| Access
Charge |
A charge for
a power supplier, or its customer, for access to a utility's transmission
or distribution system. It is a charge for the right to send
electricity over another's wires. |
| AGR |
Advanced gas-cooled reactor,
a British design of nuclear reactor |
| Aggregation |
The process of organising
small groups, businesses or residential customer into a larger, more
effective bargaining unit that strengthens their purchasing power
with utilities. |
| Ampere |
Unit that measures electrical
current in a circuit |
| Base Load |
The minimum load experienced
by an electric utility system over a given period of time |
| Base Load Unit |
A generating unit that normally
operates at a constant output to take all or part of the base load
of a system. |
| Baseload Capacity
|
Generating equipment operated
to serve loads 24 hours per day. |
| Bilateral Contract
|
A direct contract between
the power producer and user or broker outside of a centralised power
pool. |
| Biomass |
Plant materials and animal
waste used as a source of fuel. |
| Combined Heat and
Power |
Form of energy generation
where the waste heat from electricity generation is passed through
a second cycle to extract the energy from the heat |
| Capacitor |
This is a device that helps
improve the efficiency of the flow of electricity through distribution
lines by reducing energy losses. It is installed in substations and
on poles. Usually it is installed to correct an unwanted condition
in an electrical system |
| Capacity |
The maximum load a generating
unit, generating station, or other electrical apparatus is rated to
carry by the user or the manufacturer or can actually carry under
existing service conditions. |
| Capacity Charge |
An assessment on the amount
of capacity being purchased. |
| Cogeneration |
Production of heat energy
and electrical or mechanical power from the same fuel in the same
facility. A typical cogeneration facility produces electricity and
steam for industrial process use. |
| Combined Cycle |
Similar to the combustion
turbine simple cycle, but includes a heat recovery steam generator
that extracts heat from the combustion turbine exhaust flow to produce
steam. This steam in turn powers a steam turbine engine. |
| Combined Cycle Plant |
An electric generating station
that uses waste heat from its gas turbines to produce steam for conventional
steam turbines. |
| Decommissioning |
The process of removing a
nuclear reactor from service and dismantling. |
| Dispatchability |
This is the ability of a
generating unit to increase or decrease generation, or to be brought
on line or shut down at the request of a utility's system operator |
| Distributed Generation |
A distributed generation
system involves small amounts of generation located on a utility's
distribution system for the purpose of meeting local (substation level)
peak loads and/or displacing the need to build additional (or upgrade)
local distribution lines. |
| Distribution |
The system of wires, switches,
and transformers that serve neighbourhoods and business, typically
lower than 69,000 volts. A distribution system reduces or downgrades
power from high voltage transmission lines to a level that can be
used in homes or businesses. |
| Distribution Line |
This is a line or system
for distributing power from a transmission system to a customer. It
is any line operating at less than 69,000 volts. |
| Distribution Network
Operator (DNO) |
Refers to the regulated owner/operator
of the distribution system which serves retail customers. |
| Distribution System
|
That part of the electric
system that delivers electric energy to consumers. |
| Earth Summit |
The United Nations Conference
on environment and development held in Rio de Janeiro in 1992 where
World Governments fjor the first time recognised the need to address
issues of climate change and agreed the need for actionto address
the World’s environmental problems |
| ETSU |
The Energy Technology Support
Unit, which manages the DTI’s new and renewable energy programme |
| Forced Outage |
An outage that results from
emergency conditions and requires a component to be taken out of service
automatically or as soon as switching operations can be performed.
The forced outage can be caused by improper operation of equipment
or by human error. If it is possible to defer the outage, the outage
becomes a scheduled outage. |
| Fossil Fuels |
Coal, oil and natural gas,
formed from animal and plant material during the carboniferous era |
| Fuel cell |
A device that converts energy
from chemical reactions directly into electrical energy. The simplest
fuel cell 'burns' hydrogen in a flameless chemical reaction to produce
electricity. In order to 'burn' the hydrogen a fuel cell needs a source
of oxygen and this is usually obtained from air. The only by-product
from this type of fuel cell is water. |
| Gasification |
A process that exposes a
solid fuel to heat in the presence of limited oxygen to produce a
gaseous fuel. This fuel contains hydrogen but also other gases such
as carbon monoxide, carbon dioxide, nitrogen, and methane. Under suitable
circumstances, gasification can produce synthesis gas, a mixture of
just hydrogen and carbon monoxide. |
| Gigawatt |
This is a unit of electric
power equal to one billion watts, or one thousand megawatts enough
power to supply the needs of a medium sized city. |
| Global Warming |
Process by which the Earth
is getting warmer due to more of the Sun’s heat being trapped
by the Earth’s atmosphere as a result of increased concentration
of ‘green house gases’ released by human activity |
| Grid Operator |
Grid Operator Refers to the
regulated owner/operator of the transmission system only. |
| Intermittent Resources |
Resources whose output depends
on some other factor that cannot be controlled by the Utility e.g.
