Environmental standards for solar thermal collectors and their absorber surfaces

Financial incentives such as the market incentive programme were important funding instruments for increasing the use of renewable energy sources and the market penetration of the corresponding technologies. However, such financial incentives and support mechanisms were subject to different national and, in particular, European framework conditions (e.g. EU environmental aid framework).

The German government's market incentive programme to promote measures for the use of renewable energy provided for annual reviews of the subsidy rates, technical requirements and environmental standards for these reasons, among others, but also for reasons of general target achievement and adaptation to current market developments. Against this background, the research project aimed to scientifically define advanced environmental standards for solar thermal collectors in line with current market developments.

The project began with a comprehensive market analysis of the current state of the art as well as current concepts and practices in distribution, installation, operation, maintenance and take-back. Based on this market research, the environmental impact was analysed using various indicators and initial requirements for demanding environmental standards were derived. These basic requirements were validated with the help of a scientific workshop and adapted where necessary.

The environmental impact of selective coatings on solar thermal absorber surfaces was analysed in greater depth. To this end, a comparative life cycle assessment of coating processes was carried out in accordance with DIN/ISO and the service life of the coatings was determined in accordance with TASK X of the IEA.

The results of these two in-depth analyses were then combined with the basic requirements and condensed into usable environmental standards. The ambitious environmental standards developed in this way were presented to and discussed with an expert audience at an industry workshop.

By updating demanding technical environmental standards, a scientific contribution was to be made to updating the conditions for financial support for solar thermal heat generation. This should enable statements to be made about the future eligibility of solar thermal systems for funding, taking into account the requirements of the European Commission's environmental aid framework.