Economic assessment of photovoltaic greenhouses in China

Photovoltaic energy has shown a drastic increase in recent years, and photovoltaic greenhouses, as new modes of distributed photovoltaic power generation combined with agricultural greenhouses, can yield a profit from photovoltaic power generation besides agricultural planting income, while easing the pressure on the supply of land resources for the photovoltaic power station and promoting the application of photovoltaic products in agriculture, compared to traditional agricultural greenhouses. Research on economic benefits are not enough in a global manner to promote the application of photovoltaic greenhouses. Therefore, the models of costs and income of photovoltaic greenhouses were established, and an economic assessment was conducted in light of three indicators such as payback period, net present value, and internal rate of return. Then, the effects of photovoltaic installed capacity, proportion of bank loans, unit investment cost of photovoltaic systems, annual time of full power generation of photovoltaic systems, electricity price of photovoltaic power generation, and planting income on the indicators were analyzed to provide a reference for the investment of photovoltaic greenhouses. The results show that photovoltaic greenhouses with large photovoltaic installed capacity occupying a large area of land create great investment costs, which is not available for farmers, even huge enterprises. The installed capacity of photovoltaic greenhouses is not beyond 15 MW preferably in light of the investment costs and land use. It is not cost-effective to invest high-grade glass greenhouses with large photovoltaic capacity. The economic benefit of photovoltaic greenhouses decreases significantly with a big proportion of bank loans. It is crucial to reduce the market price of photovoltaic panels, and it is not economical for the investment of photovoltaic greenhouses with large photovoltaic capacity in an area with a low annual time of full power generation or electricity price. It is a good choice to plant crops with high economic income in photovoltaic greenhouses. It is necessary for a project of photovoltaic greenhouses to take into overall consideration the investment ability, investment scale, investment region, subsidy policy of photovoltaic power generation, and a planting scheme including a planting pattern and planting crops. With a suitable planting pattern and planting species in the area of adequate sunlight, the appropriate scale investment in photovoltaic greenhouses can achieve double wins of crop economy and electricity generation benefits.