TURNKEY CHP SOLUTIONS AND OPERATIONAL EXPERIENCE …

Power-Gen Asia 2003 Ho Chi Minh City,Vietnam

TURNKEY CHP SOLUTIONS AND

OPERATIONAL EXPERIENCE WITH

COMBINED CYCLE POWER PLANTS

BASED ON SIEMENS’ INDUSTRIAL

GAS TURBINES

MARTIN SIMEN

SIEMENS AG, POWER GENERATION,

ERLANGEN, GERMANY

Abstract

Cogeneration of heat and power (CHP) is acknowledged to be one of the most efficient and

environmentally favorable ways of energy conversion in the power generation industry.

Cogeneration has thus found political support, as it promotes high yield from primary energy

sources and supports decentralized energy supply. On the other hand, it is up to the producers

of power generation equipment and solutions to come up with advanced concepts for both

components and plant designs, to help cogeneration play an important role in future energy

markets from an economic point of view. In this paper, after discussing these market

requirements in detail, typical plant engineering solutions and applications are presented.

1


Introduction

For providers of power generation equipment and solutions such as Siemens, the quest for

access to new and growing markets has always been a main business driver. In this sense,

over the last years, Siemens Power Generation has extended its activities in the industrial

power plant market from ‘classical’ steam power plants to biomass power plants such as the

Siecoline® reference plant product, to special power plants such as Kalina cycle based

geothermal plants, to waste incineration power islands and last not least to ga turbine simple

cycle, simple cycle extension, combined cycle (CC or GUD®) and combined heat and power

(CHP) plants. Such a broad spectrum of activities requires careful scrutiny of underlying

external market opportunities and threats as well as internal capabilities.

In the following we take a special look at the CHP technology. From the perspective of an

equipment manufacturer and plant solution provider, we analyze the external environment as

well as available concepts and products regarding this technology. In this sense, we divided

this presentation into three sections, a view of the CHP market, a discussion of possible

solutions to meet these market requirements and a reflection of solutions implemented so far.

CHP Market

With the acquisition of the Alstom Industrial Turbine segment announced in August 2003,

market accessibility in industrial power generation has substantially improved for Siemens

Power Generation.

September 23-25, 2003 Power Generation

Product Range of Industrial Gas Turbines

4 7 8 1317

25 29

43

67

010

2030

4050

6070

GT

outp

ut in

MW

Typhoon

Tornado

Tempes

t

Cyclone

GT35C

GT10B

GT10C

GTX100

V64.3A

Fig. 1, Product Range of Industrial Gas Turbines

2


As shown in Fig. 1, Siemens can now offer gas turbine products ranging from 3 to 70 MW.

Previously only the upper range of the market could be accessed with the V64.3A as an in-

house product, whereas for smaller power demands plant solutions depended on non-Siemens

gas turbine supply. The market potential over the next five years for industrial power

generation in the 3 to 70 MW range is shown in Fig.2.. The average yearly demand according

to Siemens’ projections is strongest in the 35 to 50 MW range with approximately 6 GW. The

3 to 14 MW and 15 to 34 MW market is of approximately the same size at about 2.5 GW

annually. The market in the upper power range of 51 to 70 MW is smallest at about 700 MW

annually, which underlines the significance for Siemens to extend its product portfolio to

lower power ranges. An analysis of the regional split of the 15 to 70 MW market shows the

Americas with about 40% and Asia/Australia with about 25% as core regions market share

followed by Europe and Middle East/Africa.


Market Volume in Industrial Power Generation

Source: Siemens

Total Power Generation Market in MW (Average 03-07)

Industry and Oil&Gas

2400

24006000

700

3-14 MW15-34 MW35-50 MW51-70 MW

41%

26%

21%

12%

AmericasAsia/AustraliaEuropeMiddle East/Africa

Regional Markets for GTs 15-70 MW (Average 03-07)

Industry and Oil&Gas

Fig. 2, Market Volume in Industrial Power Generation

A yearly breakdown of market projections in the 3 to 70 MW power range is presented in

Fig. 3. For clarity, the oil and gas power generation market due to its product specific market

mechanism is excluded in this analysis. The yearly projections show that after the market

breakdown in 2002 to about 25% of the 2000 level, recovery is anticipated after 2004 to

reach a relatively stable level of about 10GW annually.

3


For an analysis of the qualitative drivers behind these quantitative projections, it is helpful to

distinguish between the short term, current situation and the long term trend, in order to cover

the strong dynamics observed in the market.

Analyzing the current situation in world regions, a leading influence is the overall market

downturn in North America which also affected industrial power generation. In Europe,

market liberalization along with changing legislation has led to uncertain economics for

investors, currently hindering growth especially in combined heat and power (CHP)

applications. The Latin American market is currently affected by overall economic slow

down and stagnant power market reforms. South East Asia shows signs of economic recovery

and increasing power demand, however still combined with relatively high reserve margins.

The Middle East and Africa represents an emerging market for CHP solutions especially for

small scale gas based power generation in oil and gas producing countries.


