This is the maximum annual gas load you will be expecting to use through your meter in a single
year, based on the maximum capacity of the gas appliances you are planning to have on site. A GasSafe
Engineer will be able to help you determine this. This information will enable Corona to accurately order
the correct amount of gas to ensure that you will always have gas available at your meter point.

Active Power
Also known as ‘Real Power’ or simply ‘Power’. Active power is the rate of producing, transfer or using electrical energy. Measured in watts and often-expressed in kW or MW.
An Amp is the unit of measure of the rate of flow of electrical current.
Anaerobic digestion
The system for dealing with organic wastes is a complex biochemical process, which takes place in the absence of oxygen, producing a mixture of carbon dioxide and methane gas and a reasonably stable granular material. This process is used to generate energy (electricity or heat).
Annual Agreed Quantity (AAQ)
The annual volume of gas consumed, measured in Kilowatt hours (kWh).
Apparent Power
The product of the voltage (volts) and the current (amps). Comprises both active and reactive power. Measured in kVA or MVA.
Authorised Supply Capacity (ASC)
The agreed maximum supply capacity, measured in kVA, which a customer is allowed to take from the distribution system through their connection point. Customers pay a monthly charge for each unit of capacity.
Availability Charge
The charge for the amount of power made available to the clients premises. It is related to the authorised supply capacity. The distribution company sets the rate and it is expressed in kVA.


Base Load
The minimum amount of electricity used in a half hour period.
The British Electricity Transmission and Trading Arrangement introduced in 2005 covering England, Wales and Scotland, replacing NETA which did not cover Scotland.
Bilateral Energy Trading
Trading whereby two parties (for example a generator and a supplier) enter into a contract to deliver electricity at an agreed time in the future.


Calorific Value
The ratio of energy to volume measured in mega joules per cubic meter (MJ/m).
An electrical device that provides reactive power to the system and is often used to compensate for inductive reactive load to improve system power factor.
Carbon Emissions Trading Scheme
A scheme in which greenhouse gas emissions are controlled by setting a cap on total transmissions and allowing the market sectors to reach an economically balanced response via trading of emissions allowances. Allowances are allocated initially, perhaps through a free distribution or through an auction, and the total allocation is adjusted periodically.
Carbon Intensity
Carbon intensity is the ratio of carbon emissions to economic activity. It is typically reported as the change in the ratio of the two. Carbon intensity can also be a measure of carbon emissions versus primary energy. Both measurements are reflections of the efficiency of the economy with respect to carbon emissions which cause climate change.
Carbon Trust
An independent not-for-profit company set up by the government with support from business to encourage and promote the development of low carbon technologies. Key to this aim is its support for UK businesses in reducing carbon emissions through funding, supporting technological innovation and by encouraging more efficient working practices.
CCGT (Combined Cycle Gas Turbine)
A gas fired electricity generation plant.
CCL Discount
The benefits of the Climate Change Levy Discount Scheme result in up to 80% discount on the CCL in return for meeting energy or carbon saving targets.
CCL Relief
A reduction of the CCL agreed as part of a trade sector Climate Change Agreement.
Chargeable Capacity
The capacity specified by the DNO in the distribution use of system charge relating to a premises.
Climate Change Agreement
Climate Change Agreements are an integral part of the UK Government’s policy response to climate change. Through the Climate Change Agreements, participants will receive an entitlement to a climate change levy reduction provided they meet the agreed energy efficiency or carbon savings targets.
Climate Change Levy (CCL)
The United Kingdom’s Climate Change Programme was launched by the British government in response to its commitment to the Kyoto Protocol on global warming. The Climate Change Levy is a tax on energy delivered to users in the United Kingdom. It came into effect on 1st April 2001 and applies to energy used in the non-domestic sector (industry, commerce, and the public sector). Electricity generated from new renewables and approved cogeneration schemes is not taxed. Major Business sells the CCL exempt suppliers ‘green’ and ‘low carbon’ electricity. Electricity from nuclear is taxed even though it causes no direct carbon emissions and goes up in price by inflation each year.
Climate Change Programme
Published in 2000, it sets out the government and Devolved Administration strategic approach to tackling Climate Change and meeting the UK’s Kyoto target of a 12% reduction in greenhouse gas emissions from 1990 levels by 2008-2012 and the domestic goal of reducing C02 emissions by 20% by 2010.
Electricity generated using fuels from sustainable sources mixed with coal.
Combined Heat and Power Levy Exempt Certificate (CHP LEC)
Under legislation in respect of the Climate Change Levy, suppliers of CHP electricity can claim exemption from CCL where a supply is made from a qualifying good quality CHP source. Major Business obtains is low carbon electricity from 100% good quality CHP sources.
Combined Heat & Power (CHP)
Makes use of both the electricity generated and the heat lost from the generating process.
Communication Charge
The monthly fee payable by a customer, which covers the collection of half hourly data by the meter operator. This can be billed direct by the MOP or passed on through the current supplier.
Connection Agreement
Agreement between the customer and the local distribution company (DNO) for the provision of the connection through which the supply is to be delivered to each of the supply points at the premises.
Current Transformer
A device that is used to reduce (or increase) the supply current levels. For example a 100 / 5 amp transformer would convert 100 amps to 5 amps. Commonly used in metering & measuring equipment.
Customer’s Installation
Any structures, equipment, lines appliances or devices used or to be used by any customer and connected directly or indirectly to the Rec’s network.


