Using six stress factors for the categorisation process and indexing them according to their intensity makes it easy to assign a RES to a certain category using very simple software. The intensity level for each stress factor has to be given as input and the correct category will be assigned. This, obviously, is a much simpler process than matching a number of time series as regards their similarity. The automatic assignment of a RES to a category is not only possible for RES for which measurements exist, but also for planned RES for which only limited data or the results of simulation software with a sufficient level of detail and time resolution exist.

For each category, recommendations will be given which describe design options, operating strategies and criteria for selecting the most appropriate product for a specific category. The most appropriate product is characterised by the most economic lifetime which, in most cases, is likely to be equivalent to the longest lifetime. Lifetime tests are therefore required, however, some existing lifetime tests for which there are readily available test results have only limited relevance to any of the six categories described above. It is therefore necessary to define those test procedures, which have the highest importance as regards RES, and rank them in their relative importance. Some of the most suitable test procedures are those investigated as part of the Qualibat project /7/.

Conclusions

The results of the project show that it is possible to evaluate measured data of existing RES or simulation data of planned RES automatically and generate detailed recommendations which take the conditions of use into account.

The results of the project will be freely accessible to the international business, technical and scientific community.

• Manufacturers will receive information on the performance requirements that their products have to fulfil for certain categories of use and how best to test them.

• Users and planners of renewable energy system will gain access to a software which will help them to identify the category of use which is most closely related to their own specific installation. They will also obtain recommendations on a wide range of topics, in particular how to select the most suitable components for their application.

Acknowledgement:

The work presented here is the result of the project Benchmarking1".

t „Benchmarking — Development of test procedures for benchmarking components in renewable energy systems applications, in particular energy storage systems". A project carried out by nine major European Research Centres, the Australian Cooperative Research Centre for Renewable Energy and the National Renewable Energy Laboratory in the USA. The project is supported by the EU under the 5lh Framework Programme (ENK6-CT-80576).

Literature

/1/ Standard Evaluation Report; Public deliverable of the Benchmarking project,

deliverable D1.2a by Adolfo Perujo, Joint Resserach Centre Renewable Energy Unit, ISPRA, available at www. benchmarking. eu. org/Publications/Publications. htm or any of the Benchmarking project participants.

/2/ Specification of Minimal Requirement of Measurement Procedures; Public deliverabe of the Benchmarking project, deliverable D1.1 by Ian Baring-Gould, Nationa Renewable Energy Laboratory, USA, available at

www. benchmarking. eu. org/Publications/Publications. htm or any of the Benchmarking project participants.

/3/ ThEsA (Technical Hybrid Energy System Analysis); Public deliverable of the Benchmarking project, deliverable D1.2 by Fraunhofer Institute for Solar Energy Systems, available at www. solar-monitoring. de/ithesa/ Password and Username ITHESA

/4/ Sauer D.-U., Bachler M., Bopp G., Hohe W., Mittermeier J., Sprau P., Willer B., Wollny M.: What happens to batteries in PV-systems? Costs, lifetime, Strains; Paper presented at LaBAT 96, Varna, Bulgaria, 1996

/5/ Categorisation of batteries in RES applications; Public deliverable of the Benchmarking project, deliverable D2 by Vojtech Svoboda, Zentrum fur Solartechnik und Wasserstoffforschung, Ulm, available at

www. benchmarking. eu. org/Publications/Publications. htm or any of the Benchmarking project participants.

/6/ Svoboda V.: The influence of fast charging on the performance of VRLA batteries;

Ph. D. dissertation thesis, Brno University of Technology, 2002

/7/ Qualibat, Investigations for a Quicker Assessment of Liefetime and other key

characteristics of photovoltaic BATteries; Publishable final report by GENEC, project funded in part by the European commission in the framework of the Non-Nuclear Emergy Programme JOuLe III, contract no. JOE3-CT97-0161