EirGrid is dedicated to the provision of transmission and market services for the benefit of electricity consumers in Ireland.

Electric Current
The rate at which electricity flows through an electrical conductor, usually measured in amperes (amps).

Electrical Cell
A device that produces or stores electricity.

Electricity can be described as being in three parts, 'real power' (kW, mW) - the usable energy, 'apparent power' (kVA) - measurable energy, and 'reactive power' (kVAr) - wasted energy. See elsewhere in this glossary. 

Electricity Meter
A device that measures the amount of electricity used.

Electricity Pool
The way by which electricity is traded between generators and suppliers (as well as some very large consumers).

A magnetic field produced when an electric current is passed through a wire wrapped around a piece of iron.

Electromagnetic field (EMF)
Field created by the presence or flow of electricity in an electric conductor or electricity consuming appliance or motor.

Electronic Data Interchange (EDI)
Allows the transfer of bill data through a secure channel so that customers can receive their bills in a specified format.

Emergency contact
Consumers of larger quantities of gas above 25,000 therms per annum are required to provide the supplier with the contact details of an individual or company who or which is contactable outside of normal working hours and has access to the property to which the gas is supplied.

Emissions Trading
A market mechanism that allows emitters (countries, companies or facilities) to buy emissions from or sell emissions to other emitters. Emissions trading is expected to bring down the costs of meeting emission targets by allowing those who can achieve reductions less expensively to sell excess reductions (e.g. reductions in excess of those required under some regulation) to those for whom achieving reductions is more costly.

Emissions Trading Scheme (ETS)
ETS is an EU mechanism for the trading of carbon dioxide and other greenhouse gas emissions.

End user
The consumer of energy.

A measure of the amount of 'work' that can be done by, or is needed to operate, an energy conversion system, sometimes measured in 'joules' (J) or 'kilowatt hours' (kWh).

Energy Charter Treaty (ECT)
A multilateral treaty to promote trade, investment and transit of energy products between Contracting Parties and sets a standard for non-discriminatory access to energy supplies.

Energy Cost
This is the cost of the electricity purchased on the wholesale market at the Notional Balancing Point (NBP) to cover current and predicted future usage. It is the single biggest component of the unit price and typically accounts for between 60 and 80% of a business's total bill. In the industry, this element is called Energy at NBP (Notional Balancing Point).

Energy Efficiency
Achieving desired levels of lighting, heating or cooling for minimum energy use. Cutting down on waste energy. A good example is an energy efficient light bulb, which produces the same amount of light as a conventional bulb but uses up to 75% less energy to do so.

Energy From Waste
Energy recovery of post recycling waste residue - an alternative to landfill.

Energy Only
An offer of electricity that has no delivery charges (DUoS & TUoS) added at the point of quotation.

Energy Performance of Building Directive (EPBD)
The principal objective of the Directive is to promote the improvement of the energy performance of buildings within the EU through cost-effective measures. There are four main aspects to the EPBD. 1) Establishment of a calculation methodology for buildings energy performance 2) See minimum energy performance requirements for new and existing buildings 3) Energy performance certificate made available 4) Inspections of boilers and air-conditioning systems

Energy Services Company (ESCo)
A company that specialises in managing energy and water conservation projects. The ESCo may perform any or all of the following services: auditing, developing packages of recommended measures, arranging financing, installing or overseeing installation of measures, resident and staff education, equipment commissioning, maintenance, measuring, verifying, and guaranteeing savings. An ESCo is normally a deregulated organisation set up to provide energy services (electricity, heat and chilled water) to a defined set of users or a local community separate from the incumbent regulated utilities serving the area.

Enriched uranium
Uranium in which the proportion of U-235 (to U-238) has been increased above the natural 0.7%. Reactor-grade uranium is usually enriched to about 3.5% U-235, weapons-grade uranium is more than 90% U-235.

Physical process of increasing the proportion of U-235 to U-238.

Entry Point
The point at which gas enters the transportation system, could be a sub-terminal, storage facility or onshore field.

Environment Agency
The leading public body for protecting and improving the environment in England and Wales.

Environment Protection Agency (EPA)
Ireland's statutory body for the balanced and sustainable protection and management of the environment.

Environmental management system (EMS)
A system assisting a company to manage environmental risk, demonstrating compliance with regulations and stated environmental policies and objectives.

ESB Networks
ESB Networks is a ring fenced subsidiary within ESB Group, is the licensed operator of the electricity distribution system in the Republic of Ireland. ESB Networks is responsible for building, operating, maintaining and developing the electricity network and serving all electricity customers in the Republic of Ireland.

European emissions prices
The rate in Euros at which EU carbon emissions (CO2e) allowances are trading (€/t CO2e).

European Union Emissions Trading Scheme
The EU emissions trading scheme (EU ETS), introduced in April 2005. See the section on Carbon emissions trading scheme, above.

European-Style Option
An option which can only be exercised on the day of expiry.

Evening & Weekend Tariff (E&W)
Expressed in pence per kilowatt hour (kWh) - an electricity tariff based on a day, and evening/weekend time split, most beneficial to, for example, pubs.

Excess Capacity
See both Maximum Available Capacity and Maximum Demand. Electricity consumption over and above the agreed Availability, charged for by the distribution company and collected by the supplier.

To put into effect the right to buy or sell.

Exercise Price
The price at which a call or put option can be exercised.

Exit Zone
A defined zone in which the point of gas offtake is situated.

The date on which an option holder must decide whether to exercise or abandon an option.

Export Metering
This enables a site to export electricity generated onsite.

Extendable Swap
A swap in which one party has the option to extend the maturity beyond the original term, the combination of a swap with a swaption.