Data Aggregator
An accredited person appointed to carry out the aggregation of data from metering equipment.
Data Collector
An accredited person appointed to retrieve, validate and process data from metering equipment.
The interruption of supply, so that electricity cannot flow from the network to the premises.
They are a government department who promote sustainable development as the way forward. A significant part of Defra’s work is concerned with preparedness for emergencies and contingencies, which fall within the remit of environment, food and rural affairs.
The requirement for power.
Demand Site Management
The planning, implementation, and monitoring of activities designed to encourage consumers to modify patterns of electricity usage, including the timing and level of electricity demand.
The permanent removal of the meter, cabling and service from the property once it is established that a supply will not be required in the future. This permanently removes the MPAN.
Distribution Generation
Sometimes called on-site or embedded generation. Electricity generation, which is connected to the distribution network rather than the high voltage transmission network. This is generally smaller generation such as renewable generation including wind, solar power and smaller CHP.
Distribution Losses
These are similar to transmission losses but are the losses incurred on the DNO’s distribution network whilst transporting the electricity from the grid supply point to the customer’s premises. Again it is expressed as a percentage of the kWhs used & varies from one DNO to another (as each DNO’s network will be slightly different) & will vary dependant upon the customer’s supply voltage. DNO losses typically vary between 3 & 6% which is higher than the transmission losses due to the lower voltages used on the DNO networks.
Distribution Network Operator (DNO)
The operator of the relevant distribution network.
Distribution System
The local cables, transformers, substations and other equipment used to distribute and deliver energy.
Distribution Use of System Charges (DUoS)
This is the ‘rental charge’ your electricity supplier has to pay the DNO for using their system to deliver the electricity to your premises. It is designed to cover the infrastructure costs i.e. cables, transformers, switchgear etc that the DNO has to provide.


Emissions Trading
A “green house gas trading system” whereby large carbon producers can buy and sell their quotas for CO2 emissions. EU Emissions Trading Scheme (EU ETS) The EU ETS is one of the policies introduced across Europe to tackle emissions of carbon dioxide and other greenhouse gases and combat the serious threat of climate change. The scheme commenced on 1 January 2005. The first phase runs from 2005-2007 and the second phase will run from 2008-2012 to coincide with the first Kyoto Commitment Period. Further five-year periods are expected subsequently. The scheme will work on a “Cap and Trade” basis. EU Member State governments are required to set an emission cap for all installations covered by the Scheme. Each installation is then allocated allowances for the particular commitment period in question. The number of allowances allocated to each installation for any given period, (the number of tradable allowances each installation will receive), will be set down in a document called the National Allocation Plan. Anyone who is not covered by the Scheme will be able to open an account on the registry and buy and sell allowances1. (See UK ETS for differences between the two).
EU Renewables Directive
The EU Renewables Directive aims to promote electricity generation from renewable sources across the EU. It sets an indicative target of 10% for renewable electricity for Member States to achieve by 2010. The Directive also requires Member States to ensure that a mutually recognisable guarantee of origin is issued on request in respect to all electricity generated from renewable energy sources. Energy Crops Growing and burning of energy crops is greenhouse neutral, as long as the regrowth rate balances the use rate, so that as much carbon dioxide is absorbed as is produced by combustion. This is used in Biomass generation.
Excess Availability Charges
A charge by distribution companies on customers who are drawing in excess of their authorised supply capacity.
Exit Point:
A point of connection at which a supply of electricity may flow between the distribution company’s system and the customers installation.
Extra High Voltage:
33,000 volts or higher.


