ELECTRICITY AND POWER DEFINITION

Auxiliary power/energy
All electricity consumed internally within the boundary of a power station or co generation plant to run the plant. All electricity consumed internally within the boundary of a power station or cogeneration plant to run the plant.

Aeroderivative gas turbine
Aeroderivative gas turbines originate from the aviation industry. They are lightweight. They have higher thermal efficiency and capital cost than industrial gas turbines and their maintenance costs can also be higher. Exhaust gas temperatures are generally lower than industrial gas turbines. Performance decreases dramatically at high ambient temperatures. Aeroderivative gas turbines originate from the aviation industry. They are lightweight. They have higher thermal efficiency and capital cost than industrial gas turbines and their maintenance costs can also be higher. Exhaust gas temperatures are generally lower than industrial gas turbines. Performance decreases dramatically at high ambient temperatures.

Auxiliary boiler
Fuel fired boiler used to raise the site steam and/or hot water requirements.

Availability (%)
Availability is an indicator of the maximum amount of electrical energy that a unit is able to generate during a period, after making allowances for outages due to all causes
(Total installed capacity (MW) * period hours - MWh losses due (Total installed capacity (MW) * period hours - MWh losses due
to all outages during the period) * 100 divided by:
Total installed capacity (MW) * period hours

Back pressure steam turbine
A simple non-condensing steam turbine. High-pressure steam is expanded through the back pressure steam turbine to generate electricity, and is exhausted at the required steam conditions for use in a process or for direct heating. A simple non-condensing steam turbine. High-pressure steam is expanded through the backpressure steam turbine to generate electricity, and is exhausted at the required steam conditions for use in a process or for direct heating.

Base load
Operating regime in which the generator operates at its full capacity (or close to it) at all times.

Biomass
Is material produced by photosynthesis or is an organic by-product of a waste stream suited as a feedstock for electrical and/or thermal energy or the manufacture of fuels and substitutes for petrochemicals and other energy intensive products. Includes a wide variety of renewable organic materials (eg sugar cane pulp, food processing waste, animal manures and sewerage, and organic municipal solid waste). Energy conversion paths include combustion and classification for heat and power (co generation), pyrolysis for liquid and gaseous fuels and chemicals, and anaerobic digestion and fermentation. Biomass fuels tend to be renewable. Is material produced by photosynthesis or is an organic by-product of a waste stream suited as a feedstock for electrical and/or thermal energy or the manufacture of fuels and substitutes for petrochemicals and other energy intensive products. Includes a wide variety of renewable organic materials (eg sugar cane pulp, food processing waste, animal manures and sewerage, and organic municipal solid waste). Energy conversion paths include combustion and gasification for heat and power (cogeneration), pyrolysis for liquid and gaseous fuels and chemicals, and anaerobic digestion and fermentation. Biomass fuels tend to be renewable.

Boiler blow down
Stream of water which is bled from the boiler drum or steam supply system to control the concentration of total solids and other contaminants in the boiler water.

Boiler drum
Generally the steam drum of a boiler where the steam generated is separated from the circulating boiler water.

Bottoming cycle
Heat is recovered from an industrial process (eg a furnace) and then used to generate steam through a boiler, which is then used to generate electricity. Lower pressure steam can also be used for process. Heat is recovered from an industrial process (eg a furnace) and then used to generate steam through a boiler, which is then used to generate electricity. Lower pressure steam can also be used for process.

Capacity
The rated continuous load carrying ability expressed in megawatts, of generation equipment; sometimes referred to as maximum continuous rating (MCR). The rated continuous load carrying ability expressed in megawatts, of generation equipment; sometimes referred to as maximum continuous rating (MCR).

Capacity factor (%)
Total energy produced for a specified period relative to the total possible amount of energy that could have been produced for the same period.
Total period energy generated (MWh) * 100 divided by: Total period energy generated (MWh) * 100 divided by:
Total installed capacity (MW) *period hours

Centralised Generation
Electricity production based on large-scale power stations which are usually remote from electricity consumers, and which require long-distance, high-voltage transmission networks.

Circuit Breakers
A type of switch used to control the flow of power in an electrical circuit. Special forms of these are used in switch yards and substations for the control of power between power (transmission and distribution) lines. A type of switch used to control the flow of power in an electrical circuit. Special forms of these are used in switchyards and substations for the control of power between power (transmission and distribution) lines.

Clean-as-new
New unit, no degradation.

Co generation
Involves the generation of two products from a single fuel. e.g. useful combined heat and power. It is typically, two to three times more efficient than major conventional, predominantly coal-fired, centralised power stations. Production efficiency is achieved by harnessing heat that would otherwise be wasted. The heat and power can also be converted into many applications such as cooling.

Condensate
Steam which has been condensed for return to the boiler.

Creep
The plastic (i.e. inelastic) movement of a metal or other solid. Temperature and stress on the material directly influence the rate of creep. The composition of the material also has a bearing on its rate of creep.
Consideration of the material's creep properties is particularly important in the selection of materials for components subject to high temperature and high stresses, such as those in boilers, turbines and super heaters.Consideration of the material's creep properties is particularly impotant in the selection of materials for components subject to high temperature and high stresses, such as those in boilers, turbines and superheaters.

Deaerator
Used to preheat feed water before entering the waste heat boiler, and to drive off non-condonable and potentially corrosive dissolved gases. Requires steam to provide the energy for heating. Not relevant to hot water case.