Are Aquavoltaics Investable? A Framework for Economic and Environmental Cost-Benefit Analysis

Aquaculture has long been a significant industry in Taiwan, contributing significantly to the country's GDP through both exports and domestic consumption. However, certain aquaculture practices have faced criticism due to their heavy groundwater usage, resulting in environmental damage such as land subsidence in the southwestern region of Taiwan. In order to change the industry's negative environmental image and achieve the ambitious targets set by the Taiwanese government, including 20 GW of solar photovoltaic power by 2025 and net-zero carbon emissions by 2050, the utilization of aquaculture lands, particularly aquaculture ponds, has emerged as a promising option for solar power development. As the government promotes the symbiosis of aquaculture and solar PV power to attain its renewable energy goals, various stakeholders have engaged in discussions surrounding this approach. Consequently, it is crucial to assess the costs and benefits of such integrated practices from both economic and environmental perspectives, as it will play a pivotal role in shaping the future of the industry. A comparative analysis reveals that an aquaculture-electricity symbiosis with a capacity of 227 MW can further reduce carbon emissions by approximately 150,393.6 tons of CO2e per year, along with reductions of 56.8 tons/year of SOx, 82.3 tons/year of NOx, 3.7 tons/year of PM2.5, and 4.6 tons/year of PM10. These environmental benefits are equivalent to approximately TWD 7626.43 million annually. (Note: CO2e refers to carbon dioxide equivalent, SOx refers to sulfur oxides, NOx refers to nitrogen oxides, PM2.5 refers to fine particulate matter, and PM10 refers to particulate matter with a diameter of 10 mu m or less).