6.1 Improved Sunlight to Electricity Conversion Efficiency: Above 40% for Direct and Above 30% for Global Sunlight
In 2013 and 2014, this project explored the use of spectrum splitting to improve the performance of a concentrator photovoltaic (CPV) receiver. By optimally dividing the solar spectrum between commercially available triple-junction (TJ) and Si solar cells, the overall amount of electricity generated can be increased by approximately 10%. The combination of such a spectrum splitting or “Power Cube” receiver and a CPV power tower system has the potential to reduce the cost of utility-scale photovoltaics. The original aim of the project was to design, fabricate and test a proof-of-concept, prototype spectrum splitting CPV module demonstrating an independently confirmed efficiency above 40%.
With this record performance level achieved in 2014, the project was extended in 2015 to target 42% efficiency CPV module efficiency and over 30% efficiency for a non-concentrating, flat-plate implementation of the approach, both for 2016. As a contribution to the AUSIAPV program, NREL has provided extensive independent testing of module performance and advice on module design.