A roof integrated solar power system includes a plurality of solar modules. Each solar module carries a photovoltaic or solar panel with solar cells. Edge regions of the solar module are disposed to the sides of the solar panel and are devoid of solar cells. An electrical component such as a junction box or micro-inverter, or DC optimizer is mounted on top of the solar module within at least one of the edge regions. Cabling for interconnecting the electrical component to electrical components of others of the plurality of solar modules also is located within the side regions. In one embodiment, the electrical component and cabling is disposed within a recess within a side region and covered by a flat access panel. In another embodiment, the electrical component and cabling is located atop the side region and is covered by an access panel in the form of a protective cover strip. The solar modules are installable on a roof in aligned or staggered courses to form the solar power system, and with the installed courses of modules together forming a water barrier protecting the roof.