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Glossary of Terms and Abbreviation

The tables below explain terminology and abbreviations commonly associated with offshore renewable energy projects and their associated electrical transmission infrastructure. Not all terms are used within the document.

A - D
Abbreviation Terminology Description
AC Alternating Current A movement of electric charge periodically reversing direction. Alternating current has been traditionally used for electricity transmission; however direct current (DC) may have some advantages over long distances or in submarine circumstances.
AIL Abnormal Indivisible Load An oversize / overweight load which cannot be broken down. They must be moved as a complete article.
AIS Air Insulated Switchgear Equipment to perform switching functions (interruption of fault current, electrical isolation of other equipment, and safe earthing of equipment) where bare conductors are used, and insulation between the conductors is provided by adequate clearance distances.
CAT Cable Avoidance Tool Hand-held tool used to detect presence of buried cables using radio frequencies.
Cefas Centre for Environment, Fisheries and Aquaculture Science An Executive Agency of Defra, Cefas undertake marine research and provide expert advice on environmental impacts.
CoS Chamber of Shipping A trade association for the UK's shipping industry.
CRoW Countryside and Rights of Way Act (2000) UK Act of Parliament enshrining, amongst other things, increased protection for SSSIs and threatened species.
DAS Design and Access Statement A short report explaining the design principles and concepts that have been applied to particular aspects of the proposal – these are the amount, layout, scale, landscaping and appearance of the development. DASs are required to accompany planning applications.
DC Direct Current A flow of electric charge only in one direction. Alternating current (AC) has been traditionally used for electricity transmission; however direct current may have some advantages over long distances or in submarine circumstances.
DCO Development Consent Order The consent required for an offshore energy generation development if it is above 100MW in capacity. It is granted by the relevant Secretary of State under the Planning Act 2008, following examination by the Planning Inspectorate.
DCLG Department  for  Communities and Local Government UK Government department responsible for planning; publisher of the National Planning Policy Framework (NPPF).
DECC Department of Energy and Climate Change UK Government department responsible for energy and climate change policy.
Defra Department for Environment, Food and Rural Affairs UK Government department body which previously held responsibility for climate change policy prior to the inception of DECC in 2008. Defra has responsibility for air quality policy and management, and compliance with habitats legislation.
DETI Department of Enterprise, Trade and Investment Northern Ireland government department responsible for administering onshore transmission licencing under the Electricity (Northern Ireland) Order 1992.
DNO Distribution Network Operator Owners and operators of regional grid systems carryingelectricity from the transmission network to consumers. There are fourteen licensed DNOs in GB, owned by six different groups, with four further Independent Distribution Network Operators running small networks embedded within a DNO network.
DoE Department of the Environment Northern Ireland government department responsible for administering planning legislation in Northern Ireland. Additionally responsible for the natural and built environment, and parent department to NIEA.
DPD Development Plan Document All the statutory component parts of the local development framework, e.g. core strategies, area action plans, site specifically allocation and supplementary planning documents. DPDs therefore set framework for planning in a local authority and are a key material consideration in the planning decisions.
DTI Department for Trade and Industry Defunct UK Government department; publisher of the 2003 Energy White Paper containing current UK emissions targets. Responsibilities and powers relevant to energy are now transferred to DECC.
E - J
EC European Commission The EC defines the general political direction and priorities of the European Union. It does not exercise any legislative functions.
EH English Heritage The government’s statutory advisor on the historic environment for England (a non-department public body). In addition, they hold accessible resources on structures and sites of key historic value. The equivalent organisation in Wales is Cadw, Scotland Scottish Heritage and Northern Ireland Northern Ireland Environment Agency.
EHV Extra High Voltage In UK electricity industry practice, EHV is used to define voltage levels in electricity distribution systems, principally 33 kV, 66 kV (where this exists) and 132kV (in England & Wales). However the term is also used internationally to define the highest voltage levels of transmission systems.
EIA Environmental Impact Assessment A statutory process of Environmental Assessment required for all developments which may have significant environmental impacts. Offshore energy projects typically require an EIA.
EMF Electromagnetic Field Emission of electrical or magnetic energy which are produced where any electrical current flows.
EMR Electricity Market Reform Policy framework for reform of the UK electricity market. A key proposal involves introducing a new form of support for low carbon generation in the form of Contracts for Difference.
ES Environmental Statement The outcome of an EIA, an ES is an environmental report detailing the likely impacts of a development upon its environment. It will include mitigation measures required to reduce any impacts found. If an EIA is required, an ES must be submitted alongside a planning application.
E-TYS Electricity Ten Year Statement A document published by National Grid that presents a range of scenarios for future onshore and offshore network development. First published in Dec 2012, the E-TYS will be supplemented by yearly updates.
EU European Union The economic and political union of European member states.
FEPA Food and Environment Protection Act 1985 UK act of parliament legislating for the licencing requirements for depositing article in the sea. Now superseded by the Marine and Coastal Access Act 2009.
GIS Gas Insulated Switchgear Equipment to perform switching functions (interruption of fault current, electrical isolation of other equipment, and safe earthing of equipment) where conductors are contained within a tank, and insulation between the conductors is provided by pressurised insulating gas.  Substations using GIS are much more compact than those using AIS.
