TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The granules: are substantially opaque to radiation over the operating wavelength range of the photovoltaic element and have a surface fill factor of not greater than 75% over the active face of the photovoltaic element; are ceramic-coated mineral core particles; are at least partially transmissive to radiation over the operating wavelength range of the photovoltaic element; transmit at least 50% of solar radiation over the operating wavelength range of the photovoltaic element; are made of glass; are glass beads or glass cullet; are made of quartz, sand, a non-vitreous ceramic or a polymeric material; are opaque to at least some visible radiation but have at least 50% energy transmissivity to solar radiation over the 750-1150 nm wavelength range, where at least some of the granules are partially transmissive granules coated with a near infrared transmissive coating; and have a size of 0.2-3 mm. The polymer structure: is a single layer of polymer; comprises many layers, where the layer distal to the active face of the photovoltaic element is a layer of polymer capable of adhering the granules; has an energy transmissivity to solar radiation of at least 50% over the operating wavelength range of the photovoltaic element; has a thickness of 50 mu m to 2 mm; and is colored but has at least 50% energy transmissivity to solar radiation over the 750-1150 nm wavelength range. The photovoltaic element is a monocrystalline silicon photovoltaic element or a poly crystalline silicon photovoltaic element. The combination of the polymer structure and the granules disposed on it has an overall energy transmissivity to solar radiation of at least 40% over the operating wavelength range of the photovoltaic element. The roofing substrate: is a roofing shingle, tile, panel, membrane or shake; is an asphalt roofing shingle; and is a roofing membrane, a ceramic tile or a metal panel. The polymer structure extends to cover the active area of the active face of the photovoltaic element. The granules disposed on the polymer structure above the active area of the active face of the photovoltaic element: not substantially opaque to radiation over the operating wavelength range of the photovoltaic element; have substantially the same composition and surface fill factor as the granules disposed on the polymer structure above the roofing substrate; and have a substantially different color distribution, composition and/ or surface fill factor as the granules disposed on the polymer structure above the roofing substrate. The polymer structure does not extend to cover the active area of the active face of the photovoltaic element. The granules are substantially opaque to ultraviolet radiation and are colored. The polymer structure is substantially opaque to ultraviolet radiation and is colored. The photovoltaic roofing element further comprises a second polymer structure having a bottom surface disposed on the active face of the photovoltaic element, and a top surface, and a second many granules disposed on the top surface of the second polymer structure. The granules of the second many granules are: substantially opaque to radiation over the operating wavelength range of the photovoltaic element, and have a surface fill factor of not greater than 75%; not substantially opaque to radiation over the operating wavelength range of the photovoltaic element; and are made of glass. The photovoltaic element further comprises at least one electrical cables, where the electrical cables are disposed between the polymer structure and the roofing substrate. The roofing substrate has a channel formed in its top face, and where the electrical cables are disposed within the channel and covered by the polymer structure.