Greenhouse Glossary

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Energy Terms Glossary

This page lists terms relevant to our business. The left column displays the term, a definition and details, and the right column shows the symbol or abbreviation where applicable.

Term and Description

Symbol or Abbreviation

A B C D E F G H I J K L M N O P Q R S T U V W X Y or Z


Acid rain

Acids (sulphurous, sulphuric, nitrous and nitric acids) can form in the atmosphere as a result of moisture in the air mixing and reacting with:

  • sulphur oxides (SOx) (from burning Fossil fuels which contain sulphur. The sulphur content of fuels varies, with North American coals and crude oil having a higher sulphur content than most Australian supplies).
  • nitrogen oxides (NOx), mainly from burning of Fossil fuels and wood

Acid rain is the general term for the deposition of this acid onto buildings, vegetation etc, either:

  • wet, in rain, mist, snow, etc, or
  • dry, as salts.

Acid rain damages buildings and other structures (especially metal and stone) weakens or kills terrestrial and aquatic plants and fish , and degrades the health of people and animals.

Because SOx and NOx are gases and because the formation of acid rain takes time, acid rain damage often occurs far from the source of the problem.


Active (building design feature or energy system.

Active features are those with moving parts and/or controls such as fans, pumps and automated blinds or louvres. For example, a solar hot water system which uses a pump to circulate water through the collector is classified as Active while one relying on natural the thermosiphon effect is classified as a Passive system.



Refers to processes which occur in the presence of oxygen (because the process needs oxygen).

This contrasts with Anaerobic processes.

See also Greenhouse gases


Aerosols (in the atmosphere)

Very small particles and droplets, excluding water, dispersed in the atmosphere. Aerosols absorb solar Radiation, then re-emit and scatter it, and so have a net cooling effect. Aerosols also they facilitate the process by which water vapour turns into cloud droplets.

The main human-activity source of aerosols in the atmosphere is Sulphur dioxide: chemical reactions convert it into sulphate aerosol.

see also Subject Area Greenhouse effect



Creating a forest(s) where there was not one before. This can be used to act as a greenhouse gas sink, and to provide timber as an alternative to destroying existing forests.

see also Deforestation, and Subject Area: Greenhouse response



the reflection of solar Radiation which falls on the earth back into space.


Alternating current



Refers to processes which are caused by the action of anaerobes which are micro-organisms which require or can survive in an oxygen-free environment.

Methane is created by the anaerobic decomposition of organic material.

Anaerobic is the opposite of Aerobic.



Caused by the human race or human activities.

Normally used in the context of “anthropogenic greenhouse effect” ie. the human addition to the natural greenhouse effect.

see also: Greenhouse effect



Hydrocarbons with a ring structure, generally with a distinctive aromatic odour, and good solvent properties, sometimes used as octane improvers in Petrol.

e.g. benzene, toluene and xylene



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An electrical device in a fluorescent or other discharge light fitting which acts to limit the electrical current in the lamp.


Barrel (of oil)

A standard measure for oil and oil products.

One barrel = 159 litres.


Barrel oil equivalent

The amount of energy equivalent to a barrel of oil, used to describe other energy sources such as natural gas, petroleum gas, etc..

One boe = 6.12 GJ

See also Measurement and Energy and power measurements


Base load

the minimum system load where the load varies, especially the overnight minimum load in a system.

Electricity Systems. State electricity systems display a base-load which can be around 60% to 75% of the daily maximum. To serve the varying load, electricity generation systems are normally designed to include:

  • Large coal-fired “base-load” power stations which are economical to run but which are not suited to short runs
  • Intermediate-load power stations, typically large gas-fired boilers and steam turbines
  • Peak-load power stations, typically gas turbines (which are similar to aircraft jet engines) fuelled by natural gas

Electricity utilities have adjusted tariffs to encourage electricity use during the off-peak periods (see also Demand side management) with special low prices for off-peak water heating (which unfortunately wastes energy both from unavoidable Standing losses in a storage heating system and the built-in Losses in the electricity generation and reticulation system). From a greenhouse gas perspective, the encouragement of electricity for water heating is also regrettable because of the very high emissions compared with Natural gas, LPG, and solar alternatives.

Customer Load Profiles. The pattern of energy consumption for a building, factory or other customer premises will also often display a base-load, even for those customers with no apparent need for energy outside working hours. Monitoring energy consumption and finding this base-load often reveal significant opportunities to reduce energy related greenhouse gas emissions and costs. In fact, it is not unusual for a business to consume as much energy outside working hours than during working hours (especially for businesses with relatively short business hours (2000 working hours per year leaves 5760 non-working hours per year).

see Efficiency, System efficiency, Standing losses, and Subject area: Efficiency


Benchmarking, performance indicators

establishment of a Quantitative reference point by which efficiency, performance or excellence can be judged and progress monitored. The benchmark will often use a parameter which will allow comparison of performance with other organisations in a similar role. For example, these may be CO2 per $ turnover, per room night, per tonne of product, per square meter or floor space, per meal served, etc.

see also Subject area: Efficiency


Biomass (energy)

Term to describe the resource of energy stored in plants and animals or released during their use or processing including as a by-product or “waste”. Examples include:

  • wood, for heating
  • bagasse (sugar cane residue) for raising steam which is used in sugar refining and for the generation of electricity which can be exported from the sugar mill to the grid.
  • residue from agricultural products, eg. straw.
  • Methane, generated from the Anaerobic decomposition of animal and plant wastes, including vegetable peelings, manure, either collected from purpose built digesters or as Land-fill gas.
  • dung.
  • tallow.

Biomass is a renewable energy source and the main source of stored energy for the majority of the human race.

See also: Ethanol, Methanol, and Subject area Energy sources.



The system comprising the earth and its Atmosphere, which supports life.



  • a device for heating water to convert it to steam for use in heating or power generation, etc.
  • also used to describe a large commercial water heater in which the water does not boil (these should really be called water heaters). Such heaters are commonly used for comfort heating in large air-conditioning systems in office building. The term atmospheric boiler is also used to describe these, because the water stays at atmospheric pressure.

British Thermal Unit

Imperial unit of energy equal to 1.055 kJ (kiloJoules).

Derivation and definition: the amount of heat necessary to raise one (1) pound of water, one (1) degree Fahrenheit.

see also: Energy and Power Measurement


Brundtland Commission.

The informal name used for the World Commission on Environment and Development (WCED), established in 1984 by the UN General Assembly, and chaired by Norwegian Prime Minister Gro Harlem Brundtland. The Commission’s report: Our Common Future (1987), established the concept of sustainable development.


Bunkers (fuel use)

energy used for international marine and air transport tasks.


Business as usual

An economic “base-case” where no actions are taken specifically because of their greenhouse abatement benefits (although they may be undertaken because of their other benefits; eg. cost savings).

see also: Greenhouse response

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Calorific value:

also referred to as “Heat Value or Heat of Combustion“. The amount of energy released from a substance when it is completed converted to heat energy, usually involving a change in chemical composition.

The heat value can be described as:

  • Gross calorific value, which includes the heat available from the products of combustion as they are cooled to ambient temperature. The GCV is also called the higher heating value.
  • Net calorific value (NCV) is the gross calorific value less the heat required to vaporise the fuel before it can be burnt and to vaporise water vapour produced during combustion (this energy is normally supplied by the fuel during the combustion process, but in a laboratory test can be supplied by an external heat source.

see also Subject Areas: Energy sources, and Measurement



Carbon dioxide

The main greenhouse gas and the gas to which other Greenhouse gases are compared. Most of the increase in CO2 concentration in the atmosphere is attributable to:

  • increasing the Source of CO2 by burning Fossil fuels and so releasing carbon which has been previously stored out of the atmosphere, and
  • reducing the capacity of the earth to remove CO2 from the atmosphere by destroying forests (see Carbon sinks).

