Glossary

ABARE

The Australian Bureau of Agricultural and Resource Economics (ABARE), located in Canberra, is an Australian government economic research agency. Their objective is to contribute to the competitiveness of Australia’s agricultural, fishing, forestry, energy and minerals industries and the quality of the Australian environment by providing rigorous and independent economic research analysis and forecasting.

API gravity

American Petroleum Institute gravity, a measure of how heavy or light a petroleum liquid is compared to water. An API gravity up to 10^o, is heavier than water and sinks. An API over 10^o means it is lighter and floats.
In general, oil with an API gravity between 40^o and 45^o is easier to refine into high valued products and therefore commands the highest prices.

 

Barrel

A unit of capacity. The Barrel is not an SI unit. The volume varies according to what is being shipped; a barrel of beer is 31 (US) gallons and a barrel of oil is 42 (US) gallons. In the context of this web site a Barrel is 159 litres (although litre or litre is not an official SI unit, the SI unit of volume is the cubic metres (m³), at least it's a metric unit).

Barrel of oil equivalent (bboe, sometimes BOE)

a unit of energy approximately equal to 1.7 MWh.

Biodiesel

Any liquid biofuel suitable as a diesel fuel substitute or diesel fuel additive or extender. Biodiesel fuels are typically made from oils such as soybeans, rapeseed, or sunflowers, or from animal tallow through a process called transesterification. Biodiesel can also be made from hydrocarbons derived from agricultural products such as rice hulls.

Biofuel

One definition of biofuel is any fuel with an 80% minimum content by volume of materials derived from living organisms harvested within the ten years preceding its manufacture.
Broadly defined as solid, liquid, or gas fuel derived from Biomass. This distinguishes it from fossil fuel, which is derived from long dead biological material.
Solid biofuel can be, for example, the biological waste product of sugar cane. Once the sugar has been extracted, the rest of the plant waste can be used to power the sugar mill.
Liquid fuels and blending components produced from biomass, such as biodiesel and ethanol, are used primarily for transportation.
Biogas typically refers to a gas produced by the biological breakdown of organic matter in the absence of oxygen. Examples are gases produced by sewage and landfill (methane). This can be used for heating or to generate either mechanical or electrical power. An added advantage is that Methane, a rather potent Greenhouse Gas, is converted (burned) into Carbon Dioxide and water.
The main advantage of biofuel is that it is renewable, but also that it is frequently a waste product.
Another advantage of biofuel, in comparison to most fossil fuels, is that it is biodegradable, and thus relatively harmless to the environment if spilled.

Biogas

Refers to gas produced by the biological breakdown (rotting) of organic matter in the absence of oxygen. Biogas is a type of biofuel.
One type of biogas is produced by anaerobic (without oxygen) digestion or fermentation of biodegradable materials such as biomass, manure or sewage, municipal waste (landfill), crops, livestock, termites and wetlands. This type of biogas is comprised primarily of methane and carbon dioxide.
The other principle type of biogas is wood gas which is created by gasification of wood or other biomass. This type of biogas is comprised primarily of nitrogen, hydrogen, and carbon monoxide, with trace amounts of methane.
Landfill gas (LFG) is created as solid waste decomposes in a landfill. This gas consists of about 50 percent methane (CH₄), the primary component of natural gas, about 50 percent carbon dioxide (CO₂), and a small amount of non-methane organic compounds. Instead of allowing LFG to escape into the air, it can be captured, converted, and used as an energy source.

Biomass

Biomass refers to all living and recently dead biological material (plant and animal).
Like coal and petroleum, biomass is a form of stored "solar" energy. The energy of the sun is "captured" through the process of photosynthesis in growing plants.

Brent

(or rather Brent Blend) is a combination of crude oil from 15 different oil fields in the Brent and Ninian systems, located in the North Sea. It is still classified as a "light" crude oil, but not as "light" as WTI. It contains about 0.37 percent of sulphur (making it a “sweet” crude oil, but again slightly less “sweet” than WTI).