0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

Tota

l GT-

Ord

er V

olum

e in

MW

MW/a

Source: Siemens

Industrial Power Generation excl. Oil&Gas (GT 3-70 MW)

Market Development in Industrial Power Generation

Fig. 3, Market Development in Industrial Power Generation

Overall, the current situation in combined heat and power (CHP) generation can be

characterized by market uncertainty. This can be linked to two main factors, uncertain effects

of legislation and uncertain economics. For example in Europe, liberalization of the

electricity and gas market has led to lower electricity prices and fluctuating, relatively high

gas prices. In addition, quite contrary to the trend in America and Asia, deregulation in

Europe continues, with all non-household consumers free to choose power supply by 2004.

4


This will lead to a separation of transmission & distribution from production & supply as

well as open access for consumers and producers to the power network, based on transparent

tariffs. In this unstable market environment, major power generation investments are

currently put on hold.

On the contrary, long term perspectives in the CHP market are favorable. Besides the long

term growing electricity demand due to population increase and economic growth, especially

the quest towards highly efficient power and heat generation and upcoming stringent

emissions regulations will lead to higher growth rates in CHP solutions. Decentralization of

power and heat supply especially favors solutions based on small industrial gas turbines.

Without a technology shift, it is expected that worldwide power generation related CO2

emissions would rise by 60% from 1997 to 2020. In consequence, for example in Europe, the

EU commission has defined a “common strategy for CHP” aiming at doubling the

contribution of CHP solutions from 9% to 18% by 2010. Environmental legislation will be a

strong driver for CHP, however it has to be monitored closely, as regulations such as

investment incentives are still country specific and subject to frequent change.

A look at the customer base in the CHP market reveals a major difference to large scale

power generation. Instead of a confined number of utilities or power producers, with power

generation as core business and competence, the CHP customer base is fragmented within a

wide variety of industries. It can range from refineries, chemicals, pulp & paper, cement,

textiles to pharmaceuticals, ceramics, food processing, timber manufacturers, breweries,

leisure parks to hospitals, universities, government offices, airports, community buildings

etc.. This variety presents a special challenge for sales activities as most customer relations

are transitory and local. On the other hand, CHP customers have the following requirements

in common:

1. Low Capital Cost

Power and heat generation is either considered a ‘no frills’ necessity to support the actual

core industrial process as e.g. for refineries, or capital funds are strictly limited as e.g. for

small scale industries in private ownership as. e.g. paper mills .

2. Low Life Cycle Cost

High efficiency and thus cost savings are a prime mover to invest in CHP solutions. This

gives gas turbine based solutions a competitive advantage over conventionally fired boilers.

3. High Reliability/Availability

5


In general industrial processes such as refineries require continuous operation. Hence,

customers for example may prefer redundant, small scale, easy to maintain gas turbines over

a single, large turbine for power generation.

4. Short Delivery Time

Frequently a gas turbine driven CHP plant is installed replacing an aged, inefficient, existing

boiler plant. To keep down-time of the industrial process to a minimum, CHP plant concepts

need to be designed for rapid installation. This favors modularized, container packaged

solutions.

5. Customized Solutions

Power and heat demand as well as layout requirements are generally site specific and within

narrow design margins. Hence, fully standardized plant solutions in general cannot be

implemented. However, a plant concept with standardized core components individually

adapted and arranged to meet site specific needs can be successfully established.

CHP Solutions

Customization can indeed be observed especially in CHP plants. A look at the installed base

can give the impression that “each plant is different”. However, the seemingly infinite variety

of heat and power combinations can indeed be classified into a limited number of principal,

underlying, thermodynamic cycle concepts, which fundamentally determine plant design

configuration. Standardization especially of gas turbines further reduces variety. Gas

turbines, other than steam turbines, are pre-designed to a fixed performance rating. Siemens’

industrial gas turbines now range from 4.35 MW electrical output for the Typhoon engine to

67.5 MW for the V64.3A engine in distinct intervals. Main conceptual classifications are

discussed in the following based on a comparative case study.

1. Simple Cycle

A benchmark for CHP cycle concepts is to compare efficiency against cycles for power

generation only. Selecting the Siemens GTX100 gas turbine with a net electrical power

output rating of 44.2MW for simple cycle base load operation on natural gas fuel, net

electrical and total cycle efficiency is at 36.4%. As parameters, ISO conditions with 15°C

ambient temperature, 60% relative humidity, sea level altitude, inlet and outlet losses of

5mbar have been assumed.

6


2. Combined Cycle

In combined GTX 100 gas and steam turbine cycle operation, net power output increases to

63.8 MW and net electrical, total cycle efficiency for power generation reaches 52.7%

applying a dual pressure heat recovery steam generator. As water-steam cycle parameters,

15°C condenser and makeup water, 0.045 bar condenser pressure 0.045bar, 5K economizer

approach and 25K superheater terminal temperature difference, 10K pinch point and 1% heat

losses have been assumed.

3. CHP for Cogeneration

As a first comparison with CHP concepts, Fig. 4 shows results under the same conditions for

the least complex CHP cycle, a gas turbine with the exhaust gas used to produce process heat

in a single pressure heat recovery steam generator.