Human activities add about 26 Gigatonnes (26 billion tonnes) of CO2 to the atmosphere every year.

See also: Energy sources and CO2 emissions, and other Greenhouse gases


Carbon dioxide equivalent

The amount of carbon dioxide to achieve the same contribution to the enhanced greenhouse effect as a given amount of another gas. This enables all emissions to be tallied to arrive at a single total.

According to Australia’s 1990 greenhouse gas inventory, 572 million tonnes of carbon dioxide equivalent emitted per year.

See also Global Warming Potential, Greenhouse gases,

CO2 equiv

Carbon dioxide fertilisation.

Improved plant growth as a result of increased concentrations of CO2 in the atmosphere


Carbon intensity

The amount of CO2 emitted for each unit of product (eg. tonne of manufactured product, GWh of electricity, dollar of value added).

See also: Energy Sources and CO2 Emissions


Carbon leakage

A term given to a hypothetical increase in emissions as a result of movement of production from an efficient country to a less efficient country, after the former introduces emission reduction initiatives which (again, hypothetically) increase the cost of production.

If this did occur, the nett global effect of the abatement action one country would be an increase in greenhouse gas emissions. However, given the wide range of emission reduction strategies which actually reduce the cost of production, this theory is not very compelling.

See also: Greenhouse effect


Carbon monoxide

A Precursor of Ozone.

See also: Greenhouse gases


Carbon sink

A way of removing carbon from the atmosphere, including natural mechanisms such as photosynthesis in trees (CO2 to wood) and calcium carbonate (CaCO3) formation by marine molluscs.

See also: Greenhouse response


Carbon source.

A pool or store of carbon.



Man-made chemical compounds containing chlorine, fluorine and carbon. Specific compounds within this family are each given suffix (e.g. CFC-11, CFC-12). CFCs are relatively inert, non-toxic but contribute to two major environmental problems:

CFCs are powerful greenhouse gases. This, combined with their long life in the atmosphere (around 50 years, because of their inertness) would make them a problem, however they also destroy ozone in the lower stratosphere, which tends to negate their direct greenhouse effect. Also, because they are the main cause of damage to the ozone layer, their use is being curtailed by the Montreal Protocol. The most common uses of CFCs have been as:

  • propellants (in aerosol cans or “pressure packs”)
  • refrigerants (in air-conditioners and refrigerators),
  • blowing agents for producing foam products, such as expanded polystyrene insulating panels, disposable cups, etc.

The use of prescribed CFCs in Australia is legal, but the manufacture and importation is banned. The use of CFCs is declining as equipment which relies on these compounds is replaced or modified. Because of the supply restrictions, the price of CFCs has sky-rocketed and so most users are getting a clear economic signal to replace CFC-based equipment.

see also Fluorocarbons, Montreal Protocol, and the Subject Area:Greenhouse gases


Climate Change (FCCC usage)

A change of climate which is attributed directly or indirectly to human activity which alters the composition of the global atmosphere and which is in addition to the natural variability observed over comparable time periods.

see also: Greenhouse effect


Climate Change (IPCC usage)

Climate change as referred to in the observational record of climate occurs because of internal changes within the climate system or in the interaction between its components, or because of changes in external forcing, either for natural reasons or because of human activities. It is generally not possible clearly to make attribution between those causes. Projections of future climate change reported by IPCC consider only the influence on climate of anthropogenic increases in greenhouse gasses and other human-related factors.

see also: Greenhouse effect


Climate System (FCCC usage)

the totality of the atmosphere, hydrosphere, biosphere and geosphere and their interactions

Source UNFCCC, Climate Change Secretariat, Definitions


Coal (CO2 emissions)

see: Emission figures for briquettes and electricity



Combined heat and power generation where both the heat and motive power or electricity outputs are put to use. This compares with electricity generation in a power station where the unavoidable heat generated usually can not be profitably employed and so is wasted.

Also called “combined heat and power” or “CHP”.

see also: Subject Area Energy sources


Compact fluorescent lamps

a fluorescent which is smaller than the original fluorescent lamps and their derivatives. Compact fluorescent lamps:

  • have power ratings from 5 Watts to 55 Watts (the latter is 535 mm long; which is not really compact but is smaller than the equivalent standard fluorescent lamp which would be 1500 mm long).
  • normally use tri-phosphor coatings, which gives them a more acceptable light colour and higher efficiency than standard lamps.
  • may either have an integral Ballast (allowing them to be used as drop-in replacements for Incandescent lamps) or rely on a ballast which is hard-wired into the light fitting.


Compressed natural gas

Natural Gas which has been compressed to allow a useful amount of energy to be stored in the limited space available in a vehicle fuel tank. The advantages of CNG for vehicles are that it burns cleaner than petrol, is cheaper than petrol, and uses a wholly indigenous fuel source. The CO2 emissions of natural gas energy use are about 10% lower than for petrol but this excludes the electricity used to compress the natural gas, which increases both the energy used and the CO2 emitted.

also called Natural Gas for Vehicles (NGV).




heat transfer through a material which does not rely on movement of the material..

see also: Convection and Radiation


Conference of the Parties

The Conference of the Parties under the FCCC, at its first meeting in Berlin (1995), initiated a negotiation over a protocol, or other legal instrument, to include quantified emission objectives beyond the year 2000, and coordinated policies and measures. Further, the Second Conference of the Parties (Geneva, 1996) called for the inclusion of legally-binding quantified objectives in the legal instrument to be negotiated at Kyoto in December 1997.



heat transfer by the movement of fluids (liquids and gases) containing heat energy.

see also: Conduction and Radiation


Conversion efficiency

the Efficiency in of the Energy conversion process.


Conversion (of energy)

see Energy conversion


Cooling degree-days

see Degree-days


Cultural change

Changing peoples human knowledge, learning methods, shared attitudes, values, goals, beliefs, social norms, practices and behaviours in an organisation or corporation to better meet the goals of the organisation and the wider community.

see also: Subject Area: Greenhouse response



In an electrical circuit, the flow of electricity, measured in Amps.

See Description in Electrical Measurements and Terms


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Loss of forest, usually as the result of clearing for agricultural (especially for cattle grazing) or other land uses such as roads and buildings.

Estimated (Source: Mintzer, 1992).deforestation causes worldwide are:

  • slash and burn timber gathering, 40-50%
  • grazing 10%,
  • 10-20%,
  • forestry and plantations for 5-10%, and
  • forest fires 1% to 15%.

Deforestation destroys what may be an important sink for excess CO2 in the atmosphere.

Although afforestation is promoted as a way of taking CO2 from the atmosphere, reducing or stopping deforestation is a much cheaper and achievable strategy, which also has the advantage of preserving a greater diversity of plant and animal species.

see land use CO2 emissions in the summary of the Australian Greenhouse gas inventory



a measure of the demand for heating (“heating degree-days”) or cooling heating (“cooling degree-days”) in a geographical location, expressed as degree-days per year to a base temperature. One degree-day means that the temperature needed to be changed by an average of 24 degree-hours during the year. For example, the Melbourne heating demand to base 18° C is 1378 heating degree-days per year; the figure for Brisbane is 238, and for Darwin 0. Programs are available to calculate the heating and cooling degree-days for periods other than continuous operation (eg. during office hours only).


Demand-side management (DSM).

Usually taken to mean managing the demand for electricity to enable existing generation and transmission assets to meet customer requirements, rather than simply building more power stations etc. The maximum demand can be managed, for example, by:

  • fuel switching (eg. from electricity to gas),
  • using more efficient appliances,
  • time-shifting loads (eg special tariffs for irrigators who pump outside the peak demand periods) which flattens the load demand profile without reducing total electricity use.

