EnBW Energie Baden-Württemberg AG

Turning primary energy efficiently into electricityThe fossil-fired power plants of EnBW

Turning primary energy efficiently into electricityThe fossil-fired power plants of EnBW

Competitive and fit for futureEnergy generation at EnBW 4

Acting sustainably and responsiblyEnvironmental protection at EnBW 8

Conventional power plant fleet

High importance for the regional economyAltbach/Deizisau heat and power plant 12

Valuable energy from waste and coalStuttgart-Münster heat and power plant 16

Full performance within minutesStuttgart-Gaisburg heat and power plant 18

Biggest coal-fired unit in the EnBW power plant fleetHeilbronn heat and power plant 20

Back up for demand peaksWalheim power plant 22

Contents

2

Airplane turbines for power generationMarbach power plant 23

High performance, efficient and innovativeRheinhafen steam power plant in Karlsruhe 24

Holdings and electricity procurementBexbach power plant 30

Lippendorf power plant 31

Rostock power plant 32

Buschhaus power plant 33

Stadtwerke Düsseldorf municipal utility 34

Grosskraftwerk Mannheim power plant 35

The technology of a power plant

Technology made easyHow fossil-fired power plants work 38

Stable and flexibleThe electricity network of EnBW 46

Glossary 48

Plant tours 52

Publishing details 53

3

EnBW believes that a balanced electricity

generation mix forms the basis for the re-

liable, competitive and environmentally

sound supply of energy to Germany as an

industrial location. This mix com prises the

increased use of renewable forms of energy,

supplemented by supplies from reliable

nuclear power plants and the

efficient use of the available fossil fuels

lignite, coal and gas.

EnBW's own power plant fleet with its core

locations on the Rhine and Neckar rivers is

backed up by holdings and procurement

agreements, some of them with suppliers

outside the home market of Baden-Würt-

temberg. EnBW makes use of the "South

Unit" of the Lippendorf lignite power

plant, for example, operates a power plant

in Rostock and receives power supplies

from the facility in Buschhaus. EnBW's

strategic position in the German power

generation market is underpinned by an

output volume of around 15,000 mega-

watts (MW).

The power plants in the EnBW portfolio

are always in line with the state of the art:

efficient operating and maintenance con-

cepts drawing on the experience of opera-

ting teams and engineers stretching back

over several decades and ongoing optimi-

sation and modernisation measures en -

sure that the facilities are equipped to

meet the energy generating challenges of

the coming decades.

Together with high safety and environ-

mental standards, it is this strategy that

enables us to meet the growing demands

in terms of the availability, efficiency and

above all flexibility of our power plants.

Energy mix of the future

On the road to a supply system primarily

based on renewable forms of energy, the

use of high-availability coal and gas power

plants will continue to play an important

role for decades to come – particularly in

global terms – as it is these facilities that

provide the necessary balance to con-

stantly cover the residual load resulting

from the gap between the demand for

electricity on the one hand and the fluc-

tuating volume of power generated from

renewable sources on the other. Indeed,

these so-called back up power plants need

to be able to meet the entire load demand

at times when there is no wind and simul-

taneously little or no sunshine. In the case

of the plants used as baseload and inter-

mediate load power plants, the number of

hours during which they operate at full

power will tend to fall more rapidly than

the volume of electricity they feed into

the grid.

Competitive and fit for futureEnergy generation at EnBW

4

In its energy concept "2020", the state

government of Baden-Württemberg de -

fined its energy mix using the formula

50/30/20, which translates into a genera-

ting structure supplying 50% of electricity

from nuclear power and 30% from fossil

fuels while increasing the share of renewa-

bles in overall generating volume to 20%.

EnBW supports this target laid out by the

state government.

In view of the need for grid stability and

the provision of reactive power, controll -

able conventional power plants constitute

key elements in the electricity supply sys -

tem. In terms of number and geographic

location, they need to be distributed based

on the peak demand load areas through -

out the network so that they ensure the

supply of electricity close to the point of

consumption.

In order to develop the cornerstone of the

EnBW business portfolio – namely the gen -

eration of electricity – as the core strate -

gic element in the long term, EnBW is

currently building two state-of-the-art

coal-fired power plant units in the 900-

megawatt class: these investments at the

Rheinhafen plant in Karlsruhe (unit 8)

and at the Gemeinschaftskraftwerk Mann-

heim plant (unit 9), in which EnBW holds

an interest, are both designed to replace

older plants.

5

Rostock(Mecklenburg-West Pomerania)(Mecklenburg-West Pomerania)

GlattNeckar

Fils

Danube

Iller

Argen

Aach

Elz

Rhine

Murg

Enz

Nagold

Itter

Main

JagstKocher

Iller power plants

Austria

Switzerland

France

Obrigheim1

Heilbronn

Neckarwestheim

Walheim

Marbach

Altbach/DeizisauGaisburg

Stuttgart-Münster

Glems

Schluchsee power plants

Fessenheim(France)

Forbach

Karlsruhe

26 Neckar power plants

Mannheim

PhilippsburgBexbach(Saarland)

Cattenom(France)

Lippendorf (Saxony)

Pforzheim

Vorarlberger Illwerke power plants

High Rhine power plants(Germany/Switzerland)

Buschhaus(Lower Saxony)

Upper Danube power plants

Operations ceased on 11 May 2005 as a result of the nuclear energy agreement in Germany.

1

Ulm

Freiburg

Stuttgart

Karlsruhe

Hydroelectric plants on the Kocher river

Hydroelectric plants on the Jagst river

Baden-Baden

Rhine power plants(CERGA/RKI)

Conventional power plantoperated by EnBW

Nuclear power plantoperated by EnBW

Conventional power plant with EnBW holding,purchase or supply agreements

Nuclear power plant withpurchase or supply agreements

Hydroelectric power plantoperated by EnBW

Hydroelectric power plant with EnBW holding,purchase or supply agreements

The power plant fleet of the future

The sparing use of fossil fuels and the ef-

fective reduction of emissions that impact

our climate is more important than ever

before. One of the levers that energy sup-

pliers worldwide can apply in order to cut

CO2 emissions is the development of eco-

nomical, highly efficient power plants for

the generation of electricity. The efficien-

cy level plays a key role in this respect; it is

an indicator for the efficiency with which

a power plant uses the fed-in energy

sources. Today, new power plants can

achieve efficiency levels of more than 45%.

If we succeed in increasing this figure

even further, we can reduce the volume

of coal input needed to create the same

energy output and therefore also cut CO2emissions.

With carbon capture and storage (CCS), a

new technology is coming to the fore that

can reduce emissions from industrial and

power plant processes and therefore make

a valuable contribution to climate protec-

tion. CCS is an important topic for EnBW,

and we are already preparing our new

power plants for the use of this techno -

logy. One example of this is the new con-

struction of unit 8 at the Rheinhafen

steam power plant, where the necessary

space is being reserved for the possible in-

tegration of a CO2 capture system. We are

also currently building a test facility at

our power plant location in Heilbronn to

test CO2 capture using an aqueous amine

solution.

The power plant fleet of the future needs

to be more flexible. This means that ex -

isting and future plants should start up

rapidly, cover as wide a partial load range

as possible and be able to vary their out-

put in high gradients (load change capa -

bility). As gas-fired power plants meet this

criterion, EnBW is looking into projects of

this kind at locations like Lubmin or in

Düsseldorf together with the city's muni-

cipal utility.

Storage power plants will also play an in-

creasingly important role in the future

generating system, as pumped-storage

concepts are currently the most efficient

and flexible way to store large quantities

of electricity that can be called on at ex -

tremely short notice. This stabilises the

grid and offsets the fluctuations in supplies

generated from renewable sources.

6

Emissions trading and reduction targets

In line with the stipulations of the Kyoto

Protocol, climate-damaging CO2 emis -

sions from the energy-intensive sectors of

the industrial nations can first be capped

and then traded based on supply and

demand. This means that states or com -

panies within these states trade their allo-

cated emission allowances within the EU.

These so-called CO2 certificates are sold

by states or companies whose production

operations are particularly efficient and

who therefore do not fully utilise the quo-

tas that have been allocated to them – and

they are sold to counterparts who have

emitted a greater amount of CO2 than

they are permitted to based on the offici-

ally agreed environmental targets.

This overall mechanism creates an incen-

tive to save CO2 and has the added effect

that capital used to reduce CO2 emissions

can be invested above all in places where

the measures are effective and cost-effi-

cient. In addition, it promotes a willing-

ness to invest in research and innovation

geared towards the improvement of

power plant efficiency. As an energy-

intensive company, EnBW takes part in

the system of emissions trading and op -

timises its plants on an ongoing basis.

