Glossary
This Glossary is a duplicate of the one found on the Committee on Climate Change (CCC) website.
We thank the CCC for permission to publish their excellent resource.
A B C D E F G H I J K L M N O P R S T U V W
Abatement
Avoiding or reducing pollution or emissions through external intervention.
Adivisory Council for Aeronautics in Europe (ACARE)
A joint European initiative with the purpose to improve the competitiveness of the European aviation industry through research.
Air Traffic Management (ATM)
A service provided by ground-based controllers who direct aircraft on the ground and in the air.
Air Traffic Movements (ATMs)
Unit of travel referring to one aircraft flight.
Anaerobic Digestion (AD)
A treatment process breaking down biodegradable, particularly waste, material in the absence of oxygen. Produces a methane-rich biogas that can be used as a substitute for fossil fuels.
Achievable Emissions Intensity
The minimum average annual emissions intensity that could be acheived in a given year, given the installed capacity, projected demand and the projected profile of that demand.
(European) Assessment of Transport Impacts on Climate Change and Ozone Depletion (ATTICA)
A series of integrated studies investigating the atmospheric effects of aviation, shipping, land traffic and applicable climate metrics (see box 6.3 for details).
Best Available Technology
The latest stage of development of a particular technology (e.g. a process or operating method) that is practically suitable for deployment.
Biofuel
A fuel derived from recently dead biological material and used to power vehicles (can be liquid or gas). Biofuels are commonly derived from cereal crops but can also be derived from dead animals, trees and even algae. Blended with petrol and diesel biofuels can be used in conventional vehicles.
Biogas
A fuel derived from recently dead biological material which can be burned in a generator or a CHP plant, or upgraded to biomethane for injection into the gas grid.
Biomass
Biological material that can be used as fuel or for industrial production. Includes solid biomass such as wood and plant and animal products, gases and liquids derived from biomass, industrial waste and municipal waste.
Biomass to liquid (BTL)
Production of jet fuel, diesel or gasoline through gasification of biomass feedstock (eg. woody crops or wastes), followed by Fischer-Tropsch (FT) synthesis and upgrading steps.
Blended wing body
Radical aircraft design in which airframe dynamics are improved through a flattened profile and wing structures that are smoothly blended to the body.
Bunker fuels (international)
Fuels consumed in international marine and air transport.
Cap and trade schemes
Cap and trade schemes establish binding controls on the overall amount of emissions from participants. Within this quantity ceiling, participants in the scheme can choose where best to deliver emission reductions by trading units which correspond to quantities of abatement.
Carbon Budget
Allowed emissions volume recommended by the Committee on Climate Change, defining the maximum level of CO2 and other GHG's which the UK can emit over 5 year periods.
Carbon Capture and Storage (CCS)
Technology which involves capturing the carbon dioxide emitted from burning fossil fuels, transporting it and storing it in secure spaces such as geological formations, including old oil and gas fields and aquifers under the seabed.
Carbon dioxide equivalent (CO2e) concentration
The concentration of carbon dioxide that would give rise to the same level of radiative forcing as a given mixture of greenhouse gases.
Carbon dioxide equivalent (CO2e) emission
The amount of carbon dioxide emission that would give rise to the same level of radiative forcing, integrated over a given time period, as a given amount of well-mixed greenhouse gas emission. For an individual greenhouse gas species, carbon dioxide equivalent is calculated by multiplying the mass emitted by the Global Warming Potential over the given time period for that species. Standard international reporting processes use the time period of 100 years.
Carbon Emissions Reductions Target (CERT )
CERT is an obligation on energy supply companies to implement measures in homes that will reduce emissions (such as insulation, efficient lightbulbs and appliances, etc). (See Supplier obligation).
Carbon leakage
Displacement of carbon dioxide emissions from one counrty to another due to the existence of (stringent) environmental policy(ies) in one country which make(s) it more attractive or viable for high carbon businesses to operate in a country with less stringent regulations.
Carbon Price
Price at which carbon is traded under an emissions trading scheme (see below).
Carbon sink
An absorber of carbon (usually in the form of carbon dioxide). Natural carbon sinks include forests and oceans.
Clean Development Mechanism (CDM )
UN-regulated scheme which allows credits to be issued from projects reducing GHG gases in Kyoto non-Annex 1 countries (developing countries).