September 23-25, 2003

100 % fuel

1-pressure HRSG

Gas Turbine

CHP for Cogeneration(GTX100)

12 % losses

35.9 % electricity

52.2 % process heat

Pgt 43.82 MWPst 0 MWPaux 0.23 MWPnet 43.59 MWHeat duty 63.4 MJ/sQfired 121.4 MJ/s

Alfa 0.69 ---Net electrical efficiency 35.9 %Net total efficiency 88.1 %

Fig. 4, CHP for Cogeneration

With a gross electrical output Pgt of 43.82MW of the GTX100, for the cogeneration case no

steam turbine power output Pst and an auxiliary power consumption Paux of 0.23MW, a

combined net electrical output Pnet of 43.59MW is achieved. From the available 121.4 MJ/s

fuel heat (Qfired), 52.2% are converted into process heat (Heat duty), 35.9% into electricity

and 12% losses remain. This yields a power to heat ratio or cogeneration index Alfa of 0.69.

Net total efficiency, also termed fuel utilization, i.e. the percentage of fuel heat converted into

electrical and thermal output, has increased to 88.1% compared to 52.7% in combined cycle

7


power generation. Relatively low investment cost, simple technology but still high efficiency

make this so called cogeneration cycle the preferred solution for smaller size industries.

4. CHP for District Heating

A second CHP concept, frequently applied with inner city power plants, is presented in Fig.

5. Heat is transferred to the district heating cycle at 78°C, i.e. at relatively low temperatures

compared to industrial process applications. The steam turbine is of backpressure type and a

dual pressure heat recovery steam generator is applied. With the added power output of the

steam turbine, compared to the conventional cogeneration cycle, electrical efficiency is

increased to 47.2% and net total efficiency to 89.3%. Conversely, heat output is reduced to

42.1%, which yields power to heat ratio to 1.12.

September 23-25, 2003

100 % fuel

Gas Turbine

ST (district heating)

90 deg C

60 deg C

2-pressure HRSG

CHP for District Heating (GTX100)

510 deg C

78 deg C

78 deg C

11 % losses

35.9 % electricity

11.3 % electricity 42.1 %

heat

Pgt 43.70 MWPst 14.18 MWPaux 0.62 MWPnet 57.26 MWHeat duty 51.1 MJ/sQfired 121.4 MJ/s

Alfa 1.12 ---Net electrical efficiency 47.2 %Net total efficiency 89.3 %

Fig. 5, CHP for District Heating

5. CHP for low Process Steam Demand

CHP solutions for relatively low process steam demands are based on the power generation

combined cycle. The same main components, gas turbine, heat recovery steam generator,

steam turbine and condenser are applied, while the process steam is extracted from the steam

turbine at the desired temperature and pressure conditions. Fig. 6 gives a typical example.

Just 21% of the available fuel heat input is converted into process heat, while 44% is

converted into power resulting in the high power to heat ratio of 2.09. The reduced power

output of the steam turbine due to steam extraction yields 44% electrical efficiency compared

8


to 52.7% of a power generation only combined cycle. However, total cycle efficiency is at

65% significantly higher than for power only cycles. CHP solutions based on extraction

steam turbines are also selected to meet specific, high temperature and pressure process steam

requirements.


CHP for low process steam demand

steam turbine

21%

condenser

processsteam

100% Brennstoff33%

20%

11%

HRSG

15%

Fig. 6, CHP for low process steam demand

6. CHP for high Process Steam Demand

For relatively high process steam and low power demands i.e. low power to heat ratios,

conventional, fired boiler power plants have been built in the past. However plant efficiency

can be significantly increased, if part of the fuel is used to produce power with a high

efficiency gas turbine, while its exhaust gas is used to produce additional steam in the boiler.

Frequently, retrofit solutions by adding a small gas turbine to an existing large existing boiler

facility are implemented. A typical example for high steam demand is presented in Fig. 7. As

62% of the fuel heat input is converted into process heat at a typical steam temperature of

275°C, the power to heat ratio is just 0.37 and electrical efficiency just 23%. However total

CHP cycle efficiency is again very high at 85%, up to 10% higher than for conventional

boiler power plants.

9



CHP for high process steam demand

15%

50 C

275 C process steam 62%

11%

gas turbine

36% fuel

12%

boiler

64% fuelo

o

520 Co

steam turbine

Fig. 7, CHP for high process steam demand

Available CHP solutions for a given gas turbine with unfired steam generators can be

summarized in a single diagram of electrical versus thermal output. For the GTX 100 turbine,

Fig. 8 shows, how electrical output drops with increasing process heat for CHP solutions

without (case 1 and 2) and with steam turbine (case 3 to 5).


