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An Introduction to Gas Turbines &Microturbines for DE Applications

World Energy Technologies Summit10 11 February 2004

Michael BrownDirector

World Alliance for Decentralized Energy (WADE)michael.brown@localpower.org

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Electricity production at the point of use, irrespective ofsize, fuel or technology:

High efficiency cogeneration / combined heat andpower (CHP)

Simultaneous production of useful power and heat fromsingle fuel source

The most efficient use of any fuel

Based on gas turbines, microturbines, engines, steam

turbines, etc On-site renewable energy

On-grid and off-grid

What is Decentralized Energy (DE)?

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Concept envisualised at beginning of 20th Century

First Industrial Gas Turbine built in 1931 by Brown Boveri

In late 1930s focus shifted to aircraft propulsion

Industrial Gas Turbine development continued afterWorld War II

Robust

Compact

Ability to operate on gas fuels

No external coolant required

Size range now 1100+ MWe

Origins of the Gas Turbine

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The Basic Conceptsimple cycle

EXHAUST

GAS

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Typical Cogeneration System

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Typical Industrial Cogeneration System

AIR INLETFILTERAIR INLETFILTER

GASTURBINEGASTURBINE

EXHAUSTBYPASSSILENCER

EXHAUSTBYPASSSILENCER

GENERATORGENERATOR

DIVERTERVALVEDIVERTERVALVE

SUPPLE-MENTARYBURNER

SUPPLE-MENTARYBURNER

HEATRECOVERYSTEAMGENERATOR(HRSG)

HEATRECOVERYSTEAMGENERATOR(HRSG)

EXHAUSTSILENCEREXHAUSTSILENCER

PROCESSSTEAMPROCESSSTEAM

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Gas Turbine Cogeneration Plant

Pulp and PaperPulp and PaperPulp and PaperPulp and Paper

Solar Turbines

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Gas Turbine Cogeneration Plant

HospitalsHospitalsHospitalsHospitals

Solar Turbines

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Power output and efficiency can be improved by:

Increasing the Firing Temperature

Greater effect on power output but required:

New Materials

Thermal Barrier Coatings

Cooling of hot section components

Increasing the Pressure Ratio

Greater effect on efficiency but required:

New materials Improved Aerodynamics

Principles for Performance Improvement

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Market Pressures for :

Lower Emissions

Water or Steam Injection

Dry Low Emissions Combustion

Fuel Flexibility New combustion and fuel systems

New coatings

Improved Reliability & Availability

Longer Component Lives

Intelligent Control Systems

Condition Monitoring

Required Developments

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Market Pressures for : Improved Efficiency

Improved individual component efficiencies

Tighter tolerances, improved aerodynamics

More complicated to manufacture

Higher Firing Temperatures

More exotic materials

Reaching firing temperature limits effectiveness of DLE

Reduced Costs Increased Power Density

Higher firing temperatures & new component designs More compact turbomachinery with lower component costs

More highly loaded components

Required Developments

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Improvements in design have led to: Reduced size

13MW gas turbine now needs same package space as a6.5MW gas turbine of 1980

Improved Efficiencies 35% electrical efficiency compared to 30% in 1980

Reduced Emissions

Single digit NOx possible on natural gas

Further improvements possible, but incremental

The Results of Technology Development

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For step change improvements, move to ComplexCycle technologies: Combined Cycle

Recuperated

Intercooled Recuperated Integration with high temperature Fuel Cells

Solid Oxide or Molten Carbonate

Reheat

Cheng Cycle

Wet Cycles

Humid Air Turbine (HAT) Cycles

Future Possibilities

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Combined Cycle (Brayton & Rankine Cycles)

GAS TURBINE STEAM TURBINE

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Uses GT exhaust gases to produce steam for SteamTurbine generator

Approximately 40 - 50% additional power

13MW gas turbine gives c.18.5MW in CCGT configuration

Approximately 15 - 20% points increase in fuel efficiency 13MW GT of 35% electrical efficiency gives 50% efficient CCGT

Increased Capital Costs

High pressure HRSG, Steam Turbine etc.