Bushel

A bushel is a unit of dry volume, usually subdivided into eight local dry gallons in the systems of Imperial units and U.S. customary units. It is used for volumes of dry commodities, not liquids, most often in agriculture. It is abbreviated as bsh. or bu.
Bushels are now most often used as units of mass rather than of volume. The bushels in which grains are bought and sold on commodity markets and for reports of grain production, are all units of mass. These bushels depend on the commodities being measured; some of the more common ones are (all exact): Oats (USA): 14.515 kg, Barley: 21.772 kg, Corn (Maize): 25.401 kg, Wheat and Soybeans: 27.215 kg.

Carbon-14

A naturally occurring radioactive isotope: half-life approximately 5,730 years.

Carbon dioxide

is an atmospheric gas comprised of one carbon and two oxygen atoms. A very widely known chemical compound, it is frequently known by its formula CO₂. In its solid state, it is commonly called dry ice.  It is present in the Earth's atmosphere at a low concentration (in 2006 381 µL/L) and acts as a greenhouse gas. According to calculations based on CO₂ measurements in ice cores, the concentration has varied between 180 - 290 µL/L over the last 400 thousand years. Atmospheric measurements since 1958 have shown a 21% increase from 316 - 381 µL/L. Burning of fossil fuel produces CO₂ and water. Plants remove carbon dioxide from the atmosphere by photosynthesis, which uses light energy to produce organic plant materials by combining carbon dioxide and water. This releases free oxygen gas.

Carbon Sequestration

refers to the provision of long-term storage of carbon in the terrestrial biosphere, underground, or the oceans so that the buildup of carbon dioxide (the principal greenhouse gas) concentration in the atmosphere will reduce or slow. In some cases, this is accomplished by maintaining or enhancing natural processes.

• Sequestering Carbon in Underground Geologic Repositories: An example would be storing liquid carbon dioxide, once captured, into deep geological strata for example in a dry oil well and sealing it.
• Enhancing the Natural Terrestrial Cycle: Identifying ways to enhance carbon sequestration of the terrestrial biosphere through CO₂ removal from the atmosphere by vegetation and storage in biomass and soils.
• Carbon Sequestration in the Oceans: Enhancing the net oceanic uptake from the atmosphere by fertilization of phytoplankton with nutrients, and injecting CO₂ to ocean depths greater than 1000 meters.
• Sequencing Genomes of Micro-organism for Carbon Management: Sequencing the genomes of microbes that produce fuels such as methane and hydrogen or aid in carbon sequestration, to allow an evaluation of their potential use to produce, for example, methane or hydrogen from either fossil fuels or other carbonaceous sources, including biomass or even some waste products.

 

Cellulosic Ethanol

is the type of ethanol that is produced from a great diversity of biomass including waste from urban, agricultural, and forestry sources. Unlike normal ethanol, whose original raw material are sugars and starches, cellulosic ethanol starting raw material is cellulose. There are at least two methods of production of cellulosic ethanol-enzymatic hydrolysis and synthesis gas fermentation. Neither process generates toxic emissions when it produces ethanol.

Clean coal

A feel-good term used by politicians. It gives the impression that using it does not harm the environment. In reality, any hydrocarbon (or in the case of coal only carbon) which is burned (e.g. to create energy) produces green house gases.  "Clean Coal" is coal chemically washed of minerals and impurities. It is then gasified, burned and the resulting flue gases i.e. carbon dioxide are captured and stored under ground, out of sight is out of mind, instead of releasing them into the atmosphere.

Coal

is a readily combustible black or brownish-black sedimentary rock.  It is formed from plant remains that have been compacted, hardened, chemically altered, and metamorphosed by heat and pressure over long periods of time i.e. millions of years. The greatest coal-forming time in history was during the Carboniferous era (280 to 345 million years ago).  Depending on the grade of coal, it contains more then 50% by weight or 70% by volume of carbon atoms.  Most coal is contaminated the a greater or lesser extend with hydrogen, sulphur, water, minerals and metals. When coal is burned, it produces carbon dioxide, a greenhouse gas.  Coal is mainly used (75%) for electricity generation with a thermodynamic efficiency of between 35 and 40%.  On current consumption, about 5,800 million tons annually, there are enough proven coal reserves to last about 164 years. It has been estimated that there are enough reserves, accessible using current mining technology, for 300 years.

