Reducing Land Competition for Agriculture and Photovoltaic Energy Generation ? A Comparison of Two Agro-Photovoltaic Plants in Japan

Photovoltaic energy generation has great potential to reduce green house gas emissions compared to conventional sources of electricity. However, its wide-spread application can cause competition of land-use to arise due to the large areas required. To lessen this competition, concepts for co-usage of photovoltaics and agriculture have been proposed. In an agro-photovoltaic plant electricity is generated from photovoltaic (PV) panels mounted in designed spacing and height, so that limited shading allows for productive agriculture on the land below. A well-designed agro-photovoltaic system can potentially reduce land-use competition and provide additional income and employment opportunities in rural areas which are currently under pressure of depopulation and over-aging in Japan. This work looks at the implementation of two realizations of the concept within the present framework in Japan. The light distribution underneath the PV arrays is calculated. Total received sun light at ground level varies greatly between the two designs with 81 % and 43 % compared to unobstructed condition. Homogeneity and time-variability of direct sun light incidence are discussed.