Rooftop agrivoltaics could allow residential buildings to produce clean energy, grow tomatoes, and generate green hydrogen within a single integrated system, according to new simulation-based research from the University of Exeter.
Can rooftop agrivoltaics really work in residential buildings?
A new feasibility study explores whether energy self-sufficient buildings can coexist with urban food production. Engineers Shanza Neda Hussain and Aritra Ghosh from the University of Exeter have tested, through advanced simulations, an innovative rooftop agrivoltaics system designed for residential use.
The concept sits at the center of new research aimed at designing a sustainable building where solar energy is combined with green hydrogen production and high-efficiency smart windows, creating an integrated energy and food system.
Rooftop agrivoltaics as a solution for energy and food competition
The study began with a clear objective: addressing the growing competition between agriculture, energy security, and urban development, while accounting for economic impacts and long-term sustainability.
The proposed solution relies on a tightly interconnected mix of technologies, ranging from bifacial solar panels and proton exchange membrane (PEM) electrolyzers to chromogenic glazing systems. This high-tech ecosystem was digitally modeled on a residential building located in Birmingham, England.
Multiple configurations for rooftop agrivoltaics systems
Using simulation software, the research team modeled a rooftop agrivoltaics system with different photovoltaic configurations. The solar setup tested both monofacial and bifacial modules across three installation layouts:
- vertical orientation at 90 degrees
- optimally tilted at 30 degrees
- dome-shaped configuration
Panel height was set at 3 meters for the dome and tilted systems, and at 1 meter for the vertical configuration, ensuring sufficient light for tomato crops grown beneath the panels. Despite varying shading conditions, agricultural output remained stable across all scenarios, with tomato yields estimated at around 0.31 kilograms per square meter.
Energy performance, however, varied significantly. Simulations showed that bifacial panels tilted at 30 degrees delivered the highest annual electricity generation, reaching 7,919 kWh. The lowest levelized cost of electricity (LCOE) was achieved with monofacial panels at the same tilt angle, at £0.061 per kWh.
Gasochromic windows and building energy performance
Rooftop agrivoltaics represented only one component of the study. Researchers also analyzed vacuum gasochromic glazing (VGC), an advanced smart window technology that adjusts transparency through the controlled use of gas.
When hydrogen is introduced into the glazing cavity, a thin tungsten trioxide layer darkens, reducing light and heat transmission. Transparency is restored by introducing a small amount of air. Modeling results showed that VGC not only achieved the lowest U-value at 1.32 W/m²K, but also improved overall building energy performance by more than 8,186 kWh compared to electochromic glazing solutions.
Onsite hydrogen production from rooftop agrivoltaics
The hydrogen required for window operation could be produced directly by the rooftop agrivoltaics system using a PEM electrolyzer. The system would need approximately 52.56 grams of hydrogen per year to manage transparency changes across 16 windows, while surplus hydrogen could be used to supply a fuel cell vehicle.
The authors note an important limitation, the lack of real-world microclimatic monitoring data. This constraint represents a critical challenge for translating the digitally modeled system into real-life applications.
Further details are available in the study “Rooftop agrivoltaic powered onsite hydrogen production for insulated gasochromic smart glazing and hydrogen vehicles: A holistic approach to sustainable residential building,” published in Energy and Buildings.
