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COGENchallenge - European Campaign for the Development and Documentation of 1000 Small-scale Cogeneration Projects in European Cities and Towns

cogeneration technologyPick the right

A technology checklist of small-scale cogenerationJuly 2006

Table of contents

Choose your technology ....................... 2

Gas turbine............................................ 3

Gas engine............................................ 4

Heating oil engine ................................. 5

Biogas engine ....................................... 6

Steam turbine........................................ 7

Stirling engine ....................................... 8

Fuel cell................................................. 9

COGENchallenge Facilitators ............. 10

Who we are ......................................... 11

1

Choose your technology You can produce heat and electricity together with different technologies: you just recover heat from the traditional electricity production unit. As the heat must be used close to the consumer, the cogeneration units needs to be approximately sized to the size of the consumer.

The range of the available technologies is quite wide. You will choose your cogeneration technology according some criteria, specific to your activity and your heat demand. The table below lists the technologies: "++" means the technology is very suitable to produce the heat you need, and "+" means less suitable. No quotation means the technology can not produce the type of heat you need, such as the Stirling engine or the fuel cell which cannot (yet) produce steam.

Cogeneration technologies

Fuels (not exhaustive) You need hot water?

You need steam?

You need hot air?

Gas turbine Natural gas, biogas, heating oil ++ ++ ++

Gas Engine Natural gas, biogas, heating oil, vegetable oil, wood ++ + +

Heating oil Engine

Natural gas, biogas, heating oil, vegetable oil, wood ++ + +

Steam turbine Natural gas, biogas, heating oil, vegetable oil, wood, etc. ++ ++ +

Stirling engine Natural gas, biogas, heating oil, wood ++

Fuel cell Hydrogen or, via reforming, all others fuels ++

2

Gas turbine

Gas turbines have become the most widely used prime mover for large-scale cogeneration in recent years. Gas turbines are not only used in large-scale applications. Smaller units, starting at around 400 kWe are available on the market. Since the late 1990s microturbines have become available. They are derived from automotive turbo-chargers and are available from 30 kWe. Microturbines use less space than conventional engines and maintenance costs are lower. Moreover, the emission of pollutant gases is reduced, especially those gases that cause acid rain and ozone layer depletion. Electrical efficiencies are typically lower than in internal combustion engines.

Smallest unit Typical small-scale unit

Electrical power: 28 kWe 250 kWe

Electrical efficiency: 26% 30%

Thermal power: 52 kWth 330 kWth

Thermal efficiency: 47% 40%

NOx emission: < 9 ppmV < 9 ppmV

CO emission: < 10 ppmV < 9 ppmV

Size (L x W x H): 1.3 x 0.7 x 1.9 m 4 x 2.2 x 2.3 m

Weight: 0.5 tons 235 tons

Investment: 2 500 € /kWe 1 500 € /kWe

Heat recoveryboiler

Exhaust gas

Water feeding

Steam Steam consumption

Post-combustion(eventualy)

Natural gas

Natural gas

Burning

Gas turbine

Gas turbineGenerator

AirFilter

Heat recoveryboiler

Exhaust gas

Water feeding

Steam Steam consumption

Post-combustion(eventualy)

Natural gas

Natural gas

Burning

Gas turbine

Gas turbineGenerator

AirFilter

3

Gas engine Most small-scale cogeneration units are internal combustion engines operating on the same familiar principles as their petrol and diesel automotive counterparts. Engines run with liquid or gaseous fuels, such as heating oil, natural gas or biogas, and are available from 5 kWe to more than 1,000 kWe. Internal combustion engines have a higher electrical efficiency than turbines, but the thermal energy they produce is generally at lower temperatures and so they are highly suited to buildings applications. The usable heat to power ratio is normally in the range 1:1 to 2:1.






NOx emission: 350 mg/Nm3 250 mg/Nm3

CO emission: 300 mg/Nm3 300 mg/Nm3

Size (L x W x H): 1 x 0.7 x 1 m 3.5 x 1.8 x 2.2 m


Investment: 3 000 € /kWe 800 € /kWe

Heat recoveryboiler

Exhaust gas

Water feeding

Hot water and/or steam consumption

Engine Gas or heating oilor biogas engine

Heat exchanger

Generator

Fuel

Exhaust gas

Cooling water

Heat recoveryboiler

Exhaust gas

Water feeding

Hot water and/or steam consumption

Engine Gas or heating oilor biogas engine

Heat exchanger

Generator

Fuel

Exhaust gas

Cooling water

4

Heating oil engine

When natural gas or biogas is not available, you can choose an heating oil engine.


Electrical power: 5.3 kWe 250 kWe


Thermal power: 10.5 kWth 314 kWth


NOx emission: 2 150 mg/Nm3 250 mg/Nm3


Size (L x W x H): 1 x 0.7 x 1 m 3.2 x 1.5 x 2.2 m



Source: 5 kWé heating oil engine in a Municipality house (Amel - Belgium)

5

Biogas engine When biogas is available, you can choose a biogas engine.