The Kyoto Protocol also allows companies

to achieve a part of their reduction targets

by implementing improvements to facili-

ties in developing countries and econo-

mies in transition. This helps to reduce the

emission of greenhouse gases; in other

words, it results in certified emission re-

ductions. This system is known as the

Clean Development Mechanism (CDM). As

the greenhouse effect is a global pheno-

menon, the funds invested in projects of

this kind have a particularly important ef-

fect when it comes to reducing emissions,

as it is irrelevant whether these emissions

are reduced in Germany or, for example,

in Kenya or Peru.

EnBW develops its own CDM projects on

various continents and using a wide range

of different technologies – including wind

farms, biogas generation, hydropower or

landfill gas incineration. In order to ach ieve

the ambitious goals, various units at EnBW

– such as the holding company, the power

plant company or the trading division –

have pooled their core expertise.

7

For EnBW, sustainable action means at -

taching equal importance to its economic,

ecological and social responsibilities.

EnBW was the first German energy com -

pany to introduce a group-wide environ-

mental management system certified in line

with ISO 14001 and has continued to ex-

pand this system in recent years. In July

2010, this 14001 certification covered the

entire value added chain including conven-

tional power generation: in absolute terms,

the system covers 25 companies or around

98% of the approx. 20,000 employees of

the EnBW Group. The certification of fur -

ther companies is scheduled up to the end

of 2011.

Compliance with the internationally valid

ISO 14001 requirements and certification

were both performed on a voluntary basis,

underlining the key importance attached to

the issue of environmental protection at

EnBW and serving as a further example of

the pioneering role played by EnBW in this

area.

The environmental management system

reviews all environmentally relevant pro-

cesses and installations to determine their

actual and potential impact on the environ-

ment. All responsibilities and interfaces are

clearly defined.

The core focus of ISO 14001 is the continu-

ous improvement of both the environmen-

tal performance of the company and its en-

vironmentally relevant processes. To this

end, group-wide environmental targets

were defined for the following topics for

the period from 2008 to 2010:

› Climate protection, saving use of re-sources, energy efficiency,

› Sustainable social responsibility,› Communication and raising awareness› Protection of mankind and the environ-ment.

Acting sustainably and responsiblyEnvironmental protection at EnBW

1 The generation portfolio includes long-term procurement agreements and generation from partly owned

power stations.2 In anticipation of the change in the method of transfer of renewable energies under the EEG as of 2010

(financial instead of physical transfer), as of fiscal 2009 the quotas are reported on the basis of the

electricity generated in the EnBW Group’s own facilities without taking into account any supplies of EEG

electricity (prior-year values were restated).3 By analogy to the disclosure pursuant to Sec. 42 German Energy Industry Act (EnWG)

8

Energy generated by the EnBW Group1

by primary source of energy2 in % 2009 2008 2007

Conventional energy 27.6 28.2 29.7Nuclear energy 57.2 56.8 54.1Renewables3 10.6 10.8 9.9Other 4.6 4.2 6.3

As the company responsible for operating

the conventional generating plants, EnBW

Kraftwerke AG has addressed these topics

and formulated four environmental prin-

ciples:

› Through our actions we ensure the pro-tection of mankind and the environ-

ment.

› As a generating company in the EnBWGroup, we are under a particular obliga -

tion to fulfil our environmental responsi-

bilities in a farsighted and active manner –

also in the competitive arena. In doing so,

we adhere to the environmental princi-

ples of the Group.

›We operate our facilities in a way thatspares the environment and aim at mini-

mising the burden on air and water with -

in the constraints of our operational re-

quirements.

›We strive to constantly improve our ef-forts for the environment’s sake. In parti-

cular, this also includes fostering the en-

vironmental awareness of our employees

and of the external contractors who we

commission to perform work on our be-

half.

2004

2005

2006

2007

2008

2009

D-20081

150

170

140

140

131

156

280

Specific sulphur dioxide (SO2) emissions from 2004 to 2009 in mg/kWh

2004

2005

2006

2007

2008

2009

D-20081

145

170

165

173

159

400

158

Specific nitrogen oxide (NOx) emissions from 2004 to 2009 in mg/kWh

2004

2005

2006

2007

2008

2009

D-20081

225

250

240

254

241

506

235

Specific carbon dioxide (CO2) emissions from 2004 to 2009 in g/kWh

1 Comparison data for German electricity mix, 2008 (source: German Association of Energy and Water

Industries, BDEW)

9

Conventional power plant fleet

Location

The Altbach/Deizisau combined heat and

power plant (CHP) is an important econo-

mic factor in the central Neckar region

and guarantees the reliable, cost-effective

and environment-friendly generation of

energy. EnBW operates several units at

this location with a total installed capacity

of approximately 1,292 megawatts. The

two units of the CHP plant are coal-fired

and can simultaneously produce electrici-

ty and district heat. In addition, there are a

combined gas and oil unit and two gas tur-

bines at the location.

The Altbach/Deizisau power plant feeds

its electricity into both the 400-kilovolt

very-high voltage network and the 110-ki-

lovolt high-voltage network and supplies

the Stuttgart-Plochingen district heat line.

History

In 1899, a water-powered plant was cre-

ated on the Neckarkanal waterway, which

had been built specifically for this purpose.

The construction of the "Kraftcentrale Alt-

bach" installation was commissioned by

Heinrich Mayer, whose aim was to supply

electric energy to the Neckar and Fils

valley. The first community supplied with

electricity from the "power plant" was

Obertürkheim. The electricity network

continued to grow and further communi-

ties followed. From 1902 onwards, the

company operated under the name

"Neckarwerke Altbach/Deizisau Heinrich

Mayer". It was transformed into a stock

corporation three years later. Then, Neckar -

werke Elektrizitätsversorgungs-AG based in

Esslingen merged with Technische Werke

der Stadt Stuttgart AG , and in 2003 the ac-

tivities and know-how of the Neckarwerke

High importance for the regional economyAltbach/Deizisau heat and power plant

View of the Altbach/Deizisau heat and power plant

12

Stuttgart AG (NWS) company created by

this alliance were merged with the exper-

tise of EnBW. Back in the seventies, the

plant was thoroughly modernised and re-

structured, and aspects such as energy ef-

ficiency, environmental protection, land-

scaping, nature conservation and architec-

ture played a key role in this process. The

first step was to replace section I of the

plant with CHP plant 1, which went into

operation in 1985. When CHP plant 2 was

built at the end of the eighties to replace

the three units of plant section II, the de-

sign successfully integrated the power

plant buildings in the surrounding land-

scape, creating a plant equipped with ad-

vanced environmental technology at the

edge of a public park.

Special features

Hybrid cooling towerBy combining wet and dry cooling meth -

ods, the hybrid technology allows low

structural heights and ensures greatly re-

duced plume formation.

First, the cooling water gives off part of its

waste heat to the air via finned tubes. It

then falls down into the cooling tower bas -

in in the form of a drizzle, where it cools

further as a result of evaporative cooling,

while giant fans press the cooling air

through the wet and dry sections. Moist

and dry air mix in the top third of the

cooling tower, and this prevents nearly

all plume formation.

During the day, the cooling tower is always

operated in hybrid mode (i.e. wet section

and dry section together) in order to mini-

mise plume formation. At night the fans

of the dry section are switched off, reduc -

ing the self-consumption of the power

plant and therefore increasing efficiency

levels.

Combined heat and power plant 2 (CHP 2)

is controlled from the central control

room

13

Compound unitThe technical concept of the combined

heat and power plants (CHPs) is deter-

mined by ecological and economic require-

ments. A high utilisation level allows effi-

cient use of the fed-in primary energy.

While CHP 1 is designed for a conventional

steam turbine process, CHP 2 is additio-

nally fitted with a gas turbine, which is

linked on the water/steam side with the

coal-fired unit. Depending on electrical

and thermal output requirements, this

combination unit achieves a fuel utilisation

rate of up to 70%.

Highly efficient systems for denitrifica -

tion, dedusting and desulphurisation sit -

uated downstream of the steam generator

clean the flue gases, removing nitrogen

oxides, dust and sulphur dioxide. The

extraction of district heat, which practically

replaces numerous industrial and private

heating systems, additionally helps to

minimise pollutant emissions.