Coking

Refining process for thermally converting and upgrading heavy residual oil into lighter products and by-product petroleum coke.
In simple terms: it breaks the long molecules into smaller pieces.

Coking Refinery

This refinery processes residual fuel, the heaviest material from the crude unit and thermally cracks it into lighter product in a coker or a hydrocraker.  The addition of a fluid catalytic cracking unit (FCCU) or a hydro cracker significantly increases the yield of higher-valued products like gasoline and diesel oil from a barrel of crude, allowing a refinery to process cheaper, heavier crude while producing an equivalent or greater volume of high-valued products.
In simple terms: it breaks the long molecules into smaller pieces.

Cracking

A refining process, whereby longer (heavier) hydrocarbon molecules are broken into 2 or more shorter molecules by the application of heat and pressure, with or without the use of catalysts. Examples are Fluid Catalytic Cracking, Thermal Cracking and Hydrocracking.
In simple terms: it breaks the long molecules into smaller pieces.

Cracking Refinery

This refinery takes the gas oil portion from the crude distillation unit (a stream heavier than diesel fuel, but lighter than HFO) and breaks it down further into gasoline and distillate components using catalysts, high temperature and/or pressure. This increases the percentage of Distillate and Gasoline.
In simple terms: it breaks the long molecules into smaller pieces.

Crude oil

A mixture of hydrocarbons of various lengths, from 5 Carbon atoms up to over 50, that exists in liquid phase in natural underground reservoirs and remains liquid at atmospheric pressure. Between 1 and 4 Carbon atoms it is generally a gas. If over 50 and up to hundreds of Carbon atoms it becomes an Asphalt. If it contains little or no hydrogen, it is basically coal. Depending upon the characteristics of the crude stream, it may also include:

• Small amounts of hydrocarbons that exist in liquid phase under pressure in natural underground reservoirs, but are gaseous at atmospheric pressure and Lease condensate recovered as a liquid from natural gas wells in lease or field separation facilities. These are later mixed into the crude stream;
• Small amounts of non-hydrocarbons produced with the oil, such as sulphur and various metals;
• Drip gases, and liquid hydrocarbons produced from tar sands, oil sands, gilsonite, and oil shale.

Liquids produced at natural gas processing plants are excluded.
Crude oil is classified as "light, heavy, sweet or sour".
Examples are WTI, Brent, Dubai Fateh.
Crude oil is refined to produce a wide array of petroleum products, including:

• ethane, propane, and butane
• gasoline, diesel and jet fuels
• heating oils
• lubricants
• asphalt

and many other products used for their energy or chemical content.

Diesel

Diesel is produced from crude oil. Diesel at the pump is a mixture of hydrocarbons. The average chemical formula is C₁₂H₂₆. However this ranges from C₁₀H₂₂ to C₁₅H₃₂.

Dubai Crude

a light sour crude oil extracted from Dubai. Dubai Crude is used as a price benchmark or oil marker because it is one of only a few Persian Gulf crudes available immediately. The other two main oil markers are Brent Crude and West Texas Intermediate (WTI).

Dubai Fateh

A Heavy Crude oil.
Other Heavy crude oils are: Alaska Crude, Venezuela Orinoco Oil Belt, Athabaska Oil Sands - Alberta, Canada.

Ethanol (CH₃- CH₂ - OH)

A clear, colourless, flammable oxygenated hydrocarbon. Ethanol is typically produced chemically from ethylene, or biologically from fermentation of various sugars from carbohydrates found in agricultural crops and cellulosic residues from crops or wood. It is used in the United States as a gasoline octane enhancer and oxygenate (blended up to 10 percent concentration). Ethanol can also be used in high concentrations (E85) in vehicles designed for its use. See Fuel ethanol.

