Building-integrated photovoltaics (BIPV) research at the National Renewable Energy Laboratory (NREL) focuses on one of the fastest growing segments of the solar industry—the integration of photovoltaic (PV) panels into buildings during construction. BIPV replaces traditional building materials such as roofs, window overhangs, and walls. NREL researchers investigate how BIPV systems are integrated into buildings to improve building aesthetics and system reliability while reducing costs and utility transmission losses. We also work to improve market acceptance of the technology.