CHP output(GTX100)

40000

45000

50000

55000

60000

65000

0 10000 20000 30000 40000 50000 60000 70000

Process heat (kJ/s)

Elec

tric

outp

ut (k

We)

33

38

43

48

53

Elec

tric

effic

ienc

y (%

)

40% 50% 60% 70% 80%

0.8 bara

2 bara

5 bara

10 bara

25% Extraction

50% Extraction

75% Extraction

Back Pressure

Cogeneration (no steam turbine) 0.8 bara

Totalefficiency90%

process heat (kJ/s)

Net

ele

ctric

effi

cien

cy (%

)

Net

ele

ctric

out

put (

kWe)

Net total efficiency (%)

Co-generation (no steam turbine)1 2

3

4

Condensing ST, with extraction Backpressure ST

Fig. 8, CHP output (GTX100)

10


Also, as a general rule, electrical efficiency drops with increasing process heat, while total

cycle efficiency increases. In addition, the diagram shows the decrease in power output for

increasing steam extraction or pressure levels. As stated initially, the large variety of possible

heat and power combinations becomes obvious. However the diagram also confirms the

statement that a limited number of principal CHP solutions (cases 1 to 5) can cover this

variety of requirements.

This conclusion is good news for plant designers trying to standardize plant layouts in an

effort to meet customer requirements to reduce cost, delivery time and increase reliability.

One successful example is the now industry wide spread use of standardized pre-packaged

modules containing the pre-tested gas turbine plus its auxiliary systems. Examples within the

Siemens product range are shown in Fig. 9 and 10.


Cyclone Modular Package

Fig. 9, Cyclone Modular Package

Depending on machine size, the auxiliary systems are either fully integrated as sub-modules

on the base frame as for the Cyclone turbine, or placed next to the turbine frame within the

gas turbine enclosure, as for the GTX100 turbine. For the V64.3A, the largest Siemens

industrial gas turbine, turbine frame size is already 12x5.5x6 meters. Therefore all auxiliaries

are placed in a single lift auxiliaries module (SLAM), which is connected to the turbine via

the single lift intermediate module (SLIM) containing interconnecting piping. The packaged

solution significantly reduces plant footprint and site installation time, while the fully

11


instrumented, wired and pre-tested turbine systems improve product quality. Finally the

standardized package design reduces cost and thus price. So overall, packaging provides a

‘win-win situation’ for both customer and manufacturer.


GTX100

V64.3A

Gas turbine Packaging

Fig. 10, Gas turbine packaging

Starting standardization at the plant core, the gas turbine, seems natural. This concept is the

base of the the Siemens reference power plant (RPP) design approach shown in Fig. 11,.

Standardization is considered to start from the insight out, while customization starts from the

outside in. Specifically, RPP design starts with the gas turbine and auxiliaries, the so called

Econopac, continues on to the power island, which additionally includes steam generator,

steam turbine, condenser and generators, furthermore includes the power block, which also

includes water steam cycle, electrical equipment, cooling water system, to finally comprise

additional turnkey plant components like fuel, water supply and treatment systems as well as

civil scope such as buildings and foundations. To optimize the balance between

standardization and adaptability, RPP design depth decreases from the inside out, while the

number of design options increases.

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HV Switch-

gear

Water Pretreatment

BuildingFacilities

Fuel OilStorage

Site Gas Preheating

FuelTransfer

CivilCooling

Tower

WaterSupply

WaterTreatment

RPP Design Approach

Electrical

W/S-Cycle

Machine House Arrangement

I&CGT

GeneratorST

Condenser

HRSG

Customizationstarts from outside to inside ...Customizationstarts from outside to inside ...

... Standardization

starts from inside to outside

... Standardization

starts from inside to outside

Fig. 11, Reference Power Plant (RPP) design approach

A typical example of power island RPP design is shown in Fig. 12. The GUD® 1S.64.3A,

rated at 99.8 MW net power output and 52.2% net electrical efficiency, is a single shaft

combined cycle power plant. The power island comprises the core power train with one

V64.3A gas turbine including gear box, one air cooled generator, a synchronous clutch and a

single casing steam turbine with axial exhaust to the condenser. The gear ratio between the

gas turbine and the generator is 5400/3000 or 5400/3600 rpm according to 50 or 60 Hz

application.

The dual pressure non reheat HRSG operates at 70 bar high pressure and 5 bar low pressure.

For CHP applications, steam extraction for industrial processes or district heating purposes is

possible over a wide range of pressure and temperature levels. A 100% steam bypass system

allows high operating flexibility and even open cycle operation w/o exhaust gas bypass.

The single shaft GUD® power train with the gas turbine and the steam turbine driving one

common generator has various advantages of the alternative multi shaft arrangement:

1. Enhanced simplicity and flexibility,

2. Increased efficiency and output,

3. Reduced lead times,

4. Lower specific investment cost,

5. Improved reliability and availability,

13


6. Simplified operation & maintenance.

Overall, the above benefits result in lower life cycle cost.


1 Gas turbine2 Air intake duct3 HET gear box4 Generator with cooler5 SSS clutch6 Steam turbine7 Condenser8 Closed cooling water pump

9 Closed cooling water heat exchanger10 Vacuum pump11 Main cooling water pipes12 Main condensate pumps13 Generator bus duct14 Lube oil tank and coolers15 Space allocated for maintenance16 Filter house17 Generator circuit breaker18 Unit transformer19 Power control center20 Unit control room21 Gas turbine auxiliaries container22 Heat recovery steam generator

48 m

20 m

21

22 1

2

14

17

18

19

15

5 6

10

20

37

89

11

1213

16

4

1SV64.3A Single Shaft Power Island

Fig. 12, 1SV64.3A Single Shaft Power Island

A unique feature of single shaft design is operating flexibility. Due to the use of a SSS clutch

between the generator and the steam turbine, the gas turbine can be started individually

without any restriction by the actual condition (hot, warm or cold) of the steam turbine and

the cooling system. After steam of appropriate quality is available from the HRSG, the steam

bypass valves will be closed and the steam turbine be started up.