DSM has several advantages over increasing energy supply:

  • most DSM methods reduce greenhouse gas emissions whereas boosting energy supply leads to increases,
  • most DSM actions have a higher return on investment,
  • reductions can be implemented in small increments, resulting in lower financing requirements and risks than increasing energy supply,
  • they have a much shorter lead time,
  • DSM actions typically use local resources and labour, whereas power stations typically use imported turbines, generators and controls, etc.

DSM has been hampered in the past by insufficient use of integrated resource planning and life cycle costing.

see also: Base load


Diesel engine,

An Internal combustion engine which uses heat and compression of the fuel air mixture to cause the mixture to ignite (hence diesel engines are also referred to as “compression ignition” engines).

Diesel engines:

  • have a higher fuel efficiency than petrol engines
  • must be made stronger than petrol engines in order to withstand the stress caused by “diesel knock” and so are heavier and more expensive to produce, but last longer.
  • emit particulates in the exhaust; these have been associated with health problems including cancer.

Diesel fuel

Fuel which as a fuel-air mixture which will spontaneously ignite in a Diesel engine because of the heat and compression.

CO2 emissions: see: Energy sources and CO2 emissions


Direct current

An electrical system where the flow of electricity does not change its direction.

See Description in Electrical Measurements and Terms


Direct greenhouse gas:

see Greenhouse effect


Discount rate

a reduction in the value of future cash flows because of the time-value of money.

see also: Financial evaluation

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Ecologically sustainable development

Development that improves the quality of life, both now and in the future, in a way that maintains the ecological processes on which life depends.

Source:  NSW EPA


Economic (actions).
Actions which are justified by the financial benefits (eg. lower operating costs) alone.

see also: financial evaluation


Economic cost

The price that is paid as the result of taking a course of action. The price may include a transfer of funds, but is not limited to monetary costs.

The economic cost also includes losses such as loss of amenity, declines in environmental integrity, aesthetic quality, noise pollution etc which are difficult or impossible to accurately cost and other costs such as a loss of leisure time where a value can be imputed by considering how much people may normally spend to save time. Other “costs” such as poor health have both a direct Financial cost (eg. hospital stays, medication, lost work time, etc) as well as the intangible cost of not feeling well.

Economic costs include both direct costs plus opportunity costs which describe the benefits which may be foregone because an action is taken.

Economic costs are often use to consider the ramifications of possible future actions.



Similar to Efficiency, except that it describes the effectiveness of converting the input resource to a useful output in a different form to the input. For example, efficacy is often used in lighting, where the input resource (electricity) is in a different form to the output (light).

see Efficiency, Fuel efficiency, System efficiency, Transmission losses and Subject area: Efficiency



Efficiency describes the portion of a resource input which is successfully converted to the desired useful output. For example, in a water turbine, the portion of the available power in the water which is converted to power in a rotating shaft.

see Efficacy, Fuel efficiency, System efficiency, Transmission losses and Subject area: Efficiency


Electricity Supply Association of Australia

The industry body representing and providing services to public and private electricity generation, distribution and retail organisations in Australia.

See also ESAA home page.


El Niño Southern Oscillation

abnormal warming of equatorial ocean North of Australia and movement of that warmed water Eastward to South America, taking rain with it. This causes droughts in Australia and increased rainfall and flooding in South America.

There is informed speculation that the El Niño is caused by global warming.

see also US National Oceanographic & Atmospheric Administration El Niño Web page.


End-use emissions

pollutant emissions which occur at the end-use such as those from gas heaters, vehicles, etc. These compare with upstream emissions which are removed from the energy end-use, such as emissions from power stations and oil refineries.

See also: Greenhouse gases



the ability or capacity to due work. Measured in Joules or (for electrical energy) Watt.hours.

See also, definition of: Energy in Electrical Measurements and Terms, and:
Energy and Power Measurement


Energy conversion

converting energy from

  • one form to another (eg. from stored potential energy to electrical energy in a hydro-electric power station, the conversion of energy from chemical energy in fuel to electricity in a power station), or
  • from chemical energy to thermal energy in a boiler) from chemical energy in natural gas to heat in hot water,
  • or to a different energy type or product of the same form (eg. from crude oil to petrol, from coal to briquettes, from high voltage to low voltage electricity).

see Efficacy,Efficiency, System efficiency and Subject area: Efficiency


Energy Dimension of Climate Change

The IEA statement on feasible and cost-effective energy policy responses to climate change.



Also called ethyl alcohol, grain alcohol; potato alcohol; alcohol; spirit. This is the alcohol found in wine.

Alcohol usually formed by the fermentation of sugars. Has been used successfully to replace petrol or as an additive to boost the octane rating of petrol (which will become more important as lead is removed from petrol supplies). Although fuel ethanol has been derived from food crops (such as corn) production from agricultural residues and wood waste (ligno-cellulose) hold the promise of reducing prices and so increasing applications.

Probably the most important cost factor in the use of alternative fuels is the potentially very high cost of modifying millions of engines. However, ethanol can be used as a blend with Petrol with little or no modifications.

The energy density is only about 60% that of petrol but this will not be a problem in a blend (eg. 20% ethanol) especially if the engine is optimised to take advantage of the higher octane rating of the ethanol blend.

The obvious greenhouse benefit is the production of a liquid fuel source from a renewable and potentially zero net-CO2 emitter (depending on the fuels used to growing, harvesting, processing and distribution).

Fuel ethanol was produced in Australia in 1995-96 by two plants: the CSR plant at Mackay in Queensland, based on a sugar molasses feedstock and the Manildra plant at Shoalhaven in New South Wales, based on the biomass waste stream from starch and gluten production. Output in 1995-96 was about 12 million litres, with a production cost of about $9 million and a sales value of about $6 million.

The Australian Government has an ethanol bounty to encourage the industry during its development

See also: Biomass, Methanol, subject area Energy sources, and DPIE NetEnergy Ethanol page.


Evaporative emission

hydrocarbon emissions resulting from the evaporation of liquid fuels, especially from vented fuel tanks and during refuelling.

see also volatile organic compounds (VOCs)



a term to describe the costs (financial or economic costs) imposed by the activities of an individual or group but borne by others. Whether a cost is external depends on the boundaries of the system being studied.

Examples include:

  • the driver of a car does not pay directly for any ill-health effects caused by pollutants emitted by the car, but the wider community does.
  • the owner of a building probably does not pay the wider community for the loss of solar access or views.
  • the cost of rising sea levels may be borne by low lying countries although the rise in sea levels may have been caused mainly by other countries.

Not including these “externalities” in the price to the individual of undertaking an activity reduces the likelihood that they will desist and act to reduce the total cost to the community. This is one example of Market failure.

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Financial cost

a cost which involves or will involve the payment of money
(compared with Economic cost).


Fluorescent lighting.

Fluorescent lamps (also called tubes) use electricity to excite a gas in the glass tube. This causes ultraviolet light to be emitted and to strike the inside surface of the tube, which is coated with a special coating which fluoresces (the radiation causes it to emit visible light).

Fluorescent lighting is typically five times as efficient as Incandescent lighting in converting electricity to light, and the lamps last about 8 times as long (8,000 hours compared with 1,000 hours). Tri-phosphor fluorescent lamps which produce about 20% more light for the same electricity consumption, have gained popularity in the early 1990s. In 1996 tri phosphor lamps were introduced with double the life (now 16,000 hours) and a much better performance maintenance over their life.



Fluorocarbons are various artificial gases containing fluorine and carbon. which have been used mainly as refrigerants and to a much lesser extent for some cleaning applications. Fluorocarbons include:

  • chlorofluorocarbons (CFCs),
  • hydrofluorocarbons (HFCs), and
  • hydrochlorofluorocarbons (HCFCs).

