Designing a solar power system takes environmental factors – such as the amount of sunlight (irradiance), cloud cover and temperature – and load requirements (how much electricity the users demand at different times of the day) into consideration. A designer must also control or select between different approaches or types of solar power system, such as:

Grid-connect or standalone

Grid-connect systems export electricity to a larger network, while standalone systems supply a local load only, usually with battery backup. Most systems close to an existing supply will be grid-connected, to avoid the high cost associated with batteries or other storage. Remote standalone power supplies often incorporate a second power generator, such as a diesel generator (genset).

Module type

Different types of PV module suit different situations. High-efficiency modules, like silicon monocrystallines, will often be chosen when installation space is limited or where frames and installation costs are high. Low-efficiency modules, like some thin films, might be chosen where installation space is plentiful. These are both types of flat plate PV module, as are polycrstyalline modules, but alternative concentrator systems (CPV) can use parabolic mirror to focus sun rays onto the PV cell and increase the energy harnessed.

Orientation

PV modules on fixed arrays will generally be oriented towards the north in the southern hemisphere. This exposes the modules to the greatest amount of sunlight through the course of a day. East-facing arrays will receive a greater share of morning light, and west facing arrays will receive proportionally more afternoon light. Arrays might be faced east or west so power generation matches the times when loads are expected to be highest.

Tilt

The tilt of an array, measured as an angle from the horizontal plane, will determine the time of year that the PV modules receive the most sunlight. Positioning an array to the installation site’s angle of latitude – for example, around 20-25° in Alice Springs – will expose the modules to the greatest amount of sunlight over a year. A flatter installation will receive more sunlight in summer when the sun is higher in the sky, and a more extreme (nearer to vertical) angle will receive more sunlight in winter.