Climate
The climate can be described simply as the ‘average weather’, typically taken over a period of 30 years. More rigorously, it is the statistical description of variables such as temperature, rainfall, snow cover, or any other property of the climate system.
Climate Change Act
UK law of 26 November 2008. It makes it the duty of the Secretary of State for Energy & Climate Change to ensure that the net UK carbon account for all six Kyoto greenhouse gases for the year of 2050 is at least 80% lower than the 1990 baseline.
Carbon Change Levy (CCL)
A levy charged on the industrial and commercial supply of electricity, natural gas, coal and coke for lighting, heating and power.
Climate sensitivity
The response of global mean temperatures to increased concentrations of carbon dioxide in the atmosphere. It is typically defined as the temperature increase that would occur at equilibrium after a doubling of carbon dioxide concentration above pre-industrial levels.
Combined Cycle Gas Turbine
A gas turbine generetor that generates electricty. Waste heat is used to make steam to generate additional electricity via a steam turbine, thereby increasing the efficiency of the plant.
Combined Heat and Power (CHP) The simultaneous generation of heat and power, putting to use heat that would normally be wasted. This results in a highly efficient way to use both fossil and renewable fuels. Technologies range from small units similar to domestic gas boilers, to large scale CCGT or biomass plants which supply heat for major industrial processes.
Company Car Tax
A tax applied where, because of their employment, a car is made available for private use by a director or an employee earning £8,500 a year or more, or to a member of their family or household. This tax is based on the CO2 performance of the car.
CONSAVE
Consave 2050 was an EC Accompanying Measure Project that developed scenarios on aviation and emissions, with a particular focus on 2050.
Contracts for Difference
A contract between a buyer and a seller, stipulating that the seller will pay to the buyer the difference between the current value of an asset and its value at contract time.
Contrail
Condensation trail (ie white line cloud often visible behind aircraft).
Derated Capacity
Electricity plant capacities expressed in terms of their average plant availability during peak demand (rather than in terms of their maximum potential output).
Discount Rate
The rate at which the valuation of future costs and benfits decline. It reflects a number of factors including a person's preference for consumption now over having to wait, the value of an extra £1 at different income levels (given future incomes are likely to be higher) and the risk of catastrophe which means that future benefits are never enjoyed. For example, the Social Discount Rate (3.5%) suggests future consumption of £1.035 next year is equivalent in value to £1 today. Discount rates in the private sector generally reflect the real cost of raising capital, or the real interest rate at which consumers can borrow.
Display Energy Certificate (DEC)
The certificate shows the actual energy usage of a building and must be produced every year for public buildings larger than 1,000m2.
Eco-driving
Eco-driving involves driving in a more efficient way in order to improve fuel economy. Examples of eco-driving techniques include driving at an appropriate speed, not over-revving, ensuring tyres are correctly inflated, removing roof racks and reducing unnecessary weight.
Elasticity of demand
The proportion by which demand changes in response to changes in price (Price Elasticity) or income (Income Elasticity).
Electric vehicle
Vehicle capable of full electric operation (i.e. without an internal combustion engine) fuelled by battery power.
Electricity production
The total amount of electricity generated by a power plant. It includes own-use electricity and transmission and distribution losses.
Energy Perfomance Certificate (EPC)
The certificate provides a rating for residential and commercial buildings, showing their energy efficiency based on the performance of the building itself and its services (such as heating and lighting). EPC's are required whenever a building is built, sold or rented out.
Energy Unserved
The amount of demand within each year that cannot be met due to insufficient supply.
Emissions factor
Constant measure of carbon intensity used for calculation of emissions from aviation (eg. to calculate emissions from aviation in the knowledge of the number of flights realised, the appropriate emissions factor would be the average CO2 emissions per flight realised).
Emissions Performance Standard
A CO2emissions performance standard that would entail regulation to set a limit on emissions per unit of energy output. This limit could be applied at plant level, or to the average emissions intensity of a power company's output.
Emissions Trading
Approach to pollution control which leverages economic incentives to deliver emissions cuts in an efficient manner by allowing polluters with the ability to cut their emissions more cheaply to 'sell' emissions credits to other polluters with less flexibility.
Energy Intensity
A measure of total primary energy use per unit of gross domestic product.
European Economic Area (EEA)
Trading group comprising members of the European Free Trade Association (EFTA) and the European Union (EU).
Energy Efficiency Commitment (EEC)
The predecessor of CERT, and a type of supplier obligation.
