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ECHAINE Résumé de rapport

Project ID: ENK5-CT-2002-00623
Financé au titre de: FP5-EESD
Pays: Greece

WP(5) Heat and power production technologies

There are several EU Directives supporting biomass based cogeneration: COM(97) 599; COM(2000) 769; Directive 2001/77/EC; Directive 2002/91/EU; Directive 2003/96/EU; Directive 2004/8/EC; SEC(2004) 547; COM (2004) 366.

There are also many climate-related initiatives since 1991, e.g. the first Community strategy to limit carbon dioxide (CO2) emissions and improve energy efficiency.

The second European Climate Change Programme was launched in 2005: COM(2000) 87; Directive 2003/87/EC; By the end of 2002, a large number of countries had ratified the Kyoto Protocol.

Combined heat and power production based on a steam turbine is of growing importance for small-scale applications. However, the lower limit for CHP plants is a nominal boiler capacity of about 5MWth due to the lower efficiency and the economy of scale.

Wood CHP units bigger than 100MWth are not suitable due to fuel supply uncertainty. Interesting technologies which are now under development are Stirling engines, hot air turbines, and Organic Rankine Cycles (ORC). The essential requirements for the selection of an appropriate CHP system are a high electrical efficiency and a well-tested technology.

Production cost for electricity varies between 15-30 Euro per MWh for a large scale production system:
- 60MWe and 120MWt, coal, wood and peat,
- 120MWe and 120MWt, natural gas, combi-cycle).

Corresponding figures for a small scale system are between 32 - 40 Euro per MWh based on the following aspects:
- Natural gas motor 5MWe and 6MWt,
- Wood and wood/peat 2MWe and 6MWt.

For both examples it is assumed that the heat price is 20 Euro per MWh. Fuel prices are the following: Natural gas: 13,5 Euro, Coal: 5,4 Euro, Wood: 10,0 Euro and Peat: 7,6 Euro per MWh. Capital cost for a biofuel boiler in effect range 2-50 MW is 650-325 Euro per MW. Corresponding figure for a pellet boiler in effect range (0.2-1 MW) is 600-250 Euro per MW. Capital cost to electricity varies between 1800 Euro per kWh to 5000 Euro per kWh within the range 1 to 20 MWe.

Key innovative results:
Drivers: Environmental benefits: Lower emissions than separate heat and centralized systems; Lower fossil energy consumption; Other benefits are, e.g. improved profitability, and reduced load on the grid. Barriers: There are technical, economic, market, institutional, political and legislative hindrances. Also there are social and environmental barriers.

Current status:
Traditionally wood has been used as fuel in grate or stoker type boilers. During the last decades fluidized-bed combustion has also been applied. The fluidized-bed technology offers a potential for high fuel flexibility and reduction of pollutants.

Grate and stoker type boilers are still used today when very problematic fuels are applied, or when the boiler units are small. Gasification technology seems to be mature enough to achieve commercialization status.

The main reason for considering gasification is that wood is converted into the more attractive process of burning gas fuel. In the small sized units woodgas is mostly used in a combustion engine whereas in larger units in a gas turbine or combined cycle plant.

Use potential:
On large scale applications, the operation of the Värnamo plant in Sweden, as well as the operation of the ARBRE plant in UK will be a serious step towards full commercialization of the IGCC technology. Co-firing of wood with fossil fuels in traditional thermal power plants is becoming increasingly popular.

As an alternative to conventional steam plants in the range 0.5 to 2MW, Organic Rankine Cycles (ORC) using a thermal oil boiler is also available. For small-scale wood power production, the externally fired Stirling engine technology is expected to enable economic power production in the future.

Expected benefits:
Biomass based CHP have lower emissions than separate heat and centralized power systems. Decreases fossil energy use. Reduces NOx, SO2 and CO2 emissions into the atmosphere. Other benefits are, e.g. improved profitability for local companies, environmentally friendly technique, and reducing the load on the grid through distributed generation.

There are several calculation models available for CHP modelling: Techno- economic, Supply, Hybrid models, Economic, Cost of Energy Calculator, Optimization, Taxation, and Adoption and diffusion. In addition there are several support tools available for CHP planning: Decision support, A check list for basic actions, SWOT analysis, Spatial decision support and Decision support for emission trading planning.

Dissemination of the results have been carried out by 1) Using Echaine web-page, 2) Presentations at two by Echaine organised international workshops (Bulgaria and Russia), 3) Presentations at national and international seminars and workshops, 4) Scientific papers.

Informations connexes


Geeorge SKODRAS, (Head of unit)
Tél.: +30-2310-996225
Fax: +30-2310-996168