The SSS clutch automatically engages when the steam turbine is accelerated to the generator

speed. Then the steam turbine is loaded. Full load can thus be achieved in less than 80 min

(120 min) at warm (cold) condition.

The steam turbine and gas turbine cycles can be decoupled not only during start-up but also

during operation via the synchronous clutch. The GT can then be operated independently

from the ST. The steam is dumped to the condenser via the bypass station. For shut-down the

GT exhaust gas and steam temperature are limited to allowable temperature transients.

Therefore, the steam turbine is disconnected from the from the GT at full steam temperature

to allow shortest possible shut-down time.

14


The short start-up, shut down, as well as the high loading/de-loading rates provide the

operator with great flexibility in timing the plant dispatch for intermediate load or plant

shifting requirements.

A typical example of a multi shaft arrangement is shown in Fig. 13. It is based on the GT10C

gas turbine, the latest product in the GT10 family introduced in 2000.


1xGTX10C multi shaft Reference Plant

Net electrical output 41.3 MWNet electrical efficiency 51.1%

Fig. 13, 1xGT10C-multi shaft Reference Plant

In combined cycle operation, the GT10C gas turbine is rated at 28.5 MW, while the steam

turbine generates an additional 13.2 MW and auxiliary loads consume 0.45MW, which brings

total net plant output to 41.3 MW and net efficiency to 51.1%. A reference multi shaft

configuration based on two GT10C gas turbines and one steam turbine yields a net total

output of 83.6MW and 51.8% efficiency.

The family of Siemens combined cycle power plant reference designs based on GT10B,

GT10C, GTX100 and V64.3A gas turbines covers a wide range of power outputs. The 1x1

configurations (one GT, one ST in single or multi shaft design) range from 36MW to

102MW, whereas the 2x1 multi shaft configurations cover a range from 73 to 201MW.

15


CHP Experience

With the extended gas turbine product range from 4 to 67.5 MW, Siemens can offer broad

and long lasting experience in CHP projects.

In the 4 to 15MW gas turbine market, Siemens CHP projects date back as far as 1954 with

the Bank of England as a customer in the United Kingdom. Meanwhile 458 units have been

installed by Siemens within this market segment for CHP applications. Within the presently

offered gas turbine range, the Tornado rated at 6.75 MW was the first to become involved in

CHP in 1981, when a food factory in the Netherlands needed heat and power to operate its

facilities. Consequently the Typhoon rated at 4.35 MW was introduced in 1989 to CHP for a

pulp & paper mill in the United Kingdom. This was followed by the Tempest turbine rated at

7.9 MW in 1996, when a ceramics and textiles plant in Turkey needed CHP. Finally the

Cyclone turbine was introduced to CHP in 2000.

Fig. 14 shows the lead Cyclone CHP site, the Bulwer Island refinery in Brisbane, Australia.

BP Refinery Bulwer Island was constructed by Amoco Australia in 1962, acquired by BP in

1984 and employs approximately 260 people. The refinery’s commercial products includes

diesel, jet fuel and fuel oil.


GT1 Package 22,051 HrsGT2 Package 22,166 Hrs

Bulwer Refinery: Cyclone Lead CHP Site

Fig. 14, Bulwer Island: Cyclone Lead CHP Site

In July 1998, Bulwer Island refinery launched the Queensland Clean Fuel Project to increase

Bulwer’s processing capacity from 73,000 to 88,000 barrels of crude oil a day and enable it to

16


produce environmentally friendly fuels with less than 50 parts per million of sulphur in its

diesel and petrol. The developer BIEP (Bulwer Island Energy Partnership) selected two

Cyclone gas turbine generating sets to provide power and heat for the cogeneration plant.

These are the world’s first operational Cyclone gas turbines and entered commercial service

in July 2000. To date 36 Cyclone gas turbines have been sold and more than 110.000

equivalent operating hours have been accumulated. Bulwer Island as the lead site has

accumulated over 22.000 hours. The cogeneration plant supplies 27 metric tons per hour of

steam or 55 MW of thermal energy and 32 MW of electricity to the refinery, with surplus

electricity exported to the Queensland grid. Prior to installing the cogeneration plant, the

refinery’s considerable energy needs were met by oil fired boilers for steam with all

electricity imported from the grid. The Cyclones operate on natural gas and incorporate a dry

low emissions combustion system to reduce NOx and CO levels to below 25ppmv. Provision

is also made for the injection of surplus steam into the turbine to provide power enhancement.

