The machine which generates AC electricity. The alternator is driven by the primemover (engine). (DECC UK)


Anthracite is a hard natural coal. It contains more than 91 % carbon. It has very high energy availability. (Vattenfall)


An underground sheet of permeable rock that groundwater runs through; often a source of water for wells and springs. (Canadian Geographic Magazine)


A large, natural indentation in the land’s surface, usually with a lake at its base. (CanadianGeographic)


A solid rock, usually dome-shaped, which encases more dense layers of rock. (CanadianGeographic)

Carbon capture and storage (CCS)

Process consisting of the separation of CO2 from industrial and energy-related sources, transport to a storage location and long-term isolation from the atmosphere. CO2 may be stored underground in old oil and gas fields, noncommercial coal fields and saline aquifers. It may also be injected into the ocean. Also known as carbon capture and geological storage (CCGS). (Point Carbon Glossary).

Carbon dioxide (CO2)

A colorless, odorless noncombustible gas with the formula CO2 that is present in the atmosphere. It is formed by the combustion of carbon and carbon compounds (such as fossil fuels and biomass) and by respiration, which is a slow combustion in animals and plants, and by the gradual oxidation of organic matter in the soil. (CWET)

Cascade control

A system which automatically starts up or stops units in a predetermined sequence to meet variations in the energy demands being served. The sequence may be changed periodically to ensure that the running time of each unit is approximately equal.(DECC UK)

Chemical dosing

The addition of conditioning chemicals to boiler feed-water or cooling water to protect plant from scaling, blocking, corrosion etc. (DECC UK)


The definitive cessation of CO2 injection into a storage site. (DIRECTIVE 2009/31/EC – CCS Directive)

CO2 Plume

Plume is a column of one fluid or gas moving through another. Several effects control the motion of the fluid, including momentum, diffusion, and buoyancy (for density-driven flows). When momentum effects are more important than density differences and buoyancy effects, the plume is usually described as a jet. Plume is a term in the hydrodynamic movement of pollutants in water or air.

CO2 stream

CO2 Equivalent – a standardised measure of greenhouse gas emissions developed to account accurately for the different global warming potentials of the various gases. (McKinsey)

Coal gasification

The process of transforming coal into fuel through the reaction of coal, water and heat. (Canadian geographic mag)

Corrective measures

Any measures taken to correct significant irregularities or to close leakages in order to prevent or stop the release of CO2 from the storage complex. (DIRECTIVE 2009/31/EC – CCS Directive)

Demonstration Plant

The demonstration plant (demo plant) is the scale-up between the pilot plant and the commercial concept that is to be developed. The main purpose of a demo plant is to validate the commercial ability of the technology.

Depreciation policy

The company’s policy for depreciating its assets to reflect wear and tear and the passage of time. (DECC UK)

Discount factor

The factor used to convert net annual cash flow to present value, depending on the interest rate and the number of years from present. Calculated by a derivation of the compound interest formula: DF = 1 (1 + r/100)n where r = % interest rate and n = number of years from now. (DECC UK).

Discount rate

The annual percentage figure used in discounted cash flow analyses to discount the future value of costs/savings to give a Net Present Value. (DECC UK)

Discounted cash flow

A cash flow analysis where the time value of cash is taken into account. (DECC UK)


Depleted oil and gas fields.

Enhanced coal bed methane recovery (ECBM)

Injecting CO2 and nitrogen into coalbeds to release methane. (Canadian Geographic mag)

Enhanced Gas Recovery (EGR)

Increased extraction rate of natural gas by by injecting other substances, mostly water or CO2. (Vattenfall)

Enhanced Oil Recovery (EOR)

Increased extraction rate of oil by by injecting other substances, mostly water or CO2. (Vattenfall)


European Allowance – Allowance to emit carbon under the European emissions trading scheme (ETS). (McKinsey)


The assessment of potential storage complexes for the purposes of geologically storing CO of activities intruding into the subsurface such as drilling to obtain geological information about strata in the potential storage complex and, as appropriate, carrying out injection tests in order to characterise the storage site. (DIRECTIVE 2009/31/EC – CCS Directive)

Exploration permit

A written and reasoned decision authorising exploration, and specifying the conditions under which it may take place, issued by the competent authority. (DIRECTIVE 2009/31/EC – CCS Directive)

Fault level

The maximum prospective current that can flow under a three-phase short circuit condition. It should be noted that it can vary according to the point in the system at which the fault occurs. The magnitude of the potential fault level has a major influence on the choice and design of the equipment to be used. (DECC UK)


Injecting substances such as CO2, steam or water to push oil towards the wells. (Canadian Geographic mag)


A duct where gases, fluids or air pass. (Canadian Geographic mag)

Flue gas

An assortment of gases passing through a flue. (Canadian Geographic mag)


Percentage ratio of debt to net assets. (DECC UK)

Geological Formation

A lithostratigraphical subdivision within which distinct rock layers can be found and mapped. (DIRECTIVE 2009/31/EC – CCS Directive)

Geological Storage

Injection accompanied by storage of CO2 in underground geological formations. (DIRECTIVE 2009/31/EC – CCS Directive).

