Energy and economic analysis of microalgae cultivation in a photovoltaic-assisted greenhouse: Scenedesmus obliquus as a case study

• Published in: Energy (Oxford) Vol. 140; pp. 116 - 124
• Main Authors: Barbera, Elena, Sforza, Eleonora, Vecchiato, Luca, Bertucco, Alberto
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-12-2017; Elsevier BV
• Subjects: Algae; Biomass; Case studies; Computer simulation; Cost analysis; Cultivation; Economic analysis; Electric power generation; Electricity; Energy; Exploitation; Greenhouse; Greenhouses; Growth simulation; Industrial engineering; Industrial production; Irradiation; Land use; Light intensity; Manufacturing engineering; Optimization; Photoinhibition; Photovoltaic cells; Photovoltaics; Ponds; Production costs; Scenedesmus obliquus; Shading; Simulation; Solar cells; Surface area; Light intensity; Greenhouse; Scenedesmus obliquus; Growth simulation; Photovoltaics
• ISSN: 0360-5442; 1873-6785
• DOI: 10.1016/j.energy.2017.08.069

Microalgal industrial production requires high surface area, resulting in production costs currently unacceptable. A possible optimization of land use for the cultivation of Scenedesmus obliquus is proposed, by conjoint production of biomass and electricity using photovoltaic cells (PV). For this purpose, biomass cultivation in a continuously operated 1 ha open pond placed inside a greenhouse was considered, at two different Italian latitudes, as case studies. The greenhouse roof surface was partially covered with commercial PV modules, resulting in a reduced average irradiation. The light profiles and the average temperatures inside the greenhouse were simulated for different seasons, and the corresponding microalgal productivities were calculated based on a validated growth model. The partial pond shading limited photoinhibition in summer at Southern location, resulting in higher productivities. On the other hand, the loss of sunlight, due to the partial roof covering, resulted in a lower productivity in the other cases and for the Northern location. The presence of PV, however, allowed a better exploitation of light to produce electricity, which supports the energy duties of the process, with an additional net electricity production. Finally, an economic analysis was carried out showing a reduction of biomass production costs when PV is present.
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•A photovoltaic assisted greenhouse for cultivation of S. obliquus is proposed.•The biomass production is simulated based on the seasonal irradiation and temperature.•The presence of PV allows to reduce photosaturation and photoinhibition effects.•The energy from PV entirely sustains the duties of microalgal production process.•The market price of biomass is decreased by the presence of PV.