The cogen plant is Queensland’s cleanest and, at 75%, also the most efficient. It will help

reduce greenhouse gases in the State by 90,000 tonnes per year. An innovative CHP concept, implemented at the Papier und Kartonfabrik in Varel, north-

west Germany, is presented in Fig. 15.


Varel paper mill, Germany: Tempest CHP site

Fig. 15, Varel paper mill, Germany: Tempest CHP site

17


The paper mill manufactures quality cardboard and papers for corrugated board. It produces

350,000 tonnes of grey and brown board, laminated board, test liner and colour cover board.

The paper products are sold to France, Norway, Sweden and Austria. The paper mill uses

substantial amount of electricity and steam for production which are provided by its own on-

site cogeneration plant. The existing utility comprised of one conventional 60 ton steam

power unit feeding two steam turbines of 3 MW each and one System Hutter® combined gas

and steam unit generating 45 tonnes of steam and 10 MW of electrical power. The patented

combined cycle system developed by Friedrich Hutter GmbH Consulting Engineers was

commissioned in 1989 and has been operating for more than 120,000 hours at a reliability

rate of 99.5 %.

In view of further expansion of paper production and quality improvement, the paper mill

decided on a second combined cycle System HUTTER and retrofitted the existing 60 tonnes

radiation type boiler. The decision was based on a feasibility study, showing superior results

of internal rate of return comparing with all other technologies.

The new combined gas and steam cogeneration scheme consists of a Tempest gas turbine

generating set, a waste heat boiler and a steam turbine. The boiler is a radiation type boiler

uprated to 70 bars, 470 °C with a steam rate of 65 tons per hour and the steam turbine has a

power output of 8.8 MW. The upstream arranged Tempest gas turbine contributes to the

overall power output. The gas turbine’s exhaust gas has an oxygen content of 15% volume

and feeds into the main power burner of the radiation type boiler. The firing rate of the main

burner is 38 MW and the heat content of the gas turbine’s exhaust gas contributes one third of

the boiler’s input demand for generating superheated steam. This is the first Tempest gas

turbine sold in Germany and also represents the 50th Tempest to be sold worldwide.

With a fuel utilization of 93%, this CHP system allows Papier und Kartonfabrik to have a

continuous production process at highest efficiency and also contribute environmentally by

reducing CO2 emissions. The utility operates continuously, connected to the remote

monitoring system EDEN (Electronic Data Exchange Network) for diagnostics within a

Siemens service center. As of August 2003, the gas turbine has logged 1685 hours and 136

starts.

In the 15 to 50 MW gas turbine market, application of Siemens gas turbines in CHP date back

to 1984 with a GT10 gas turbine installed in a cogeneration plant at Runcorn, Great Britain.

Complete CHP plants have been delivered since 1991 based on the KA10 reference design.

Fig. 16 gives an overview, how installed plants are regionally distributed. With a focus on

18


Europe, projects with gas only or dual fuel supply have also been implemented in the Middle

East and Asia. As of today, plant design experience comprises 37 CHP or combined cycle

(CC) projects. Whereas the GT35, rated at 17 MW has once been selected for CHP projects,

the GT10/10B rated at 24.8 MW is the workhorse with 26 CHP plant applications. The

GT10C engine rated at 29.1MW has just recently been introduced to the market with 5 units

sold to date.


GT10 CHP/CCPP Worldwide References

Ängelholm 1xDHKarlskoga 1xDHLund 1xCGLinköping 1xDH

Den Bosch 1xCEHelmond 1xCEEerbeek 2xCEBorculo 2xCEBergen op Zoom 1xCETer Apelkanaal 1xBErica 2xDHKlazienaveen 2xDH

Lausanne 1xDH

Dessau 1xDHGera 2xDHRostock 3xDHPotsdam 2xDHNeubrandenburg 2xDHFrankfurt Oder 2xDHBonn 1xCG

Electrostal 1xCG

Maricogen 1xB

Soporcel 2xB

Borsodchem 1xCG

Titan, Pasir Gudang 2xCGTitan, Tanjung Langsat 1xC

Gaza 2xC

B: Backpressure STC: Condensing STCE: Extraction STCG: CogenerationDH: District Heating

Fig. 16, GT10 CHP/CCPP Worlwide References

Of special interest is the largest and most efficient Siemens unit in this market segment, the

GTX100 rated at 43 MW, which was first applied to CC power generation in 1998. As shown

in Fig. 17, to date 22 units have been sold with 11 units in CC and 10 units in CHP

applications. Approximately 50.000 operating hours have been accumulated.

The lead site with the first GTX100 installed is the Västhamn plant, located in Helsingborg, a

city of around 115.000 people in the south of Sweden. The owner, Öresundskraft, a

municipally-owned energy utility in Helsingborg, serves more than 1700 commercial

buildings and 5500 homes with electricity, district heating/cooling, supply of natural gas and

communication services within Helsingborg and also sells electricity within Sweden and

Denmark.