European Union Allowance (EU A)
Units corresponding to one tonne of CO2 which can be traded in the EU ETS.
European Union Emissions Trading Scheme (EU ETS )
Cap and trade system covering the power sector and energy intensive industry in the EU.
Exogenous
A variable in an economic model which is determined outside of the model and is not a result calculated by the model (eg. consumer tastes in a supply and demand model).
Fast-Charging
A process of charging a battery quickly by delivering high voltages to the battery.
Feed-in-tariffs
A type of support scheme for electrictiy generation, whereby renewable generators obtain a long-term guaranteed price for the output they deliver to the grid.
Fischer-Tropsch (FT) process
Catalytic production process for the production of synthetic fuels. Natural gas, coal and biomass feedstocks can be used.
Fleet rollover model
Technology model which calculates the carbon efficiency characteristics of a vehicle fleet taking into account it's age and scrappage cycle.
Fluorinated Gases (F-gases)
Family of greenhouse gases (containing fluorine hydrofluorocarbons (HFC's), perfluorocarbons (PFC's), and sulphur hexafluoride (SF6)) used in industrial processes, refrigeration and air conditioning. They have a high global warming potential.
Fossil Fuel
A hydrocarbon deposit, such as petroleum, coal or natural gas, derived from the accumulated remains of ancient plants and animals and used as fuel.
Fuel cell
A device that can be used to convert hydrogen or natural gas into electricity. Various types exist that can be operated at temperatures ranging from 80oC to 1,000oC. Their efficiency ranges from 40% to 60%. For the time being, their application is limited to niche markets and demonstration projects due to their high cost and the immature status of the technology, but their use is growing fast.
Fuel duty
A tax on petrol and diesel. In May 2008, the UK tax was £0.55per litre for diesel and £0.52 for unleaded petrol.
Fuel efficiency
The efficiency by which a vehicle converts energy contained in a carrier fuel into motion. In the context of aviation this can be expressed in terms of fuel burn per seat-km or per passenger-km
Fuel poverty
A fuel-poor household is one that needs to spend in excess of 10% of household income on all fuel use in order to maintain a satisfactory heating regime.
Full hybrid
A vehicle powered by an internal combustion engine and electric motor that can provide drive/train power individually or together.
Functional airspace block
An area of airspace established based on operational requirements and not national boundaries (eg. Central Europe, Danube, Baltic).
Funded Decommissioning Programme (FDP)
A plan developed by operators to tackle back-end waste and decommissioning costs of nuclear power stations.
G8 countries
A forum for governments of the eight richest countries in the world to discuss key issues. These are the UK, USA, France, Italy, Germany, Russia, Japan and Canada.
Generic Design Assessment (GDA)
Generic Design Assessment, also know as pre-licensing, is intended to ensure that the technical aspects of designs for nuclear power plants are considered ahead of site-specific license applications.
GLOCAF
The Global Carbon Finance model was developed by the Office of Climate Change to look at the costs to different countries of moving to a low carbon global economy, and the kind of international financial flows this might generate.
Global Temperature Potential
A means for measuring the radiative effect of emissions based on the effect on the global mean surface temperature at some future point in time. (See box 6.2 for details).
Global Warming Potential
A metric for comparing the climate effect of different greenhouse gases, all of which have different lifetimes in the atmosphere and differeing abilities to absorb radiation. The GWP is calculated as the intergrated radiative forcing of a given gas over a given time period, relative to that of carbon dioxide. Standard international reporting processes use a time period of 100 years.
Great circle distance (GCD)
A defintion of the shortest flight distance between two point, taking the curve of the Earth's surface into account.
Greenhouse gas (GHG)
Any atmospheric gas (either natural or anthropogenic in origin) which absorbs thermal radiation emitted by the Earth’s surface. This traps heat in the atmosphere and keeps the surface at a warmer temperature than would otherwise be possible, hence it is commonly called the Greenhouse Effect.
Gross Domestic Product (GDP)
A measure of the total economic activity occurring in the UK.
Gross Value Added (GVA)
The difference between output and intermediate consumption for any given sector/industry.
Gt
A gigatonne or 1000 million tonnes.
GWh (Gigawatt hour)
A measure of energy equal to 1000MWh.
Heat pumps
Can be an air source or ground source heat pump to provide heating for buildings. Working like a ‘fridge in reverse’, heat pumps use compression and expansion of gases or liquid to draw heat from the natural energy stored in the ground or air.
