With the completion of Task 7, the IEA-PVPS activity focused on PV use in the Built Environment, a number of reports summarizing the results of the group’s work has recently been published.

Building Integrated Photovoltaic Power Systems - Guidelines for economic evaluation
Robust economic analysis procedures are essential for fair evaluation of the long-term viability of capital-intensive BIPV systems.
This report (IEA-PVPS T7-05:2002) undertakes an assessment of common economic evaluation methodologies to identify those most appropriate to PV. In order to derive valid results, it is important that all costs and benefits attributable to the system are reflected in the economic model, so this study presents a broad range of cost and benefit parameters, providing international examples where possible. It includes consideration of environmental, educational and thermal benefits, benefits to utilities, effects of incentive programmes, power quality, metering, shading, security and multiple building functions, plus evaluation of the costs of the system related to components, installation, interconnection, regulations and maintenance. Given the diverse and rapidly developing market, the report does not give definitive costs and benefits, but instead reflects an extensive list of valuable data relevant for an economic analysis.

Market deployment strategies for PV systems in the built environment – An evaluation of incentives, support programmes and marketing activities
Market penetration of decentralized grid-connected PV systems has increased tremendously world-wide over the last decade, brought about by a wide variety of promotion strategies and dissemination programmes.
Beginning with an analysis of PV customers and types of dissemination strategies, this report (IEA-PVPS T7-06:2002) goes on to examine specific government target pro- grammes – both voluntary and mandatory – that have been employed around the world. Incentives such as rebates, soft loans and tax benefits as well as strategies based on regulated prices and financial incentives for investors are described. Green power tariffs, solar stock exchanges and green power marketing are also considered, as are NGO strategies, retailer alliances and public building programmes.
Amongst a range of findings, the study highlights affordability as the customers’ key concern, as opposed to a necessity for long-term cost-effectiveness. It also indicates that willingness to pay for PV is generally higher than programme designers anticipate. In conclusion, eight key factors for successful dissemination strategies are provided.

Reliability study of grid-connected PV systems - Field experience and recommended design practise
Following an IEA survey on faults, failures and poor performance of mainly residential PV installations across 11 countries, this report (IEA-PVPS T7-08:2002) demonstrates a ‘learning curve’ of decreasing failure rates. The failure analysis leads to recommendations for good design and installation practice and improved junction boxes.
The use of modern Class II components can remove the need for string diodes and string fuses, giving simpler and more reliable systems. Minimum maintenance recommendations include yearly array inspections, regular array cleaning if there is soiling, and monthly electrical production checks.
Cited reasons for low yield in the German 1000-Roofs programme include over-rated modules, faulty DC connections, shading and soiling. Inverters still prove to be the weakest component, but have matured remarkably, with recent projects showing trouble-free operation for 10 years and some good rapid replacement services operated by manufacturers. Standard PV modules have reached a high quality standard.

Ordering details for these and other recently published reports are given in the publications' section of this website.

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