See also: Greenhouse gases


Fossil fuels

Energy sources which derive from marine and terrestrial organisms which once lived, and have been transformed by geological forces over extremely long periods. Fossil fuels include:

  • natural gas,
  • coal, and
  • crude oil (and its derivatives such as petrol, diesel fuel, aviation fuels, etc).

see also: Energy sources


(UN) Framework Convention on Climate Change

The text of the Convention adopted at the United Nations Conference on Environment and Development (UNCED) held in Rio de Janeiro, Brazil, in June 1992. The FCCC was signed for Australia by the then Minister for the Environment, Ros Kelly and ratified by Australia in December 1992. The agreement came into force in March 1994 after ratification by the required fifty countries.

More than 150 countries have now committed themselves to respond to the threat of climate change under the United Nations Framework Convention on Climate Change. Among these nations, industrialised nations (IEA/OECD member countries and countries with economies in transition) agreed to an aim to return their greenhouse gas emissions to 1990 levels by the year 2000.

see also: UNFCCC official home page and subject area: Greenhouse response


Fuel cell

A device which converts a fuel directly into electricity without the usual intermediate steps of heat and motion. Fuels cells have several advantages, including high efficiency (60%+), high temperature heat (further boosting total efficiency) compactness (up to 1 MW per cubic metre) and silent operation.

Possible energy sources include hydrogen and natural gas.


Fuel efficiency
The useful output divided by the fuel input (eg. a boiler which converts 80% of the heat value of the fuel used into steam has a fuel efficiency of 80%). Where the input and output are measured in different units, these need to be stated, eg. lumens per Watt, tonnes of product per GJ.

see Efficacy, Efficiency, System efficiency, Transmission losses and Subject area: Efficiency


Fuel intensity.

This is the inverse of fuel efficiency, i.e. fuel consumed per unit of useful output (eg. litres fuel per 100 km travelled, MJ per meal, kWh per $ of product, MJ per patient night).

see Efficacy, Efficiency, Fuel efficiency, System efficiency and Subject area: Efficiency


Fuel oil

A heavy fuel product of the refinery process used in some furnaces, boilers, and large
Diesel engines. Fuel oil is classified as heavy (HFO) or light (LFO).

Until mid 1995, some transport operators (trains, passenger ferries) were converting diesel engines from automotive diesel fuel to LFO because of the lower fuel cost. However, the price was lower because LFO was exempt from those taxes and excise intended for transport applications, on the assumption that LFO would only be used in stationary equipment. When the trend to circumvent the tax was noticed, the Commonwealth Government removed the exemption for LFO.

see also: Energy sources. For CO2 emissions: see: Energy sources and CO2 emissions


Fugitive emissions

Emissions of pollutants in the form of chemicals leaking from systems into the environment, eg:

  • natural gas escaping from the distribution pipe-work,
  • Evaporative emissions,
  • refrigerants leaking from refrigeration and air-conditioners.

Full fuel cycle emissions

the total emission from both the energy End-use and from the extraction, processing, conversion, refining, transport, distribution, storage, retailing.

see also: Greenhouse effect

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General lighting service.

A standard Incandescent lamp or “light bulb” of less than 150 Watts.


Generating capacity

the rating of electricity generating equipment which describes the electrical Power it can produce.


Geothermal energy

Energy obtained from the heat below the Earth’s surface.



A Metric prefix used to modify the meaning of a unit of measurement.

Giga means billion = one thousand million = 109.



Used to express quantities of CO2 emissions.

One Gg = one thousand tonnes.


Giga tonne

One billion tonnes.

See also Measurement



See also Measurement and : Energy and Power Measurements


Global Warming Potential

An index of the cumulative radiative forcing of a gas during a period (eg. 100 years) compared with the same mass of CO2. The calculation of the index considers both the relative radiative effectiveness of the gas and its expected lifetime in the atmosphere.

See also Carbon dioxide equivalent


Green electricity

electricity which is generated from sources which are judged to harm the environment less than conventional methods. Green electricity sources could include:



    small and existing large dams (not new large dams), and

    some biomass.

One such scheme is NSW DEUS’  “Green Power” initiative.


Green grid

a system for storing electricity in batteries and supplying grid-quality electricity when required, using an inverter. The storage and conversion facility makes the green grid suitable for:

  • supplying a quality, reliable power source even when the grid may be unreliable due to overloading, supply outages, etc.
  • storing electricity generated by intermittent Renewable sources (hence the name green grid).

This type of equipment is now commercially available with a capacity to support the requirements of a homestead.


Green power (DEUS NSW)

A brand of Green electricity promoted by the NSW Sustainable Energy Development Authority (DEUS). Electricity companies may be licensed to sell electricity as “green power” providing that they have satisfied the DEUS’s criteria which include specifying a mix of green generating technology (ie. it is not sufficient to rely solely on relatively cheap hydro and ignore Photovoltaic generation.

see also: Internet, DEUS Green power page


Greenhouse effect:

The Natural Greenhouse Effect.

The effect of water vapour, CO2, and other gases which allow heat radiated from the sun to pass through to the earth, but restrict the heat radiated from the earth. This imbalance in heat flows is a natural phenomenon which causes the earth to be warmer than it would otherwise be, and so makes life possible. This effect, known as the greenhouse effect, was discovered late in the 1800s.

 The Anthropogenic or Enhanced Greenhouse Effect

Since mankind has begun burning Fossil fuels in the late 1700s, the concentration of CO2 has been increasing. The removal of forests has also increased the concentration of CO2 in the atmosphere, by reducing the size of the available Carbon sink. We know that this increase in CO2 concentration will cause air temperatures to rise, although we are not yet able to precisely state the magnitude and timing of the change.

see also: greenhouse gases (following) & Subject Areas: Greenhouse effect, Greenhouse gases


Greenhouse gas:

Normally taken as meaning a gas contributing to the enhanced or anthropogenic greenhouse effect, and so ignoring water vapour which is the most significant of all the greenhouse gases, but the one where the human contribution is insignificant compared with the total.

 indirect. Gases which do not themselves trap infra-red radiation but which influence the concentrations of direct greenhouse gases including:

See also:: Description of greenhouse effect, and Greenhouse gases in the Subject Area, Table of greenhouse gases


Greenhouse gas:

  • abatement. see reduction.
  •  reductionmeans reduction in the emission of greenhouse gases compared with a Business as usual base-line case.As the base-line case probably has the total emissions of CO2 equivalent increasing, the reduction may not be a reduction in absolute terms.
  • mitigation. to reduce the amount and impact of emissions.

Greenhouse gas inventory

see: National Greenhouse Gas Inventory


Greenhouse gases, descriptions, main sources

see table in the Subject area: Greenhouse gases


Greenhouse scorecard

Australian Home Greenhouse Scorecard

An educational computer kit developed for EPA Victoria, NSW EPA, Environment Australia and ANZECC and available from Edsoft PO Box 314 Blackburn VIC 3130

Tel 1800 338 873, Fax 1800 674 899


Gross calorific value


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a salt formed by the union of carbon with a negatively chargedHalogen.

See also: Greenhouse gases



Any one of the following electro-negative elements: astatine, bromine, chlorine, fluorine of iodine. These elements combine with metals to form a salt.



A compound is said to be halogenated when it contains a Halogen. A fully halogenated CFC is one in which contains no hydrogen — all hydrogen has been replaced with chlorine and fluorine. A partially halogenated CFC is one in which some hydrogen remains.



Compounds containing bromine which are used as fire extinguishing agents (eg. yellow BCF fire extinguishers). These fire extinguishers are now banned in Australia.


Heat island, micro climate

The effect of an urban area being warmer than the surrounding areas because of the additional heat absorption by roads and buildings etc. This heat island effect was initially offered as an explanation of higher temperatures being recorded, however, the pioneering work by CSIRO and overseas researchers has shown that air and ocean temperatures are increasing in remote areas.


Heat pump

a mechanical device for moving heat energy from one place to another, cooling the former and heating the latter. Examples include refrigerators, chillers, air-conditioners and heat-pump water heaters.


Heat transfer

the movement of heat energy from one place to another by one or a combination of Conduction, Convection, and Radiation.