Excise

A tax on the sale of fuel, tobacco and alcohol (including fuel ethanol and blended fuel ethanol).
Fuel ethanol excise:
On 18 September 2002, denatured ethanol locally manufactured for use in an internal combustion engine became subject to excise duty at the same rate as petrol. This rate is currently 38.143 cents per litre. Fuel ethanol imported for use in internal combustion engines also attracts customs duty at the same rate. A subsidy (equal to the excise rate) would also be provided to domestic ethanol producers for the next 12 months. In May 2003, the Government announced that the producer grant would remain in place until 2008. In early 2004, this producer subsidy was extended until June 2011 and was to be administered by the Tax Office under the cleaner fuels grants scheme (to then be progressively phased out over the next five years up to 2015). These measures are intended to provide encouragement for the conversion to cleaner fuels. They also form part of the reforms to the existing fuel tax arrangements which will bring all currently untaxed fuels used in internal combustion engines into the excise system by 2011. See ATO web site (opens in new window) (ATO=Australian Taxation Office).

Fahrenheit

A temperature scale on which the boiling point of water is at 212 degrees above zero on the scale and the freezing point is at 32 degrees above zero at standard atmospheric pressure. To convert Fahrenheit to Celsius; Fahrenheit - 32 * 5 / 9. For example: 212 - 32 = 180, times 5 = 900, divide by 9 = 100 degrees Centigrade (Celsius).

Flash Point

of a flammable liquid is the lowest temperature at which it can form an ignitable mixture with air.

Fossil fuel

An energy source formed in the earths crust from decayed organic material. The common fossil fuels are petroleum, coal, and natural gas.

Fuel Ethanol (C₂H₅OH)

An anhydrous denatured aliphatic alcohol (ethanol) intended for gasoline blending as described in the Oxygenates definition.

Fuel Cell

A fuel cell operates like a battery. But unlike a battery, a fuel cell does not run down or require recharging. It will produce energy in the form of electricity and heat as long as fuel is supplied. A fuel cell consists of two electrodes sandwiched around an electrolyte.
Oxygen (air) passes over one electrode and hydrogen over the other, generating electricity, water and heat. Using a catalyst (usually Platinum), the hydrogen atom splits into a proton and an electron, which take different paths to the cathode. The proton passes through the electrolyte. The electrons create a separate current that can be utilized before they return to the cathode, to be reunited with the hydrogen and oxygen in a molecule of water.
The voltage from a single cell is about 0.7 volts. When the cells are stacked in series, the operating voltage increases to 0.7 volts multiplied by the number of cells stacked.

Gasoline

or petrol is a petroleum-derived liquid mixture. With the exception of Canada, most Commonwealth countries or former Commonwealth countries, use the term "petrol" (abbreviated from petroleum spirit). The term "gasoline" is commonly used in North America where it is often shortened in colloquial usage to "gas".

Gasification

High prices of oil and natural gas are leading to increased interest in "BTU Conversion" technologies such as coal gasification, methanation, liquefaction, and solidification.  Coal gasification breaks down the coal into its components, usually by subjecting it to high temperature and pressure, using steam and measured amounts of oxygen. This leads to the production of carbon dioxide and oxygen, as well as other gaseous compounds. Gasification is also a possibility for future energy use, as it generally burns hotter and cleaner than conventional coal and can thus spin a more efficient gas turbine rather than a steam turbine. It also makes for the possibility of zero carbon dioxide emissions even though the energy comes from the conversion of carbon to carbon dioxide. This is because gasification produces a much higher concentration of carbon dioxide than direct combustion of coal in air (which is mostly nitrogen). The higher concentrations of carbon dioxide makes carbon capture and storage more economical than it otherwise would be.

