German @ Oxley

At the equator, the sun provides about 1000 watts of energy per a square metre
In general, direct solar power involves a single transformation of sunlight which results in a usable form of energy.

Sunlight hits a photovoltaic cell creating electricity.
Sunlight warms a thermal mass.
Sunlight strikes a solar sail on a space craft and is converted directly into a force on the sail which causes motion of the craft.
Sunlight strikes a light mill and causes the vanes to rotate as mechanical energy, little practical application has yet been found for this effect.
In a direct solar water heater the water heated in the collector is used in the domestic water system.

In general, indirect solar power involves multiple transformations of sunlight which result in a usable form of energy.