Hydraulic Unit

Hydraulically connected pore space where pressure communication can be measured by technical means and which is bordered by flow barriers, such as faults, salt domes, lithological boundaries, or by the wedging out or outcropping of the formation. (DIRECTIVE 2009/31/EC – CCS Directive).

Immiscible CO2

CO2 injections make oil swell and become more viscous, improving oil flow. (Canadian Geographic mag).

In-duct burner

A burner comprising an arrangement of fuel nozzles located within a duct along which the combustion air (or oxidant) flows. The fuel nozzles may have their separate supply of cooling or stabilising air. This arrangement is commonly used for supplementary firing of additional fuel using the residual oxygen in gas turbine exhaust as oxidant to boost the exhaust gas temperature before it enters the heat recovery boiler. (DECC UK)


A method of forcing gases or liquids into wells using pressure. (Canadian Geographic mag).

Internal rate of return (IRR)

A widely used rate of return for performing economic analysis; This method solves for the interest rate that equates the equivalent worth of an alternative’s cash receipts or savings to the equivalent worth of cash expenditures, including investments. The resultant interest rate is termed the internal rate of return (IRR) (PwC Glossary)


Any release of CO2 from the storage complex. (DIRECTIVE 2009/31/EC – CCS Directive).


A geological layer made of near-impermeable dolostones. (Canadian Geographic mag).

Miscible CO2

CO2 injections combine with the crude oil to become one mixture. (Canadian Geographic mag).


Reduction of emissions. (vattenfall)

Nameplate rating

The full-load continuous rating of a generator or other electrical equipment under specified conditions as designated by the manufacturer, and written on the nameplate. (Washington State University)

Natural gas reservoirs

Large underground pockets where natural gas collects. (Canadian Geographic mag).

Operating lease

A rental agreement for a fixed period of time during which the risks and rewards of ownership remain with the lessor (i.e. the finance company) rather than the lessee (i.e. the business customer). At the end of the lease period, the equipment is returned to the lessor or, alternatively, it is purchased by the lessee for an agreed sum. (DECC UK)


Any natural or legal, private or public person who operates or controls the storage site or to whom decisive economic power over the technical functioning of the storage site has been delegated according to national Legislation. (DIRECTIVE 2009/31/EC – CCS Directive).

Oxyfuel combustion

A type of CO2 capture system that uses oxygen, or a combination of oxygen, water and CO2. (Canadian Geographic mag).


1. A fine liquid or solid particle such as dust, smoke, mist, fumes, or smog, found in air or emissions.(NREL Biomass Glossary) 2. Particles of solid matter, usually of very small size, derived from the fuel either directly or as a result of incomplete combustion (DECC UK)

Physical trapping

CO2 remains trapped within the underground formation due to the presence of an impermeable caprock above the reservoir. This provides a natural seal that prevents the CO2from moving upwards. (Vattenfall)

Post closure

The period after the closure of a storage site, including the period after the transfer of responsibility to the competent authority. (DIRECTIVE 2009/31/EC – CCS Directive).


A system that captures CO2 after combustion. (Canadian Geographic mag).


A system that captures CO2 before combustion. (Canadian Geographic mag).


The upgrade or modification of existing equipment. (McKinsey)

Saline aquifers

A layer of porous rock that holds an abundance of salt water.


A sedimentary rock formed mostly of sand grains. (Canadian Geographic mag).


Reservoirs that process carbon naturally, such as forests and oceans. (Canadian Geographic mag).


A chemical agent that can dissolve or weaken other substances. (Canadian Geographic mag).

Sour gas

A foul-smelling, toxic and flammable natural gas that contains hydrogen sulphide. (Canadian Geographic mag).

Spinning reserve

1. Any back-up energy production capacity that can be made available to a transmission system at 10 minutes’ notice and can operate continuously for at least two hours once it is brought online (Energy Risk Glossary) 2. Non-spinning Reserve: Generating capacity that is capable of being brought online within 10 minutes if it is offline, or interrupted within 10 minutes if it is online, and which is capable of either being operated or interrupted for at least two hours. (PwC Glossary)

Storage complex

The storage site and surrounding geological domain which can have an effect on overall storage integrity and security; that is, secondary containment formations. (DIRECTIVE 2009/31/EC – CCS Directive)


A geological layer made of permeable limestone (Canadian Geographic mag).

Water alternating gas (WAG)

A method of flooding that switches between water and gas injections to maximize oil recovery. (Canadian geographic mag)

Water Column

The vertically continuous mass of water from the surface to the bottom sediments of a water body. (DIRECTIVE 2009/31/EC – CCS Directive)


A long hole drilled into the ground for oil production; also called a borehole. (Canadian geographic mag)