Heating degree-days

see Degree-days



A measure of land area. The greenhouse context is its use to describe the size of plantations used as carbon sinks.

One hectare = 10,000 square metres
eg. a block of land 100 m x 100 m
= 2.47 acres

The hectare is a non-standard metric measurement which is retained because it is much more useful for describing land areas than the square metre (m² ).

see also: The Metric system



A measure of frequency or how many times a process cycles.

One Hertz = 1 cycle every second.

see also: Alternating Current, and Frequency.


House energy rating scheme.

A method of comparing the energy efficiency of different house designs, considering layout, orientation, materials and appliances. The evaluation can be manual or assisted by software.

For further information: DPIE NetEnergy


Hurdle rate (financial evaluation)

In investment appraisal, the minimum acceptable rate of return of a project for it to proceed.

Source: Accounting Glossary. See also Subject area Financial evaluation



Compounds containing hydrogen, fluorine and carbon. Unlike the CFCs, they do not contain chlorine.

See also: Fluorocarbons, Greenhouse gases



A chemical compound which contains only carbon and hydrogen, including most liquid fuels and methane.



This is a chlorofluorocarbon (CFC) which contains some hydrogen (it is a “partially halogenated” chlorofluorocarbon). An example is HCFC-22. This family of chemical compounds are being used as temporary substitutes for CFCs (eg as refrigerants) as they are less harmful to the ozone layer, but are not harmless.



The atmosphere’s primary oxidising agent, this is an ionic (electrically charged) molecule composed of one oxygen and one hydrogen atom (OH), which acts as a single unit. It takes part in many chemical reactions without being changed by the reaction. Hydroxyl reacts easily with methane; this reaction leads to the production of CO and CO2. Because it reacts in this way with several different compounds, including CFCs, hydroxyl (which is only present as a gas, in minute quantities in the atmosphere) is dubbed “the detergent of the atmosphere.” Hydroxl is the main sink for methane, and for all of the hydrogenated halocarbons (including the CFCs).


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Incandescent (lighting)

Lighting which uses a filament which is heated to white hot by the electric current it carries (and so incandesces). This is the least efficient form of electric lighting and so is appropriate only for lights with low burning hours or very low light output requirements.


Infra-red radiation

Electromagnetic Radiation lying in the wavelength interval from 0.7 µ to 1000 µ . Its lower limit is bounded by visible radiation, and its upper limit by microwave radiation. Most of the energy emitted by the Earth and its atmosphere is at infra-red wavelength.

Water vapour, carbon dioxide, and ozone, absorb infra-red radiation and play important roles in the propagation of infra-red radiation in the atmosphere.

also called “long-wave radiation.”


Intergovernmental Panel on Climate Change

A panel of climate change specialists and the principal world body investigating greenhouse issues. The IPCC was formed in 1988 by the World Meteorological Organisation and the United Nations Environment Program (UNEP).

Working Group 1 concentrates on science; Working Group 2 on impacts and response options; Working Group 3 on economics and cross cutting issues. The Panel provides technical input for implementation of the Framework Convention on Climate Change.

The aim and strength of the IPCC is the provision of balanced expert advice across the spectrum of climate change sciences.

see also IPCC home page


Interim Planning Target

Adopted By The Australian Government In 1990, the Interim Planning Target forms the basis of the 1992 National Greenhouse Response Strategy. The target is:

    the stabilisation of greenhouse gas emissions at 1988 levels by the year 2000, and

    reducing these emissions by 20% by 2005

subject to the caveat that Australia not suffer adverse economic effects in the absence of similar action by other major greenhouse gas emitting countries.


Internal combustion engine

an engine where fuel is burnt inside the engine (eg. petrol and diesel engines), compared with an external combustion engine where the fuel is burnt in one part and the heat energy converted to motion in another part (eg. steam engine, Stirling engine).

The most common internal combustion engine is the petrol fuelled piston engine found in most cars and light commercial vehicles. These have an efficiency of around 25% under ideal conditions but the real-world efficiency is about 10% because of factors such as the very low average load, poor maintenance and operation, etc. Because of the difficulty in controlling combustion in the very short time allowed in an internal combustion engine and the cooling near the cylinder walls, the combustion is poor and pollutant levels are higher than in a steady-state combustion process such as a power station boiler or even a small steam engine.

Internal combustion engines are the main consumer liquid fuels, which in Australia are mainly imported.

Other internal combustion power sources include:

    rotary engines,

    jet engines (gas turbines), turbo-fan aero-engines, and



Internal rate of return

The rate of return at which a project is expected to achieve break even or for which the net present value is zero.

Source: Accounting Glossary, see also Subject area Financial evaluation



The process of including Externalities in the cost of an activity, so that those who cause costs bear those costs.


International Energy Agency

The International Energy Agency, based in Paris, is an autonomous agency linked with the Organisation for Economic Co-operation and Development (OECD).

The International Energy Agency was established as an intergovernmental organisation in November, 1974 under the Agreement on an International Energy Program (IEP) after the oil shock of 1973/1974. IEA Member countries commit themselves to take effective measures to meet any oil supply emergency and, over the long term, to reduce dependence on oil. Means to attain their objective include increased energy efficiency, conservation, and the development of coal, natural gas, nuclear power and renewable energy sources.

Australia joined the IEA on 27 May 1979.

For further information, see the International Energy Agency home page


Inventory, greenhouse gases

see description under National Greenhouse Gas Inventory


Inversion (temperature)

a layer of cold air sitting over a warmer layer of air which acts as a blanket trapping pollutants and preventing their dispersion.



a device used to convert Direct current (DC) electricity (eg. from batteries) to Alternating current (AC) electricity which is used by most domestic and commercial electrical appliances. These are commonly found in remote area power systems (RAPS).




ISO 14000

International Standards Organisation standard number14000 which commits organisations to a systematic approach to, and measurement of, environmental performance. The standard provides a set of tools to assist businesses to implement systems which ensure and prove that their processes are sustainable and environmentally friendly…

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Joint Implementation

Collaboration between two countries, where a donor country gains credits toward achieving its greenhouse gases reduction commitments by assisting the other country to reduce its emissions. This assistance would normally involve both funding and implementation expertise.

One benefit is the early intervention to reduce developing country emissions which are projected to increase rapidly unless corrective action is taken.



A unit of energy equal to the work done when a force of 1 Newton is

applied to an object, moving it a distance of 1 metre in the direction of force.

see also: The Metric System,Measurement and : Energy and Power Measurements


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prefix meaning “thousand”. eg. 3kW = 3 kiloWatts = 3,000 Watts

see also, The Metric System, and Metric prefixes.



a measure of (electrical) Energy equal to one kiloWatt for one hour.

one kWh = 3.6 MJ

(one kWh of electrical energy = 3.6 MJ of electrical energy)

but one kWh of electrical energy does not equal 3.6 MJ of gas!

see also Energy and power measurements



In December 97, venue for negotiations on binding greenhouse gas emission targets.

see also: Framework Convention on Climate Change

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Land fill gas

a mixture of gases (mainly methane and carbon dioxide, both greenhouse gases) generated as the result of anaerobic decomposition of organic matter in land-fill rubbish dumps. This gas can be used in spark ignition gas engines (usually about 1 MW generation capacity) to produce electricity. This has a double greenhouse benefit of burning the greenhouse gas methane which would otherwise escape to the atmosphere, and the electricity generated reduces the amount which needs to be produces using coal or natural gas.

In some cases, the waste heat from the engines can be used (combined heat and power), e.g. for nearby horticulture. Another benefit is the prevention of damage to grass cover and other vegetation on closed land-fill sites.


Latent heat

the reversible heat storage in a material by changing its phase (eg from solid to liquid or liquid to a gas) or by a chemical reaction. Latent heat allows much more energy to be stored in a given physical volume than relying on Sensible heat.


