gas as a vehicular fuel will becomeincreasingly common.Natural gas vehicles have suffered in the past from limited

driving range and limited storage space, due to the volume ofthe CNG that must be carried on-board. However, research iscurrently underway to develop a mid-sized NGV, with similarrange and storage space as its gasoline powered counterpart.While driving range, storage space, and initial cost are currentlypreventing the mass production of dedicated natural gasvehicles (which in turn is preventing the expansion ofpublic natural gas fueling stations), it is expected that withimproved technology, research, and infrastructure, the useof NGVs in non-fleet settings will increase in the future.Natural gas vehicles present an exciting opportunity to

reduce the damage of one of our most polluting sectors.For more information on Natural Gas Vehicles, please visitthese websites:The Natural Gas Vehicle CoalitionThe International Association for Natural Gas VehiclesThe Natural Gas Vehicle ForumThe Alternative Fuels Data CenterNow that we have examined the role that natural gas is playing in keeping our transportation sectoras clean as possible,

Electric Generation Using Natural Gas

Natural gas, because of its clean burning nature, hasbecome a very popular fuel for the generation ofelectricity. In the 1970's and 80's, the choices formost electric utility generators were large coal ornuclear powered plants; but, due to economic,environmental, and technological changes, naturalgas has become the fuel of choice for new powerplants. In fact, in 2000, 23,453 MW (megawatts) ofnew electric capacity was added in the U.S. Of this,almost 95 percent, or 22,238 MW were natural gas

fired additions. The graph below shows how,according to the Energy Information Administration(EIA), natural gas fired electricity generation isexpected to increase dramatically over the next 20years, as all of the new capacity that is currentlybeing constructed comes online.There are many reasons for this increased reliance on natural gas to generate our electricity. Whilecoal is the cheapest fossil fuel for generating electricity, it is also the dirtiest, releasing the highestlevels of pollutants into the air. The electric generation industry, in fact, has traditionally been one ofthe most polluting industries in the United States. Regulations surrounding the emissions of powerplants have forced these electric generators to come up with new methods of generating power, while

Natural Gas Powered PublicTransitSource: NGSA

NGV of the Future?

Source: Sandia National Libraries


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lessening environmentaldamage. New technology hasallowed natural gas to play anincreasingly important role in theclean generation of electricity.For more information on theenvironmental benefits of naturalgas, including its role as a clean

energy source for the generationof electricity, click here.

Steam Generation UnitsNatural gas can be used togenerate electricity in a variety ofways. The most basic naturalgas fired electric generationconsists of a steam generationunit, where fossil fuels areburned in a boiler to heat water

and produce steam, which then turns a turbine to generate electricity. Natural gas may be used forthis process, although these basic steam units are more typical oflarge coal or nuclear generation facilities. These basic steamgeneration units have fairly low energy efficiency. Typically, only 33to 35 percent of the thermal energy used to generate the steam isconverted into electrical energy in these types of units.

Centralized Gas TurbinesGas turbines and combustion engines are also used to generateelectricity. In these types of units, instead of heating steam to turn aturbine, hot gases from burning fossil fuels (particularly natural gas)

are used to turn the turbine and generate electricity. Gas turbineand combustion engine plants are traditionally used primarily for peak-load demands, as it is possibleto quickly and easily turn them on. These plants have increased in popularity due to advances intechnology and the availability of natural gas. However, they are still traditionally slightly less efficientthan large steam-driven power plants.

Combined Cycle UnitsMany of the new natural gas fired power plants are what are knownas 'combined-cycle' units. In these types of generating facilities,there is both a gas turbine and a steam unit, all in one. The gasturbine operates in much the same way as a normal gas turbine,

using the hot gases released from burning natural gas to turn aturbine and generate electricity. In combined-cycle plants, thewaste heat from the gas-turbine process is directed towardsgenerating steam, which is then used to generate electricity muchlike a steam unit. Because of this efficient use of the heat energyreleased from the natural gas, combined-cycle plants are much

more efficient than steam units or gas turbines alone. In fact, combined-plants can achieve thermalefficiencies of up to 50 to 60 percent.