Global warming

An increase in the near surface temperature of the Earth. Global warming has occurred in the distant past (before humans) as the result of natural influences such as the fluctuations in the amount of energy emitted by the Sun, the earth's orbit and volcanic emissions, but the term is today most often used to refer to the warming some scientists predict will occur as a result of increased anthropogenic emissions of greenhouse gases. Irrespective of the causes, the fact is that the temperature has increased in the last 100 years by about .7 degrees celsius. Furthermore, the increase in greenhouse gases seem to be an accelerating factor. See Global Warming

Greenhouse effect

The result of water vapour, carbon dioxide, and other atmospheric gases trapping radiant (infrared) energy, thereby keeping the earth's surface warmer than it would otherwise be. Greenhouse gases within the lower levels of the atmosphere trap this radiation, which would otherwise escape into space, and subsequent re-radiation of some of this energy back to the Earth maintains higher surface temperatures than would occur if the gases were absent. Both primary and secondary effects of global warming — such as higher temperatures, lessened snow cover, rising sea levels, and weather changes — may influence not only human activities but also ecosystems. Some species may be forced out of their habitats (possibly to extinction) because of changing conditions, while others may flourish. See Global Warming

Greenhouse gases

Those gases, such as water vapour, carbon dioxide, nitrous oxide, methane, hydro fluorocarbons (HFC's), perfluorocarbons (PFC's) and sulphur hexafluoride, that are transparent to solar (short-wave) radiation but opaque to long-wave (infrared) radiation, thus preventing long-wave radiant energy from leaving Earth's atmosphere. The net effect is a trapping of absorbed radiation and a tendency to warm the planet's surface.

Heavy Crude

Heavy Crude oils (an API gravity below 22.3 ^o) usually contain high concentrations of sulphur and several metals, particularly nickel and vanadium, and high amount of wax. These are the properties that make them difficult to pump out of the ground or through a pipeline and interfere with refining. These properties also present serious environmental challenges. Heavy oil can be broken into the smaller petrol molecules, through the use of a "catalytic cracker", but this process uses energy and the resulting petrol is thus more expensive. That cost is offset by the cheaper cost per barrel of the heavy crude.

Hubbert Peak Theory

see Peak Oil.

Hydrocarbon

Any chemical compound that consists only of the elements carbon (C) and hydrogen (H). The Carbon and Hydrogen atoms are arranged in chains. In the case of Diesel there are 12 Carbon atoms and 26 Hydrogen atoms (twice as many +2). In the case of Petrol there are 8 Carbon and (2 * 8 +2 = 18) 18 Hydrogen atoms. When you burn hydrocarbons, every Carbon atom combines with 2 O(oxygen) atoms, forming CO₂. In doing so it releases a certain amount of energy. In addition to this every two Hydrogen atoms also combine with 1 Oxygen atom forming water (H₂O) and more energy. (Note: For illustration purposes we use 8 carbon atoms. However, petrol is in fact a mixture of hydrocarbons consisting of between 5 and 12 carbon atoms per molecule.)
The longer the chain, the fewer Hydrogen atoms compared to Carbon atoms.
Methane for example which is the simplest Hydrocarbon only has 1 Carbon atom, and therefore (2 * 1 + 2 = 4) 4 Hydrogen atoms. When burned, it forms only one CO₂ molecule + energy and 2 Water molecules + energy. When petrol gets burned, it forms 8 CO₂ molecules + energy and only 9 Water molecules + energy. The percentage of CO₂ molecules increases the longer the chain is. Coal on the other hand consist only of Carbon atoms and therefore creates only CO₂ molecules + energy.
So strictly on a litre by litre basis, petrol is better for the environment than diesel. In fact petrol produces 2.3 kilograms of CO₂ per litre compared with diesel 2.7 kilograms. And LPG is cleaner again, emitting about 1.5 kilograms of CO₂ per litre.
But it's not that simple. We need to take into account the fuel consumption. Because diesel has a higher energy content than petrol, you need less of it. In addition to this, (Turbo) diesel engines are more efficient than petrol engines. (45% compared to 30%).

