Energy Glossary
Energy
BBI
Barrel of oil (159 litres).
Benmore
The New Zealand Electricity Market's South Island reference point or node for wholesale electricity prices. (Haywards is the North Island node).
Bid
The price at which buyers offer electricity from New Zealand Electricity Market at a grid exit point.
Biodiesel
Diesel fuel derived from plant or animal sources.
Bio-energy
Energy derived from the use of biomass. Bio-energy technologies can generate electricity by burning biomass in its solid form or by converting it to gas (biogas) and burning the gas.
Bioethanol
A form of alcohol derived from plant or animal sources. May be blended in low concentrations with petrol and used in conventional petrol vehicles, or used in higher concentrations in especially modified petrol vehicles.
Biofuel
Any fuel derived from plant or animal sources, including biodiesel and bioethanol.
Biogas
Energy produced from the anaerobic digestion of sewage and industrial waste.
Biomass
Any organic matter that is available on a renewable or recurring basis, including dedicated energy crops and trees, agricultural food and feed crop residues, wood and wood wastes, animal wastes and other waste materials.
Calorific Value
The energy content of a fuel can be measured as the heat released on complete combustion. It can be expressed as an upper (or gross) value and a lower (or net) value. The difference between the two is the energy consumed in evaporating the water created in the combustion process. All figures in this document are net values.
Car
Cars are defined as vehicles designed primarily for the carrying of passengers, including sport utility vehicles (SUVs).
Carbon Capture and Storage
A technology under which carbon dioxide is extracted from the flue gases of power plants or industrial facilities and injected back into geological structures, such as depleted oil and gas reservoirs, unminable coal beds, or deep saline aquifers.
Carbon Dioxide
CO2, a naturally occurring gas, and also a by-product of burning fossil fuels and biomass, as well as of land-use changes and other industrial processes. It is the most important man-made greenhouse gas.
Carbon Sequestration
Any process for removing carbon dioxide from the atmosphere. May be natural (such as forests) or artificial (see Carbon Capture and Storage).
CCGT
Combined Cycle Gas Turbine. A gas turbine whose exhaust is used to heat a boiler, allowing generators to be driven by both a gas turbine and a steam turbine.
CH4
Methane. A greenhouse gas. Also the principle component of natural gas.
c/kWh
Cents per kilowatt-hour.
CNG
Compressed natural gas. Natural gas which has been compressed, or contained under pressure, in a small volume. CNG is used as a fuel by some vehicles. It is also a potential competitor to LNG as a way of shipping natural gas.
CO2
Carbon dioxide, which is the most important man-made greenhouse gas.
CO2-e or CO2-equivalent
Measures the combined climate changing potential of emissions of multiple greenhouse gases. Emissions of each gas are converted to an amount of CO2 that would cause the same climate change impact and summed.
Congeneration
The simultaneous or sequential production of two or more forms of useful energy (usually electricity and heat) from a single primary energy source.
Commercial
The commercial sector includes non-manufacturing business establishments such as hotels, motels, restaurants, wholesale businesses, and retail stores. It also includes health, social, educational, and government institutions.
Condensate
A liquid similar to light crude oil that is removed and recovered from raw natural gas.
Congestion pricing
Charging road users for driving during peak periods, or within defined areas, to reduce traffic congestion.
Consumer energy
The amount of energy used by consumers, excluding energy used or lost in the process of transforming primary energy into other forms - such as electricity - and transporting it.
Consumption
The electrical energy consumed by a 1,000 watt(1kilowatt) heater in an hour is one kilowatt hour (1KWH). A KWH is also known as a unit of electricity and as such is the basis of retail sales of electricity.
Crude Oil
Oil as it is originally produced.
Demand-side management
Methods to manage energy demand, including energy efficiency, load management and fuel switching.
Distributed generation
Any electricity generation facility that produces electricity for use at the point of location, or supplies electricity to other consumers through a local lines distribution network.
Distribution
The transport of electricity through a local network of low voltage power lines. Distribution networks connect electricity users with the national grid.
EECA
Energy Efficiency and Conservation Authority. See www.eeca.govt.nz.
Elasticity
A measure of the responsiveness of demand to price. Measured as the percentage change in quantity demanded in response to a one percent increase in price. Usually negative in sign.
Emmissions charge
A charge applied to fossil fuels and industrial process emissions to reflect, in some measure, their environmental costs.
Endogenous
A variable that is a function of other variables in the model. That is, a variable that is determined inside the model.
Energy Efficiency
Any measure of the ratio of useful energy services to energy input.
Energy intensity
Energy use per unit of gross domestic product.
Exogenous
A variable that is determined outside the model.
