Following up on the IBO’s April 30 article on photovoltaic energy (PV), the International Energy Agency (IEA) released its Technology Roadmap for PV earlier this month, highlighting PV’s bright future. Solar energy currently leads all clean energy technology in terms of venture capital investments, with an 88% increase from 2007 to 2008 to $5.45 billion. Four countries have an installed PV capacity of over 1 GW. In 2008, Germany and Spain had the highest cumulative installed PV capacities of 5.3 GW and 3.4 GW, respectively. Japan and the US had installed capacities of 2.1 GW and 1.2 GW, respectively. For the next decade, the Roadmap predicts average annual growth of the PV market of 17%, leading to a global installed PV capacity of 200 GW and a 50% reduction of system and generation costs by 2020. Also, over the same 10-year period, the costs of utility PV are expected to become lower than wholesale electricity prices in several countries at 10 cents/kWh.

Crystalline silicon PV cells currently represent 85%–90% of the current global annual PV market and thin films account for 10%–15%, but by 2020 both are predicted to have equal market shares. Today, commercial crystalline silicon cells have a conversion efficiency of about 14%–20%, but the IEA predicts a 19%–23% increase in efficiency by 2020. The R&D activities that will be most important to crystalline silicon cells from 2010 to 2015 are the investigation of new silicon materials, impurity reduction and further advances in cell contacts and emitters.

Thin films have a conversion efficiency of around 10%–14%, but are lower cost than crystalline cells. Thin film efficiency is expected to increase to 12%–15% efficiency by 2020. Important R&D activities for the next five years will be the enhancement of large-area deposition processes and improving substrates and transparent conductive oxides.