Long an Net Power Station

8/8/2019 Long an Net Power Station

1/4

ongannet Power Station at

Kincardine-on-Forth is the

second largest coal-fired

power station in the UK and

one of the largest in Europe.

It is a coal-fired station with

an installed capacity of four 600

megawatt (MW) units. Operating at full

load, it can produce enough electricity to

meet the needs of two million people.

Longannet, with its landmark 183 metre

chimney, has played an important role inmeeting Scotlands energy needs since

1972, providing electricity for

businesses, transport, homes, hospitals

and schools throughout south and central

Scotland.

Electricity generated at Longannet is also

sold in the wholesale markets in England

and Wales and, since December 2001, to

Northern Ireland. The power is exported

via a system of high voltage transmission

lines which is linked to other networks

across the British Isles. Longannet

occupies a site of 89 hectares on the

edge of the River Forth near Kincardine

Bridge. Part of the station was built on

land reclaimed from the estuary using ash

from Kincardine Power Station, which

stood nearby until its demolition in 2001.

In 2000-2001 Longannet achieved the

highest generation output in its 30-year

history, supplying more than 12,250

Gigawatt hours, with coal burn for the

year topping five million tonnes.

Significant investment continues to be

made in the station to improve its

reliability, flexibility and environmental

performance.

Longannet Power Station,

Kincardine-on-Forth, by Alloa,

Clackmannanshire, FK10 4AA.

Tel: 01259 730631

LONGANNET POWER STATION

L


2/4

The turbines have two parallel lines of rotors

(rotating shafts fitted with rings of blades)

each turning the electromagnet of a 300 MW

electrical generator at 50 revolutions a

second. There are many rings of blades on

both lines of rotors. To allow for the

expansion of the steam through the turbines,progressively larger blades are fitted towards

the low pressure ends of the machines. The

largest blades are 914 mm long.

the turbine blades causes the

turbine shaft to spin at high

speed. At the generator end

the spinning shaft of the rotorrotates at 3,000 rpm within

the tightly-fixed coils of the

stator, creating electricity.

The steam is returned for

reheating and then directed to

the intermediate pressure and

then the low pressure

cylinders of the turbine.

Afterwards the steam is

condensed back into water

using cooling water from theForth Estuary up to 327,000

cubic metres (72 million

gallons) every hour. This water

is later returned to the river.

to the high pressure cylinders of the

turbines. The steam is fed to

turbogenerators where the force of it striking

Driving force for industry, commerce

FUELLongannet burns Scottish coal from

Scottish opencast operations and other

sources. This is delivered directly to

Longannets coal store which can hold over

two million tonnes.

Coal is transferred from the storage area tobunkers in the boiler house by a

one-and-a-half-kilometre long conveyor

system. From the bunkers, the coal goes

into roller mills which pulverise the coal to a

fine dust, the consistency of face powder,

before it is mixed with preheated air, blown

into the furnaces and burned at very high

temperatures. Each of the four boilers is

served by eight pulverising mills.

WATER FOR STEAMAND COOLINGInside each of the boilers at Longannet is a

very large number of tubes which are filled

with water. The water used is taken from

the local towns water supply and purified

further by the stations water treatment

plant to avoid furring up the boiler.

As the very hot gases from combustion of

the coal pass over the water-filled tubes the

water boils and forms steam.

The steam up to 1,800 tonnes an hourper boiler is produced at a pressure of

169 bars. This is super heated to a

temperature of 568 C before being piped

The central control room is the nerve centr

introduced a revolutionary PC-based control

degree of automation.

LOMIS, pictured above being operated, ena

processes from starting up and shutting doprocessing. Operators can check on any as

any time, with just a few clicks of a mouse.

ensured via a sophisticated protection syste

The Nerve Centre of

The power of Scotland ... from left, Lstore, a Low NOxBurner arrives forturbine hall, big enough to accomm


3/4

and homes

technique involves passing natural gas at

high velocity over the coal flame, causing a

chemical reduction which converts NOx into

elemental nitrogen and water vapour. When

used in conjunction with Low NOx Burners, it

can cut emissions of NOx by up to 80%. It

also reduces emissions of sulphur dioxide,dust and ash by around 20% and cuts CO2

emissions by 8%. The technique was

developed by ScottishPower in association

with a number of international partners at

Longannet Power Station between 1993 and

1998, with assistance from the EUs

THERMIE programme.

The environmental value of Gas Reburn was

recognised by a Queens Award in the

Sustainable Development category in 2001.