Heavy good vehicle (HGV)
A truck over 3.5 tonnes (articulated or rigid).
Hydrogenated renewable jet (HRJ)
Conversion of vegetable oils (eg. conventional oil crops such as palm and soy, but also new oil crops such as jatropha and cameline) and algal oils to aviation fuel through a process including treatment with hydrogen.
Infrastructure Planning Commission
A new body established by the Plannig Act (2008) tp take decisions on planning appications for major infrastructure projects.
Intergovernmental Panel on Climate Change (IPCC)
The IPCC was formed in 1988 by the World Meteorological Organisation (WMO) and the United Nations Environment Programme (UNEP). It is designed to assess the latest scientific, technical and socio-economic literature on climate change in an open and transparent way which is neutral with respect to policy. This is done through publishing a range of special reports and assessment reports, the most recent of which (the Fourth Assessment Report, or AR4) was produced in 2007.
Intergrated Gasification Combined-Cycle (IGCC)
A technology in which a solid or liquid fuel (coal, heavy oil or biomass) is gasified, followed by use for eletricity generation in a combined-cycle power plant. It is widely considered a promising electricity generation technology, due to its potential to achieve high efficiencies and low emissions.
International Air Transport Association (IATA)
Intergovernmental organisation which acts as energy policy advisor to 28 countries.
Justification
The concept of Regulatory Justification is based on the internationally accepted principle of radiological protection that no practice involving exposure to ionising radiation should be adopted unless it produces sufficient net benfits to the exposed individuals, or society, to offset any radiation detrient it may cause. This principle is derived from the recommendations of International Commission on Radiological Protection (ICRP) and included in the European Council Directive 96/29/Euratom 13 May 1996 which sets the basic safety standards for protecting the health of workers and the general public against dangers arising from ionising radiation.
Kerosene
Hydrocarbon fuel for jet aircraft.
kWh (Kilowatt hour)
A measure of energy equal to 1000 Watt hours. A convenient unit for consumption at the household level.
kWp (Kilowatt peak)
A measure of the peak output of a photovoltaic system under test conditions.
Kyoto gas
A greenhouse gas covered by the Kyoto Protocol.
Kyoto Protocol / Agreement
Adopted in 1997 as a protocol to the United Nations Framework Convention on Climate Change (UNFCCC), the Kyoto Protocol makes a legally binding commitment on participating countries to reduce their greenhouse gas emissions by 5% relative to 1990 levels, during the period 2008-2012. Gases covered by the Kyoto Protocol are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulphur hexafluoride (SF6), hydrofluorocarbons (HFC's) and perfluorocarbons (PFC's).
Levelised Cost
Lifetime costs and output of electricity generation technologies are discounted back to their present values to produce estimates of cost per unit of output (e.g. p/kWh).
Level of Scientific Understanding (LOSU)
This is an index on a 4-step scale (High, Medium, Low and Very Low) designed to characterise the degree of scientific understanding of the radiative forcing agents that effect climate change.
Life-cycle
Life-cycle assessment tracks emissions generated and materials consumed for a product system over its entire life-cycle, from cradle to grave, including material production, product manufacture, product use, product maintenance and disposal at end of life. This includes biomass, where the CO2 released on combustion was absorbed by the plant matter during its growing lifetime.
Light Goods Vehicle
A van (weight up to 3.5 tonnes; classification N1 vehicle).
Lithium-ion Batteries
Modern batteries with relatively high energy storage density. Presently used widely in mobile phones and laptops and likely to be the dominant battery technology in the new generation of plug-in hybrid and battery electric vehicles.
Load factor
Number expressing the degree of occupancy of an aircraft (the higher the number, the fuller the aircraft) such that a full aircraft has a load factor of 100%.
Marginal abatement cost curve
Graph showing costs and potential for emissions reduction from different measures or technologies, ranking these from the cheapest to most expensive to represent the costs of achieving incremental levels of emissions reduction.
MARKAL
Optimisation model that can provide insights into the least-cost path to meeting national emissions targets over the long-term.
Micro Hybrid
Vehicle engine with stop-start and capable of regenerative braking.
Mild Hybrid
An internal combustion engine which can be assisted by an electric motor when extra power is needed, but where the electric motor cannot power the vehicle independently.
Mitigation
Action to reduce the sources (or enhance the sinks) of factors causing climate change, such as greenhouse gases.
