Understanding the Language
Alternating current – A periodic current the average value of which over the period is zero. A current that reverses at regularly recurring intervals of time and that has alternatively positive and negative values.
Ash – The residual inorganic material left after combusting coal.
Baseload power plant – Provide power to the grid between 20 – 100 percent of the system load during annual hours.
Boiler sludge – Boiler water solids which settle out in headers‚ in drums and on the boiler surface.
Boiler – A vessel in which water is heated.
Calorific value is the amount of heat released during the combustion of a specific amount.
Capacity – The load for which a generator‚ turbine‚ transformer‚ transmission circuit or system is rated.
Cogeneration – A generating facility that produces electricity and another form of useful thermal energy used for industrial‚ commercial‚ and heating and cooling purposes.
Combined cycle plant – both a steam turbine and gas turbine produce electricity
Combine-cycle cogeneration plant – both a steam turbine and gas turbine produce electricity and process steam
Critical boilers – Boilers in which pressures exceed 221.72 bar and 375C
Direct current – Unidirectional current; a practically nonpulsating current.
Economic efficiency = (Production costs / Energy output) – Refers to the cost to produce one unit of electricity
Electric generators – rotating machines that convert mechanical energy to electrical energy.
Feedwater – The total flow of water supplied to the boiler; the sum of condensate and makeup water.
Fission – Process in which a heavy nucleus splits into two or more large fragments and releases kinetic energy.
Generation – The act or process of producing electric energy from other forms of energy.
Heat Rate = (Heat supplied/Energy Output) – The fuel required to generate one unit of electricity
Heating plant – location where only steam or hot water is produced
Installed capacity – The sum of the capacities in a powerplant or power system as shown by the nameplate ratings.
IGCC – Integrated Gasification Combined Cycle Plant turns coal into gas (synthsis gas). It them removes impurities from the coal gas before combustion resulting in lower emissions.
Intermediate – Provide between 5 – 20 percent of annual demand hours
1 kilowatt – 1.341 horsepower
A kilowatt hour is a unit of energy and is the product of power in kilowatts and time in hours. It is not kilowatts per hour.
Load factor = (Minimum demand / average demand) – Refers to the steadiness of the load factor over time
Megawatt (MW) – One thousand kilowatts or 1 million watts. One megawatt is enough power to power 1‚000 homes on average.
Net summer capability – A common measure of generating capacity‚ defined as the steady hourly output that generating equipment is expected to supply to the system load‚ exclusive of auxiliary power
Nuclear core – Region within a reactor occupied by the nuclear fuel that supports the fission chain reaction.
Peaking power plants – Provide power during the highest 5% of annual demand hours
Power Factor – The ratio of the circuit power (watts) to the circuit volt amperes.
Power Plant – location where only electricity is produced
Quadrillion btu – Equivalent to 10^5 British thermal units
Rated capacity – The electrical load for which a generator‚ turbine or power is system is rated.
Reaction turbine – A turbine which uses both kinetic energy and the pressure of the water column to produce power. Francis‚ Kaplan and fixed-blad turbines are all reaction turbines.
Renewable energy – Energy obtained from sources that are essentially inexhaustible‚ such as wood waste‚ solar and wind.
Sub-critical Boiler – Boilers in which pressure are below 220 bar and 375C
Thermal efficiency (Desired Energy Output / Energy Cost) – The desired energy output is the shaft work‚ and the energy that it costs is the heat input to the boiler (steam plant example).
Transmission – The transporting of electric energy in bulk to a convenient point‚ where it is subdivided for delivery to the distribution system.
Types of coal – Anthracite‚ Bituminous‚ Sub bituminous‚ Lignite
Watt – The basic electrical unit of power or rate of dong work. The rate of energy transfer equivalent to one ampere flowing under a pressure of one volt at unity power factor. One horsepower is equivalent to approximately 746 watts.
Ultra Supercritical boilers – Boilers in which pressures exceed 305 bar and 600C