Electricity Generation by Fuel 1970-2020 (billion kilowatthours)

A Centralized Gas Turbine

Generation Station

A Gas Fired Turbine - The Sizeof a Locomotive


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Distributed GenerationTo this point, methods of generating power have been discussed in thecontext of large, centralized power plants. However, with technologicaladvancements, there is a trend towards what is known as 'distributedgeneration'. Distributed generation refers to the placement ofindividual, smaller sized electric generation units at residential,commercial, and industrial sites of use. These small scale powerplants, which are primarily powered by natural gas, operate with small

gas turbine or combustion engine units, or natural gas fuel cells.Typically, electricity is generated in large, centralized power plants.However, deregulation in the electricity industry, coupled with newtechnology and environmental regulations, is leading the way towardsdistributed generation. This refers to the practice of generatingelectricity on-site, instead of in a large centralized power plant.Distributed generation offers opportunities across all sectors, from verysmall residential and commercial on-site generators, to larger outputindustrial generators.Distributed generation can take many forms, from small, low outputgenerators used to back up the supply of electricity obtained from the

centralized electric utilities, to larger, independent generators that supply enough electricity to poweran entire factory. Distributed generation is attractive because it offers electricity that is more reliable,more efficient, and cheaper than purchasing power from a centralized utility. Distributed generationalso allows for increased local control over the electricity supply, and cuts down on electricity lossesduring transmission. Below is a discussion of the various forms of natural gas fired distributedgeneration.Natural gas is one of the leading energy sources for distributed generation. Because of the extensivenatural gas supply infrastructure, and the environmental benefits of using natural gas, it is one of theleading choices for on-site power generation. There are a number of ways in which natural gas maybe used on-site to generate electricity. Fuel cells, gas-fired reciprocating engines, industrial naturalgas fired turbines, and micro-turbines, are all popular forms of using natural gas for on-site electricity

needs.Industrial Natural Gas Fired TurbinesIndustrial natural gas fired turbines operate on the same concept as the larger centralized gas turbinegenerators discussed above. However, instead of being located in a centralized plant, these turbinesare located in close proximity to where the electricity being generated will be used. Industrial turbines- producing electricity through the use of high temperature, high pressure gas to turn a turbine thatgenerates a current - are compact, lightweight, easily started, and simple to operate. This type ofdistributed generation is commonly used by medium and large sized establishments, such asuniversities, hospitals, commercial buildings, and industrial plants, and is typically21 to 40 percent efficient.However, with distributed generation, the heat that would normally be lost as waste

energy can easily be harnessed to perform other functions, such as powering aboiler or space heating. This is known as Combined Heat and Power (CHP)systems.In addition, on-site natural gas turbines can be used in a combined cycle unit, asdiscussed above. Due to the advantages of these types of generation units, agreat deal of research is being put into developing more efficient, advanced gasturbines for distributed generation.Micro-turbinesMicro-turbines are scaled down versions of industrial gas turbines. As their namesuggests, these generating units are very small, and typically have a relativelysmall electric output. These types of distributed generation systems have the

A Proposed Natural GasCombined Cycle PowerPlant in New York

Gas Fired Micro-turbine


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capacity to produce from 25 to 500 kilowatts (kW) of electricity, and are best suited for residential orsmall scale commercial units.

Advantages to micro-turbines include a very compact size (about the same size as a refrigerator), asmall number of moving parts, light-weight, low-cost, and increased efficiency. Using new waste heatrecovery techniques, micro-turbines can achieve energy efficiencies of up to 80 percent.Gas Fired Reciprocating Engines

Gas fired reciprocating engines are also used for on-site electricgeneration. These types of engines are also commonly known as

combustion engines. They convert the energy contained in fossilfuels into mechanical energy, which rotates a piston to generateelectricity. Gas fired reciprocating engines typically generate fromless than 5 kW, up to 7 megawatts (MW), meaning they can beused as a small scale residential backup generator, to a base loadgenerator in industrial settings. Gas fired reciprocating engines offerefficiencies from 25 to 45 percent, and can also be used in a CHPsystem to increase energy efficiency.Fuel Cells

Fuel cells are becoming an increasingly important technology for the generation of electricity. Theyare much like rechargeable batteries, except instead of using an electric recharger, they use a fuel,

such as natural gas, to generate electric power even when they are in use. Fuel cells for distributedgeneration offer a multitude of benefits, and are an exciting area of innovation and research fordistributed generation applications.One of the major technological innovations with regard to electric generation, whether distributed orcentralized, is the use of Combined Heat and Power (CHP) systems. These systems make use ofheat that is normally wasted in the electric generation process, thereby increasing the energyefficiency of the total system.