Modal Shift
A change from one means to another (eg. car to cycling, air to rail).
MtCO2
Million tonnes of carbon dioxide (CO2).
MWh (Megawatt hour)
A measure of energy equal to 1000 kWh.
Narrow body aircraft
An airline with a fuselage aircraft cabin diameter of 3 to 4 metres (10 to 13 feet), and airline seats arranged 2 to 6 abreast along a single aisle.
National Air Traffic Services (NATS)
ATM service provider for flying in UK airspace, and over the eastern part of the North Atlantic.
National Authority
In the Climate Change Act, “national authority” means any of the following: the Secretary of State; the Scottish Ministers; the Welsh Ministers; the relevant Northern Ireland department.
National Atmospheric Emissions Inventory (NAEI)
Data source compiling estimates of the UK's emissions to the atmosphere of various (particularly greenhouse) gases.
National Balancing Point (NBP)
A measure of the wholesale price of gas in the UK (measured in p/therm or p/kHh).
National Policy Statement (NPS)
The Government would produce National Policy Statements (NPS) that would establish the national case for infrastructure development and set policy framework for the Infrastructure Planning Commission.
Non-Power Train
Relating to parts of a vehicle that are not components of the engine or transmission.
Novel synthetic hydrocarbons
Generic term which covers a variety of new methods for the production of biofuels relying on conversion of biomass to jet fuel via biological or chemical processes.
NOx
A generic term for mono-nitrogen oxides (NO and NO2). These oxides are produced during combustion, especially combustion at high temperatures.
Offset credits
Credits corresponding to units of abatement from projects, such as those generated under the Kyoto treaty’s project based flexibility mechanisms, Joint Implementation (JI) and Clean Development Mechanism (CDM).
Ofgem (Office of Gas and Electricity Markets)
The regulator for electricity and downstream gas markets.
Open rotor engine
Radical engine design in which the rotating fan blades are not surrounded by a casting.
Passenger-kilometre
Unit of travel referring to one passenger moved through a distance of one kilometre.
Plug-in Hybrid
A full hybrid vehicle with additional electrical storage capacity which can be charged form an exernal electrical source such as mains supply.
Point to point
Modelling term for a journey between two cities. Modelling in this way allows emissions to be calculated on the basis of real trips as opposed to basing them on hypothetical geographical ranges.
Powertrain
Relating to the engine and transmission of a vehicle.
Pre-industrial
The period before rapid industrial growth led to increasing use of fossil fuels around the world. For the purposes of measuring radiative forcing and global mean temperature increases, 'pre-industrial’ is often defined as before 1750.
Pumped Storage
A technology which stores energy in the form of water, pumped from a lower elevation reservoir to a higher elevation. Lower cost off-peak electric power is generally used to run the pumps. During periods of high electrical demand, the stored water is released through turbines.
Radiative forcing
A standard metric for measuring the contribution of changes in individual atmospheric constituents to the energy imbalance of the earth-atmosphere system, relative to pre-industrial times (usually dated at 1750).
Radiative forcing index
An index designed by the IPCC for their 1999 report to measure the total radiative effect of aviation compared to that from CO2. (See box 6.2 in main body of report for details).
Reference case
Modelling scenarios created to reflect different possible states of the world which are external and prior to the analysis (ie. exogenous), (eg. different fossil fuel prices or levels of GDP growth).
Renewables
Energy resources, where energy is derived from natural processes that are replenished constantly. They include geothermal, solar, wind, tide, wave, hydropower, biomass and biofuels.
Renewable Energy Strategy (RES)
Government strategy aiming to increase the use of renewable energy in the UK, as part of the overall strategy for tackling climate change and to meet the UK’s share of the EU target to source 20% of the EU's energy from renewable sources by 2020. Draft strategy was published for consultation in 2008.
Renewable Heat Incentive (RHI)
Will provide financial assistance to producers (households and businesses) of renewable heat when implemented in April 2011.
Renewables Obligation Certificate (ROC)
A certificate issued to an accredited electricity generator for eligible renewable electricity generated within the UK. One ROC is issued for each megawatt hour (MWh) of eligible renewable output generated.
Reserved Powers
Policy areas governed by the UK Government. Also refers to 'excepted' matters in the case of Northern Ireland.
Riblet
One of a series of microscopic grooves inscribed on the surface of an adhesive-backed tape and used on airplanes and boat hulls to reduce drag.
