Harvesting Indoor Light for Electricity Recovery Using Semitransparent CdTe Solar Cells for Energy Efficient Buildings

Abstract This study presents a preliminary proof-of-concept demonstration exploring how indoor artificial lighting - specifically LED systems - can serve a dual function: providing illumination while enabling electricity generation through integration with semitransparent photovoltaic (PV) panels. Using cadmium telluride (CdTe) PV cells with varying visible light transmittance levels, we show that diffused indoor LED lighting can generate meaningful electrical output, even under relatively low light power densities. A multi-layer panel configuration further enhances power output, underscoring the system's potential scalability. While detailed PV performance data are provided, the broader objective is to initiate discussion on integrating energy-harvesting systems within interior spaces - walls, ceilings, and floors - as a pathway toward energy-neutral buildings. From a cost-benefit perspective, if 15% efficient PV panels were installed on just 30% of the Willis Tower’s surface area, the projected annual electricity savings would be approximately $0.81 mil-lion/year. These findings highlight an untapped opportunity to transform indoor lighting into a sustainable energy asset, supporting long-term building efficiency and environ-mental goals.