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GTX100 CHP/CCPP Worldwide References

Helsingborg 1xDH

Arjo Wiggins 1xCOGEmin Leydier 1xCOGCerestar 1xCOG

Gendorf 1xCOGHöchst 1xCOG Sandreuth 2xCOGWurzburg 1xCOG

Solvay 1xCOG

Michelin 1xCEBlackburn 1xCE

MMPA 1xSCRedding 1xCOGVernon 2xC

Moscow 4xDH

Riga 2xDH

B: Backpressure STC: Condensing STCE: Extraction STCG: CogenerationDH: District Heating

Fig. 17, GTX100 CHP/CCPP Worlwide References

The plant consisted originally of a 220 MW boiler supplying 78.5 kg/s of steam at 110 bar/

538C to a single-casing, axial-flow steam turbine, rated 64 MWe (electrical). The steam

turbine exhausted into two-stage district heating condensers supplying 132 MWt (thermal) to

the district-heating network. When the plant opened in 1983, it was fired by coal (main fuel)

and oil (backup fuel) to stabilize combustion at low loads. However, wood pellets have been

used increasingly in recent years, accounting for more than half the fuel used during the latest

years.

The key objectives of the extension project were, to

1. increase the output of the plant, primarily in electrical but also thermal output, minimizing

investment cost,

2. increase plant electrical and total efficiency,

3. significantly reduce emissions,

4. maintain availabiltiy and fuel flexibility of the existing plant.

The resulting optimum concept was to extend the plant with a dual fuel GTX100 gas turbine

and a heat recovery steam generator, while retrofitting the steam turbine for higher mass

flows.

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As a result, the extended retrofit CHP plant as presented in Fig. 18, had electrical output

almost doubled from 64 to 126 MW, whereas thermal output was merely increased from

132MWt to 186MWt. Electrical efficiency increased from 30 to 38.5% and total plant

efficiency for 90 to 96%. NOx emissions were signifcantly reduced from 800 to 300

ktons/year, and CO2 emissions for 350 to 200 ktons/year.


Västhamn plant: GTX100 CHP retrofit site

DH supply

DH return

MWe tot = 126MWth tot = 186Alfa = 0.67% el. efficiency = 38.5% tot. efficiency = 96

HelsingborgGTX 100

Fig. 18, Västhamn plant: GTX100 CHP retrofit site

Within the Siemens gas turbine product range, the 50-70MW market segment is covered by

the V64.3A gas turbine. In 1994, Siemens Power Generation (PG) launched the advanced

V64.3A based on a scale-down approach from the V84.3A/V94.3A. The goal was to reduce

the specific kW-price of the engine by improving the turbine output and implementing

design-to-cost measures based on the proven V64.3 design, while leaving as many

components as possible left unchanged. The gas turbine, rated at 67.5 MW gross electrical

output and 34.8% gross electrical efficiency, was especially designed for application in mid-

size CHP and combined-cycle (CC) plants, allowing base load as well as cycling duty (daily

start-stop) operation. It can be synchronized to both 50 and 60 Hz grids using a reduction

gearbox. Design and factory full load testing was completed in 1998. Meanwhile, as shown in

Fig. 19, with the first unit in operation in 1999, 13 V64.3A turbines have been sold to operate

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in ten power plants for 50 and 60 Hz grids worldwide. It has logged over 150.000 operating

hours mainly in cogeneration, but also combined cycle applications.


V64.3A CHP/CCPP Worldwide References

CHP/CCPPCHP/CCPP

Norhtern IrelandBallylumford / 2002

GermanyAltbach HKW 2 / 1999Hannover Linden 3 / 2000Lausward GuD / 2000

Dominican RepublicSan Pedro de Macoris 1 / 2001San Pedro de Macoris 2 / 2001San Pedro de Macoris 3 / 2002

Czech RepublicBRNO Cervený Mlýn / 1999

CIS-RussiaTjumen / 2004

PolandRzeszow / 2003

ItalyTerni / 2000

GhanaEffasu 1 / 2000Efasu 2 / 2000

Fig. 19, V64.3A CHP/CCPP Worlwide References

The lead site for first CHP application of the V64.3A is the Altbach-Deizisau plant located in

Altbach, Germany. In 1993, Neckarwerke Elektrizitätswerke AG, Germany, ordered the first

commercial V64.3A gas turbine, a steam turbine and I&C equipment for implementation in a

new 420-MW cogeneration plant called HKW 2, replacing three 35-year-old steam turbine

units in the existing Altbach-Deizisau plant. As shown in Fig. 20, in the parallel-fired

combined cycle, steam for the 350 MW supercritical steam turbine is generated by a once-

through coal-fired boiler and a heat recovery steam generator. The V64.3A gas turbine

operating on natural gas, exhausts into the unfired HRSG, which is connected in parallel to

the steam cycle for supplementary steam generation in order to improve overall efficiency.

Both steam generators are of the Benson-type once-through design. The GT and the ST can

be operated independently, resulting in high flexibility. The gas turbine is operating in a

daily start-stop cycle with only few operating hours a day. The new plant was commissioned

in 1997 and in operation 1999.