Fossil fuels
Coal, natural gas, liquefied petroleum gas (LPG), crude oil and fuels derived from crude oil, including petrol and diesel.
Fuel switching
The use of different energy sources or fuels to achieve the same energy services.
Fugitive Emissions
Emissions resulting from the leakage of gases during various human activities. In practice, this refers to emissions from natural gas flaring and processing, as well as leakages of gas in transmission and distribution. Also includes methane emissions from coal mining and post-coal mining activities, and emissions from geothermal fields.
Gas Turbine
A stationary relative of the jet engine, often used to drive an electricity generator. May burn gas or liquid fuel.
GDP
Gross domestic product, a measure of the overall output of the national economy.
Gross Domestic Product (GDP
The total market value of the goods and services a country produces in a year.
Greenhouse Gases
Gases in the Earth's atmosphere that trap heat from the Sun and make the planet's surface warmer.
GWh
Gigawatt-hour. A unit of electrical energy. 106 kilowatt-hours. See Metric System Multiples.
GJ
Gigajoules. 109 joules. A generic unit of energy. See Metric System Multiples.
Greenhouse Gases
Atmospheric gases that increase the earth's temperature by absorbing outgoing infrared radiation from the earth's surface. Man-made greenhouse gases that have a direct effect are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Indirect greenhouse gases which react to form direct greenhouse gases in a relatively short time include carbon monoxide ( CO), other oxides of nitrogen (NOx), and non-methane volatile organic compounds (NMVOCs). Water vapour (H2O) is also a greenhouse gas, however, its concentration in the atmosphere is naturally regulated.
Gross Energy
See Calorific Values
Haywards
The New Zealand Electricity Market's North Island reference point or node for wholesale electricity prices. (Benmore is the South Island node).
HCV
Heavy Commercial Vehicle. Commercial vehicles are those designed primarily for the carriage of goods such as vans, utilities, and trucks. HCVs are commercial vehicles with a gross vehicle mass more than 3.5 tonnes.
Heat Pump
Basically an air conditioner that can be run in reverse, heating the indoors and cooling the outdoors. Since heat pumps only move heat rather than create it, they are generally significantly more energy efficient than conventional electric heaters.
IEA
International Energy Agency. This organization helps coordinate the energy policies of its member countries. Membership consists of 26 primarily oil-importing industrialised countries including New Zealand. See www.iea.org.
IGCC
Integrated Gasification Combined Cycle. A system for manufacturing gas from coal used in combination with a combined cycle gas turbine (CCGT) to convert the gas to electricity. IGCC could potentially allow easy capture of greenhouse gas emissions from a coal-fired electricity plant.
Industrial Process Emissions
Emissions that are a by-product of industrial or chemical processes other than combustion. In New Zealand, these emissions come primarily from the manufacture of iron and steel, aluminium, hydrogen, cement and lime.
Industrial Process Emissions
Refers to a product whose demand does not vary much with price, generally because the product is considered a 'necessity'.
International Energy Agency (IEA)
An international organisation established within the framework of the OECD as an agency for energy cooperation between 26 member countries, including New Zealand.
International Transport
Transport between New Zealand and other countries.
IPCC
Intergovernmental Panel on Climate Change. The IPCC coordinates scientific and technical assessments related to climate change. It is sponsored by two United Nations organizations. www.ipcc.ch.
Kilowatt (kW)
A unit of electrical power equal to 1000 watts. See Metric System Units.
Kilowatt-hour (kWh)
Unit of electrical energy equal to 0.0036 GJ.
Kyoto Protocol
A 1997 international agreement to address climate change which sets greenhouse gas emission targets for developed countries. A subsidiary agreement to the United Nations Framework Convention on Climate Change.
LCV
Light Commercial Vehicle. Commercial vehicles are those designed primarily for the carriage of goods such as vans, utilities, and trucks. LCVs are commercial vehicles with a gross vehicle mass less than 3.5 tonnes.
Lignite
A low grade coal. Also known as soft coal or brown coal.
Load Duration Curve
A simple way of modelling the hourly fluctuations in electricity demand. All the hours of the year are grouped into a small number of classes by demand level. So instead of having to model 24 x 365 different hours, we model only a few classes of hours.
Load management
Measures to reduce electricity demand at peak load times or to shift some of it to off-peak times.
Long run marginal cost
Refers to the cost of building increments in generation capacity.
LNG
Liquefied Natural Gas. Natural gas which has been converted to a liquid by chilling it to extremely low temperatures. Natural gas is frequently moved by ship in the form of LNG.
LPG
Liquefied petroleum gas. It consists of propane (60%) and butane (about 40%). LPG is a gas at room temperature, but is a liquid under pressure.
MED
Ministry of Economic Development. See www.med.govt.nz.