NATURAL GAS - FROM WELLHEAD TO BURNER TIPThe process of getting natural gas out of the ground, and to its finaldestination to be used, is a complicated one. There is a great deal of

behind-the-scenes activity that goes into delivering natural gas to yourhome, even though it takes only the flick of a switch to turn it on. Thissection provides an overview of the processes that allow the natural gasindustry to get their product out of the ground, and transform it into thenatural gas that is used in your homes and in industry.

The Exploration outlines how natural gas is found, and how companies decide where to drill wells forit.The Extraction section focuses on the drilling process, and how natural gas is brought from itsunderground reservoirs to the surface.

The Production section discusses what happens once the well is drilled; including the processing ofnatural gas once it is brought out from underground.The Transport section outlines how the natural gas is transported from the wellhead and processingplant, using the extensive network of pipelines throughout North America.The Storage section describes the storage of natural gas, how it is accomplished, and why it isnecessary.The Distribution section focuses on the delivery of natural gas from the major pipelines to the endusers, whoever they may be.The Marketing section discusses the role that natural gas marketers play in getting the gas from thewellhead to the end user.

Gas Fired ReciprocatingEngine
http://www.naturalgas.org/naturalgas/exploration.asphttp://www.naturalgas.org/naturalgas/extraction.asphttp://www.naturalgas.org/naturalgas/production.asphttp://www.naturalgas.org/naturalgas/transport.asphttp://www.naturalgas.org/naturalgas/storage.asphttp://www.naturalgas.org/naturalgas/distribution.asphttp://www.naturalgas.org/naturalgas/marketing.asphttp://www.naturalgas.org/naturalgas/exploration.asphttp://www.naturalgas.org/naturalgas/extraction.asphttp://www.naturalgas.org/naturalgas/production.asphttp://www.naturalgas.org/naturalgas/transport.asphttp://www.naturalgas.org/naturalgas/storage.asphttp://www.naturalgas.org/naturalgas/distribution.asphttp://www.naturalgas.org/naturalgas/marketing.asp


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Please click on the links to the left to learn about how natural gas gets from deep underground, all theway to the burner tip!


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ExplorationThe practice of locating natural gas and petroleumdeposits has been transformed dramatically in the last 15years with the advent of extremely advanced, ingenioustechnology. In the early days of the industry, the only wayof locating underground petroleum and natural gasdeposits was to search for surface evidence of theseunderground formations. Those searching for natural gas

deposits were forced to scour the earth, looking forseepages of oil or gas emitted from underground beforethey had any clue that there were deposits underneath.However, because such a low proportion of petroleum andnatural gas deposits actually seep to the surface, thismade for a very inefficient and difficult exploration process.

As the demand for fossil fuel energy has increased dramatically over the past years, so has thenecessity for more accurate methods of locating these deposits.Sources of DataTechnology has allowed for an incredible increase in the success rate of locating natural gasreservoirs. In this section, it will be outlined how geologists and geophysicists use technology, and

knowledge of the properties of underground natural gas deposits, to gather data that can later beinterpreted and used to make educated guesses as to where natural gas deposits exist. However, itmust be remembered that the process of exploring for natural gas and petroleum deposits is rife withuncertainty and trial-and-error, simply due to the complexity of searching for something that is oftenthousands of feet below ground.Geological SurveysThe exploration for natural gas typically begins with geologists examining the surface structure of theearth, and determining areas where it is geologically likely that petroleum or gas deposits might exist. was discovered in the mid 1800's that anticlinal slopes had a particularly increased chance ofcontaining petroleum or gas deposits. These anticlinal slopes are areas where the earth has folded upon itself, forming the dome shape that is characteristic of a great number of reservoirs.

