Glossary
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Baseload generation
Power plants that do not change their electricity generation output quickly. These plants are less flexible with meeting electricity demand.
Calorific value
The amount of energy that can be generated by burning a fuel. Usually expressed in megajoules per kilogram (MJ/kg). A calorific value may either be a gross calorific value (GCV) or a net calorific value (NCV) — see the relevant entries in this glossary.
Capacity factor
A measure of how often an electricity generation plant runs in a period of time. It is calculated as the amount of electricity generated by a plant divided by the maximum amount that could have been generated if it operated continuously at full power in that period of time.
Coal ranks
Used to refer to different types of coal. In New Zealand, we have three main types of coal:
- Bituminous coal is the highest rank of coal in New Zealand. Bituminous coal is generally exported for steelmaking.
- Sub-bituminous coal is mainly used in heating and electricity generation. In New Zealand, steel can be made using sub-bituminous coal due to the unique processes used at the Glenbrook mill.
- Lignite, also known as brown coal, is the lowest grade coal with the least concentration of carbon.
Cogeneration
When electricity plants generate electricity and heat at the same time. Otherwise known as combined heat and power, or CHP.
Conversion efficiency
The amount of energy produced in a transformation process divided by the amount of energy that went into the process.
Conversion losses
The energy lost in transforming one type of energy to another. This is calculated as the difference between the amount of energy that has gone into a transformation process and the amount of energy that has been produced.
Direct use
The use of energy without it first going through a transformation process (such as electricity generation). For example, the use of geothermal energy to heat greenhouses.
Energy consumption
The amount of energy consumed by final users, excluding any energy transformation (eg into electricity) and energy used in its transmission or distribution. Sometimes also referred to as “end use”.
Energy use
The use of fuel to provide energy (for example, burning coal to heat a boiler, or using electricity to power a motor). Sometimes also referred to as "energy end use".
Feedstock
Any raw material used as an input for an industrial process. In New Zealand, natural gas is used as a feedstock to produce both urea and methanol. Use of a fuel as a feedstock is considered to be non-energy use.
Generation capacity
The maximum amount of electricity that can be produced by an electricity generation plant running at full power at a specific point in time.
Grid Exit Point (GXP)
A point where electricity leaves the national grid operated by Transpower and enters the local distribution network.
Gross Calorific Value (GCV)
The total amount of energy released when combusting a fuel. This value will be higher than a fuel's net calorific value.
Hydro inflows
The volume of water flowing into a hydroelectric reservoir or system from upstream sources such as rivers, rainfall, snowmelt, or other tributaries.
Net calorific value (NCV)
The amount of energy that can be recovered when combusting a fuel. Some energy from combustion will always be lost due to heating water vapour and other factors, and the net calorific value takes this into account. This value will be lower than a fuel's gross calorific value.
Non-energy use
The use of energy for purposes other than combustion. This includes, for example, the use of bitumen in the construction of roads and the use of natural gas in ammonia production.
Process heat
The energy used for warming spaces and industrial processes (such as drying milk powder). This is often in the form of steam, hot water, or hot gases.
Reserves (1P, 2P and 3P)
The amount of crude oil, LPG, or natural gas that is believed to be available and commercially producible in an oil or natural gas field. These are reported at different levels of confidence or certainty.
- 1P reserves are Proven reserves (both developed and undeveloped). These reserves have a 90% certainty of being produced.
- 2P reserves are the sum of Proven reserves and Probable reserves. These reserves have a 50% certainty of being produced.
- 3P reserves are the sum of Proven reserves, Probable reserves, and Possible reserves. These reserves have a 10% certainty of being produced.
Resources, Contingent (2C)
2C Contingent resources are resources estimated at a particular time to be potentially recoverable but are not yet commercially recoverable. This could be a result of technological barriers or economic factors. It is possible for remaining reserves to be reclassified as Contingent resources (or vice versa) because of changing economic conditions.
Self-sufficiency
A measure of a country’s ability to meet its own energy supply requirements and is calculated as domestic production divided by total primary energy supply. A value of 100% indicates that a country produces all the energy it needs, whereas values above or below 100% indicates it is a net exporter or importer of energy, respectively.
Total final energy consumption (TFEC)
Energy consumed by end-users such as factories and households.
Total primary energy supply (TPES)
The total amount of energy available for use in New Zealand, accounting for domestic production and trade.
Transformation
Any process by which one energy type is transformed into another energy type. For example, the production of electricity by burning coal is a transformation process, as is the conversion of crude oil into petroleum. If an energy type is transformed into a non-energy form, this is instead non-energy use.
Utility-scale solar
Large solar photovoltaic (PV) projects that directly supply an electricity grid or network.
Waste heat
Heat that is generated from a by-product chemical reaction and used to generate electricity.
Conversion equivalents
To convert values from one unit to the other:
- Find the unit your value is in on the column of the table.
- Find the unit you wish to convert to in the top row of the table.
- Multiply your value by the listed amount.
| TJ | PJ | GWh | TWh | |
|---|---|---|---|---|
| Terajoule | 0.001 | 0.2778 | 0.0002778 | |
| Petajoule | 1000 | 277.778 | 0.2778 | |
| Gigawatt hour | 3.6 | 0.0036 | 0.001 | |
| Terawatt hour | 3600 | 3.6 | 1000 |