Global Climate Change

The combustion of fossil fuels, such as coal

and oil, causes emissions of carbon dioxide

(CO2) the most abundant of the greenhouse

gases which have been linked with long term

climate change. ScottishPowers Generation

business is addressing this issue by ensuring

a balanced mix of generation, including wind

and hydro power as well as coal and gas.

At Longannet, steps have been taken to

reduce CO2 emissions by improving thethermal efficiency of the plant and through

the use of our Gas Reburn system, where

natural gas displaces 20% of the coal.

ENVIRONMENTLongannet Power Stations Environmental

Management System is accredited to two

key standards, the international standard

ISO 14001 and the EUs Eco-Management

and Audit Scheme (EMAS). The station

addresses key environmental issues in anumber of ways:

Acidification & Air Quality

Emissions from coal-fired power stations

such as sulphur dioxide (SO2) and oxides of

nitrogen (NOx) can cause acid rain. This is

associated with damage to eco-systems,

especially watercourses. Both SO2 and NOx

have been linked with respiratory irritation in

humans. Longannet uses mainly Scottish

coal which is naturally low in sulphur.However, the station is taking steps to

reduce SO2 emissions further through the

planned installation of Flue Gas

Desulphurisation (FGD) technology. The

technique chosen by Longannet, known as

Seawater Scrubbing, does not employ

quarried limestone but instead uses

seawater to dissolve SO2 from the boiler flue

gases. A study at Longannet has shown that

the technology has minimal impact on the

environment. To minimise NOx the station hasLow NOx Burners fitted on all four of its units

and has developed and proven a pioneering

NOx reduction technique, Gas Reburn. This

he power station. Longannet

em, LOMIS, in 1999, providing a high

the control and monitoring of all

enerating units, to on-line dataof the electricity generation process at

integrity and safety of operations is

ur Flagship station

annets massive coalallation and thee an ocean liner


4/4

Electric experience

for our visitorsThousands of people have flocked to

Longannet Power Stations Visitors

Centre since it opened in 1998.

The Centre explains, through a host of

interactive displays, how electricity is

produced, covering the entire process

from coal mining to the transmission of

electricity and the disposal of ash.

There are also sections on the

environment and ScottishPowers

renewable energy operations.

Visitors to the Centre can also see inside

Longannets massive turbine hall big

enough to accommodate an ocean liner from the viewing gallery.

DUST

AND ASH

Generating electricity from coal produces

a significant amount of dust and ash.

Electrostatic precipitators capture dust

from the flue gases and prevent it

reaching the atmosphere.

The ash produced is of two types, thelight and more abundant Pulverised Fuel

Ash (PFA) and the heavier Furnace

Bottom Ash (FBA).

During recent years much of the ash

produced at Longannet has been

sold by ScotAsh, our joint

marketing venture with Blue Circle,

for use in construction and

products such as grout and cement.

Ash storage facilities, pictured above,

are in place at the station.

The remainder is transferred to ash

lagoons at Valleyfield nearby. Here it

accumulates, dries out and eventually

creates land, which is capped and

planted for amenity use by the

local community.

The lagoons are part of the

wider Torry Bay Local Nature

Reserve and ScottishPower

sponsors a full-time countryside

ranger to manage the lagoons in

the interests of biodiversity.Valleyfield is a haven for wildlife,

especially birds, along with butterflies,

such as the spectacular Peacock, below,

dragonflies, damsel flies and small

mammals. A leaflet on wildlife at the

lagoons has been produced and further

information is published in Longannets

EMAS Statement and the annual

Generation Environmental Factsheet.

TRANSPORTING ELECTRICITY

Electricity from Longannets generators is

fed into transformers which step up the

voltage from 17 to 275 kilovolts (kV). The

electricity passes through the switch

house beside the main building and is

sent out via overhead transmission lines

to transforming and switching stations on

ScottishPowers transmission network.

The high voltage transmission network

carries electricity at high voltage to

population centres. The voltage is then

stepped down at substations before it

passes into local distribution systems.

WASTE DERIVED FUELLongannet is involved in a project to

achieve useful energy recovery fromwaste derived fuel (WDF). The lightweight

granulised fuel is made from heat-treated

and dried sewage sludge at the Daldowie

sludge drying facility near Glasgow.

Up to 65,000 tonnes of WDF, which has

an energy content similar to brown coal,

will be burned along with coal at

Longannet Power Station to produce

electricity, combining waste disposal with

useful energy recovery. The project

received a Gold Award for its

environmental benefits in the UK-wide

Green Apple Awards during 2001.

Long an Net Power Station

Documents