A tariff that a utility or grid operator must pay to a renewable electricity producer, a tariff set by government.
Firm Gas
Gas supplied to a customer on a guaranteed basis, without interruption.
Fixed Charge
A monthly of quarterly charge levied by the supplier.
Forwards Contract
An agreement to buy electricity or gas from another party at a specified time in the future at a specified price with money changing hands at the delivery date.
Fossil Fuel
An energy source formed in the earth’s crust from organic material. The common fossil fuels are oil, coal, and natural gas.
Fuel Labelling
Obliges suppliers to issue a fuel label on or with customer’s bills once a year and on materials intended to promote the sale of electricity.
Futures Contract
Similar to a forwards contract these are normally traded through an exchange on standard contract terms with profits or losses calculated and paid daily.


Gas Substation
A pressure reduction station located on the customers’ premises where gas is reduced from mains pressure regulated at a medium or low pressure for domestic or industrial use.
Gate Closure
In relation to a settlement period, the time 3.5 hours before the start of that settlement period. It defines the moment when bilateral contracting ends and the Balancing Mechanism for each associated trading period begins.
This covers the production of electricity at power stations. At present the main fuels used are gas, nuclear and coal, although there is now a growing use of renewable forms of energy, such as wind power, the burning of gas from landfill and waste incineration.
Gigawatt (GW)
A unit of power equal to 1 billion watts; 1 million kilowatts, or 1,000 megawatts
Gigawatt-hour (GWh)
A unit of energy equal to million kilowatt-hours. 1 GWh is equivalent to the total electricity typically used by 250 homes in one year.
Good Quality CHP
Good Quality CHP refers to CHP generation that is energy efficient in operation. The CHP Quality Assurance programme (CHPQA) launched in May 2000 determines that quality by providing a practical method for assessing all types and sizes of CHP scheme.
Green Fund
EDF Energy does operate a ‘Green Fund’ in which a premium from ‘Green Tariff’ residential customers is matched by EDF Energy and used to fund renewable energy projects.
Grid Supply Point
A point of supply from the national transmission system to the local system of the distribution network operator.
Guaranteed Service Standard – customer service standards of performance that are set by OFGEM.


Half-Hour Data (HHD)
This is the product of the half-hour data meter. The data is used for invoicing, tendering and reporting purposes.
High Voltage (HV)
In excess of 415 volts.
Hydro-electric power
When water is passed through a turbine, the mechanical power produced is turned to electrical power by a generator.


A situation where there is a difference between the amount of power consumed and the amount of electricity contracted or sold.
A connection or link between power systems that enables them to draw on each other’s reserve capacity in time of need.
Interruptible Gas
Gas supplied to a customer whose site has an alternate fuel source, on the basis that the supply might be interrupted for a specified period.
IPPC (Integrated Pollution Prevention Control)
Regulatory demands on industrial activity throughout the EC are more stringent than ever. The Integrated Pollution and Control (IPPC) directive means companies face new aspects for consideration, controls to put in place and an increase in work required to obtain and comply with environmental permits


Kilovolt Amperes (KVA)
Also known as Apparent Power. The resultant effect of the active (kW) and reactive (kVAr) power kVA = kW/power factor.
Kilowatt-hour (kWh)
A unit of energy consumption. A typical home uses around 3,300 kWh of electricity per annum.
Kilowatt (kW)
A standard unit of electrical power equal to 1,000 watts, or to energy consumption at a rate of 1,000 joules per second.
Kyoto Protocol
The treaty set legally binding targets for countries to reduce their emissions of greenhouse gases. It was negotiated in Kyoto, Japan in December 1997, opened for signature on March 16, 1998, and closed on March 15, 1999. The agreement came into force on February 16, 2005 following ratification by Russia on November 18, 2004. As of October 2006, a total of 166 countries and other governmental entities have ratified the agreement (representing over 61.6% of emissions from Annex I countries).


Large scale hydro power
Relies on a dammed mass of water which is released through a turbine at great force. Levy Exempt Certificate (LEC) Evidence of CCL exempt electricity supply generated from qualifying renewable sources. A renewable LEC applies to ‘Green’ electricity, whereas ‘low carbon’ energy has a good quality CHP LEC associated.
Liquified Natural Gas (LNG)
When natural gas is cooled to a temperature of approximately -160 degrees at atmospheric pressure, it condenses to a liquid called Liquified Natural Gas (LNG). Natural gas is composed primarily of methane (typically at least 90%), but may also contain ethane, propane and heavier hydrocarbons.
The amount of electric power delivered or required at any specific point or points on an electrical system. The requirement originates at the energy-consuming equipment of the customer.
Load Factor
Measures the relationship between unit consumption and maximum demand and is the percentage capacity utilisation figure of a site’s power consumption. To calculate load factor take the total number of units of consumption, divide by the maximum demand, divide by the number of hours in the period, and multiply by 100.
Load Management
The process of shifting the use of electricity from periods of high demand to periods of lower demand, when the cost of electricity is usually lower.
Low Voltage, normally at 240 or 415 Volts.