Rising Block Tariff
Energy is priced at low initial rate up to a specified volume of consumption, and then the unit price increases as consumption increases.
Seat-kilometre (Seat-km)
Unit of travel referring to one vehicle seat (occupied or otherwise) moved through a distance of one kilometre.
Security of Supply
The certainty with which energy supplies (typically electricity, but also gas and oil) are available when demanded.
Sensitivity analysis
The study of how the variation (uncertainty) in the output of a mathematical model can be apportioned to variation in different input assumptions.
Smart meters
Advanced metering technology that allows suppliers to remotely record customers' gas and electricity use. Customers can be provided with real-time information that could encourage them to use less energy (e.g. through display units).
Smarter Choices
Smarter Choices are techniques to influence people’s travel behaviour towards less carbon intensive alternatives to the car such as public transport, cycling and walking by providing targeted information and opportunities to consider alternative modes.
Social tariff
An energy tariff where vulnerable or poorer customers pay a lower rate.
Solar photovoltaics (PV)
Solar technology which use the sun’s energy to create electricity.
Solar Thermal
Solar technology which uses the warmth of the sun to heat water to supply hot water to buildings.
Solar water heating
Solar technology which uses the warmth of the sun to heat water to supply hot water in buildings.
Solid Recoverable Fuel (SRF)
Fuel that can be produced from waste using particular processes, especially MBT, and can substitute for fossil fuels, e.g. coal use in cement kilns.
Standard Assessment Procedure
UK Government's recommended method for measuring the energy rating of residential dwellings. The rating is on a scale of 1 to 100. It can raise above 100 if the dwelling is a net exporter of energy.
Stop start
Vehicle engine with automated starter motor.
Strategic Siting Assessment (SSA)
The Government is undertaking a process called Strategic Siting Assessment (SSA), to identify sites that are suitable or potentially suitable for the deployment of new nuclear power stations by the end of 2025, which included assessing the sites against set criteria. These sites will be included in a National Policy Statement.
Supplier Obligation
An obligation that the Government places on energy suppliers, to help householders reduce their carbon footprint. The current policy is the Carbon Emissions Reductions Commitment (CERT) running from April 2008 to 2011.
Technical potential
The theoretical maximum amount of emissions reduction that is possible from a particular technology (e.g. What would be achieved if every cavity wall were filled). This measure ignores constraints on delivery and barriers to firms and consumers that may prevent up take.
Tidal range
A form of renewable electricity generation which uses the difference in water height between low and high tide by impounding water at high tide in barrages or lagoons, and then releasing it through turbines at lower tide levels.
Tidal stream
A form of renewable electricity generation which harnesses the energy contained in fast-flowing tidal currents.
Total final consumption (TFC)
The sum of consumption by the different end use-sectors.TFC is broken down into energy demand in the following sectors:
- Industry, transport, other (includes agriculture, residential, commercial and public services) and non-energy uses.
- Industry includes manufacturing, construction and mining industries. In final consumption, petrochemical feedstocks appear under industry use. Other non-energy uses are shown under non-energy use.
Turbine Engine Temperature (TET)
Temperature at which air enters a jet engine.
TWh (Terawatt hour)
A measure of energy equal to 1000 GWh or 1 billion kWh. Suitable for measuring very large quantities of energy – e.g. annual UK electricity generation.
United Nations Framework Convention on Climate Change (UNFCCC)
Signed at the Earth Summit in Rio de Janeiro in 1992 by over 150 countries and the European Community, the UNFCCC has an ultimate aim of ‘stabilisation of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system'.
Vehicle Excise Duty (VED )
Commonly known as road tax, an annual duty which has to be paid to acquire a vehicle licence for most types of motor vehicle. VED rates for private cars have been linked to emissions since 2001, with a zero charge for the least emitting vehicles (under 100 gCO2/km).
Videoconferencing
Videoconferencing here means a broad suite of communications technologies (including videoconferencing) of various degrees of sophistication.
Vulnerable household
A household containing someone aged 60 or over or under 16, or someone who is disabled or has a long-term illness.
Wave electricity generation
A form of renewable electricity generation which converts the energy contained in the movement of the waves into electricity.
Wide body aircraft
A large airliner with a fuselage diameter of 5 to 6 metres and twin aisles.
Winglet
A short vertical fin on the tip of an aircraft wing for reducing drag.
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