Main transformer of combined heat and power plant 2 (CHP 2)

14

The central laboratoryThe central laboratory of EnBW Kraftwerke

AG was set up in 2004 at the Altbach/Dei-

zisau location. The lab is a competence

centre pooling the corporate know-how in

the fields of power plant chemistry, oil

analysis and organic analysis as well as

trace element and heavy metal analysis. It

is also responsible for catalytic converter

management at the power plants. With its

state-of-the-art equipment, the central

laboratory is ideally placed to handle key

chemical issues not just within but also

beyond the EnBW Group.

Technical data

Year built: 1899Units: 2 coal units (1 coal, 1 compound unit)

2 gas turbine systems1 gas-oil compound block in cold reserve

Gross electrical rating: 1,215 MWelExtractable district heat output: 210 MWth

15

The EnBW central lab in Altbach/Deizisau

Location

The Stuttgart-Münster heat and power plant

is a unique facility in the EnBW power plant

fleet: the main purpose of the plant is not to

generate electricity but to handle the ther-

mal treatment of waste and to produce dis -

trict heat. Electricity and district heat are

produced simultaneously in Stuttgart-

Münster based on the cogeneration principle

in order to ensure improved fuel utilisation.

The heat and power plant comprises three

coal boilers, a waste incineration system

with three waste boilers, three steam tur -

bines and a gas turbine system. All in all, this

location has an electrical capacity of 184 MW

and a district heat capacity of 447 MW.

Two new waste boilers were built and put in-

to service in 2007. The processing capacity

of the waste-fired heat and power plant to-

tals 420,000 tons a year (reference calorific

value: 11,000 kJ per kg). In this way, EnBW

makes a key contribution to the reliable, en-

vironment-friendly and cost-effective dis-

posal of residual waste in Baden-Württem-

berg.

The contractual basis for these operations

dates back to 2003, when the city of Stutt-

gart and the Esslingen and Rems-Murr ad-

ministrative districts signed a disposal

agreement with EnBW Kraftwerke AG. Ac-

cording to this agreement, the city of Stutt-

gart and the two districts deliver around

225,000 tons of waste to Münster every

year. T-plus GmbH, a company belonging to

EnBW's disposal division, can draw on an

additional 185,000 tons of incinerating ca-

pacity. This EnBW subsidiary also disposes

of residual municipal waste in the Stuttgart

heat and power plant – this waste comes

from places like the Lake Constance admi-

nistrative district and the Reutlingen/Tü-

bingen region.

Valuable energy from waste and coalStuttgart-Münster heat and power plant

The Stuttgart-Münster heat and power plant on the Neckar

16

History

In 1908, the power plant began generating

electricity to meet the growing energy

demand in the region under the name

"Dampfkraftwerk des städtischen Elektrizi-

tätswerks" (steam power station of the mu-

nicipal electricity works). From 1933 until

the 1970s it also generated traction current,

and it started producing district heat in co-

generation mode in 1935. The first district

heat customers were the mineral baths and

the hospital in the town of Bad Cannstatt.

The capacity of the power plant was also ex-

tended in the 1950s during the reconstruc-

tion of Germany: the waste incineration

plant went into operation in 1965, signal ing

the start of a new era in the history of the

location – the beginning of generation of

electricity and district heat from waste.

In the 1980s and 1990s, more stringent en-

vironmental protection requirements ne-

cessitated the construction of large-scale

cleaning systems for the flue gases result-

ing from the firing of coal and waste. First,

the catalytic denitrification systems for the

coal boilers went into service in 1986. These

were followed in 1988 by the flue gas desul -

phurisation system to clean the flue gases

from the coal boilers. Finally, in 1993, a

state-of-the-art flue gas scrubbing system

was started up to clean the waste gases

from the refuse incineration plant. On -

going optimisation work at the power plant –

such as the construction of the central

waste hopper in 1997 – ensures that the plant

in Stuttgart-Münster meets all the require-

ments for a modern waste disposal facility.

Special features

Flue gas cleaningThe flue gases produced by the waste incin -

eration process contain various pollutants

which need to be removed from the gases

before they leave the 180 metre-high stack.

Cleaning takes place in the flue gas cleaning

system, which consists of a dust separator, a

wet scrubber and a catalytic converter.

Both electric and fabric filters are used to

remove the dust. These filters can remove

up to 99% of the dust from the gases. In the

next stage, the dedusted flue gas flows

through a four-stage wet scrubber which

17

uses caustic soda to remove – primarily –

the hydrogen chloride, hydrogen fluoride,

sulphur dioxide, heavy metals, aerosols and

fine dust. A small amount of activated car-

bon is added to reduce dioxin levels and

bind the mercury. The separated pollutants

are extracted at the end of the process in

the form of dry salts and disposed of under-

ground. The catalytic converter – the third

stage of the cleaning process – is where the

remaining organic components, in particu-

lar any remaining dioxins and furans, are

denitrified and destroyed by oxidisation.

Back-pressure turbineAt the end of 1999, a back-pressure turbine

went into operation to supplement the two

extraction condensation turbines. The tur-

bine reduces the pressure of the steam in

the boiler to 4.5 bar – so that it can be fed in

to the heat exchangers for the district heat

system – and also drives an electric genera-

tor (18.5 MW).

Technical data

Year built: 1908Units: 1 coal unit with 3 coal boilers and 3 waste boilers

1 gas turbine systemGross electrical rating: 184 MWelExtractable district heat output: 447 MWth

Location

The Stuttgart-Gaisburg CHP plant is located

on the left bank of the Neckar river in the

suburb of Gaisburg. The characteristic

features of the plant are the two adjacent

stacks measuring 160 and 125 metres in

height.

The complex consists of two power plant

units and a gas turbine system. The power

plant is used almost exclusively to generate

district heat and is the location of EnBW's

only fluidised bed boiler.

In December 2009, a 22-MW district heat

back-pressure turbine was installed at the

Stuttgart-Gaisburg power plant. The waste

steam (6 bar) from the turbine heats the

district heat water for three different net-

works via heat exchangers.

History

The older of the two current power plant

units went into commission as a coal-fired

common-heater heat and power plant in

1950 and is today designated as unit 2. In

1958, the Heizkraftwerk Stuttgart GmbH

company leased the plant to Technische

Werke der Stadt Stuttgart AG, one of the

four predecessor companies of EnBW.

Special features

Fluidised bed boilerIn this boiler type, a mixture of ash, coal and

lime is fluidised in an air stream and then

burnt. The special feature of this technology

is the direct addition of lime, which directly

binds the pollutants created in the combust-

ion chamber. This ensures compliance with

the stipulated emission limits with out the

need for secondary flue gas cleaning systems.

Full performance within minutesStuttgart-Gaisburg heat and power plant

Gaisburg is only a few kilometres downriver of the Münster location.

18

Gas turbineThe 60-MW gas turbine in power plant 1 is

primarily designed to secure electricity

supplies in the event of the failure of other

plants but is also used to cover peak loads.

The only fuel still used today is natural gas.

Following a normal start-up, the gas turbine

reaches full power after around eight min -

utes; after a rapid start-up it is fully up and

running after just under five minutes. A

diesel assembly ensures that the turbine is

black start capable; in other words that it

can be started up without any outside ener-

gy in the event of a complete network black

out.

19

Technical data

Year built: 1950Units: 1 coal unit

1 gas turbine system1 unit in cold reserve

Gross electrical rating: 194 MWelExtractable district heat output: 273 MWth

Work on the compressor of the gas turbine

Location

The Heilbronn combined heat and power

plant is located in an industrial and commer-

cial estate on the outskirts of the town right

next to the Neckar river. The plant is opera-

ted in cogeneration mode and is one of the

biggest coal-fired power plants of EnBW

Kraftwerke AG with an electrical output of

over 1,000 MW and an extractable thermal

capacity of 320 MW. Three of the original

seven units are still in operation today.

Units 5 and 6 went into operation in the mid-

sixties and are today equipped with state-of-

the-art flue gas cleaning systems. Unit 7 com-

pleted in 1985 is the biggest coal-fired unit in

our entire conventional power plant fleet.

The plant was technically optimised by the

implementation of wide-ranging modernisa-

tion measures in 2009 and equipped to

meet the challenges of the coming decades.

The result? A permanent output boost of

around 40 MW and a further reduction in

CO2 emissions.

Unit 7 was the first coal-fired unit in Germa-

ny originally equipped with highly efficient

cleaning systems and therefore played a pio-

neering role in terms of environmental pro-

tection. Coal combustion produces air pollu-

tants like nitrogen oxides, dust and sulphur

dioxide. The use of efficient flue gas cleaning

systems (denitrification, dedusting and de-

sulphurisation) ensures that the pollutant

content in the flue gas is within the limits

set by legislation.