Increased Space Requirements

Combined Cycle

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Recuperation

Uses exhaust gases to preheat combustion air

Improves efficiency for same mass flow, but slight power reduction

Intercooling

Reduces the work required to compress air Increases power output for same mass flow but no efficiency gains

When combined with recuperation (ICR), improves efficiency too

Rolls Royce WR21

Simple Cycle 13MW 35% efficiency

Recuperated 12MW 40% efficiency ICR 15MW 45% efficiency

Recuperation and Intercooling

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Can integrate gas turbines with High Temperature FuelCells Fuel flexible

Increases power density of FC

Offers very high electrical efficiencies Concept designs and pilot plant

200kW pilot scheme from NKK/JFE, Japan with 2000 hrsexperience

300kW plant of 57% efficiency under construction in USA

< 1MW scheme from Siemens Westinghouse within 2 -3years

40MW concept based around WR21 ICR Gas Turbine

Combined Gas Turbine / Fuel Cell Derivatives

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Gas Turbine Cogeneration - Selection Criteria

Gas Turbine with

Cogeneration or STAC

2:1

Recip or Gas Turbinewith Low GradeHeat Recovery or STAC

STAC System orCombined-Cycle withBack Pressure orExtraction Steam Turbine

1:1

6:1 Process Heat-to-Power RatioStand AloneProcess Heat(Package Boiler)

P

ROCESSHEAT

,MWt

ELECTRIC LOAD, MWe

Gas Turbine with

Cogeneration or STAC

2:1

Recip or Gas Turbinewith Low GradeHeat Recovery or STAC

STAC System orCombined-Cycle withBack Pressure orExtraction Steam Turbine

1:1

STAC System orCombined-Cycle withBack Pressure orExtraction Steam Turbine

1:1

6:1 Process Heat-to-Power RatioStand AloneProcess Heat(Package Boiler)

6:1 Process Heat-to-Power RatioStand AloneProcess Heat(Package Boiler)

P

ROCESSHEAT

,MWt

ELECTRIC LOAD, MWe

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Direct Heating

Fluid Heating / Hot Water

Steam Production

Absorption Chilling

Preheated Combustion Air

Heat Recovery Methods

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Food Processing

Pharmaceutical

Pulp and Paper

Manufacturing Refinery

Hospitals

Universities

Industries using Gas Turbine Cogeneration

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Need for reliable electric and thermal Energy

Facility Heat to Electricity Ratio of 2:1

Electricity Price to Gas Price Ratio of 2:1

Continuous Operation

Cogeneration Economic Factors

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Simple Cycle designs are approaching their limits

Application flexible

Complex Cycles offer improved efficiencies and higherpower densities

More complicated designs

Danger of becoming application specific

Optimum component technologies may differ from simplecycle designs

Uncertain market conditions Will conditions allow commercialisation of new technologies ?

Gas Turbine Summary

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Small, high-speed generator power plants, 25200 kWe

One moving part

Primarily fuelled with natural gas; major biogas potential

Relatively low capital, O&M costs

Lower emissions than conventional reciprocating engines Several applications

Traditional cogeneration, hospitals etc

Generation using waste and biofuels

Backup power

Remote Power for those with Black Start capability

Peak Shaving.

Microturbines

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30-60 kW power output

Multi-fuel capability

High cogen efficiency

Low maintenance

Low emissions 2-to-100 unit multipacking

2,500 sold worldwide

>5 million operating hours

Microturbinesthe Capstone System

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Combustion

chamber

Exhaust output

Recuperator

Fuel injector

Air bearings

Compressor

Generator

Air intake

Cooling fins

Turbine

One moving part

No coolants or lubricants

Compact and lightweight

Deep Inside the Microturbine

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Non-profit organisation created June 2002

Mission To accelerate the deployment of DE systems worldwide

WADE is supported by: National Cogen/DE organisationsincluding COGEN

Portugal

Cogen/DE companies with international interests

Caterpillar, Capstone, Solar Turbines, FuelCell Energy,MTU, Marubeni, Primary Energy, Dalkia, Wartsila

UN agencies

National governments (eg US, Norway, Canada)

WADEKey Points

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WADE Network

In train

WADE Annual International Conferences

1st (Washington, 2000)

4th (Rio, 2003)

2nd (Amsterdam, 2001)

3rd (Delhi, 2002)

WADE Network of DE Promotional Organisations

5th (Beijing, 2004

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WADE action

Documenting DE development and barriers World Survey of Decentralized Energy 2004

National DE Surveys: China, Brazil

Promoting worldwide knowledge:

Cogeneration & On Site PowerJournal of international DEindustry

Annual International CHP & DE Conferences Washington(2000), Amsterdam (2001), Delhi (2002), Rio de Janeiro (2003),Beijing (2005).

Promoting DE with international agencies, eg WorldBank institutions and UN agencies

Building international network of DE organisations

Carbon credit development from DE