Managed Load
The fixed energy base load of the total curve. This can be purchased either all at once or step-by-step.
Marine Current Turbines
A turbine driven by energy from tidal currents, creating predictable steady flows of electricity.
Maximum Demand (MD)
Maximum Demand (in kW) equates to two times the highest consumption (in kWh) occurring in a half hour period.
Megawatt (MW)
The equivalent to one thousand kilowatts (kW).
Meter Operator (MOP or MO)
The organisation appointed to install and maintain metering equipment.
Meter Point Reference Number
A unique reference number identifying each meter and used in the preparation of supply tenders.
A 13-digit number (the bottom line of the Supply Number) made up of the: Distributor Identifier (first two digits), the company which provides the distribution network for the supply address. Meter Point unique reference (11-digit number), which is linked to the supply address.
The Meter Point Registration System is owned by the distribution companies. It contains all the MPAN’s for that distribution area.
MPRN (existing services only)
This is the unique Meter Point Reference Number (MPRN) for any existing service. This information will help us to trace the existing installation and where known, determine the size and capacity of the existing meter. The MPRN can be found on your gas bill.


Net Capacity
The maximum load that a generating unit, station or other electrical apparatus can carry under specified conditions for a given period of time without exceeding approved limits of temperature.
NETA – New Electricity Trading Arrangements
This came into force on the 27th March 2001 and replaced the old ‘electricity pool’. NETA is a new wholesale market, comprising trading between generators and suppliers of electricity in England and Wales. Under NETA, bulk electricity will be traded forward through bi-lateral contracts and on one or more power exchanges. Those trading will include generators, suppliers, traders and customers.
National Grid Company, the company which runs the England and Wales Balancing Mechanism and transmission system.
Non Half hourly sites – sites that take a power supply less than 100kW.


Ocean Thermal Energy Conversion (OTEC)
Electricity generation by making use of the temperature difference between the top and bottom layers of the ocean to convert a fluid to vapour, which in turn powers a turbine generator.
Office of Gas and Electricity Markets (OFGEM)
Regulator and competition authority for the downstream electricity and gas industries in England, Wales and Scotland. Off-shore wind turbines Work on the same principle as on-shore wind turbines, but in order to take full advantage of the strong and consistent offshore wind conditions, typically they are larger than their on-land counterparts.


Peak Demand
The maximum load during a specified period of time.
This is the maximum hourly gas load you will be expecting to use through your meter in a single hour, based on the maximum capacity of the gas appliances you are planning to have on site. A GasSafe Engineer will be able to help you determine this. This information will be used to determine the size of the meter required, the diameter of the service required to meet the demand and also the size of the Emergency Control Valve (ECV) required.
Plant Mothballing
When a plant is not operating because there is no demand for its services the plant is ‘mothballed’.
Power Factor
A Power Factor is a measure of how effectively electricity is being used on a site. Certain types of equipment (e.g. electric motors) can cause poor power factor .This results in a system drawing more power from the network than is actually required. Distribution companies will charge customers for this through reactive power charges. Power factor can be improved by the installation of power factor correction equipment. Power Purchase Agreement (PPA) The off-take contract from a large customer to buy the electricity generated by a power plant.


Reactive Charges
Charges applied to a client’s invoice in cases where certain suppliers and distribution companies enforce a penalty for reactive power use.
OFGEM is the Office of the Gas and Electricity Markets, regulating the gas and electricity industries in the UK. You can get further information about gas and electricity from Energywatch, the gas and electricity consumer organisation. This is a statutory body representing the interests of gas and electricity consumers in the UK.
Any alteration to the existing system designed to enable the system to distribute an increased amount of electricity.
Renewable Energy Guarantee of Origin (REGO)
A certificate that energy generators can request to act as evidence that energy is from a renewable source
Renewable LEC
A tax exempt certificate acknowledging that a quantity of electricity constitutes renewable source electricity. EDF Energy is able to demonstrate that its ‘Green Energy’ comes from eligible renewable generation sources that have been accredited by Ofgem to issue Renewable Levy Exempt Certificates under the Climate Change Levy enacted by the Finance Act 2000 and audited by HM Customs and Excise
Renewable Obligation Certificates (ROC)
These are presented to Ofgem by licensed suppliers to show compliance with the Renewable Obligation.