CO emission: 1 000 mg/Nm3 650 mg/Nm3

Size (L x W x H): 1.8 x 0.8 x 1 m 3.5 x 1.6 x 2.3 m



Source: 1.25 MWé biogas engine in a Food Industry Lutosa (Electrabel – Belgium)

Source: 102 kWé biogas engine in a small village (La Surizée - Belgium)

6

Steam turbine

Steam turbines have been used as prime movers for large-scale cogeneration systems for many years. Typically, steam turbines are associated with larger power stations but also smaller units starting with 200 kWe are frequently used. The overall efficiency generally is very high, achieving up to 84%. Steam turbines run with solid, liquid or gaseous fuels, both fossil and renewable. The typical heat to power ratio of steam turbines is around 6:1.

Typical small-scale unit

Electrical power: 500 kWe

Electrical efficiency: 10%

Thermal power: 3,000 kWth

Thermal efficiency: 70%

NOx emission:

CO emission:

Size (L x W x H):

Weight:

Investment:

depending on the boiler

High pressure boiler

Exhaust gas

Water feeding

Low pressure steam

Steam consumption

Fuel

Steam turbine

GeneratorHigh pressure steam

Steam turbineHigh pressure boiler

Exhaust gas

Water feeding

Low pressure steam

Steam consumption

Fuel

Steam turbine

GeneratorHigh pressure steam

Steam turbine

7

Stirling engine

For very small-scale applications with a capacity between 0.2 kWe and 9 kWe, Stirling engines can be used. These engines are external combustion devices and therefore differ substantially from the conventional models. The Stirling engine has fewer moving parts than conventional engines, and no valves, tappets, fuel injectors or spark ignition systems. It is therefore quieter than normal engines. Stirling engines also require little maintenance and the emission of pollutants is low.


Electrical power: 1 kWe 7.5 kWe






Size (L x W x H): 0.5 x 0.6 x 0.85 m 1.3 x 0.7 x 1 m

Weight: 0.15 tons 0.46 tons

Investment: 6 000 € /kWe 2 600 € /kWe

Cooler

Heater

Expansion cylinder

Expansion piston

Generator

Regenerator

Cooling water

Compressioncylinder

Compressionpiston

Cooler

Heater

Expansion cylinder

Expansion piston

Generator

Regenerator

Cooling water

Compressioncylinder

Compressionpiston

SOLO 161

Note this is new technology as the investment costs are still falling.

8

Fuel cell A new development is the use of fuel cells for cogeneration. It needs to be said, however, that fuel cells are not yet commercially available. Fuel cells convert the chemical energy of hydrogen and oxygen directly into electricity without combustion and mechanical work such as in turbines or engines. The hydrogen is usually produced from natural gas by a process known as reforming. The total efficiencies of cogeneration systems reach 85 to 90%, while the heat to power ratio is in the range 5:4 and tends towards 1:1. Fuel cells with a capacity of 1 kWe provide heat and power to single family houses, whereas bigger applications of around 200 kWe can be used in hospitals for example.


Electrical power range: 1 kWe 200 kWe


Thermal power range: 1.2 kWth 217 kWth


NOx emission: < 2 ppmV (if natural gas) < 1 ppmV (if natural gas)

CO emission: < 2 ppmV (if natural gas) < 2 ppmV (if natural gas)

Size (L x W x H): 0.9 x 0.9 x 1.8 m 5.4 x 3 x 3 m


Investment: up to 100 000 € /kWe up to 5 000 € /kWe

E L E C T R O L Y T E

E X H A U S T Source: Fuel Cell Hand

Note this is new technology as the investment costs are still falling.

9

COGENchallenge Facilitators

GERMANY:

Paul Fay Stadt Frankfurt am Main - Energiereferat Galvanistraße 28 D- 60486 Frankfurt am Main (Germany) Tel: +49 69 212 39199 Fax: +49 69 212 39472 Email: [email protected]

FRANCE:

Reinhard Six Rhônalpénergie Environnement (RAEE) 10 rue des Archers FR-69002 Lyon (France) Tel: +33 4 78 37 29 14 Fax: +33 4 78 37 64 91 Email: [email protected]

BELGIUM:

Ismaël Daoud Cogeneration Facilitator for Wallonie COGENSUD asbl Bd Frère Orsban, 4 B-5000 Namur (Belgium) Tel: +32 81 250 480 Fax: +32 81 250 490 Email: [email protected]

AUSTRIA:

Jan Bleyl Grazer Energieagentur Kaiserfeldgasse 13/I A-8010 Graz (Austria) Tel: +43 316 811 848-20 Fax: +43 316 811 848-9 Email: [email protected]

SPAIN:

Carlos García Fundación Asturiana de la Energía (FAEN) Área de Relaciones Externas C/ Fray Paulino, s/n E-33600 Mieres (Spain) Tel: +34 985 46 71 80 Fax: +34 985 45 38 88 Email: [email protected]

SLOVENIA:

Stane Merse "Jozef Stefan" Institute - Energy Efficiency Centre Jamova 39 SI - 1000 Ljubljana (Slovenia) Tel: +386 1 5885 250 or 210 Fax: +386 1 5885 377 Email: [email protected]

10

mailto:[email protected]






Who we are

11

pick the right - grazer energieagentur: news · gas turbines are not only used in large-scale...

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