Hydrotreating

A process used in an oil refinery to remove sulphur from finished products. As the legal requirement to produce ultra low sulphur products increases, additional hydrotreating capability is being added to refineries. Refineries that currently have large hydrotreating capability have the ability to process crude oil with a higher sulphur content.

Hydrogen

Hydrogen, H₂, is a gas, colourless, odourless and tasteless. Hydrogen is usually combined with Oxygen, for example water H₂O or Carbon, forming the Hydrocarbons like methane, petrol or diesel etc. Hydrogen is being proposed as a clean fuel.

Light Crude

Light crude oil is defined as having a low specific gravity. (An API gravity higher than 31.1 ^o). This grade of oil is easier to pump, transport and refine into high value products like petrol, diesel and jet fuel. Because of this, it tends to be more expensive.

Liquefaction

Coal can be converted into liquid fuels like gasoline or diesel by several different processes. However, all of these liquid fuel production methods release carbon dioxide (CO₂) in the conversion process, far more than is released in the extraction and refinement of liquid fuel production from petroleum. If these methods were adopted to replace declining petroleum supplies carbon dioxide emissions would be greatly increased on a global scale.  Coal liquefaction is one of the backstop technologies that could potentially limit escalation of oil prices and mitigate the effects of transportation energy shortage under peak oil.
This is contingent on liquefaction production capacity becoming large enough to satisfy the very large and growing demand for petroleum. Also, a risk is that the extra carbon dioxide released in the process could catastrophically accelerate global warming/adverse climate effects.

Methane

The simplest hydrocarbon, methane, is a gas with a chemical formula of CH₄.  Apart from gas fields, sources of methane are biogas generated by the fermentation of organic matter including manure, wastewater sludge, municipal solid waste or any other biodegradable feedstock, under anaerobic conditions. It is also caused by animals' natural gas. It is a Greenhouse Gas.
As a greenhouse gas it is effectively 20-21 times as strong as CO₂. Two thirds of all methane produced in Australia comes out of burping livestock, helping to make the agriculture sector Australia's second largest greenhouse gas polluter after the energy sector.
A typical dairy cow can produce between 200 and 600 litres of methane per day, some 50 to 150 kilograms a year.

Octane Rating

Is a measure of the auto ignition resistance of petrol and other fuels. When a fuel is compressed, as in a cylinder, the fuel can ignite without the use of a spark. This creates pre-ignition or detonation, also known as "knocking" or "pinging". The higher the octane rating, the more compression the fuel can withstand before it self-ignites. With higher compression you get more powerful engines.
Some additives like lead (tetra-ethyl lead) and ethanol will increase the octane rating of petrol. Because of the detrimental effect on our health and the environment lead in petrol has now been phased out in most countries.

Oxygenates

Substances which, when added to gasoline, increase the amount of oxygen in that gasoline blend.
Ethanol, Methyl Tertiary Butyl Ether (MTBE), Ethyl Tertiary Butyl Ether (ETBE), and methanol are common oxygenates.

Peak Oil

refers to a singular event in history: the peak of the entire planet's oil production. After Peak Oil, according to the Hubbert Peak Theory, the rate of oil production on Earth will enter a terminal decline.
In practice there are several "peaks".

• An absolute peak.
• A relative peak - There is more oil in the ground, but using current technology, it is impossible to get it out. This peak keeps shifting as technology improves.
• A political peak - The oil is there, but due to political reasons it is not recoverable (at the moment).
• An economic peak - The oil is there; we have the technology, but it is not economical to get it out.
  However as world oil prices increase this peak will shift. The reserves will also increase with an increase in the price of crude oil, as the oil is only counted towards the "reserve" if it is economically and technically recoverable.