GW Gigawatt 1,000,000,000 (1 billion) watts
HDD Horizontal Directional Drilling A process of lateral drilling using a specialist rig which is required when open-trenching is not possible e.g. when a cable route crosses an arterial road.
HVDC High Voltage Direct Current An electricity transmission option for the bulk transfer of electricity over long distances or in submarine circumstances. It presents an alternative to the more commonly used alternating current.
ICPC International Cable Protection Committee The international submarine cable authority. Provides guidance on issues related to submarine cable security and reliability.
IMO International Maritime Organisation United Nations agency responsible for the safety of shipping and the prevention of marine pollution by ships. Provides key protocols, guidelines and information on marine pollution and shipping issues as relevant to offshore developments.
IPC Infrastructure Planning Commission Prior to 2012, held responsibility for examining applications for NSIPs. Duties now transferred to the Planning Inspectorate.
IRR Internal Rate of Return Equivalent to the effective interest rate of an investment, excluding external (environmental) factors.
JNCC Joint Nature Conservation Committee UK government advisory body on national and international conservation. Hold resources on national and international conservation sites, including SSSIs, SPAs, SACs, Ramsar sites and Marine Conservation Zones.  Have the role of statutory nature conservation body in offshore waters.
K - N
kW Kilowatt 1,000 (1 thousand) watts
LDF Local Development Framework The planning framework for a local authority, consisting of multiple development plan documents such as a core strategy, area action plans, site specific allocations and supplementary planning documents. The local development framework is a key material consideration in the planning decisions.
LPA Local Planning Authority Authority responsible for exercising duties under the Town and Country Planning Act 1990. These include reviewing planning applications. Local planning authorities often correlate with local authorities, but can also be a national park authority.
MCAA Marine and Coastal Access Act 2009 Act of parliament that established the MMO, introduced the current system for licencing marine developments, and introduced current system for designating Marine Conservation Zones in England and Wales.
MCU Marine Consents Unit A non-departmental Welsh Government body with responsibility for administering the marine licensing and consents system for marine developments. This role may change with the creation of the new government body Natural Resources Wales in 2013.
MCZ Marine Conservation Zones These are a type of marine protected area in England and Wales, designated under the Marine & Coastal Access Act 2009, which will exist alongside European marine sites to form an ecologically coherent network of marine protected areas.
MFA Marine and Fisheries Agency Predecessor to the MMO, the MFA was an executive agency of the UK government with responsibility for licensing and advice regarding the UK fishing industry. Relived of its powers in 2010.
MITS Main Interconnected Transmission System The main elements of the GB electricity transmission system.
MMO Marine Management Organisation A non-departmental government body created in 2010 with responsibility for (amongst other things) administering the marine licensing and consents system for marine developments in England and Wales, developing marine plans for England,  and holding key resources on the state of the UK's marine regions.
MPA Marine Protected Area Umbrella term for marine conservation sites around the UK. They includes SPAs, SACs, SSSIs, Ramsar sites and MCZs.
MPS Marine Policy Statement Published in 2011, the UK MPS provides the policy framework for the planning system which applies to all new developments within UK marine areas. Marine Plans, outlining specific planning policy will follow, making reference to the MPS.
MVA Mega volt-ampere 1,000,000 (1 million) Volt-Amperes (see FAQs)
MW Megawatt 1,000,000 (1 million) watts
NE Natural England UK government advisory body on the natural environment. Natural England is a statutory consultee on the natural environment during an EIA.
NEAS National Environmental Assessment Service A unit of the Environment Agency with responsibility for assessing and managing the environmental risks of coastal and flood management strategies. They hold responsibility for reviewing EIA for these projects.
NIEA Northern Ireland Environment Agency UK government advisory body on the natural and built environment in Northern Ireland. NIEA is the Marine Licensing Authority for Northern Ireland.
NETSO National Electricity Transmission System Operator Responsible for managing the operation of the GB transmission system, performed by National Grid.  Separate function from ownership of the transmission networks.
NPPF National Planning Policy Framework Introduced in 2012, the NPPF, sets out the UK-wide planning policy. All local development frameworks must use the NPPF as the key consideration during creation. The NPPF replaces the pre-existing system of Planning Policy Guidance and Statements.
NPS National Policy Statement A UK-wide policy statement issued by a government department. In 2011 the UK government approved six NPSs for Energy (EN1-6). NPSs are a key consideration in the planning process for Nationally Significant Infrastructure Projects such as large offshore wind farms.
NSIP Nationally Significant Infrastructure Project Projects which are deemed major infrastructure developments, (as defined within the Planning Act 2008) and are therefore required to apply for a development consent order under the Planning Act 2008. For offshore energy generation, an NSIP is any development over 100MW generation capacity.
O – SO
Ofgem Office of Gas and Electricity Markets Independent economic regulator for GB gas and electricity markets. Duties include regulating network monopolies (including TOs, DNOs and OFTOs) and administering environmental schemes such as the Renewables Obligation.