History

For more than 80 years, the Heilbronn loca-

tion has been a byword for coal-fired electri-

city generation – and for over 50 years also

for the reliable supply of district heat. The

first turbine sets went into operation in 1923

but soon had to compete with the hydro -

Biggest coal-fired unit in the EnBW power plant fleetHeilbronn heat and power plant

View of the Heilbronn heat and power plant on the Neckar

20

electric power plants in the surrounding

region. Then, in the early post-war period,

damage caused by wartime bombing led to

operational delays. A new era began in the

1950s, when planning work began on a new

large-scale power plant. A total of six power

plant units had been built by the mid-1960s:

units 1 and 2 were shut down in 1988 and

were followed by units 3 and 4 in 2006, but

the last two units are still in operation.

In 1960, the power plant supplied heating

steam to a nearby industrial facility for the

first time, and construction work on a dis -

trict heating network began just one year

later. A decision was made in the late 1970s

to build unit 7, which was completed in 1985.

Special features

Co-combustion of sewage sludgeSewage sludge has been co-combusted in

unit 7 since 1998, paving the way for envi-

ronment-friendly disposal with no pollu-

tants detectable in either the flue gas or

the incineration residues from power plant

operation. The co-combustion process is a

sustainable method of using the energy

contained in the sewage sludge to generate

electricity and district heat.

Training centreAt the Heilbronn power plant location,

young people have been trained for future

careers in the energy sector for more than

25 years. EnBW set up the centre (originally

housed in the mechanical workshop) back

in 1983 in response to the growing impor-

tance of company-based training pro -

grammes. The training centre was moder n -

ised in 2002 and extended in 2008.

21

Coal stockpile at the Heilbronn location

Technical data

Year built: 1923Units: 3 coal units

3 auxiliary steam generatorsGross electrical rating: 1,010 MWelExtractable district heat output: 320 MWth

Location

The Walheim power plant is also located

on the Neckar. It was built between 1962

and 1967 by Neckarwerke Elektrizitätsver-

sorgungs-AG and is equipped with two

coal-fired units. Unit 1 went into operati-

on in September 1964, unit 2 in August

1967.

History

In the winter of 1981/1982, a gas turbine

housed in a separate building and fired

with light fuel oil went into operation. As

it can be started up and begin feeding elec-

tricity into the network within a few minu-

tes, it is used to cover peak demand and al-

so serves as a reserve unit.

Environmental technology was retrofitted

to the two coal-fired units between 1987

and 1989 mainly for desulphurisation and

the reduction of nitrogen concentrations

in the flue gases.

When it fitted a nitrogen oxide reduction

system for a slag-tap boiler with ash

feedback, the company entered uncharted

technical territory; and the construction

of the system was therefore subsidised by

the German Environmental Agency. The

gas turbine was retrofitted in 1990 for low-

nitrogen oxide operation.

Unit 1 had been conserved and placed in

cold reserve back in April 2000. As part of

our reactivation measures for our power

plant fleet, we put the facility back into

operation in January 2005.

Back up for demand peaksWalheim power plant

Rapid availability when needed – the reserve and peak load plant in Walheim

22

Technical data

Year built: 1964Units: 2 coal units

1 gas turbine systemGross electrical rating: 391 MWel

Location

The EnBW power plant is located directly

on the Neckar a little way outside Marbach.

It went on line in 1940, and the units 2 and 3

meanwhile generate an output of 413 MW.

History

The coal-fired power plant was once the most

important power plant of Energie-Versorgung

Schwaben AG, a predecessor company of

EnBW. During the post-war period, it made a

key contribution to the economic upturn in

the region. As new, technically improved and

more cost-effective power plants were built in

other locations, the volume of electricity ge-

nerated in Marbach began to decline in the

1960s. Initially just the older installations and

soon the entire power plant was used as a re-

serve only. In 1981, the power plant unit Mar-

bach I was finally shut down.

In 1970, the unit Marbach 2 went into opera -

tion with a gas turbine plant powered by jet

turbines made by Rolls Royce. This plant is

still used today to generate peak load energy

and as a minute reserve.

Marbach 3 is an oil-fired gas and steam tur -

bine plant. When it was started up in 1974, this

combination unit was designed to cover in-

termediate load requirements. Following the

rise in oil prices and the introduction of a pol-

icy geared towards decreased dependency on

oil in the 1970s, however, the power plant

soon became a peak load plant and per -

formed the key generating reserve function.

Today, Marbach 2 and 3 are safety reserve

units – in other words, they need to be con-

stantly ready to go into operation.

In January 2005, the steam section of the fuel

oil-fired Marbach 3 unit went back into opera-

tion as part of modernisation and reactivation

measures. This section had been conserved

and shut down in 1998; only the gas turbine

was still in operation, generating elec tricity

in peak load periods when required.

23

Marbach – specialist for peak demand and minute

reserve

Airplane turbines for power generationMarbach power plant

Technical data

Year built: 1940Units: 1 gas turbine system

1 combination unitGross electrical rating: 413 MWel

Location

EnBW Kraftwerke AG operates the Rheinha-

fen steam power plant situated on the road

leading to the Rheinhafen port in Karlsruhe.

With a total installed electrical capacity of

1,260 MW and a maximum district heat ex-

traction volume of 220 MW, the power plant

plays an important and reliable role in the

cost-effective and environment-friendly

generation of electricity and district heat

within the EnBW power plant fleet.

The power plant went into operation in 1955

and today comprises four units: unit 4 is a

modern natural gas-fired plant with combi-

ned gas turbine and steam power processes.

The two oil- and gas-fired units 5 and 6 have

been operating in cold reserve since 1993.

The biggest unit at the Rheinhafen facility is

the coal-fired unit 7, which has been generat -

ing not just electricity but also district heat

since 1985. The plant received the certificate

for the European eco-audit in July 2000 and

was the first coal- and gas-fired power plant

in Germany to be awarded this certification.

A new unit has been under construction at

this location since the spring of 2008. Build -

ing work on the coal-fired unit 8 is on sche-

dule, and when it goes into operation it will

be possible to feed a maximum 220 MW of

thermal output in the form of extracted dis -

trict heat into the district heat network of

the city of Karlsruhe.

High performance, efficient and innovativeRheinhafen steam power plant in Karlsruhe

Energy for the Karlsruhe economic region – the power plant in the Rheinhafen port

24

History

By the late 1940s, planning had already be-

gun for the construction of a power plant in

Karlsruhe. The aim was to meet the rising

demand for electricity resulting from the

economic upturn and to reduce dependence

on power procured from other suppliers.

The location selected for the plant was a site

in the southern "Maxauer Rheinaue" district

on the Rhine, which created ideal conditions

for the operation of a power plant: direct

delivery of coal by waterway, the ability to

meet cooling water requirements for the

once-through cooling system by creating a

direct link to the Rhine and the option of

feeding electricity into the European inter-

connection grid via the transformer station

in nearby Daxlanden.

Units 1 and 2 went into operation in Februa-

ry 1955 and were followed by units 3 and 4 at

the beginning of the 1960s. In order to be

able to meet the growing demand for elec-

tricity in the years that followed, Badenwerk

AG – a predecessor company of EnBW – built

a number of additional power plant units:

the gas and oil-fired units 5 and 6 were com-

pleted in 1967/68, and the next milestone in

the history of the Rheinhafen power plant

was the construction of unit 7 in 1985. After

this unit was completed, units 1 to 4 were la-

ter shut down and units 5 and 6 used in cold

reserve mode. Unit 4 was repowered in 1997,

when it was converted from a coal-fired

plant into a combined cycle plant.

Today, units 7 and 4 are the key components

in the Rheinhafen power plant in Karlsruhe;

together with units 5 and 6, they have a total

installed capacity of 1,260 MW.

25

Work on a coal mill in unit 7

Gas turbine in unit 4

Special features

CoolingThe power plant units are not cooled

using a cooling tower but by a process

known as direct cooling. The cooling water

is taken from the Rhine river, mechanical-

ly cleaned and routed through the con-

denser. When it flows back into the river, it

is at most 10 degrees Celsius warmer than

when it was taken out. The Rhine carries

around 1,100 m3 of water per second on

average – and still carries over 500 m3

when average water levels have already

been low for many years. Before the cool -

ing water enters the system, it is mecha -

nically cleaned with the help of coarse and

fine rakes as well as a screening belt. In

this way, around 75 tons of dirt and waste

are removed from the Rhine river every

year.

