ECN publication
Warmte/Kracht, van kwantiteit naar kwaliteit.
Beeldman, M.
Published by: Publication date:
ECN Policy Studies 3-10-1994
ECN report number: Document type:
ECN-C--94-091 ECN publication
Number of pages: Full text:
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The number of installations for Combined Heat and Power production in the Netherlands has been growing rapidly since the early 1990’s and the rapid growth is expected to continue. Due to this growth a surplus capacity in electricity is about to be created. Because of this development the evaluation of new CHP-installations is tending from quantity-oriented towards quality-oriented. ECN policy studies has been asked to develop an instrument for the evaluation of Combined Heat anti Power projects. In this study the effects of Combined Heat and Power production are related to the effects of solitary electricity production and solitary heat production. The criteria used for evaluation are based on the criteria for the overall energy supply system: clean, reliable and cost-effective. The effects of different projects are compared to each other, based on a so-called ’measurement unit’. Traditionally the effects of Combined Heat and Power have been expressed in absolute terms or relative terms. Applying the ’measurement unit’ implies that the absolute effects of CHP are divided by this unit. The choice of which unit to use as ’measurement unit’ depends on the surroundings. The measurement unit is to represent the limiting factor. In the present situation of surplus of electric capacity the most likely measurement unit is MWe. Applying this method of evaluation to ten existing projects leads to general conclusions conceming characteristics that are important for the quality of Combined Heat and Power projects. The first characteristic is the load factor. Projects with higher load factors save more energy and show a larger reduction of CO2-emission. Policy instruments conceming variabilisation of tariffs make projects with high load factors more attractive. Furthermore evaluating with electri¢ capacity as measurement unit stresses the importance of high overall efficiencies of Combined Heat and Power projects. In a situation without electric surplus capacity optimization based on local heat demand should be performed. In this case high electric efficiencies and high power/heat ratios become attractive. However this situation is not tobe expected in the near future. It is also possible to use other measurement units like investment or non-dispatchable capacity. Using these measurement units leads to more or less the same conclusions as using electri¢ capacity. However in using measurement units it is important to realize whether the present measurement unit is still the limiting factor in the (heat) future. In chapter five sensitivity analyses are performed for both the project level (changes in project characteristics) and the surroundings (for example tariff structures). The evaluation of changes in project characteristics depends partly on the choice of measurement unit and thus, indirectly, to the limiting factor in the surroundings of CHP. Finally, all results show that the quality of Combined Heat and Power depends partly on the surroundings.

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