By surveying and mapping the surface and sub-surface characteristics of a certain area, the geologistcan extrapolate which areas are most likely to contain a petroleum or natural gas reservoir. Thegeologist has many tools at his disposal to do so, from the outcroppings of rocks on the surface or invalleys and gorges, to the geologic information attained from the rock cuttings and samples obtainedfrom the digging of irrigation ditches, water wells, and other oil and gas wells. This information is allcombined to allow the geologist to make inferences as to the fluid content, porosity, permeability, age,and formation sequence of the rocks underneath the surfaceof a particular area. For example, in the picture shown, ageologist may study the outcroppings of rock to gain insightinto the geology of the subsurface areas.Once the geologist has determined an area where it is

geologically possible for a natural gas or petroleumformation to exist, further tests can be performed to gainmore detailed data about the potential reservoir area. Thesetests allow for the more accurate mapping of undergroundformations, most notably those formations that arecommonly associated with natural gas and petroleumreservoirs. These tests are commonly performed by ageophysicist, one who uses technology to find and map underground rockformations.

Seismic Exploration

A Seismic Exploration Crew in the Arct

Surface Geology


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ExtractionOnce a potential natural gas deposit has been located by a team of exploration geologists andgeophysicists, it is up to a team of drilling experts to actually dig down to where the natural gas isthought to exist. This section will describe the process of drilling for natural gas, both onshore andoffshore. Although the process of digging deep into the Earth's crust to find deposits of natural gas

that may or may not actually exist seems daunting, the industry has developed a number ofinnovations and techniques which both decrease the cost and increase the efficiency of drilling fornatural gas. The advance of technology has also contributed greatly to the increased efficiency andsuccess rate for drilling natural gas wells.

The decision of whether or not to drill a well depends on avariety of factors, not the least of which are the economiccharacteristics of the potential natural gas reservoir. Itcosts a great deal of money for exploration and productioncompanies to search and drill for natural gas, and there isalways the inherent risk that no natural gas will be found.The exact placement of the drill site depends on a variety

of factors, including the nature of the potential formation tobe drilled, the characteristics of the subsurface geology,and the depth and size of the target deposit. After thegeophysical team identifies the optimal location for a well,it is necessary for the drilling company to ensure that theycomplete all the necessary steps to ensure that they canlegally drill in that area. This usually involves securingpermits for the drilling operations, establishment of a legalarrangement to allow the natural gas company to extractand sell the resources under a given area of land, and adesign for gathering lines that will connect the well to the

pipeline. There are a variety of potential owners of the land and mineral rights of a given area.If the new well, once drilled, does in fact come in contact with natural gas deposits, it is developed toallow for the extraction of this natural gas, and is termed a 'development' or 'productive' well. At thispoint, with the well drilled and hydrocarbons present, the well may be completed to facilitate itsproduction of natural gas. However, if the exploration team was incorrect in its estimation of theexistence of marketable quantity of natural gas at a well site, the well is termed a 'dry well', andproduction does not proceed.

Source: Anadarko Petroleum Corporation

A Seismograph


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Onshore DrillingDrilling into the Earth in the hopes of uncovering valuable resources isnothing new. In fact, the digging of water and irrigation wells dates back tothe beginning of recorded history. At first, these wells were primarily dug byhand, then by crude stone or wood tools. Metallurgy brought about the use ofiron and bronze tools to delve beneath the Earth's surface, and innovationsled to more efficient ways of removing debris from the newly dug hole. Thefirst recorded instance of the practice of 'drilling' holes in the ground came

about around 600 B.C., when the Chinese developed a technique ofrepeatedly pounding bamboo shoots capped with metal bits into the ground.This crude technology was the first appearance of what is now known as'percussion drilling'; a method of drilling that is still in use today. Muchadvancement has been made since these first bamboo drilling implements,with the realization of the value and increased demand for subsurfacehydrocarbons. This section will cover the basics of modern onshore naturalgas drilling practices.There are two main types of onshore drilling. Percussion, or 'cable tool' drilling, consists of raising anddropping a heavy metal bit into the ground, effectively punching a hole down through the Earth. Cabletool drilling is usually used for shallow, low pressure formations. The second drilling method is known

as rotary drilling, and consists of a sharp, rotating metal bit used to drill through the Earth's crust. Thistype of drilling is used primarily for deeper wells that may be under high down hole pressureCable Tool DrillingCable tool or percussion drilling is recognized by many as the first drilling method employed to dig weinto the Earth for the purpose of reaching petroleum deposits and water. This method is still in use insome of the shallow wells in the Appalachian Basin, although rotary drilling has taken over the bulk ofmodern drilling activities.The basic concept for cable tool drilling consistsof repeatedly dropping a heavy metal bit into theground, eventually breaking through rock andpunching a hole through to the desired depth.