Leakage (carbon)

see Carbon leakage


Life cycle analysis

analysis of the total costs and benefits of a course of action, including initial purchase price, cost of capital, fuel, raw materials and other operating and maintenance costs, labour requirements, provision of infrastructure, decommissioning, and disposal .etc.


Life cycle emissions

the total Full fuel cycle emissions of greenhouse gases from a product or process including those resulting from manufacture, operation, maintenance, provision of infrastructure, decommissioning, and disposal.


Liquefied natural gas

Natural Gas which has been liquefied by cooling below its boiling point of -162°C, increasing its energy density 600 fold. This makes transport of natural gas in storage vessels (eg. purpose-built ships from the North West shelf) viable.

See also: Compressed Natural Gas


Liquefied petroleum gas

A mixture of light hydrocarbon gases which are liquefied (by cooling the gases to very low temperatures) to increase the amount of energy which can be stored in a vehicle fuel tank. The main components are:

  • propane (C3H8),
  • butane (C4H10), and (to a lesser extent)
  • propylene (C3H6).

For CO2 emissions: see: Energy sources and CO2 emissions.


Long-wave radiation

see Infra-red radiation

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Marginal cost (of reducing greenhouse gas emissions)

The unit Economic cost of reducing greenhouse gases emissions (CO2 equivalent). This term assumes that there will be a cost, but with such a high potential to reduce greenhouse gases emissions using economic actions, dwelling on actions with a net cost is unwarranted.


Market failure

The failure of economic signal to produce optimal outcomes for the participants and the community as a whole, because of factors such as:

External costs not being included in Financial costs

people not fully analysing choices and acting rationally (eg. acting on impulse, conspicuous consumption, fashion, etc).

people not have the necessary information to be able to make a considered and rational decision (this really applies to all decisions as nobody ever has all the facts pertaining to a choice).

people not dedicating the time required to make a rational decision.

Despite the prevalence of these and other factors, some economist and economic modellers debate whether market failures occur.


Measure (noun)

A deliberate and specific government act or policy aimed at reducing greenhouse gas emissions.



prefix meaning “million”. eg. 3 MegaWatts = 3,000,000 Watts



A gaseous, colourless, explosive, hydrocarbon and the main component of Natural gas, and a powerful greenhouse gas. Also called “swamp gas” because it is produced by bacteria when organic matter decomposes without oxygen (eg. in land-fills and swamps). Also produced in the gut of animals (especially ruminants such as cattle) and found in coal beds. Methane is the only greenhouse gas which is produced in greater quantities in developing countries than in developed countries.

The main sources of methane are:

Anaerobic decomposition of putrescible organic material in swamps, rice paddies, land-fill rubbish dumps, etc.

leakage and drainage of methane during coal mining, and

leakage from natural gas distribution pipes.

See also: Greenhouse gases,



also called wood alcohol or methyl alcohol. The simplest form of alcohol, it is usually manufactured (can also be made from coal and natural gas, and from wood (at a higher cost). As a fuel, it blends easily with petrol.

Methanol requires few if any engine modifications to extract the maximum power from this fuel, and has long been used as an octane improver racing vehicles. It lowers some exhaust emissions, such as HC, CO, as well as NOx.

Methanol contains only half the energy per litre of petrol but the high octane rating allows higher compression ratios and so higher fuel efficiency (when used as an additive).

see also Ethanol


Metric System.

Also called SI measurement.



prefix meaning “millionth”.

also used to describe the smallest systems, being smaller than “mini” systems (eg. “Micro-hydro“, micro-climate, etc).

see also: Metric prefixes


Micro hydro

A system which derived useful power from flowing water, with a power rating of less than 100 kW.


Montreal Protocol.

Montreal Protocol on Substances that Deplete the Ozone Layer of 1987, and the subsequent amendments in London in 1990, Copenhagen in 1992, and Vienna in 1995 The principal international agreement under which ozone-depleting compounds are regulated, including ceasing production in developed countries. Australia is a signatory.

The most significant category of substances are CFCs and HCFCs will be replacing many of these in the short term. However, hydrocarbons can also be used as refrigerants, often requiring little or no modification to CFC refrigerant systems.

The possible replacement of CFC based refrigeration equipment (eg. chillers) demands a capital investment and so presents an ideal opportunity to consider energy efficient solutions such as reducing the demand for cooling, cogeneration and absorption cooling, installation of a high efficiency chiller, etc.


Myths (about greenhouse)

CSIRO Greenhouse Myths web page.

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National Greenhouse Gas Inventory:

The National Greenhouse Gas Inventory is a compilation of greenhouse gas emissions resulting from human activities and recorded as sources or sinks in the inventory. The compilation follows international guidelines, is retrospective and categorised under designated sectors such as energy, agriculture, land use change and forestry and others.

A greenhouse gas inventory is essentially a data base of human-induced greenhouse gas emission sources and sinks which are categorised into sectors (eg energy, agriculture, land use change and forestry) following international guidelines and assessed retrospectively.

Source: Environment Australia, Greenhouse gases inventory


Natural / background level

the level of an activity, concentration, or emission without the influence of human activities


Natural greenhouse effect


Natural gas

The main gaseous fuel used in Australia, distributed by pipe to supplied to homes and businesses. The principal constituent is Methane (typically 95%) with traces of other hydrocarbons (eg. ethane propane and butane), carbon dioxide, and nitrogen. Natural gas occurs in underground reservoirs either alone or in association with crude oil deposits. Natural gas is odourless (the smell of the commercial product is added to make leaks easier to detect). Natural gas is non-toxic (unlike manufactured gas or town gas which contains carbon monoxide).

see also: Energy sources and CO2 emissions


Natural gas for vehicles

see Compressed Natural Gas


Net calorific value


Nitrogen oxides

compounds containing nitrogen and oxygen and no other elements.

NOx gases are Precursor gases which react with sunlight to form ground-level Ozone and contributes to other adverse effects including aggravation of respiratory disease, fading of some fabrics, contribution of nitric acid to Acid rain and the formation of smog.

see also: Greenhouse gases


Nitrous oxide, nitrogen dioxide

a gaseous compound whose concentration is increasing in the atmosphere because of biomass burning, fertiliser use and some industrial processes. It has an estimated atmospheric lifetime of 120 years.

see also: Greenhouse gases


No-regrets policy (and no regrets measures).

Policy based on the idea that the problem of global climate change is linked to other critically important problems of environment and development. The combined risks are serious enough, and the eventual benefits of action great enough, to require urgent and bold initiatives, even if they impose a substantial immediate cost. Advocates of this policy argue that strong action will lead to a “no regrets” outcome, even if climate change turns out to be an exaggerated fear. The benefits will include experimentation, foresight, and cost-effective prevention. Moreover, say the proponents, early actions offer the prospective extra benefit of learning through experience: of gaining better information about the benefits and costs of action through our first steps (Source: Mintzer, 1992).


Non methanic volatile organic compounds

Volatile organic compounds other than methane. These are mainly hydrocarbon compounds which are used as solvents for printing, painting and cleaning. They are used to form a liquid solution to enable a substance to be applied in a liquid form, and then dry (the solvent evaporates).

see also: Greenhouse gases


Noxious emissions

Gaseous emissions which are offensive or harmful to health, including odours, particulates, NOx, sulphur dioxide, and Volatile organic compounds.

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Opportunity cost

The income or benefit foregone by not using resources for the best other alternative.

Source: Accounting Glossary, see also Subject area Financial evaluation



A molecule made up of three atoms of oxygen. In the Stratosphere, it occurs naturally and it provides a protective layer shielding the Earth from ultraviolet radiation and subsequent harmful health effects on humans and the environment. In the Troposphere, it is a chemical oxidant and major component of photochemical smog

see also: Precursor gases


Ozone layer.

Ozone found throughout the stratosphere, which protects the Earth from UV radiation.

