The photovoltaic (PV) solar electricity market has shown an impressive 33% growth per year since 1997 until today with market support programs as the main driving force. The rationales for this development and the future projections towards a 100 billion E industry in the 2020s, by then only driven by serving cost-competitively customer needs are described. The PV market, likely to have reached about 600 MW in the year 2003, is discussed according to its four major segments: consumer applications, remote industrial electrification, developing countries, and grid-connected systems. While in the past, consumer products and remote industrial applications used to be the main cause for turnover in PV, in recent years the driving forces are more pronounced in the grid-connected systems and by installations in developing countries. Examples illustrating the clear advantage of systems using PV over conventional systems based, e.g., on diesel generators in the rural and remote electrification sector are discussed. For the promotion of rural electrification combined with the creation of local business and employment, suitable measures are proposed in the context of the PV product value chain. The competitiveness of grid-connected systems is addressed, where electricity generating costs for PV are projected to start to compete with conventional utility peak power quite early between 2010 and 2020 if time-dependent electricity tariffs different for bulk and peak power are assumed. The most effective current-pulling force for grid-connected systems is found to be the German Renewable Energy (EEG) Feed-in Law where the customers are focusing on yield, performance, and long-life availability. The future growth in the above-defined four market segments are discussed and the importance of industry political actions in order to stimulate the markets either in grid-connected systems by feed-in tariff programs as well as for off-grid rural developing country applications by long-term financing schemes are pointed out. A technology roadmap is presented with special emphasis on the fact that different customer needs are best served with best-adopted technologies and not vice versa. The need for the third generation PV technologies, implying that so called first (c-Si-wafer)- and second (thin-film)- generation PV technologies will be overcome in a short to medium time scale, is obsolete; in contrast, the excellent scientific ideas developed within 'Third generation' concepts-like utilization of hot electrons, quantum wells and nanostructures-are shown to be part of `New Technologies' opening new product ideas and additional market segments. The rationale for decreasing cost by increasing productivity for all technologies as well as the interpretation of price learning curves is presented. The role of PV in the future global energy supply chain is lined out. Due to a fast growing market driven by increasing widespread acceptance of PV, a substantial PV business and creation of employment in coming decades is expected. This in turn can provide solutions for nowadays global issues, such as a global energy justice by providing environmentally benign power to billions of people, who otherwise will lack energy solutions severely. (c) 2006 Elsevier B.V. All rights reserved.