wind or sun. Thus, the capacity varies by day and by hour. |
| Interruptible Power |
This refers to power whose
delivery can be curtailed by the supplier, usually under some sort
of agreement by the parties involved. |
| Interruptible Rates
|
These provide power at a
lower rate to large industrial and commercial customers who agree
to reduce their electricity use in times of peak demand. |
| Kilowatt (kW) |
The electrical unit of power
equal to 1,000 watts. |
| Kilowatt-Hour (kWh)
|
The basic unit of electric
energy equal to one kilowatt of power supplied to or taken from an
electric circuit for one hour. |
| Losses |
The general term applied
to energy (kWh) and capacity (kW) lost in the operation
of an electric system. Losses occur principally as energy transformations
from kWh to waste heat in electrical conductors and apparatus.
This power expended without accomplishing useful work occurs primarily
on the transmission and distribution system. |
| Magnox |
Early British type of reactor
so-called after its magnesium alloy fuel cans. |
| Megawatt |
One million watts. |
| Megawatt hour (MWh) |
One thousand kilowatt-hours
or one million watt hours. |
| Municipal Solid Waste |
A Biomass resource
that can be used to produce energy by the process of incineration. |
| Non Dispatchable |
This refers to non-predictable
energy sources, where there is little or no ability of a generating
unit to increase or decrease generation, or to be brought on line
or shut down at the request of a utility's system operator. |
| Ofgem |
Office of the electricity
and gas regulator (markets). |
| Outage |
Time during which service
is unavailable from a generating unit, transmission line, or other
facility. |
| PWR |
Pressurised water reactor. |
| Photovoltaic (PV)
cells. |
(Also known as solar
cells.) A photovoltaic cell is made of thin wafers of two slightly
different types of silicon, which, when exposed to light, will produce
an electric current. Photovoltaic cells thus convert light energy
into electrical energy. |
| Pyrolysis |
A process which involves
heating biomass to drive off the volatile matter, leaving
behind the black residue we know as charcoal. More sophisticated pyrolysis
techniques have been developed recently to collect volatile gaseous
compounds that are otherwise lost to the system. The collected volatiles
produce a gas rich in hydrogen and carbon monoxide. |
| Renewable Energy
|
Energy that is capable of
being renewed by the natural ecological cycle, for example, wind,
waves and sun. |
| Reserve Capacity
|
Capacity in excess of that
required to carry peak load. |
| Reserve Generating
Capacity |
The amount of power that
can be produced at a given point in time by generating units that
are kept available in case of special need. This capacity may be used
when unusually high power demand occurs, or when other generating
units are offline for maintenance, repair or refuelling. |
| Scheduled Outage |
A pre-arranged period of
time during which a system is taken out of service, for example, to
carry out routine maintenance |
| Solar Cells |
(Also known as Photovoltaic
(PV) cells) Solar cells are made of thin wafers of two slightly
different types of silicon, which, when exposed to light, will produce
an electric current. Solar cells thus convert light energy into electrical
energy. |
| Spinning Reserve
|
Reserve generating capacity
running at zero load. |
| Standby Facility |
A facility that supports
a system and generally running under no load. |
| Terawatt |
A million million watts. |
| Transformer |
A device for changing the
voltage of alternating current. |
| Transmission and
Distribution (T&D) Losses |
Losses in energy between
the generation facility and the customer. |
| Transmission and
Distribution (T&D) System |
An interconnected group of
electric transmission lines and associated equipment for the movement
or transfer or electric energy in bulk between points of supply and
points at which it is transformed for delivery to the ultimate customers. |
| Volt |
A unit of electrical pressure.
It measures the force or push of electricity. Volts represent pressure,
correspondent to the pressure of water in a pipe. |
| Volt-amperes |
The volt-amperes of an electric
circuit are the mathematical products of the volts and amperes of
the client. |
| Waste-to-Energy |
This is a technology that
uses refuse to generate electricity. In mass burn plants, untreated
waste is burned to produce steam, which is used to drive a steam turbine
generator. In refuse derived fuel plants, refuse is pre-treated, partially
to enhance its energy content prior to burning. |
| Watt |
The basic unit of power (the
rate at which energy is used) in the metric system is the watt (W);
a kilowatt is 1000 watts. A watt is a very small amount of power and
in most mechanical applications we count power in kilowatts. A car
engine typically produces 50 to 100 kilowatts. One horsepower is equivalent
to approximately 746 watts. |
| Watt-Hour |
One watt of power expended
for one hour.
Wholesale Power Market The purchase and sale of electricity from generators
to resellers (who sell to retail customers) along with the ancillary
services needed to maintain reliability and power quality at the transmission
level. |