The bit, usually a blunt, chisel shapedinstrument, can vary with the type of rock that isbeing drilled. Water is used in the well hole tocombine with all of the drill cuttings, and isperiodically bailed out of the well when this 'mud'interferes with the effectiveness of the drill bit.Cable tool drilling has historically taken manyforms. In the early days of percussion drilling,equipment was very crude compared to today'stechnology. The 'springpole' technique, used inthe early 1800's, consisted of a flexible pole

(usually a tree trunk) anchored at one end, andlaying across a fulcrum, much like a divingboard. The flexible pole, or springpole, would have a heavy bit attached at the loose end. In order toget the bit to strike the ground, workers would use their own body weight to bend the pole towards theground, allowing the bit to strike rock. The tension in the pole would spring the bit free, should itbecome stuck in the ground.Much advancement has been made since these early percussion rigs. In fact, it was from cable tooldrilling that one of the most important drilling advancements was made. In 1806, David and JosephRuffner were using the springpole technique to drill a well in West Virginia. In order to prevent their wefrom collapsing, they used hollow tree trunks to reinforce the sides of the well, and to keep water andmud from entering the well as they dug. They are credited as the first drillers to use a casing in their

Early Percussion Rigs in Pennsylvania - Late1800's


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well - an advancement that made drilling much more efficient and easily accomplished. It is believed bmany that 'Colonel' Drake's 1856 well achieved success due to the use of steel casing to reinforce thewell. Drake's well was drilled using steam powered cable tool drilling methods.

Innovations, such as the use of steam power in cable toodrilling, greatly increased the efficiency and range ofpercussion drilling. Conventional man-powered cable toorigs were generally used to drill wells 200ft or less, whilesteam powered cable tool rigs, consisting of the familiar

derrick design, had an average drilling depth of 400 to 50feet. The deepest known well dug with cable tool drillingwas completed in 1953, when the New York Natural GasCorporation drilled a well to a depth of 11,145 ft.Despite the historical significance of cable tool drilling,modern drilling activity has shifted mainly towards rotarydrilling methods. However, the foundation of knowledgelaid by years of cable tool drilling is, in many cases,directly transferable to the practice of rotary drilling.

A Modern, Mobile Cable Tool Drilling Rig


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Rotary DrillingRotary drilling uses a sharp, rotating drill bit to dig downthrough the Earth's crust. Much like a common handheld drill, the spinning of the drill bit allows forpenetration of even the hardest rock. The idea of usinga rotary drill bit is not new. In fact, archeological recordsshow that as early as 3000 B.C., the Egyptians mayhave been using a similar technique. Leonardo Da

Vinci, as early as 1500, developed a design for a rotarydrilling mechanism that bears much resemblance totechnology used today. Despite these precursors, rotarydrilling did not rise in use or popularity until the early1900's. Although rotary drilling techniques had beenpatented as early as 1833, most of these early attemptsat rotary drilling consisted of little more than a mule,attached to a drilling device, walking in a circle! It wasthe success of the efforts of Captain Anthony Lucas andPatillo Higgins in drilling their 1901 'Spindletop' well inTexas that catapulted rotary drilling to the forefront of

petroleum drilling technology.While the concept for rotary drilling - using a sharp, spinning drill bit to delve into rock - is quite simplethe actual mechanics of modern rigs are quite complicated. In addition, technology advances so rapidthat new innovations are being introduced constantly. The basic rotary drilling system consists of fourgroups of components. The prime movers, hoisting equipment, rotating equipment, and circulatingequipment all combine to make rotary drilling possible.Prime MoversThe prime movers in a rotary drilling rig are those pieces of equipment that provide the power to theentire rig. Up until World War II, rotary rigs were traditionally powered by steam engines. Dieselengines became the norm after the war. Recently, whilediesel engines still compose the majority of power