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very small pieces of solid or liquid matter such as particles of soot, dust, fumes, mists or Aerosols. The physical characteristics of particles, and how they combine with other particles, are part of the feedback mechanisms of the atmosphere


Parts per billion by volume

used for expressing concentrations of elements in very low concentrations, e.g. Nitrous oxide concentration in the atmosphere in 1994 was about 312 ppbv.


Parts per million by volume

used for expressing concentrations of elements in very low concentrations, e.g. CO2 concentration in the atmosphere in 1994 was 358 ppmv (= 0.0358%).


Parts per trillion by volume

used for expressing concentrations of elements in extremely low concentrations, e.g. SF6 concentration in the atmosphere is about 3 pptv, CFC-11 in 1994 was about 268 pptv.


Passive (building design feature or heating systems etc).

Passive features are those which reduce energy needs without having moving parts and/or controls. Passive features include shading using fixed eaves, trees, etc, appropriate building orientation, insulation and thermal mass, thermo-siphon hot water systems, etc).

This contrasts with Active features.



pronounced petta

A Metric prefix used to increase the value of a measurement by a factor of 1015 which is a million billion. This prefix is useful for describing very large quantities of energy (eg. the amount of natural gas Australia consumed each year) using the very small units (Joules) which are used to measure energy.

For example ..

see also, The Metric System, and Metric prefixes.



A measure of energy equal to 1015 joules.

see also, The Metric System, and Metric prefixes. and Energy and power measurements



a mixture of Volatile liquid hydrocarbons such as hexane, heptane, and octane. Petrol is produced by distilling naturally occurring Petroleum to separate its constituent “fractions”. As well as naturally occurring hydrocarbons, petrol contains additives such as knock suppressors (octane improvers), rust inhibitors, lubricants, detergents, anti-rust agents and dyes.

Petrol is used mainly as the fuel for spark ignition engines (or simply “petrol engines” in cars, light passenger and freight vehicles and portable engine driven equipment such as mowers, generators, etc.

Petrol is sometimes called motor spirit.
Also, the American term for the same product is gasoline orgas.

Confusingly, petrol was once called petroleum.

For CO2 emissions: see: Energy sources and CO2 emissions



Another term for crude oil and an obsolete term for petrol.

A naturally occurring substance found in varying quantities on all continents. Petroleum’s composition varies from deposit to deposit, and contains mainly hydrocarbons plus sulphur, oxygen and trace metals. Petroleum can be distilled to separate it into its constituents or “fractions” and further processed to produce:

  • Petrol,
  • kerosene,
  • aviation gasoline (Avgas),
  • aviation turbine fuel (Avtur or jet fuel),
  • diesel fuel
  • lubricating oils and greases, and
  • tars.

Phase change materials (energy storage).

the reversible heat or cold storage in a material by changing its phase (eg from solid to liquid or liquid to a gas) using a suitable phase change material. Phase change materials allow much more energy to be stored in a given physical volume than relying on Sensible heat, but have the disadvantage of having to match the phase change temperature of the material to the temperature at which heating or cooling is required. For example, ice stores cooling capacity and releases this as it changes from ice to water, but ice’s phase change temperature of 0° C is not suitable for storing energy in a greenhouse or home..



materials or devices which convert light energy into electrical energy. The electricity produced is Direct current (DC) and so can be used for appliances which use DC (eg calculators, instruments, radios, battery chargers), or converted to Alternating Current (AC) for use in standard appliances. Because of the intermittent availability and variability of the energy source, battery storage is normally included in PV systems.



Any direct or indirect alteration of the physical, chemical, thermal, biological or radioactive properties of any part of the environment by discharging, emitting or depositing wastes or substances that adversely affect beneficial use, or that cause a condition that is hazardous or potentially hazardous to public health, safety or welfare or the condition of flora and fauna.

Source: NSW EPA Glossary


Power factor


Power factor correction

a method of increasing the efficiency of the use of the installed electricity generation and distribution system. Power factor correction is often undertaken by customers to reduce their electricity costs and so it is often confused with energy efficiency measures.


Precautionary principle

If there are threats of serious or irreversible environmental damage, lack of full scientific certainty should not be used as a reason for postponing measures to prevent environmental degradation.

Source: NSW EPA Glossary


Precursor gases

A gas which, with the aid of sunlight can react to give another gas (especially a pollutant). For example, carbon monoxide (CO) is a weak greenhouse gas but it is an important precursor to tropospheric Ozone (O3).

VOCs and NOx react with sunlight to form ground-level ozone. Ground-level ozone is a major component of smog and has been linked to respiratory disease in humans and damage to vegetation agricultural crops.

see also: Greenhouse gases, and in the Subject Index: Greenhouse gases


Primary energy

A non-renewable energy source in its natural state which may be used in that form or transformed into a secondary energy source before use. Most primary energy sources require some processing before use, with the degree of transformation depending on the type of primary energy and the end source. For example Coal (a primary energy source) can be used in its natural state for producing heat, but is highly transformed in the production of electricity (which is a secondary energy source).

Care should be taken not to directly compare quantities of primary energy and secondary energy.(eg. a MJ of electricity is not interchangeable with a MJ of natural gas).



see Photovoltaic


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Quadrillion (1,000,000,000,000,000) BTU. = 1015 BTU

An imperial (non-metric) measure of energy equal to 1.055 exa.Joules (1018Joules)

See also Measurement and : Energy and Power Measurements



a qualitative description pertains to the qualities of quality of that being described and does not include precise numerical description of those qualities.



a quantitative description includes numerical measurements and descriptions of the characteristics being described.

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heat transfer across a space without the use of convection or conduction. Radiation can be in the visible part of the spectrum or the infra-red part.

see also: Conduction and Convection


Radiative forcing

A change in the energy available to the earth and atmosphere resulting from the action of greenhouse gases, normally expressed as an annualised, global average value. Positive radiative forcing tends to increase global temperature and negative radiative forcing tends to reduce global temperature.

Some of the causes of changes in radiative forcing include:, clouds, ice, greenhouse gases, and volcanic emissions activity, and water vapour.


Rebound effect

Possible increase in consumption of greenhouse gases emitting processes or services as a result of greenhouse gases abatement measures making those products or services more efficient and hence more affordable.


Regional economic integration organisation (FCCC usage)

an organisation constituted by sovereign States of a given region which has competence in respect of matters governed by FCCC or its protocols and has been duly authorised, in accordance with its internal procedures, to sign, ratify, accept, approve or accede to the instruments concerned.

Source UNFCCC, Climate Change Secretariat, Definitions


Remote area power supply

A power system which derives its electricity from sources other than the grid. Possible energy sources include wind, photovoltaic, and micro-hydro and non-renewable sources such as diesel generators.


Reservoir (FCCC usage)

a component or components of the climate system where a greenhouse gas or a precursor of a greenhouse gas is stored.

Source UNFCCC, Climate Change Secretariat, Definitions


Rio de Janeiro

see Framework Convention on Climate Change


Renewable (energy sources)

energy sources which are continually renewed at the same rate as their use, by natural means alone (eg. solar, wind, wave, hydro)

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Scorecard (greenhouse)

see Greenhouse Scorecard


Sea level

If the earth’s atmosphere warms, the upper layers of the oceans will also warm. Like most substances, water expands when heated. Expansion will raise sea level. Land-based ice in the temperate regions of the world (such as South and North America and Greenland) will melt more rapidly. Glaciers may retreat. Melting will also contribute to increased sea level. (Floating sea ice does not change the sea level when it melts.) On the other hand, increased precipitation over. Antarctica and Greenland would lock water away in the ice caps. Scientists estimate that by the end of the 21st century, global warming will raise average sea level by between 13 and 110 cm above the 1990 level. Regional variations of up to 50 per cent are possible. Records show that global sea level has risen by between 10 and 25 cm during the past century. However, it is not possible to attribute this increase to the enhanced greenhouse effect.