Combined cycle power plantThe combined cycle power plant unit 4

allows EnBW to achieve an excellent effi-

ciency level of around 57% using natural

gas as a fuel; this spares natural resources

and takes the strain off the environment –

by reducing CO2 emissions, for example.

In addition, state-of-the-art combustion

technology reduces the formation of ni-

trogen oxides.

Steam turbine in unit 7 in Rheinhafen

26

CogenerationUnit 7 operates according to the cogenera-

tion principle. Heat is extracted at the tur-

bine in the form of hot steam and forwarded

via heat exchangers to the hot water sys -

tem of the Stadtwerke Karlsruhe GmbH

utility, supplying district heat to around

23,000 private households and over 1,300

industrial and commercial customers.

The extraction of district heat raises the

utilisation rate of unit 7. This not only

spares valuable energy resources but also

has a positive impact on the air quality in

the city of Karlsruhe: this is not surprising,

as the central district heat supply system

replaces a high number of decentral in-

dividual heating systems with relatively

high pollutant emissions.

27

Technical data

Year built: 1955 Units: 1 combination unit

1 coal unit2 oil- and gas-fired units in cold reserve

Gross electrical rating: 1,208 MWelExtractable district heat output: 220 MWth

Combination unit 4 in

Rheinhafen

Innovative new facility

Unit 8 in Rheinhafen is being built to the

east of the existing facilities and is sche-

duled for completion in 2012.

The innovative technology of the new coal-

fired unit will increase efficiency levels

and reduce specific CO2 emissions by 30%

compared to the current global average.

This EnBW investment helps to boost

energy efficiency. The extremely high effi-

ciency level is due to the high steam para-

meters at the steam turbine inlet, the low

condenser pressure and the high internal

efficiency levels of steam turbine, genera-

tor and transformer. The fact that up to

220 MW of district heat can be extracted

from unit 8 will additionally increase the

utilisation rate.

The construction site comes to life in the early morning hours

28

Technologies that spare the environment

Numerous innovative new features have

been incorporated in the new power plant

in order to ensure even more effective

protection of the environment:

› A modern firing concept reduces nitro-gen oxide formation and the amount of

excess air during combustion – and there -

fore also increases the efficiency of the

boiler.

› The use of a new blade concept booststhe internal efficiency of the turbine.

› A so-called wet stack without flue gas reheating increases the efficiency of the

overall plant.

› In addition, unit 8 in Rheinhafen has sufficient space for the subsequent re -

trofitting of a CO2 capture system.

The CO2 capture concept is currently not

feasible on a large scale. EnBW is involved

in the development of new capture tech -

niques and is working on potential solu -

tions together with various universities.

29

Technical data

Start-up: 2012Units: 1 coal unitGross electrical rating: 912 MWelExtractable district heat output: 220 MWth

View of the construction site for unit 8 in Rheinhafen

Location

The Bexbach coal-fired power plant is

located in the Saarland region close to a

former coalmine and has the biggest out-

put of any unit-type power plant in the

Saarland.

History

The Barbara I power plant was built at this

location back in 1953 and was fired using

low-grade coal from the Bexbach mine. A

further power plant, Barbara II, went into

operation in 1960, and 1979 saw the start

of building work on the current power

plant unit, which went on stream in 1983

after a four-year construction period.

The power plant is jointly owned by EnBW

Kraftwerke AG and Evonik Power Saar

GmbH. EnBW has a 100% electricity sup-

ply entitlement in Bexbach, while Evonik

Power Saar GmbH has been responsible

for operation of the power plant since it

first started up.

Holdings and electricity procurementBexbach power plant

The Bexbach power plant is the biggest unit-type plant in the Saarland region

30

Technical data

Year built: 1953Units: 1 coal blockGross electrical rating: 750 MWel

Location

The Lippendorf power plant is around 15

kilometres to the south of Leipzig. The two

lignite units "S" and "R" went into opera -

tion in 1999. Unit R is owned by the opera-

tor of the power plant, Vattenfall Europe

Generation AG, while unit S belongs to

EnBW Kraftwerke AG. The power plant also

supplies district heat to the city of Leipzig.

History

As far back as 1926, an industrial power

plant was already operating at the Lippen-

dorf location and supplied electricity to

the Böhlen chemical factory. A further

power plant was added in the 1960s to gen-

erate power for the chemical company

and to act as a baseload supply plant for

the southern region of the former East

Germany. When new environmental legis-

lation came into effect in 1990, the owners

decided that it would not be feasible to re-

trofit modern environmental technology

and drew up plans to build an optimised

lignite-fired double-unit plant. After the

new plant went on line, the old power

plants were closed down and decommis-

sioned step by step. The two units have a

gross installed capacity of 920 MW each.

When they went into operation, they were

considered the biggest and most efficient

lignite power plant units worldwide. The

facility has a net efficiency of around 42%;

the extraction of district heat boosts the

fuel utilisation rate to 46%. The Lippen-

dorf plant has been co-combusting sewage

sludge since 2004.

31

Lippendorf power plant

The Lippendorf power plant not only generates electricity but also supplies the

city of Leipzig with district heat

Technical data

Year built: 1999Units: 2 coal unitsGross electrical rating: 1,840 MWel

Location

The Rostock power plant is located in Ros -

tock's sea port. The coal-fired power plant

went into operation in September 1994.

On January 1, 2010, EnBW acquired a 100%

stake in Gesellschaft für die Beteiligung

an dem Kraftwerk Rostock mbH, which

in turn holds a 50.4 percent share in the

Rostock power plant. The other share-

holders are Vattenfall Europe (25%) and

RWE Power (24.6%).

History

Construction work on the power plant be-

gan in June 1991, and the facility was mod -

ernised to meet the requirements of the

liberalised electricity market in 1998. The

coal-fired power plant has a gross capacity

of 553 MWel and feeds 150 MWth of heat -

ing energy into Rostock's district heating

network. It therefore currently produces

more than half of all electric energy gen -

erated in the state of Mecklenburg-West

Pomerania and covers around one third of

electricity demand in the entire state as

well as 20% of the district heat require-

ments in the city of Rostock.

The power plant has an efficiency level of

43.2%, and full utilisation of heat extracti-

on increases the utilisation rate to as high

as 62%. One of the special features of the

power plant is the 141.5 metre-high cool -

ing tower that uses seawater and also acts

as a chimney stack.

Rostock power plant

The power plant is located in the sea port in Rostock

32

Technical data

Year built: 1994Units: 1 coal unitGross electrical rating: 553 MWelExtractable district heat output: 150 MWth

33

Buschhaus power plant

Location

The Buschhaus power plant is around

eight kilometres from the town of Helm-

stedt. The lignite plant went into opera -

tion in 1985 and was modernised in 2002.

It is operated by E.ON Kraftwerke GmbH,

and 45.2% of the energy generated by the

plant (159 MW) is supplied directly to

EnBW Kraftwerke AG.

History

Helmstedt is a lignite mining town and

has been generating electricity since 1906.

All in all, nine power plants have been

commissioned since then, the Buschhaus

facility being the most recent addition.

The baseload power plant is specially de -

signed to incinerate the sulphurous high-

salt lignite from the Schöningen open-cast

mine.

The plant always keeps temperatures to

below 1,100 degrees Celsius during the

combustion process to minimise the for-

mation of nitrogen oxides, thus rendering

a denitrification system unnecessary. The

special feature of the Buschhaus plant is

its stack: at a height of 307 metres, it is the

highest stack anywhere in Germany and is

easily visible from afar.

Specialist for high-salt lignite – the Buschhaus power plant

Technical data

Year built: 1906Units: 1 coal unitGross electrical rating: 392 MWel

34

Location

Stadtwerke Düsseldorf (SWD) is a munici-

pal utility in which EnBW holds a majority

stake. SWD operates a network of different

types of generating facilities, including

fossil-fuelled power plants like those at

the "Lausward" and "Flingern" locations.

History

The first municipal gasworks went on line

back in 1866. Today, there are two units

operating at the "Lausward" location in

Düsseldorf's port district: a gas and steam

plant with a capacity of 103 MWel and 75

MWth completed in 2003. This facility is

particularly efficient and has an efficiency

rating of up to 87%. The unit with the high -

est output is the natural gas-fired "Emil"

combination unit dating back to 1972 with

capacities of 420 MWel and 140 MWth.

