ENERGY ALTERNATIVES: RENEWABLE
ENERGY AND ENERGY CONSERVATION
TECHNOLOGIES
(b) Solar Pumps :
Recent technological progress makes solar energy for water
lifting, in the 100-800 W range, a realistic option under
certain conditions. The solar pump system consists of a
photovoltaic array, a motor and a pump. Particularly, the
pump efficiencies have been improved up to 65 to 70 per cent,
and the overall costs have been reduced. Typical applications
are irrigation of landholdings up to two hectares with 60 m3
of water per day through static heads of 2 to 10 m, or the
supply of some 20 m3 of drinking water per day through static
heads of 10 to 30 m for a village of up to 1,500 people.
However, solar pumps are still expensive, which implies that
this technology is attractive only when alternatives (diesel,
wind, etc.) are lacking. Investment costs are still such that
pay back periods may exceed 5 years. It is expected that in a
few years time the costs will fall further so as to make
solar pumps more competitive among prevailing alternatives.