sources on rotary rigs, other types of engines are alsoin use. Natural gas or gasoline engines are commonlyused, as are natural gas or gasoline poweredreciprocating turbines, which generate electricity onsite. The resulting electricity is used to power the rigitself. Other rotary rigs may use electricity directly frompower lines. Most rotary rigs these days require 1,000to 3,000 horsepower, while shallow drilling rigs mayrequire as little as 500 horsepower. Rotary rigsdesigned to drill in excess of 20,000 feet below surfacemay require much more than 3,000 horsepower. The

energy from these prime movers is used to power therotary equipment, the hoisting equipment, and thecirculating equipment, as well as incidental lighting,water, and compression requirements not associateddirectly with drilling.Hoisting EquipmentThe hoisting equipment on a rotary rig consists of thetools used to raise and lower whatever other equipmentmay go into or come out of the well. The most visible part of the hoisting equipment is the derrick, thetall tower-like structure that extends vertically from the well hole. This structure serves as a support forthe cables (drilling lines) and pulleys (draw works) that serve to lower or raise the equipment in the we

For instance, in rotary drilling, the wells are dug with long strings of pipe (drill pipe) extending from the

A Rotary Drilling Rig

Working on an Onshore Drilling Rig


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Offshore DrillingDrilling for natural gas offshore, in some instances hundreds of miles away from the nearestlandmass, poses a number of different challenges over drilling onshore. The actual drillingmechanism used to delve into the sea floor is much the same as can be found on an onshore rig.However, with drilling at sea, the sea floor can sometimes be thousands of feet below sea level.Therefore, while with onshore drilling the ground provides a platform from which to drill, at sea an

artificial drilling platform must be constructed.Drilling offshore dates back as early as 1869, when one ofthe first patents was granted to T.F. Rowland for hisoffshore drilling rig design. This rig was designed tooperate in very shallow water, but the anchored fourlegged tower bears much resemblance to modern offshorerigs. It wasn't until after World War II that the first offshorewell, completely out of sight from land, was drilled in theGulf of Mexico in 1947. Since then, offshore production,particularly in the Gulf of Mexico, has been verysuccessful, with the discovery and delivery of a great

number of large oil and gas deposits.

The Drilling TemplateSince the land that is going to be drilled through cannot provide a base for offshore drilling as it doesfor onshore drilling, an artificial platform must be created. This artificial platform can take many forms,depending on the characteristics of the well to be drilled, including how far underwater the drillingtarget is. One of the most important pieces of equipment for offshore drilling is the subsea drillingtemplate. Essentially, this piece of equipment connects the underwater well site to the drilling platformon the surface of the water. This device, resembling a cookie cutter, consists of an open steel boxwith multiple holes in it, dependent on the number of wells to be drilled. This drilling template is

placed over the well site, usually lowered into the exact position required using satellite and GPStechnology. A relatively shallow hole is then dug, in which the drilling template is cemented into place.The drilling template, secured to the sea floor and attached to the drilling platform above with cables,allows for accurate drilling to take place, but allows for the movement of the platform above, which wilinevitably be affected by shifting wind and water currents.In addition to the drilling template, a blowout preventer is installed on the sea floor. This system,much the same as that used in onshore drilling, prevents any oil or gas from seeping out into thewater. Above the blowout preventer, a specialized system known as a 'marine riser' extends from thesea floor to the drilling platform above. The marine riser is designed to house the drill bit and drill-string, and yet be flexible enough to deal with the movement of the drilling platform. Strategicallyplaced slip and ball joints in the marine riser allow the subsea well to be unaffected by the pitching

and rolling of the drilling platform.Moveable Offshore Drilling RigsThere are two basic types of offshore drilling rigs: those that can be moved from place to place,allowing for drilling in multiple locations, and those rigs that are permanently placed. Moveable rigsare often used for exploratory purposes because they are much cheaper to use than permanentplatforms. Once large deposits of hydrocarbons have been found, a permanent platform is built toallow their extraction. The sections below describe a number of different types of moveable offshoreplatforms.