In 1956 Dr Hubbert predicted that U.S. oil production would peak in about 1970 and decline thereafter. He was ridiculed by just about everyone, including his then employer Shell.
His theory was more a calculation based on the extrapolation of the then known reserves and has proved to be remarkably accurate.
His theory is mainly quoted in relation to crude oil, however in his presentation in 1956 he also gave calculations for gas, coal and nuclear material.
Dr Hubbert was a man with foresight, who in 1949 predicted "that the fossil fuel era would be of very short duration." If only our politicians had such foresight.

see also: Oil-Are we running out?

Petrol

see Gasoline

 

REC

Renewable Energy Certificates (RECs). In short, The act itself is 127 pages, for every 1 MWh of renewable energy created 1 certificate gets created. These certificates may then be sold or traded. The value of the certificates changes on a daily basis. Over the last few years it has been between $6 and $36 per REC.

 

Sequestration

See Carbon Sequestration

SI Unit

The International System of Units (abbreviated SI from the French language name Système International d'Unités) is the modern form of the metric system. It is the world's most widely used system of units, both in everyday commerce and in science.
The system is nearly universally employed and most countries do not even maintain official definitions of any other units. Three nations have not officially adopted the International System of Units as their primary or sole system of measurement: Liberia, Myanmar and the United States.

Spot price

spot price or spot rate of a commodity (like crude oil), a security or a currency is the price that is quoted for immediate (spot) settlement (payment and delivery). Spot prices reflect current supply and demand, not future price expectations. Example: Brent spot.

Sulphur Dioxide (SO₂)

Sulphur dioxide is a gas. It is invisible and has a nasty, sharp smell. It reacts easily with other substances to form harmful compounds, such as Acid Rain - sulphuric acid, sulphurous acid and sulphate particles.
About 99% of the sulphur dioxide in air comes from human sources. The main source of sulphur dioxide in the air is industrial activity that processes materials that contain sulphur, e.g. the generation of electricity from coal, oil or gas that contains sulphur
Sulphur dioxide is also present in motor vehicle emissions, as the result of fuel combustion. In the past, motor vehicle exhaust was an important, but not the main, source of sulphur dioxide in air. However, this is no longer the case.
In December 2002, a new standard was introduced, reducing the maximum sulphur content of diesel from 1300 parts per million (ppm) in 1999 to 500 ppm. By 2008, the sulphur level in premium unleaded petrol will be 50 parts per million and, by 2009, sulphur levels in diesel will be 10 parts per million.

Sulphur Dioxide is not a greenhouse gas. In fact sulphur can be used to combat Global Warming.
Nobel laureate Paul Crutzen from the Max Planck Institute for Chemistry in Germany and the Scripps Institution of Oceanography, University of California at San Diego suggests carrying sulphur into the atmosphere via balloons and using artillery guns to release it, where the particles would stay for up to two years, reflecting sunlight.
When Mount Pinatubo erupted in the Philippines in 1991, millions of tons of sulphur were injected into the atmosphere, enhancing reflectivity and cooling the Earth’s surface by an average of 0.9 degrees Fahrenheit (0.5 degrees Celsius) in the year following the eruption.

 

Sweet / Sour Crude

Sweet Crude has small amounts of sulphur (mainly hydrogen sulphide H₂S) (.5% or less) and carbon dioxide, and is used primarily in petrol. Sulphur does damage to the equipment when refining and does damage to the environment (and your car's engine) if not removed. If the percentage exceeds .5% it is classified as sour. Because of the costs involved in removing the sulphur, sour oil tends to be cheaper than sweet oil.

Stratosphere

the part of the earth's atmosphere which extends from the top of the troposphere to the bottom of the mesosphere, about 50 kilometres above the earth's surface. Clouds form in the troposphere but rarely in the stratosphere. Temperature in the stratosphere increases with altitude.