OFTO Offshore Transmission Owner An entity licensed by Ofgem to own and operate offshore transmission assets constructed to transport the electricity from offshore generation.
ODIS Offshore Development Information Statement Until 2011 National Grid issued a yearly ODIS on strategic planning. This worked alongside the Seven Year Statement. These two statements have now been replaced by the E-TYS.
ONO Onshore Network Operator An organisation responsible for an onshore transmission and/or distribution network in Great Britain. This is a term used in this document and is not a widely used term.
OREI Offshore Renewable Energy Installation Any offshore renewable energy generator, including wind farms, wave and tidal generators.
OSP Offshore Substation Platform Physical foundation for an offshore electrical substation.
PINS Planning Inspectorate The Planning Inspectorate examines applications for DCOs required under the Planning Act 2008.
POC Point Of Connection The point at which responsibility for the ownership and operation of the electrical system passes from a generating plant to the electricity network operator.
PPG Planning Policy Guidance Prior to 2012, along with PPSs PPGs provided the planning policy framework for the UK. They were superseded by the NPPF.
PPS Planning Policy Statement Prior to 2012, along with PPGs PPSs provided the planning policy framework for the UK. They were superseded by the NPPF.
RAV Regulated Asset Value Total value of assets of network monopolies; determined through the regulatory framework.
REZ Renewable Energy Zone The area of the sea outside of UK territorial waters to which the UK has claimed right to engage in exploitation for energy production from renewable sources. It was declared under the Energy Act 2004.
RO Renewables Obligation A UK government financial mechanism to incentivise renewable electricity generation. The RO places an obligation on UK electricity suppliers to source an increasing proportion of electricity they supply to consumers from renewable sources. It is administered by Ofgem. The RO is expected to be replaced by an alternative funding mechanism, as part of proposals for Electricity Market Reform.
ROV Remotely Operated Vehicle A device often used to lay and bury subsea transmission cables.
RSS Regional Spatial Strategy Provided a regional level planning policy framework for the UK prior to revocation in the Localism Act 2011.
RUK RenewableUK Trade and professional body for the UK wind and marine renewables industries. Formerly BWEA.
s36 Section 36 consent A consent to construct power generation plants, required for projects of <100MW generating capacity under the Electricity Act 1989. For offshore projects, granted by the MMO or Marine Scotland (formerly granted by DECC).
s37 Section 37 consent A consent to construct overhead lines as laid out in the Electricity Act 1989. Consent is granted by the Secretary of State for Business, Enterprise and Regulatory Reform.
SAC Special Area of Conservation Protected sites designated under the UK Habitats Regulations (derived from the EU Habitats Directive). Sites are designated for contribution to conserving key habitats and species.
SEA Strategic Environmental Assessment A statutory process of environmental assessment required for all public plans and programmes which may have significant environmental impacts. Plans / programmes involving energy generation are typically required to produce an SEA.
SGT Supergrid Transformer Power transformers which interconnect the 400 kV and 275 kV transmission system with the distribution systems (typically 132kV or 66 kV).
SHETL Scottish Hydro Electric Transmission Limited Owns the transmission system in northern Scotland. Assesses grid applications to their networks in conjunction with National Grid.
SoS Secretary of State Cabinet minister in charge of a government department. SoS for Energy and Climate Change grants DCOs for energy generating NSIPs(following examination by PINS).
SP – W
SPA Special Protection Area Protected sites designated under the UK Habitats Regulations (derived from the EU Birds Directive). Sites are designated for supporting rare and vulnerable birds and migratory species.
SPTL Scottish Power Transmission Limited Owns the transmission system in southern Scotland. Assesses grid applications to their networks in conjunction with National Grid.
SMA Sensitive Marine Area Non-statutory marine areas containing notable animal and plant communities and providing support to adjacent statutory sites e.g. SPAs.
SSSI Site of Special Scientific Interest UK protected sites designated under the Wildlife and Countryside Act 1981. Sites are designated for their wildlife or geological value.
SVC Static VAR Compensator Equipment including power-electronic devices, which can be controlled to produce or consume reactive power, with very fast response time.  Reactive power flows in an electricity network can be used to control the voltage at specific points on the network.
SYS Seven Year Statement Until 2011 National Grid issued Seven Year Statements alongside their ODIS. These have now been replaced by the E-TYS.
TCE The Crown Estate The Crown Estate manages estates held by the Crown.  This includes the majority of the UK seabed out to the 12 nautical mile limit. The Crown Estate has also been granted renewable energy rights within the Renewable Energy Zone. The Crown Estate is responsible for leasing areas of seabed for offshore renewable energy generation.
TCPA Town and Country Planning Act (1990) UK Act of Parliament codifying the planning process in England and Wales. Local Authorities' duties with regard to reviewing planning applications and the consents required by onshore transmission infrastructure are legislated for by the TCPA.
TSO Transmission Systems Operator NETSO is the TSO for Great Britain (see NETSO).
TW Terawatt 1,000,000,000,000 (1 thousand billion watts)
WTG Wind Turbine Generator A device that converts the energy in moving air into electrical energy.