With its combination of gas turbine and

steam boiler, "Emil" is a mixture of a gas

and steam plant and a heat and power

plant. In the city district of Flingern, the

steam from the waste incineration plant

generates up to 55 MW of electricity and

100 MW of district heat. Two peak-load

boilers, each with a capacity of 50 MWth,

serve as back up systems. A gas turbine

has also been in operation at this location

since 1973, and this turbine acts as a kind

of emergency power assembly: its six

aircraft turbines can produce 90 MW of

electricity within the space of just a few

minutes.

Stadtwerke Düsseldorf municipal utility

The "Lausward" plant is at the heart of the city and generates energy for Düsseldorf and

the surrounding region

Technical data

Year built: 1866Units: 1 combination unit

1 gas and steam unit1 waste incineration system

Gross electrical rating: 668 MWelExtractable district heat output: 315 MWth

35

Grosskraftwerk Mannheim power plant

Location

Grosskraftwerk Mannheim AG (GKM)

operates one of the most efficient coal-

fired power plants in Europe. Located di-

rectly on the Rhine, it is ideally situated

to ensure generation and feed-in of power

close to the points of consumption. The

GKM power plant is jointly owned by RWE

Power AG (40%), EnBW Kraftwerke AG

(32%) and MVV RHE GmbH (28 %).

History

The Mannheim power plant was set up in

1921 by the Pfalzwerke der Stadt Mann-

heim utility, the Badische Landeselektrizi-

tätsversorgung company (later Badenwerk

and today EnBW) and the Neckar AG cor-

poration. The first boilers went into opera-

tion in 1923. For around 90 years now,

GKM has reliably been producing electrici-

ty and district heat for Mannheim and the

Rhine-Neckar metropolitan region. The

plant consists of the coal-fired units 3, 4, 6,

7 and 8 with an aggregate net capacity of

1,520 MW of electricity and around 1,000

MW of extracted district heat. One of the

special characteristics of the Mannheim

facility is that 190 MW of the net capacity

are rerouted to supply a power line of the

Deutsche Bahn rail company. As part of

the modernisation programme for the

power plant fleet, GKM is building a new

coal-fired unit on the eastern section of its

operating site: unit 9 is scheduled to go on

stream at the end of 2013 with an output

of 911 MW and will replace units 3 and 4.

The power plant supplies electricity and heat to the city of Mannheim and the

Rhine-Neckar region

Technical data

Year built: 1921Units: 5 coal unitsGross electrical rating: 1,675 MWelExtractable district heat output: 1,000 MWth

The technology of a power plant

The power plant process

A coal-fired power plant converts thermal

energy into electric energy with the help

of steam – which is why it is also called a

steam power plant.

The combustion of coal produces hot flue

gases which are used to generate steam.

The steam flows through a turbine and

passes on its energy to the turbine blades.

This energy is converted into rotational

energy. The turbine shaft drives a genera-

tor which generates electricity. The spent

steam is cooled in the condenser to create

water, which is then pumped back into the

steam generator. In this way, thermal and

mechanical energy are used to convert

chemically bound energy into the desired

electric energy.

Technology made easyHow fossil-fired power plants work

Emission monitoring

Desulphurisation Dedusting Denitrification Steam generator

Transformer

Burner Coal mill

Steam turbine

Condenser

Generator

River

Feed water pump

Cooling water cleaning

Induced draught fan

38

How a fossil-fired power plant works

Combined cycle plant

In a gas and steam turbine power plant,

the energy generation function of the gas

turbine is combined with the steam power

process. The hot flue gases from the gas

turbine are not discharged into the atmos -

phere unused but forwarded to a heat

recovery steam generator to generate

steam which is used in the steam turbine.

The combina tion of these two processes

increases the efficiency of the plant.

39

River

Steam turbine

Condenser

Flue gas Fresh airSound absorber

Compressor

Generator

Generator

Feed water pump

Reheater

Heat recoverysteam generator

Transformers

Switchgear

TurbineFuel

How a combined cycle plant works

Cogeneration

As a rule, power plants generate electricity

by burning fossil fuels. Plants that pro duce

not only electricity but also heat (e.g. district

heat) on the other hand, operate on the co-

generation principle and are also called

combined heat and power plants. The heat

is extracted from the turbine in the form of

hot steam. It is then forwarded via heat ex-

changers to a distribution system that sup-

plies the heat to private households (heat-

ing energy) and industrial companies (pro-

cess heat). The simultaneous genera tion of

electricity and heat exploits the primary

energy of the fuel more effectively and

there fore significantly improves the fuel

utilisation rate of cogeneration plants. Pol-

lutant emissions are also reduced, as central

district heat supplies from the heat and

power plant replace a high number of de-

central individual heating systems.

40

Emission monitoring

Desulphurisation Dedusting Denitrification Steam generator

Transformer

Coal mill Steam turbine Condenser Generator

Cooling tower

District heat extraction

Cooling water cleaning

Fans

Induced draught fan

District heat extraction – the example of unit 8 in Rheinhafen

Steam turbine

The guide blades of the steam turbine di-

rect the steam towards the rotor blades at

an optimum angle, and the rotor blades

then set the turbine shaft in motion. The

pressure of the steam falls as it passes

through the blades while the volume of

the steam increases. This is why the blades

are always longer towards the end of the

turbine.

41

Rotor blades

Guide blades

Live steam

Turbine shaft

Steam outlet to reheater

Sectional view of a high-pressure turbine

Gas turbine

Gas turbines can work to full capacity with -

in the space of just a few minutes: large

volumes of intake air are compressed in

the compressor and flow into the com -

bustion chamber of the gas turbine, where

natural gas is incinerated together with

the compressed air. The hot flue gas then

flows onto the turbine at high tempera -

ture and drives the turbine.

Fresh airGenerator

Combustion chamber

Flue gas

Turbine

Fuel feed

Compressor

42

Sectional view of a gas turbine

Cooling process

There are three main techniques used for

cooling in modern power plants: once-

through cooling, discharge cooling and circuit

cooling. In all three methods, the steam flows

from the low-pressure turbine to the conden-

ser, which houses a tubular system through

which the cooling water flows. The incoming

steam condenses to water on the outside of

the tubes and gives off its evaporation heat to

the cooling water. The condensate is then

pumped back into the boiler, which once

again generates steam.

In once-through cooling systems, the cool -

ing water is extracted from the so-called re-

ceiving water course (river, lake, ocean) and

discharged directly back into the receiving

water course after the steam has been cool -

ed in the condenser. In discharge cooling,

the cooling water is cooled in a cooling

tower by giving off its heat to the ambient

air before being routed back into the re-

ceiving water course. In circuit cooling, the

cooling water constantly circulates between

cooling tower and condenser. Water is only

fed into the circuit to replace the cooling

water loss, which is generally visible in the

form of the steam plume above the tower.

There are also different types of cooling

tower. A tall tower is a sign of a natural

draught wet cooling tower, in which the

cooling water is finely drizzled. The air ris -

ing in the tower reduces the temperature of

the cooling water. The high tower creates a

natural draught that causes the air to flow

43

Wetted surface

Fans

Cooling water basin

PumpHeat exchanger

Hybrid cooling tower

Condenser

Condensate at 39°C to feed water tank

Outlet steamfrom turbineapprox. 35°C - 40°C0.07 bar

through the cooling tower. The mechanical-

draft cooling towers operate on the same

principle but do not need to be anywhere

near as high – but they do need fans to ensure

sufficient air flows and this increases the au-

xiliary consumption of the power plant.

The hybrid cooling tower is a special kind of

tower which combines wet cooling and dry

cooling techniques. This combination almost

totally eliminates plume formation. This type

of tower also uses fans to generate the cool -

ing air flow. This means that hybrid cool -

ing towers do not have to be particularly high,

and they therefore blend in with the surround -

ing area around a power plant. Only five hy-

brid cooling towers are currently in operation

worldwide, and three of them are part of the

EnBW power plant fleet.

Cooling at the combined heat and power plant 2 (CHP 2) at the Altbach/Deizisau location

Denitrification

The denitrification system uses the so-

called selective catalytic reduction method:

ammonia is sprayed into the hot flue gas

and the mixture is then routed via cata-

lysts in which a chemical reac tion takes

place. During this process, over 70% of the

nitrogen oxides are converted into harm-

less nitrogen (N2) and water (H2O).

Flue gas containing nitrogen

Ammonia (NH3)

Catalysts

Nitrogen (N2)

Water (H2O)

Flue gas with nitrogen concentration 100 mg/Nm3

44

Dedusting

During the dedusting process, the fly ash

is removed from the flue gas. This process

takes place in large electrostatic precipita-

tors, where discharge electrodes create a

strong electric field. The ash particles are

negatively charged and settle on the posi-

tively charged separator plates before

being removed by beater mechanisms.