Source: ChevronTexaco Corporation
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Drilling BargesDrilling barges are used mostly for inland, shallow water drilling.This typically takes place in lakes, swamps, rivers, and canals.Drilling barges are large, floating platforms, which must be towedby tugboat from location to location. Suitable for still, shallowwaters, drilling barges are not able to withstand the watermovement experienced in large open water situations.Jack-Up Rigs

Jack-up rigs are similar to drillingbarges, with one difference. Oncea jack-up rig is towed to thedrilling site, three or four 'legs' arelowered until they rest on the seabottom. This allows the workingplatform to rest above the surface of the water, as opposed to afloating barge. However, jack-up rigs are suitable for shallowerwaters, as extending these legs down too deeply would beimpractical. These rigs are typically safer to operate than drillingbarges, as their working platform is elevated above the water level.

Submersible RigsSubmersible rigs, also suitable for shallow water, are like jack-uprigs in that they come in contact with the ocean or lake floor. These

rigs consist of platforms with two hulls positioned on top of one another. The upper hull contains theliving quarters for the crew, as well as the actual drilling platform. Thelower hull works much like the outer hull in a submarine - when theplatform is being moved from one place to another, the lower hull is filledwith air - making the entire rig buoyant. When the rig is positioned over thedrill site, the air is let out of the lower hull, and the rig submerses to thesea or lake floor. This type of rig has the advantage of mobility in the

water, however once again its use is limited to shallow water areas.Semi-submersible RigsSemisubmersible rigs are the most common type of offshore drilling rigs,combining the advantages of submersible rigs with the ability to drill indeep water. Semisubmersible rigs work on the same principle assubmersible rigs; through the 'inflating' and 'deflating' of its lower hull. The main difference with aSemisubmersible rig, however, is that when the air is let out of the lower hull, the rig does notsubmerge to the sea floor. Instead, the rig is partiallysubmerged, but still floats above the drill site. Whendrilling, the lower hull, filled with water, provides stability tothe rig. Semisubmersible rigs are held in place by huge

anchors, each weighing upwards of ten tons. Theseanchors, combined with the submerged portion of the rig,ensure that the platform is stable and safe enough to beused in turbulent offshore waters. Semisubmersible rigscan be used to drill in much deeper water than the rigsmentioned above.Drill shipsDrillships are exactly as they sound: ships designed tocarry out drilling operations. These boats are speciallydesigned to carry drilling platforms out to deep-sea locations. A typical drillship will have, in additionto all of the equipment normally found on a large ocean ship, a drilling platform and derrick located on

A Drilling Barge

A Drillship in the Beaufort Sea

A Semisubmersible Rig

A Jack-Up Rig


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the middle of its deck. In addition, drillships contain a hole (or 'moonpool'), extending right through theship down through the hull, which allow for the drill string to extend through the boat, down into thewater. Drillships are often used to drill in very deep water, which can often be quite turbulent.Drillships use what is known as 'dynamic positioning' systems. Drillships are equipped with electricmotors on the underside of the ships hull, capable of propelling the ship in any direction. Thesemotors are integrated into the ships computer system, which uses satellite positioning technology, inconjunction with sensors located on the drilling template, to ensure that the ship is directly above thedrill site at all times.

Offshore Drilling and Production PlatformsAs mentioned, moveable rigs are commonly used to drill exploratory wellsIn some instances, when exploratory wells find commercially viablenatural gas or petroleum deposits, it is economical to build a permanentplatform from which well completion, extraction, and production can occur.These large, permanent platforms are extremely expensive, however, andgenerally require large expected hydrocarbon deposits to be economicalto construct. Some of the largest offshore platforms are located in theNorth Sea, where because of almost constant inclement weather,structures able to withstand high winds and large waves are necessary. Atypical permanent platform in the North Sea must be able to withstand

wind speeds of over 90 knots, and waves over 60 feet high.Correspondingly, these platforms are among the largest structures built byman. There are a number of different types of permanent offshoreplatforms, each useful for a particular depth range.

This depiction of offshore drilling and completion platforms gives an idea of just how massive theseoffshore rigs can

Natural Gas Principles

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