Small scale hydro power
Power may be produced from even a small stream with minimum environmental impact and is usually a more attractive and cost effective proposal
Solar Photovoltaic
Photocells convert sunlight directly into electricity.
Solar Power
Energy from the sun’s radiation converted into heat or electricity.
Solar Thermal
Solar thermal energy refers to the idea of harnessing solar power for practical applications from solar heating to electrical power generation.
Supply Offtake (Daily) Quantity measured in kWh.
Spark Spread
The difference between market price and the cost of gas fired electricity generation.
Standing Charge
A Monthly or quarterly charge levied by the local distribution company.
The term often used when a property owner installs a separate meter to monitor the consumption of a utility such as water, gas or electricity.
Facility equipment that switches, changes, or regulates electric voltage.
Supply Agreement
A contract between a supplier and the customer to supply electricity or gas at an agreed rate for an agreed duration of time.
System Buy Price (SBP)
The price paid in the Balancing Mechanism by a party that requires more energy to meet its contractual commitments. Prices are often volatile and very high.
System Sell Price (SSP)
The price paid in the Balancing Mechanism by a party that has produced more electricity than it had customers to buy. Prices are very volatile and often negative, meaning that a payment would need to be made to dispose of the unwanted electricity produced.


Terawatt-hour (TWh)
The equivalent to one thousand gigawatt hours (GWh).
The Carbon Trust
The Carbon Trust is an independent, not-for-profit company, which was created by the UK government. The Carbon Trust helps business and the public sector cut carbon emissions, and supports the development of low carbon technologies.
This is a unit of measurement for gas. 1 therm is equal to 29.3071kWh
Tidal Power
Tidal movement is caused by the gravitational pull of the moon on the earth. As the moon obits the earth, water is dragged around the globe to create tidal rises and falls. At present a number of devices are being developed to capture this energy.
Top-up Load
Electricity used in excess of the base load
Trade Association
An association of firms that operate in a specific industry.
UK gas transportation and emergency service.
An electrical device for changing the voltage or current of an alternating (a.c.) electricity supply.
The transfer of electricity at extra high voltage from power stations to the grid supply points on the local distribution networks.
Triad Demand is measured by the National Grid as the average demand on the national transmission system over three half hours between November and February (inclusive) in a financial year. These three half hours comprise the half hour of system demand peak and the two other half hours of highest system demand which are separated from system demand peak and each other by at least ten days. A customer’s triad charge is calculated by averaging the customer’s actual demands at the times of the national grid triad demands & multiplying by the triad charge applicable to their transmission zone (as published by National Grid).
TUoS (Transmission Use of System)
The charges incurred for transmitting electricity across the National Grid network from the source of generation to the network of the local distribution company. These charges include transmission losses & triad demand charges.
Wind turbines are an efficient method of converting wind energy into electrical power both onshore and off.


UK Emissions Trading Scheme
The UK emissions trading scheme is the world’s first economy-wide greenhouse gas emissions trading scheme. The scheme was launched in March 2002, and runs until December 2006, with final reconciliation in March 2007. Thirty-three organisations (“direct participants” in the scheme) have voluntarily taken on emission reduction targets to reduce their emissions. The scheme is also open to the 6000 companies with Climate Change Agreements. These negotiated agreements between business and Government set energy-related targets. Companies meeting their targets receive an 80% discount from the Climate Change Levy, a tax on the business use of energy. These companies can use the scheme either to buy allowances to meet their targets, or to sell any over-achievement of these targets. Anyone can open an account on the registry to buy and sell allowances. It is important to note that UK ETS and EU ETS are two separate schemes and no installation is in both UK ETS and EU ETS. There are three principal differences between UK ETS and EU ETS: 1. The EU scheme is a mandatory CO2 only scheme whereas the UK scheme is voluntary with incentive monies and covers all six greenhouse gases. 2. In the EU scheme, emissions from electricity generation are assigned to the electricity generators whereas in the UK scheme they are assigned to end-users of electricity. 3. The UK scheme is economy-wide and encourages a broad range of sectors to participate, whereas the EU ETS focuses essentially on a subset of sectors covered by the IPPC Directive (and some smaller combustion installations).


Voltage Transformer
A device that reduces (or increases) the supply voltage, for example a 11000/415 Volt transformer would convert an 11,000 volt supply to a 415 volt supply.


Wave Power
Wave power refers to the energy of ocean surface waves and the capture of that energy to do useful work – including electricity generation, desalination, and the pumping of water (into reservoirs).
Wind Farm
Where several wind turbines are grouped together, collectively.
Wind power
Wind power is the kinetic energy of wind, or the extraction of this energy by wind turbines. These usually start to operate when the wind is blowing at around 3-5 metres per second and shut down if the wind reaches above 25 metres per second.
Is a type of energy crop which is carbon dioxide neutral and gives off only as much CO2 when burnt as it stores during its lifetime.

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