Glossary

Baseload generation
Baseload generation refers to power plants that do not change their electricity generation output quickly. These plants are less flexible with meeting electricity demand and take a long time to start up and shut down.

Biomass
Organic material from plants or animals which can be used as fuel for producing heat or electricity.

Black liquor
A recycled by-product made during the pulping of wood in the paper making industry. It is burned in a boiler to produce heat and electricity and is considered to be a solid biofuel.

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, sub-bituminous and lignite.

  • 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 coal, 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.

Electric vehicles
Vehicles that run either partially or fully on electricity. These include:

  • Battery electric vehicles (BEV) can only be powered by electricity.
  • Plug-in hybrid electric vehicles (PHEV) have both an internal combustion engine that runs on petrol and a rechargeable battery for electricity.

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".

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 Points (GXP)
Grid Exit Points (GXP) are the points 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.

Indigenous production
The production of primary energy sources within New Zealand. This includes extracting fossil fuels (such as coal and natural gas) and capturing energy from renewable sources (such as water and the wind).

Modern renewables
A classification for all renewable energy types excluding traditional use of solid biomass. 'Traditional use' refers to the use of solid biomass with basic technologies, such as a three-stone fire, often with no or poorly operating chimneys.

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 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 process
The conversion of one energy type to another. For example, the conversion of geothermal energy to electricity.

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 between units of energy

TJ PJ GWh TWh
Terajoule 1 0.001 0.2778 0.0002778
Petajoule 1000 1 277.778 0.2778
Gigawatt hour 3.6 0.0036 1 0.001
Terawatt hour 3600 3.6 1000 1