This process removes more than 99.9%

of the fly ash from the flue gas.

Discharge electrode

Collector plate

Beater mechanism

Ash hopper

Fly ash

++ ++ ++ ++__

99.9% dedusted flue gas

Flue gas with fly ash

Voltage between the electrodes:40,000 to 60,000 volts

__

Denitrification and dedusting in the power plant process

45

Desulphurisation

In the desulphurisation process, the waste

gas containing sulphur dioxide flows up-

wards in a scrubber and is sprayed with a

suspension of limestone and water. The

SO2 binds and is then captured in the ab-

sorber sump. The injected air causes the

calcium sulphite – the reaction product of

sulphur dioxide, limestone and water – to

oxidise to form calcium sulphate (gyp-

sum). In the wet scrubbing process, the

capture rate for sulphur dioxide is in ex-

cess of 90%.

Stack

Flue gas

Limestone powder

Limestone silo

Limestone suspension tank Oxidation air Absorber

Process water

Hydrocyclone

Gypsum silo

Gypsum for reutilisation

Filtrate to absorber

Belt filter

Clean gas

Desulphurisation in the power plant process

The electricity grid of EnBW is made up of

the transmission network and the various

distribution networks. EnBW Transport-

netze AG (TNG) operates the transmission

network in Baden-Württemberg. This net-

work comprises around 3,650 kilometres

of 380 and 220 kilovolt (kv) very high-vol-

tage lines which are connected to the re-

gional 110 kv distribution networks of the

various companies via 81 transformers.

The biggest 110 kV network is operated by

EnBW Regional AG (REG). The TNG trans-

mission network is ideally integrated in

the German and European interconnec -

tion system via 36 coupling points. It is

directly connected to the transmission

networks within Germany as well as those

crossing over into France, Austria and

Switzerland.

In line with the German Energy Industry

Act, the job of TNG is to provide all market

participants with access to the transmis -

sion network at transparent and non-dis -

criminatory conditions and to ensure the

reliable supply of electricity at all times.

To this end, we continuously monitor and

control the energy flows in the network,

performing maintenance work and expand -

ing the network as and when necessary.

With the aim of ensuring a balance bet-

ween generation and consumption in the

electricity supply system in Baden-Würt-

temberg at all times and controlling the

exchange of electricity with other coun-

tries, TNG is responsible for planning and

implementing the following measures:

› Regulation of the power frequency, in other words, using balancing energy to

ensure a stable frequency of 50 Hertz

throughout Europe

› Schedule management – the coordinationof the import, export and power plant

schedules of the electricity traders and

power plant companies in the TNG con-

trol area

› Marketing the forecast and actual feed-inof energy volumes from renewables on

the electricity exchange

The EEG legislation that gives precedence

to renewable sources of energy has extend -

ed the remit of the German transmission

system operators. As a result – and due to

the central location of the TNG control

area – TNG has to transport wind energy

feed-in in the north to the core consump-

tion areas in the south.

Stable and flexibleThe electricity network of EnBW

46

Environmental protection measures

In the construction and operation of its

electricity networks, EnBW attaches major

importance to minimising the impact on

existing ecosystems: cableways are laid to-

gether, maintenance routines are based on

ecological considerations and planning

concepts take account of breeding seasons

and vegetation periods.

EnBW has long played a pioneering role in

Germany when it comes to bird protection

in the medium-voltage network. At the

end of the 1990s, work began on nume-

rous programmes to make overhead cables

safer in coordination with the Baden-

Württemberg Environmental Affairs Min -

istry: based on the catalogue of measures

laid out by the German Association of

Energy and Water Industries in consultation

with nature conservation associations,

for example, most of the 20-kV overhead

line network has been equipped with pro-

tective hoods, perches and deterrents to

make the system safe for birds.

In 2007, EnBW initiated a study to explore

the hazard potential of high and very-high

voltage lines. The findings formed the

basis for the identification and implemen-

tation of a number of effective bird protec -

tion measures. The high safety standard is

underpinned by constant checks and ser-

vicing measures.

47

Combination plant, combination unit –power plant in which the gas turbine and

steam power process are combined. Either

the flue gases from the gas turbine are used

as combustion air in a steam generator, or

steam is generated directly in a heat exchanger

(gas and steam turbine plant).

Combination unit –� combination of gas tur-bine heat recovery steam generator system

and steam power plant. The steam generated

in the heat recovery steam generator using

the gas heat is fed into the steam cycle of the

steam power plant. The advantage of a com-

bination unit is that steam power plant and

gas turbine can also be operated indepen-

dently of one another.

Demand peak – peak load

Efficiency – ratio of produced output to re-source input – in the case of a machine, for

example, the ratio of energy output to ener-

gy input. Only a part of the energy is con -

verted into a new usable form of energy; the

remainder is converted into a form of energy

that cannot be used at all or is difficult to use.

An electric motor, for example, transforms

the input energy not only into useable kine-

tic energy but also to a lesser degree into

Baseload – the basic demand for electricitythat exists irrespective of all load fluctua -

tions. Baseload is covered by power plants

that can operate around the clock more or

less throughout the entire year.

Black start – start-up of a power plant unitwithout electricity from the electricity net-

work. Black start capable units are used to

build up the electricity network again after

a black out.

Carbon capture and storage (CCS) – capture and geological storage of the green-

house gas CO2 occurring in industrial and

power plant processes.

Clean Development Mechanism (CDM) – an instrument under the Kyoto Protocol de -

signed to limit the growth-related increase

in greenhouse emissions in economies in

transition and developing countries through

the implementation of cost-effective and effi -

cient measures. The achieved emission re-

ductions are credited to the investor in the

form of certified emission reductions (CERs).

Companies can use CERs to meet their sur-

render obligation in line with the European

allowance trading scheme (emissions trad -

ing).

Cogeneration – the simultaneous generationof electricity and heat based on the cogen -

eration principle ensures the best possible

utilisation of the energy contained in the

fuel. The heat from a power plant can be

used in the vicinity to heat buildings or as

process heat in industry. A power plant that

produces both electricity and heat is called

a combined heat and power plant.

Cold reserve – a power plant that is not tobe used for an indefinite period of time but

operated once again at a later date is "con-

served" and placed in cold reserve. It gener-

ally then takes a few months to prepare the

unit to return to fully-fledged operation.

Combined heat and power plant (CHPplant) �– energy conversion plant that simul-taneously generates electricity and useful

heat (cogeneration). Big power plants are

operated on an electricity-led basis (in other

words, district heat or process steam is de-

coupled). Smaller combined heat and power

plants tend to be heat-led – in other words,

they are operated in response to heat con-

sumption and electricity is a desirable by-

product. Heat-led combined heat and power

plants have utilisation rates of over 70%.

Glossary

48

non-usable thermal energy. Due to the laws

of thermodynamics, the efficiency of a sys -

tem is always lower than 1, even in ideal con-

ditions.

Electric output – installed capacity

Emission allowance trading – trading withemission certificates is an environmental pol-

icy instrument and is designed to promote

climate protection. In the Kyoto Protocol,

the industrialised nations agreed to reduce

worldwide greenhouse gas emissions. In or-

der to maximise the efficiency with which

the reduction quota for greenhouse gases is

divided up, the admissible emission volume

of each country is split into so-called emis -

sion certificates that permit the emission of

specific volumes of greenhouse gases. These

emission allowances can be traded between

countries. In order to achieve its emission

reduction targets, the European Union has

introduced an allowance trading scheme on

company level. European Union allowances

(EUAs) are issued to the participating com -

panies based on National Allocation Plans

(NAPs). Companies who need more allowance

units than they have been allocated have to

purchase additional units. Companies who

receive more units than they need can sell

49

them. Each market participant is free to

decide whether to buy allowance units or

implement modernisation measures.

Flue gas cleaning – extensive reduction inthe volume of flue gas components like ni-

trogen oxides, dust and sulphur dioxide oc-

curring during the combustion of solid fuels

like coal. In this process, the flue gases from

the boiler pass through separate cleaning

stages.

Flue gas desulphurisation system – serves

to reduce the concentration of sulphur di-

oxide in the flue gas flow. The most common

technique is to spray the flue gases with a

limestone suspension in a wet scrubbing

process. During the scrubbing stage using

the absorption solution, the sulphur oxides

in the flue gas bind with the limestone to

form calcium sulphite, which then oxidises

to form gypsum in the scrubber sump

follow ing the injection of air.

