Solar power is often considered to be one of the most promising alternative energy sources around. The process has a virtually perpetual source in the sun, creates no dangerous exhaust, and would not leave a lasting carbon footprint on the Earth. There are a number of disadvantages of solar power, however, which have continued to limit its practical widespread use.

One disadvantage of solar power is consistency and reliability. Solar-powered devices rely on the steady delivery of special particles called photons to keep the electricity generating process going. As soon as the sun falls below the horizon at night, photons stop striking the solar panels and the power drops instantly. This means that storage technology, such as batteries, or an alternative source of energy is always required to ensure uninterrupted power flow. Otherwise, if there is no sun, there is simply no power.

Some of the major disadvantages of solar power are economic in nature. Solar panels designed to generate electricity are still fairly expensive to produce. Since single solar panels can only generate a relatively small amount of electricity, an large arrays of solar panels are needed to provide a sufficient level of electricity to power a number of homes. These solar panels also have to be adjusted throughout the day in order to maintain a direct angle with the sun, so a mechanical orientation system also needs to be implemented to turn all of the solar panels.

Other disadvantages of solar power are technical. The materials used to create a solar panel are constantly exposed to other things besides photons. The constant bombardment of ultraviolet (UV) rays and other solar radiation often causes the panels themselves to deteriorate, much like any other material left exposed to the sun for extended periods of time. Other environmental factors like rain and dirt also take their toll.

Technology changes rapidly, and the number of disadvantages of solar power that seemed virtually insurmountable only a few years ago are now relatively minor inconveniences. With continuing advances in photovoltaics and other solar power technology, the cost of adding solar panels to houses, for example, has dropped significantly. The growing "green movement" has also spurred further development of alternative fuels, and created a greater interest in overcoming those disadvantages of solar power that remain.