22



Altbach-Deizisau Unit 2:V64.3A Parallel-powered CHP Plant

Maximum possible heat extraction 280 MW

G~

Station efficiency

G~

~ 90°C

Heat-recoverysteamgenerator

A1

A2 - A3

A5 - A7

A4

540°C59 bar25.3 kg/s

565°C560°C

CoalAir

GT

Air Fuel gas

64.8 MW

540°C239 bar247 kg/s District heat

(max. 280 MW)

347.1 MW

0.071 bar

Hybrid-coolingtower

Parallel-powered combined-cycle operation

Steam generator(alone)

Gas turbine(alone)

50

45

40

35

30

25

20

150 100 200 300 400

Net output in MW

Fig. 20, Altbach-Deizisau Unit 2: Parallel-powered CHP Plant

The largest V64.3A turnkey project built to date is the combined cycle facility San Pedro de

Macoris, located in the Dominican Republic. Siemens PG built the state-of-the-art 300 MW

CCPP San Pedro de Macorís power plant in the Dominican Republic for CESPM, a

consortium consisting of Cogentrix USA and CDC England. The project was executed on the

basis of a turnkey EPC contract, which became effective in April 2000 after financial close

and construction started in May 2000. The project site is located approximately 65 km east of

the capital city of Santo Domingo.

As shown in Fig. 21 the plant consists of three nominal 100-MW GUD® 1S.V64.3A blocks.

Each module is equipped with a V64.3A gas turbine, an air-cooled generator, a single-

casing/axial exhaust industrial-type steam turbine and gearbox aligned on a single shaft. A

duct-fired, dual-pressure, non-reheat HRSG converts the exhaust energy of the gas turbines to

live steam for the steam turbines. The condenser is cooled by a forced-draft, cell-type cooling

tower. The plant is operated exclusively on #2 fuel oil for the first few years. Due to the

choice of #2 fuel oil, water injection is necessary to reduce NOx emissions. Once natural gas

(LNG) becomes available on the island, the engines will be converted to dual-fuel operation.

Using a configuration with three identical blocks allows a reduction of redundancies for the

main pumps in the feed and condensate system. This consequently reduces capital costs and

maintenance efforts. Under the given ambient conditions with fuel oil and water injection, the

plant achieves an output of 3x 99.2 MW and 48.2% net efficiency

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The first concrete was poured in late June 2000. Erection of the steel structure commenced in

October 2000. The first turbine building was finished in December 2000 and ready for the

start of electro-mechanical erection in January 2001. The first heavy load-transport for Unit

10 with gas turbine, gearbox, generator, steam turbine, condenser, lube oil tank, transformers

and three Power Control Centers (PCC) arrived at the site on January 11, 2001. After a

construction period of only 15 months, the first unit went into commissioning and was handed

over to the client on November 19, 2001. Unit 2 followed in December 2001 and Unit 3 in

January 2002, five weeks ahead of schedule. Cogentrix de La República Dominicana was

formed to operate and maintain the facility with a staff of 31 employees (two expatriates and

29 Dominicans).


San Pedro, Dominican Republic:3xV64.3A turnkey CCPP site

3 x 100 MW el, Single Shaft3 x V64.3A, ST Condensing 38 MWCommercial Operation 2001

3 x 100 MW el, Single Shaft3 x V64.3A, ST Condensing 38 MWCommercial Operation 2001

Fig. 21, San Pedro, Dominican Republic: 3xV64.3A turnkey CCPP site

Conclusion

Future outlook for CPH plant applications is positive. Despite current market uncertainties,

long-term demand for highly efficient, low emissions CHP solutions will grow. Customer

requirements for low capital and life cycle costs, high reliability, short delivery time, and site

customization can be met by available technologies. Optimized CHP concepts exist for a

wide variety of applications ranging from low cost cogeneration plants, highly efficient

district heating plants, steam extraction concepts tailored for industrial processes, to parallel

gas turbine and fired boiler plants for ultimate flexibility. Concepts for fuel utilization of

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around 90% and power to heat ratios between 0.3 and 2.1 have been presented. Plant power

outputs may vary from 4MW to 100MW based on single Siemens industrial gas turbines.

Reference power plant designs have been developed for single and multishaft applications,

optimizing standardization and design flexibility. To build up a sustainable and profitable

competitive advantage in the future, CHP plant providers will have to offer product based

rather than merely project specific plant solutions.

Acknowledgements

This paper would not have been possible without the contribution in particular of the

following individuals: Jan Wikner, Siemens Power Generation, Finspong, Sweden, Mike

Welch, Siemens Power Generation, Lincoln, UK, Geraldine Roy, Siemens Power Generation,

Lincoln UK, Rob Barnes, Siemens Power Generation, Lincoln, UK, Harald Dichtl, Siemens

Power Generation, Erlangen, Willibald Fischer, Siemens Power Generation, Erlangen, Klaus

Huettenhofer, Siemens Power Generation, Erlangen

References

- K. Huettenhofer/ A. Lezuo, Cogeneration Power Plant Concepts, VGB Kongress 2000

- J. Wikner, Conceptual review of different GT-cycles and their abilities concerning

electrical efficiency, total efficiency and power/heat ratio, Dresden 2002

- W. Fischer, Turnkey CCPP and CHP Solutions based on Siemens’ V64.3A Gas Turbine,

PowerGen Europe, 2003

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