Tapis (Blend or Crude)

is a Malaysian crude oil used as a pricing benchmark in Singapore. While it is not traded on a market like Brent Crude or West Texas Intermediate, it is often used as an oil marker for Asia. API gravity =31.6 ^o Sulphur content = 0.03%

Ton

Imperial unit of measurement.
This is a case where 'a ton by any other name is NOT a ton'.
There is a Long Ton, equivalent to 1016 and a bit kg (precisely 1016.0469088 kg), a Short Ton, equivalent to 907 and a bit kg, a Ton Shortweight, equivalent to a long ton i.e. about 1016 kg, a Ton Longweight, about 1088.6 kg.
Then there are:
The Assay Ton, used for ore, (depending on long or short either 32 2/3 gram or 29 1/6 gram),
The Freight Ton also known as a Measurement Ton (equivalent to 40 cubic feet) also known as the US shipping ton. This one is about 5% smaller than the British shipping ton, which is 42 cubic feet.
The Register Ton or a Gross Registered Ton (equivalent to 100 cubic feet) and a Water Ton (equivalent to 224 Imperial Gallons, not to be confused with American Gallons).
Don't be fooled by thinking this would be the same as the displacement ton, which is exactly 35 cubic feet.
The Deadweight Ton, (dwt) a measure of a ship's carrying capacity, including bunker oil, fresh water, crew and provisions. It could be expressed in long tons, (1016kg) or metric tonnes (1000 kg).
The Harbour Ton is equivalent to 2000 pounds or a short ton.
The Panama Canal Net Ton, a unit for billing for ships going through the Panama Canal, is the same as the register ton.
Then there are the Ton of TNT (equal to 10⁹ (thermo chemical) calories (please note: small calories (cal), nothing to do with the large Calories (Cal) used in diets))
This is to name but a few.
(A ton is also used in cricket, where it equivalent to 100 runs, also known as a century.)
Confused? That's why we use the "tonne".

Tonne

Not to be confused with Ton.
Where there might be any confusion the term Metric Ton(ne) is used.
The Tonne is a measurement of mass equal to 1000 kilograms.
It is not an SI unit, but is commonly accepted as one in practice. (In the SI system it should be referred to as mega-gram, but nobody does).

Topping plant

A type of oil refinery, (the simplest) which consists only of a distillation unit and probably a catalytic reformer to provide octane.  Yields from this plant would most closely reflect the natural yields from the crude processed. Typically only condensates or light sweet crude would be processed at this type of facility unless markets for heavy fuel oil (HFO) are readily and economically available.  Asphalt plants are topping refineries that run heavy crude oil because they are only interested in producing asphalt.

Transesterification

In organic chemistry, transesterification is the process of exchanging the alkoxy group of an ester compound by another alcohol. These reactions are often catalyzed by the addition of an acid or base. One of the first uses of transesterified vegetable oil (biodiesel) was powering heavy duty vehicles in South Africa before World War II. The name "biodiesel" has been given to transesterified vegetable oil to describe its use as a diesel fuel.

Troposphere

The lowest part of the earth's atmosphere in which most weather changes occur. It extends from the earth's surface to the bottom of the next layer, the stratosphere. The thickness of troposphere varies between 7km at the poles and 17km at the equator. Temperature in the troposphere decreases with altitude.

WTI (West Texas intermediate)

crude oil at a reference sales point in Cushing, Oklahoma. This oil is of very high quality and is excellent for refining a larger portion of gasoline. It is a “light” crude oil (API=39.6 ^o), and it contains only about 0.24 percent of sulphur (making it a “sweet” crude oil)

Yield

The amount of product you get when refining a barrel of crude oil.
This amount depends on the type of oil used i.e. heavy or light, and what the refinery operator needs.
Yields from the simplest refinery, a topping plant, would most closely reflect the natural yields from the crude processed. A light crude would yield a higher percentage of Distillate and Gasoline than a very heavy crude.
The yield of higher-valued products like gasoline and diesel oil from a barrel of crude using a cracking refinery would be greater, and that of a coking refinery would be greater still.
The operator of the last two types of refineries, can adjust the percentages, depending on requirement. In winter more heating oil is needed, in summer more oil for transport.

Comparison of Yields by Refinery Type illustrating that using the same crude input (in this case a heavy crude with a 27 API) yields a very different range of petroleum products depending on the refining units and processes used.