Application of Agrivoltaics (Agri-PV) technology in microalgae cultivation

Spirulina (Arthrospira platensis) has been applied in many food and cosmetic products. However, production cost competitiveness remains a challenge, and one of the key expenses is electricity. Thailand benefits from consistent sunlight throughout the year. The implementation of Agrivoltaics/ Agri-Photovoltaics (Agri-PV) technology, which integrates solar energy generation with agricultural practices, offers a potential solution to optimize land utilization and decrease energy costs. However, its impact on microalgae productivity needs to be evaluated. In this study, we intended to evaluate the use of Agri-PV for Spirulina cultivation by examining its environmental impact and biomass production when PV panels were installed above outdoor raceway ponds. The results showed that shading from PV panels influenced light intensity and water temperature, affecting algal growth. The shaded pond had an average biomass productivity of 7.3 ± 1.0 g m^-2 d^-1, whereas the unshaded pond produced 9.7 ± 0.9 g m^-2 d^-1. However, the biochemical composition of Spirulina cells remained unchanged. Cells contained approximately 53% protein, 33% carbohydrates, and a valuable compound, phycocyanin, which accounts for approximately 23% dry weight.  Moreover, the cultivation system used only about one-third of the electricity generated by the PV panels. The remaining surplus energy was available for other uses. These findings demonstrate that Agri-PV can effectively reduce energy costs while holding promise for enhancing microalgae biomass production.

Keywords: Agri-PV, microalgae cultivation, Spirulina