Source: CSIRO Greenhouse web page


Secondary energy

see Primary energy


Sensible heat

stored heat which can be sensed by measuring the temperature of the material storing the heat, compared with Latent heat which is stored and released (and so varies) at a constant temperature.


Sink, carbon

see Carbon sink


Social cost, societal cost

The total costs of an activity which are borne by the society as a whole. This total includes the costs borne by individuals undertaking the activity (private costs) plus the indirect costs which those individuals escape (public costs or Externality).


Solar cells

see Photovoltaic


Source, carbon

See Carbon source


Spinning reserve

electricity generation capacity which is not required to operate to meet immediate needs for electricity but is kept running unloaded to cope with a sudden loss of electricity supply caused by the failure of a generator in the same supply system.

The electricity generation system also needs reserve capacity to allow for the normal diurnal variation in load, which can be as much as 40% of the peak demand (eg. in NSW in Winter).

see also: Base-load


Standing losses

losses (usually energy) which occur whether or not a system or appliance is performing any useful purpose. For example, a storage water heater will lose heat from the water storage tank whether or not water is being used. If the equipment is used infrequently or well below its capacity, these standing losses become a very high percentage of the total energy consumption and can easily be greater than the energy used in delivering a useful service. Examples of equipment with high standing losses include heating devices (including those in water heaters, drink heaters, laser printers and photocopiers, deep fryers etc), and lightly loaded but running electric motors (eg motor generator sets, most pumps, many fans, etc.).


Static efficiency, frozen efficiency

predicting future resource use assuming the same efficiency as at present.

see also Business as usual, Efficiency,, Fuel efficiency, System efficiency, Transmission losses and Subject area: Efficiency





Ions containing sulphur and oxygen (SO4) which react easily with hydrogen to become sulphuric acid (H2SO4). In the atmosphere, sulphate particles have increased markedly over the past 50-100 years, due to industrial emissions of Sulphur dioxide (SO2). Sulphate aerosols are key components of several atmospheric feedback processes. For example, they cool the Earth both directly (by reflecting away incoming solar radiation under clear sky conditions) and indirectly (by making maritime clouds more reflective) (Source: Mintzer, 1992).


Sulphur dioxide(US spelling sulfur).

also called:

Sulphurous acid anhydride, sulphurous oxide

a gas released by coal-burning power stations and. Once the sulphur dioxide is in the atmosphere it can form Most of the Sulphur dioxide in the atmosphere is there as a result of the human activities, especially burning Fossil fuels with a high sulphur content (some coals and oils) and during the processing of mineral ores. Australian coals are normally low in sulphur. The main concern about Sulphur dioxide is that it combines with water to form sulphurous and sulphuric acid (see Acid rain), which in turn destroys buildings, vegetation and degrades agricultural land.

Further information on:

  • sulphur dioxide and the atmosphere: CSIRO
  • Sulphur dioxide industrial uses (e.g. as a fumigant and wine preservative, etc.). ICI Australia


Sulphur hexafluoride

Sulphur hexafluoride is a clear odourless, non-toxic gas, which is used mainly (80%) as an insulator in gas insulated switchgear (GIS) and circuit breakers (because of its high dielectric strength and arc-quenching properties), and as a cover gas as a cover gas in magnesium and aluminium production and casting to prevent oxidation and fires.


Sulphur oxides (US spelling is sulfur)

see Sulphate



Meeting present needs without compromising the ability of future generations to meet their needs. This includes managing finite resources (such as fossil fuels which are being exhausted at over 1000 times the rate of regeneration) and protecting the natural environment.


System efficiency:

The Efficiency of a system in delivering a useful outcome, ie. the portion of the total resources consumed which are converted to the useful output. This should include all parts of the system which are necessary to arrive at an accurate figure. For example, with vehicle use it is possible to calculate the fuel efficiency of individual vehicles but if petrol engine vehicles are being compared with alternatives (eg. improved town planning, working from home, electric trams, etc) then the system efficiency for each alternative must be assessed. For petrol vehicles, the resource inputs would include the energy used in:

  • finding and extracting the Petroleum from the ground,
  • transporting the petroleum to a refinery,
  • energy conversion losses at the refinery,
  • transporting the refined products to the retailer,
  • retailing (operating the petrol stations).
  • provision, maintenance and disposal of infrastructure and other assets (eg. roads, tankers, vehicles, etc).

For an electricity system and equipment, the analysis should include stages such as:

  • mining and transport of coal,
  • Energy conversion losses at the power station (efficiency typically 25% to 50%).
  • other energy consumption at the power station for the operation of ancillary equipment, lighting, etc,
  • transforming (from one voltage to another) energy losses (typically about 98% efficient)
  • Transmission losses (about 90% efficiency but can be much lower).
  • the efficiency of the equipment using the electricity.

Calculation of the system efficiency is further complicated for most equipment and applications because they do not operate continuously at full load, and so Standing losses become significant.

see Efficacy, Efficiency, Fuel efficiency, Standing losses, Transmission losses, and

Subject area: Efficiency

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Ton, tonne

A metric tonne is 1000 kg (2205 pounds), a long ton is 2240 pounds, a short ton 2000 pounds.


Ton of coal equivalent

Imperial measurement of energy.

One tce = 29.3 GJ (Giga.Joules)

See also Measurement and Energy and power measurements


Ton of oil equivalent

Imperial measurement of energy.

One toe = 43.2 GJ (Giga.Joules)

See also Measurement and Energy and power measurements


Toronto target.

A plan adopted by the Changing Atmosphere: Implications for Global Security Conference held in Toronto in 1988. The target is:

  • the stabilisation of greenhouse gas emissions at 1988 levels by the year 2000, and
  • reducing these emissions by 20% by 2005

This target has been adopted by Australia as an Interim Planning Target


Tradeable permits, tradeable emissions

Tradeable permits could be issued to emitters of greenhouse gases (or other pollutants). Creating a market in tradeable permits provides an indication of the cost of reducing emissions, and creates an incentive for existing polluters to reduce their emission in order to sell their permits.


Transmission losses (energy)

energy used in the transmission or transport of energy from one place to another. For example:

  • the diesel fuel used by a road-tanker to transport fuel to petrol stations,
  • the fuel oil used by tanker ships to transport crude or refined oil products,
  • electricity losses in an electricity distribution network including transformer losses. Transmission losses of 10% are often quoted as a system figure, but the losses in highly loaded systems in rural areas can be much higher.
  • leaks in natural gas reticulation pipe-work

see Efficacy, Efficiency, Fuel efficiency, System efficiency, and Subject area: Efficiency


Turbine, (water, steam, gas)

a device which uses the kinetic (movement) energy in a fluid flow (eg. wind, river, dam outlet) to turn a shaft, which can then drive another device (usually an electricity alternator).

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United Nations Framework Convention on Climate Change

see Framework Convention on Climate Change


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Volatile organic compounds

Volatile in this context means easily evaporated, or evaporated at commonly encountered temperatures and pressures. Organic compounds are those which were once living organisms, including hydrocarbons and carbonyls.

Volatility is a benefit in liquid fuels because it promotes cold starting, and improved fuel-air mixing which in turn increases fuel efficiency. However, the ease with which fuel evaporates also means that it can easily escape (as a vapour) from vented fuel tanks and during refuelling operations. This is a problem because these fuel vapours are both a . . .

VOCs in Petrol include:

  • formaldehyde (H2CO),
  • benzene (C6H6), and
  • butadiene.

See also: Non methanic volatile organic compounds



A measure of the Apparent Power in an Alternating Current electrical circuit.




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a metric measure of Power equal to one Joule per second.


Wind farm

a collection of wind generators, at the one site, usually electrically connected.


Wind generator

A device for converting some of the energy in wind into electrical energy. These range in capacity from about 50 Watts to 3 MegaWatts.

see also: Energy sources

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