Megawatt (MW)
One million watts. One megawatt is enough power to supply the peak electricity needs of about 500 houses. See Metric System Multiples.
Merit Order
Term used for the ranking of power stations in terms of increasing order of fuel costs.
Methane
CH4, a greenhouse gas. Also the principle component of natural gas.
Metric System Multiples
1,000 = 103 = kilo (k) 1,000,000 = 106 = mega (M) 1,000,000,000 = 109 = giga (G) 1,000,000,000,000 = 1012 = tera (T) 1,000,000,000,000,000 = 1015 = peta (P) 1,000,000,000,000,000,000 = 1018 = exa (E)
Mt
Million tonnes. See Metric System Multiples.
Multivariate
A model created by fitting a curve to several variables.
National grid
The high voltage network that transports electricity from approximately 40 major power stations to the power lines (local networks) operated by lines companies.
National grid
The high voltage transmission network that transports electricity throughout the country. The grid has more than 12,000 kms of transmission lines, carrying electricity from generators to distributors and directly to some major industrial users.
National Transport
Transport within New Zealand only. Also called Domestic Transport.
Natural Gas
Consists mainly of methane occurring naturally in underground deposits.
NEECS
National Energy Efficiency and Conservation Strategy.
Negotiated Greenhouse Agreement (NGA)
A voluntary contract between a business and the government that requires the business to follow an agreed pathway to world's best practice targets in the management of its greenhouse gas emissions, in return for a full or partial exemption from the emissions charge.
N2O
Nitrous oxide, a greenhouse gas.
Net Energy
Refer to calorific values.
Nitrous Oxide
N2O, a greenhouse gas.
NIWA
The National Institute of Water and Atmospheric Research, also known as NIWA Science. NIWA is a Crown Research Institute. See www.niwascience.co.nz.
NZEM
New Zealand Electricity Market: a voluntary, self regulating market where much of New Zealand's wholesale electricity is sold and bought on a daily basis. Back to Top
NZES
New Zealand Energy Strategy.
OPEC
Organization of the Petroleum Exporting Countries. This is an international organization that helps coordinate the energy policies of its member countries. Membership consists of Algeria, Indonesia, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, the UAE, and Venezuela. See www.opec.org.
Photovoltaic
A solar energy technology that uses semiconductor materials to convert sunlight directly into electricity.
PJ
Petajoules. 1015 joules. A generic unit of energy. Approximately: 1 PJ = 278 GWh of electricity 1 PJ = 44,000 tonnes of sub-bituminous coal 1 PJ = 21,000 tonnes of petrol 1 PJ = 26 Mm3 Maui gas.
Power
The rate at which electrical energy is produced, or consumed. The unit of measurement of power is kilowatts (thousands of watts) or megawatts(millions of watts).
Primary energy
Energy extracted from natural sources, by contrast with consumer energy.
Profiling
A system that enables electricity retailers to assess how much electricity their customers are using every 30 minutes.
Projects to Reduce Emissions
A government programme providing Kyoto Protocol carbon credits to projects that will reduce New Zealand's greenhouse gas emissions during the Kyoto Protocol's first commitment period (2008-2012).
Renewable
A form of energy that can be produced indefinitely without depleting the supply. Includes hydro, wind, geothermal, wave, tidal, and solar energy.
Renewable energy
Energy produced from sources that are not depleted by use, or which can be renewed after use, including solar, wind, hydro, biomass, tidal, wave, and ocean current sources. Geothermal energy is considered renewable, although geothermal fields can be depleted if fluids are extracted at a higher rate than they are replenished.
Takeback Effect
The tendency of consumers to increase their purchases of energy when energy efficiency is improved due to the perceived lower cost of energy services (such as kilometres driven or warmer homes)
Terawatt-hour (TWh)
Unit of electrical energy, equal to 1000 GWh. See Metric System Units.
Thermal Generation
The generation of electricity by heat, usually from burning fossil fuels but also including geothermal generation.
United Nations Framework Convention on Climate Change (UNFCCC)
A 1992 international agreement to address climate change that includes a range of non-mandatory commitments by member countries. Followed by the Kyoto Protocol.
United Nations Inter-governmental Panel on Climate Change (UNIPCC or IPCC)
An organisation established in 1988 by the United Nations Environment Programme and the World Meteorological Organisation to assess the scientific, technical and socio-economic information relevant to understanding climate change.
VFEM
Vehicle Fleet Emissions Model. A transport energy and emissions model developed by the Ministry of Transport and used by MED to produce the transport energy demand projections in this publication.
Wholesale electricity market
A computerised trading system enabling electricity purchasers, including retailers and large power users, to buy electricity off the generators. It includes a half-hourly spot market, longer-term contract markets, and security and reserves markets.
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