Glossary of Terms
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
A
Absorption Chillers
Absorption chillers use heat instead of electricity as a source of energy to produce cooling for buildings. Typically they provide much less cooling output per unit of input than an electric chiller. However, because they can be run using otherwise wasted heat from CHP, they can compare favourably to more efficient electric chillers. Absorption chillers usually take their heat directly from a CHP engine and so are usually co-located with the engines with chilled water distributed around a site using a cooling network. However, they can also be located in individual buildings with heat from the heat network.
Authority
Gas and Electricity Markets Authority (GEMA), known as the Office for Gas and Electricity Markets (Ofgem) is the statutory regulatory authority for the electricity and gas markets.
Balancing Mechanism
A market-based mechanism that enables National Grid to instruct generators and suppliers to vary electricity production or consumption close to or in real-time, in order to maintain safe operation of the system.
BERR
The Department for Business, Enterprise and Regulatory Reform: it is the Government Department responsible for Energy.
BETTA
British Electricity Transmission and Trading Arrangements: The introduction of NET throughout Britain by combining English/Welsh and Scottish rules on 1 April 2005.
Biodiesel
Liquid fuel produced from crops such as oil palm or rapeseed oil. Biodiesel is a type of biofuel.
Biofuel
Liquid fuel produced from biological material, usually energy crops. Common biofuels include biodiesel and bioethanol. More accurately referred to as "agrofuels".
Biomass
Renewable organic matter such as agricultural crops and residue, wood and wood waste, animal waste, aquatic plants and organic components of municipal and industrial wastes. The most common forms of biomass for heat generation schemes are wood chips and wood pellets.
Biomass CHP
Combined heat and power plant using biomass as a fuel source instead of natural gas. Biomass is typically wood chip, wood pellets or energy crops such as miscanthus or willow. Usually biomass is either burnt and the heat used to produce electricity in a steam turbine, or the biomass is gassified and this gas is used as the input gas for a conventional CHP engine.
Borehole Cooling
A form of cooling that makes use of the relatively low temperature of the earth and groundwater tens of meters below the earth's surface. Borehole cooling can be either open or closed loop. An open loop system extracts water from the ground and passes it over a heat exchanger before either reinjecting the water into an aquifer or dumping to drains. A closed loop system typically uses a brine solution in sealed pipes run underground, where a heat exchange takes place between the brine and surrounding matter.
BREEAM
BRE Environmental Assessment Method comprises a group of methods and tools for assessing on-domestic schemes in terms of their environmental impacts.
BSC
The Balancing and Settlement Code: Industry code covering the rules for electricity balancing and imbalance charges in Great Britain
BSUoS
Balancing Services Use of System Charges: Charges paid by suppliers and generators based on the energy taken from or supplied to the National Grid system in each settlement period. These charges are paid to cover the cost of keeping the system in balance and maintaining the quality and security of supply.
Carbon Reduction Commitment
The carbon reduction commitment starts in 2010 and covers all large businesses whose aggregate electricity consumption across all sites is over 6,000MWh for parties who are not covered by climate change agreements or the EU ETS. Although measured by electricity consumption, it will cover all emissions including energy used for heating. For the first three years there will be fixed price sale of allowances for CO2 emissions. For the CRC, heat from CHP is deemed as "zero" CO2 making CHP and district heating more attractive for retail and commercial customers.
Cash Out Arrangements
Arrangements whereby generators and suppliers pay or are paid for imbalances i.e.shortages and surpluses of power relative to their contracted commitments.
CCL
Climate Change Levy: A tax on energy delivered to non-domestic users in the UK, aimed atproviding incentives to increase energy efficiency and reduce carbon emissions. Energy generated from renewable sources is not taxed.
Code for Sustainable Homes
The Code for Sustainable Homes is a national standard for sustainable design and construction of new homes, which came into use in April 2007 and, within England, replaces the EcoHomes scheme, developed by the Building Research Establishment (BRE).The Code measures the sustainability of a new home against categories of sustainable design, rating the 'whole home' as a complete package. The Code uses a 6-level rating system to communicate the overall sustainability performance of a new home.
CUSC
Connection and Use of System Code: the industry document which regulates the connection to the transmission network and its use. Licensed electricity parties must sign the CUSC.
DCMF
Distribution Charges Methodology Forum: A group which meets every six to twelve weeks toconsider and progress policy relating to the DNOs' charging methodologies.
DCUSA
Distribution Connection and Use of System Agreement: The industry document which regulates the connection to the local distribution networks. Parties connecting to the distribution network are parties to the DCUSA.
