Harnessing Photovoltaic–Thermal (PVT) Heat to Cultivate Algae for Renewable Energy Efficiency and Plastic Pollution Reduction
Katherine Hee-Yeon Tae
Phillips Academy, Andover, MA, USA
Publication date: July 10, 2026
Phillips Academy, Andover, MA, USA
Publication date: July 10, 2026
DOI: http://doi.org/10.34614/JIYRC2026I19
ABSTRACT
This study investigates the integration of photovoltaic (PV) panel waste heat with a two-stage microalgal cultivation system using Chlorella sp. to enhance biomass productivity and polyhydroxybutyrate (PHB) biosynthesis. Waste heat recovered from illuminated PV modules was utilized to maintain algal cultures within a near-optimal temperature range (28–30 °C) during the growth phase, followed by a nutrient-limitation stage to induce PHB accumulation. Bench-scale cultivation was conducted under controlled illumination and temperature conditions, with parallel ambient-temperature controls to evaluate the effect of thermal stabilization. Thermal coupling is expected to promote faster growth kinetics and higher cell densities, corresponding to an estimated 20–40% increase in biomass productivity relative to non-heated systems. During subsequent nitrogen- and phosphorus-limited cultivation, thermally optimized cultures are anticipated to exhibit elevated intracellular PHB content, increasing from typical values of approximately 5–15% to an estimated 20–30% of dry cell weight. This enhancement translates to a projected 1.5–2-fold increase in volumetric PHB productivity, reaching approximately 0.05–0.12 g L⁻¹ day⁻¹, depending on illumination regime. Together, these findings support the feasibility of coupling solar energy infrastructure with microalgal bioprocesses to simultaneously valorize waste heat and produce sustainable bioplastics.
This study investigates the integration of photovoltaic (PV) panel waste heat with a two-stage microalgal cultivation system using Chlorella sp. to enhance biomass productivity and polyhydroxybutyrate (PHB) biosynthesis. Waste heat recovered from illuminated PV modules was utilized to maintain algal cultures within a near-optimal temperature range (28–30 °C) during the growth phase, followed by a nutrient-limitation stage to induce PHB accumulation. Bench-scale cultivation was conducted under controlled illumination and temperature conditions, with parallel ambient-temperature controls to evaluate the effect of thermal stabilization. Thermal coupling is expected to promote faster growth kinetics and higher cell densities, corresponding to an estimated 20–40% increase in biomass productivity relative to non-heated systems. During subsequent nitrogen- and phosphorus-limited cultivation, thermally optimized cultures are anticipated to exhibit elevated intracellular PHB content, increasing from typical values of approximately 5–15% to an estimated 20–30% of dry cell weight. This enhancement translates to a projected 1.5–2-fold increase in volumetric PHB productivity, reaching approximately 0.05–0.12 g L⁻¹ day⁻¹, depending on illumination regime. Together, these findings support the feasibility of coupling solar energy infrastructure with microalgal bioprocesses to simultaneously valorize waste heat and produce sustainable bioplastics.
