Using a ray-tracing program to analyze the characteristics of monofacial-cell and bifacial-cell-types of flat-plate static-concentrator photovoltaic modules revealed that about 90% of the annual irradiation can be collected by a monofacial-cell module with a concentration ratio of 1.5 and by a bifacial-cell module with concentration ratio of 2.0. Preliminarily, small modules were fabricated and dependence of optical performance on light incident angles were measured. The optical collection efficiency of a monofacial-cell module with a concentration ratio of 1.5 was 87.6% and that of bifacial-cell module with a concentration ratio of 2.0 was 85.6%. (C) 2001 Elsevier Science B.V. All rights reserved.