Alternator

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

Bituminous Coal

The most common coal, which is dense, black and has a moisture content of less than 20%; Used for generating electricity, making coke, and space heating (Platts)

Briquettes - Patent Fuel and Brown Coal/Peat (BKB)

Patent fuel is a composition fuel manufactured from coal fines with the addition of a binding agent (pitch). The amount of patent fuel produced is, therefore, slightly higher than the actual amount of coal consumed in the transformation process. BKB are composition fuels manufactured from brown coal, produced by briquetting under high pressure. These figures include peat briquettes, dried lignite, fines and dust. (IEA.org)

Brown coal or lignite

Coal with a gross calorific value less than 23,865 kJ/kg on an ash-free but moist basis (approximately 22,730kJ/kg on a net calorific value basis) such as black lignite, brown coal and hard lignite. This category includes peat and lignite/brown coal derived products, such as briquettes (UNIPEDE 1991)

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)

Coal Bed Methane (CBM)

CBM is form of natural gas found along with coal seams underground. As the name suggests, methane is adsorbed to the surface of the coal in a process called adsorption. In recent times it has become a major source of energy in several countries. It is also called as ‘sweet gas’ because of lack of hydrogen sulphide in it. The main difference of the natural gas obtained from the conventional reservoir to that from CBM is that it contains only little amount of heavier hydrocarbons like propane or butane. (Powerplantccs.com)

Coal Mine Methane (CMM)

Coal mine methane is a subset of coal bed methane. The methane that is recovered from working mines is referred as coal mine methane. The factors that drive the recovery of methane from the coal mines are safety of coal mines and mitigating significant emissions of methane during the mining activities. (Powerplantccs.com)

Coal seam

An underground layer of coal.

Coke

Hard coke, gas works coke, coal semi-coke , milled coke and lignite coke, produced by distillation of coal or lignite (UNIPEDE 1991)

Coke-oven gas

Gas recovered as a by-product of cove ovens (UNIPEDE 1991)

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)

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)

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)

Gearing

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

Hard coal

All grades of anthracite and bituminous coal with a gross calorific value equal to or greater than 23,865 kJ/kg on an ash-free but moist basis (This approximates to a net calorific value of 22,730kJ/kg). It also includes patent fuel (coal fines with a binding agent), middlings, slurries and combustible shale which cannot be classified according to the type of coal form which they are obtained. (UNIPEDE 1991)

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)

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)

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)

Patent fuel

Patent fuels of hard coal are artefacts of specified shape produced by hot milling under pressure, with the addition of binding material (pitch). REGULATION (EC) No 1099/2008

Peat

Peat (turf) is an accumulation of partially decayed vegetation. One of the most common components is Sphagnum moss, although many other plants can contribute. Soils that contain mostly peat are known as a histosol. Peat forms in wetland conditions, where flooding obstructs flows of oxygen from the atmosphere, reducing rates of decomposition.

Petroleum coke

Petroleum coke is defined as a black solid residue, obtained mainly by cracking and carbonising of petroleum derived feedstocks, vacuum bottoms, tar and pitches in processes such as delayed coking or fluid coking. It consists mainly of carbon (90 to 95 per cent) and has a low ash content. (OECD)

Pitch

By-product obtained during the distillation of hard coal in coking plants (UNIPEDE 1991)

Sub-bituminous Coal

Refers to non-agglomerating coal with a gross calorific value between 17 435 kJ/kg (4 165 kcal/kg) and 23 865 kJ/kg (5 700 kcal/kg) containing more than 31 % volatile matter on a dry mineral matter free basis. (REGULATION (EC) No 1099/2008)

Tar

By-product obtained during the distillation of hard coal in coking plants (UNIPEDE 1991).