Flue gas scrubbing system – flue gas scrub-

bing reduces the concentration in the gas of

pollutants resulting from waste incineration.

The system consists of a wet scrubber. The

pollutants – HCI (hydrochloric acid), SO2(sulphur dioxide), HF (hydrogen fluoride),

heavy metals, dioxins and furans as well as

dust – are washed out and removed at the end

of the process in the form of dry salts.

Gas and steam turbine plant – in a combinedgas turbine and steam power process, the

thermal energy of the extremely hot gases

from the gas turbine is not discharged into

the atmosphere unused but transferred via a

heat exchanger to a steam power process

which makes use of this energy. This makes

it possible to combine the advantages of

both processes: the high inlet temperature

of the combustion gases into the gas turbine

and the lower temperature of the steam at

the end of the water-steam cycle. Utilisation

of this high temperature differ ential greatly

improves the efficiency level.

Gas turbine – a gas turbine essentially con-sists of a compressor, a combustion chamber

and a turbine. Air is taken in from the sur-

rounding atmosphere via the compressor

and compressed. The compressed air is

routed into the combustion chamber of the

gas turbine, where it reacts with the feed fuel.

In the turbine section of the gas turbine – like

in a steam turbine – the gases are then flashed

to ambient pressure. The flashed combustion

gases are then discharged through a stack

Primary energy – the energy stored in natu-ral energy sources like coal, crude oil or natu-

ral gas.

Reactive power – reactive power is the elec-trical output needed to create magnetised

fields (in motors or transformers, for exam-

ple) or electrical fields (e.g. in condensers)

and that does not contribute to "useful

work".

Repowering – repowering is when old powerplants are replaced by new, modern, general-

ly more efficient plants. Power plants are on-

ly designed for a certain service life. To allow

operation after this time, the core compo-

nents have to be replaced with modern com-

ponents that are in line with the state of the

art. Repowering also provides an opportuni-

ty to change the type of power plant. When a

power plant is repowered, it generally con -

tinues to use the existing infrastructure.

Reserve capacity – this secures the opera -tion of the interconnection grid even in the

event of the unexpected failure of large-scale

generating units.

Retrofit – a term used to describe the moder-nisation of existing power plants. One of the

either directly or via a heat exchanger which

utilises the heat of the waste gases.

Gas turbine process – cyclical process, thepurpose of which is to produce work using air

as the working medium. The thermodynamic

comparison process is the so-called hot air or

Joule process.

Generating reserve – reserve capacity

Interconnection grid – the totality of all syn-chronously interconnected transmission net-

works.

Intermediate load – level of increased electri-city demand. This is where there are regular

fluctuations of the load curve above the base-

load – in times of increased electricity con-

sumption in the morning, at midday and in

the evening, for example.

kV – kilovolt; 1 kilovolt = 1,000 volts

Minute reserve – this output reserve is need -ed if additional output has to be fed into the

network in order to prevent the network fre-

quency dropping below 50 Hertz. This reserve

is supplied by storage, pumped-storage and

gas turbine power plants.

MW – megawatt; 1 megawatt = 1,000 kilo-

watts = 1,000,000 watts. This unit of output

measurement is used for large-scale electri-

cal facilities.

Peak load – the level of highest electricitydemand. This short-term peak load on the

electricity network is generally foreseeable

based on long experience and is mainly

covered with the help of storage, pumped-

storage and gas turbine power plants. The

machines in these power plants can operate

at full power inside a matter of minutes.

Power output – the product of current andvoltage or work per unit of time. Power out-

put is expressed in watts or joules per sec -

ond. In the area of power plants, the power

output is measured in megawatts (MW).

Power plant by-products – by-products likefly ash, boiler ash and gypsum occur in the

power plant industry and are used as second -

ary raw materials in the building sector. The

energy industry believes these by-products

fully meet the requirements for by-products

under the Waste Framework Directive and

are therefore subject to the REACH legislati-

on, an EU regulation that came into effect on

June 1, 2007. REACH stands for registration,

evaluation and authorisation of chemicals.

50

main reasons individual power plant compo-

nents are modernised is to increase their effi-

ciency. Retrofit measures also pave the way

for the generation of "green megawatts": this

means that a technically optimised facility is

able to generate a higher volume of electricity

from the same fuel input.

Safety reserve – minute reserve

Sewage sludge co-combustion – mechani-cally dewatered and thermally dried sewage

sludge can be incinerated together with coal.

The precondition is that the sewage sludge

complies with the waste sewage sludge regu-

lations. This waste from sewage plants pro -

duced by humans used to be mainly disposed

of in landfill sites or used in agriculture and

within the framework of recultivation meas -

ures at exhausted lignite sites. Since June 1,

2005, however, the "German Technical Regula -

tions on Municipal Waste" have prohibited

the disposal of sewage sludge at landfill sites

for household waste. This makes thermal utili -

sation in power plants a technically feasible

and environmentally sparing disposal option.

The high combustion temperatures ensure

that the organic pollutants, in particular the

halogenides, are completely destroyed; the

residual moisture in the sewage sludge eva -

51

porates. In-depth investigations by certified

laboratories have confirmed that, up to a

certain volume, the co-incineration of sewage

sludge has no effect whatsoever on the quality

of the clean gas and residual substances result -

ing from operation of the power plant.

Steam power process – thermodynamic cyclical process designed to produce work.

Water and steam are used as working media.

All steam power processes are based on the

so-called Clausius Rankine process.

Thermal capacity – in physics, the thermalcapacity is a parameter of an energy conver -

sion installation that generates heat. It is nor-

mally measured in watts or joules per second.

In steam power plants, this is the energy con-

tained in the steam generated by the steam

generator based on steam volume, steam

temperature and steam pressure. In a steam

generator, the thermal capacity corresponds

to the heat content of the fuel used (thermal

fir ing capacity) minus the losses due to waste

gases and any other heat transfer from the

plant to the environment.

Once-through cooling – in once-throughcooling, water is taken from a river, mechani-

cally cleaned and routed through the cooling

tubes of the condenser. The steam flowing

out of the turbine into the condenser gives

off its evaporation heat to the cooling water,

which is then discharged back into the river.

Utilisation rate – a measure of how much ofthe energy stored in the energy source is ac-

tually utilised as usable energy. In the case of

systems generating electricity in cogenera -

tion mode, the utilisation rate describes the

ratio of total utilised energy output (electri-

city and heat output together) to the energy

input (primary energy). The difference bet-

ween the utilisation rate and efficiency is

that the latter only takes account of pure

electricity generation.

Waste incineration plant – the purpose ofwaste incineration plants is to dispose of

waste while using the energy it contains to

generate (for example) electricity and heat.

This also reduces the volume of waste that

needs to be stored in landfills. Since June 1,

2005 the "Technical Regulations on House-

hold Waste" have prohibited the disposal of

household waste unless it has been pro -

cessed. Thermal processing of waste in waste

incineration plants is therefore also used to

pre-treat household and industrial waste

prior to landfill storage.

EnBW Info CentresCentral Visitor ManagementPhone: 0800 2030040

E-mail: besichtigungen@enbw.com

Power plant locationsAltbach/Deizisau heat and power plantIndustriestraße 11

73776 Altbach

Rheinhafen steam power plant in KarlsruheFettweisstraße 44

76189 Karlsruhe

Münster residual waste heat and power plantVoltastraße 45

70376 Stuttgart

Grosskraftwerk Mannheim power plantThe Grosskraftwerk Mannheim

Aktiengesellschaft (GKM) company in

Mannheim-Neckarau opened an informa-

tion centre for interested visitors at the

end of 2010. The centre provides informa-

tion on the GKM itself as well as on the

new "Unit 9" construction project. You can

find more details at www.gkm.de.

Plant tours

52

PublisherEnBW Energie Baden-Württemberg AG

Durlacher Allee 93

76131 Karlsruhe

Internet: www.enbw.com

Responsible for corporate publicationsCorporate Communications,

Karlsruhe

Layout and designCorporate Competence Centre Marketing,

Stuttgart

PhotosArtis Foto, Karlsruhe

Volker Dautzenberg, München

Daniel Döbler, Poppenweiler

TranslationAnthony Tranter-Krstev, Germersheim

LithographyRepro 2000, Leonberg

Printed bySommer Corporate Media, Waiblingen

ISBA: B.2567.1012

Published in December 2010

Publishing details

EnBW EnergieBaden-Württemberg AG

Durlacher Allee 9376131 KarlsruhePhone +49 (0)721 63-06Fax +49 (0)721 63-12725info@enbw.comwww.enbw.com