DEWG
Distributed Energy Working Group: A working group set up by Ofgem and BERR to discuss the commercial, environmental and regulatory issues arising in the context of small, low carbon generation, and potential solutions to these problems.
Distributed Energy/Distributed Generation
Any generation which is connected directly into the local distribution network, as opposed to the transmissions network, as well as combined heat and power schemes of any scale.The electricity generated by such schemes is typically used in the local system rather than being transported for use across the UK.
District Cooling Network
A district cooling network transports chilled water from a central plant to a customer interface unit within a building. Cooling is used by that customer and warmer water is returned back to the central plant. District cooling flow pipes are typically 7oC and 6bar, while the return pipes are typically 13oC and 6bar.
District Heating Network
A district heating network transports hot water from a central plant to a customer interface unit within a building. Some of the heat is used by that customer and cooler water is returned back to the central plant. District heating flow pipes are typically 90oC and up to 10bar, while the return pipes are typically 45oC and 10bar.
DNOs
Distribution Network Owners: Monopoly providers of local, lower voltage electricity networks. These networks operate at 132kV and below in England and Wales and below 132kV in Scotland.
DUoS
Distribution Use of System charges: Charges paid by generators and suppliers for the use ofthe distribution network.
Elexon
Elexon is a not for profit company that manages the day to day operations of the Balancing and Settlement Company, enforcing and operating the Balancing and Settlement Code(BSC).
Embedded Benefits
Benefits set out under the trading rules for those who have generation connected to a distribution network and customers within that same distribution area. The embedded benefits include the avoidance of transmission charges, transmission losses, BSUoS and Elexon charges. The value of the embedded benefits varies by half hour and by the type of customers associated with that generation. Under the trading rules, embedded benefits accrue to the supplier. Generally, embedded benefits are shared between the supplier and generator, but a generator cannot expect to capture the entire embedded benefits.
ESCO
Energy Services Company: an energy company, often not licensed, that provides energy supply for specific sites within a distribution network. It would normally carry out activities such as customer billing and payment collection as well as the purchase of top-up and spill electricity. In addition, it often reads meters and bills customers for thermal products such as heating, cooling and hot water.
EU ETS
European Union Emission Trading Scheme: The EU-wide greenhouse gas emissions trading scheme, under which governments must set emission limits for all large emitters of carbon dioxide in their country. Each installation is then allocated an allowance for the particular phase in question, with the first phase running from 2005 - 2007 and the second from 2008 -2012. Installations may meet their cap by either reducing emissions below the cap and selling the surplus, or letting their emissions remain higher than the cap and buying allowances from other participants in the EU emissions market.
Exempt Supply Services
Services provided to exempt suppliers by a licensed supplier. These might include meter registration, data processing, and providing top-up and back-up services.
Grid Code
Electricity Industry Code that governs the maintenance and operation of the transmission network. Licensed electricity parties are signatories to the Grid Code.
Heat Meter
Used to measure a customers heat (or cooling consumption), a heat meter measures the input and output temperatures as well as the flow rate to calculate the heat (or cooling) consumed in kilowatt hours (kWh).
HIU
The hydraulic interface unit allows a customer or building to interface with a district heating or cooling network. A hydraulic interface unit contains one or more heat exchangers, which can allow the customer's heating (or cooling) network to remain separate from the district heating network and provide all the heating and hot water (or cooling) fora customer. HIU's either provide instantaneous hot water or can be used in conjunction with a local hot water cylinder.
HOB
A heat only boiler produces heat for a single unit, building, or heating network. They are required in most DE installations to provide backup heating and to meet the entire heating demand when other heat sources are being maintained. HOBs typically use natural gas or biomass asa fuel source.
IDNO
Independent Distribution Network Operators: These are independent distribution companies working within the distribution areas, typically serving new developments. IDNOs are licensed and are required to charge similar tariffs to the host distribution network company.
LCCA
London Climate Change Agency. An agency established by the Mayor of London as the primary delivery vehicle for reducing London's carbon dioxide emissions.
LECs
Levy Exemption Certificates: Evidence of CCL-exempt electricity supply generated from qualifying renewable or low carbon sources. Organisations that pay the CCL can enter into agreements with suppliers to purchase renewable electricity which is exempt from the levy. Due to expire March, 2013. However, expectations are that the LEC regime will be extended.
License Exemption Order
The Exemption Order 2001 allows schemes of under a certain size to operate without the need to apply for a generation, distribution, and/or supply license. For generation, the limit is 100MW when consumption is for own use, or 50MW where it is for on-site third party use. For distribution, the limit for residential load connected via a private wire is 1MW(approximately 1,000 homes), and for supply the limit is 1MW for residential customers supplied on-site or via private wires. Sites supplying commercial customers only can supply up to 2.5MW.
Licensed supplier
A licensed supplier is a company who has been granted a license to sell electricity to commercial and/or domestic customers. It has demonstrated it is able to comply with the electricity market rules.
LLF
Line Loss Factor: Factor that is entered into settlement as an estimate of the electricity losses in distribution network lines.
Merton Rule
The Merton Rule is a planning rule requiring a percentage (usually 10% or 20%) reduction in CO2 from on site renewables for new developments.
MPAN
Meter Point Administration Number: A unique number relating to a metering point underthe MRA
MRA
Master Registration Agreement: The agreement that sets out terms for the provision of Metering Point Administration Services and procedures in relation to the Change by the Supplier to any premise/metering point.
MUSCO
Multi Utility Services Company: A MUSCO provides all the energy related services of an ESCO, but also provides telecoms and/or water services for the site.
NETA
New Electricity Trading Arrangements: A system of wholesale electricity trading based on bilateral contracting between suppliers and generators, introduced in England and Wales inMarch 2001.
Private Wires
Private wires are distribution networks which are unlicensed because they are small enough to be part of the licensing exemption regime. The threshold for licensing is 1MW peak of residential load (approximately 1000 domestic properties) and/or 2.5MW peak of commercial load.
PV
PV or photovoltaics use solar energy to directly produce electricity. PV can be installed over existing walls and roofs or can form part of the roof or wall cladding in lieu of conventional cladding materials.
Renewables Obligation (RO)
The government's main support programme for renewable energy generation, under which electricity suppliers must source a proportion of their supply from renewable generation.The proportion of energy increases each year under the RO. Suppliers failing to source sufficient renewable energy to cover their requirement are charged a penalty fee per MWh of shortfall. These penalty funds collected are then redistributed to compliant suppliers.
ROCs
Renewable Obligation Certificates: Certificates received by eligible renewable generators for each MWh of electricity generated. These can be sold to suppliers in order to fulfil their obligations under the RO. The number of ROCs received per MWh of generation varies by technology type. The ROC arrangement is due to expire 2027.
RPZ
Registered Power Zone: An area of the national grid network specifically designated for the research, development and demonstration of new technologies concerning the power network, specifically to develop solutions to the problems associated with connecting generating capacity at the distribution network level.
SAP
The Government's Standard Assessment Procedure for energy use in dwellings. This procedure is followed as part of compliance with building regulations Part L (and CSH) and currently covers space heating, water heating, lighting, pumps, and fans.
Solar Thermal
Solar thermal collectors use solar energy to produce hot water. Typically these installations are installed for individual houses and complement other sources of hot water production. Large solar thermal collectors can be integrated into a wider district heating network.
SPV
Special Purpose VehicleSuppliers licenseA company license to sell electricity.
Top-up/Back-up
Additional electricity provided to an exempt supplier by a licensed supplier to meet any shortfalls in production relative to customer demand and to cover plant outages due to failure or maintenance.
Transmission Access for Distributed Generation (TADG)Working Group
Working Group established by Ofgem in July 2006 to review and develop high level options for change to the existing transmission arrangements with respect to distributed generation.
Transmission Network
The electricity network in England and Wales owned and operated by National Grid and atvoltages above 132kV. The networks in Scotland are owned by Scottish Power and Scottish & Southern and operating at 132kV and above.
TNUoS
Transmission Network Use of System Charges: Charges paid by generators and suppliers directly connected to the electricity transmissions grid for use of the grid.
UKPX
UK Power Exchange / APX Power UK: The main short-term trading exchange for wholesale electricity in the UK.
Waste to energy
The term applies to various means of extracting energy from waste. This includes direct incineration, gasification to form syngas, anaerobic digestion of organic waste, and reclamation of methane at landfill. This is used to generate electricity and (ideally) heat.
Wind turbines
Wind turbines make use of wind to produce electricity. Wind turbines vary in size and output, from small domestic machines of 1kW capacity through to 2MW turbines. Typicallya wind turbine requires wind speeds of 4m/s or above. Wind turbines qualify as a renewable technology and receive ROCs for their output.
ZCH
Zero Carbon Homes: The government's zero-carbon homes policy, set out in the Housing Green Paper, "Building a Greener Future", proposes that all new homes in England should be zero-carbon from 2016.