What is Solar Power?

Solar Power - How Does It Work?

Understanding how solar power works does not have to be complicated.

To use a basic analogy, consider a common – very natural – solar converter: A simple flower.

The leaves of a flower are a photovoltaic array, each leaf being a a photovoltaic module. The task of the leaves in the solar collection process, is to adsorb the rays of the sun.

The stems and stalk rotate the flower to face the sun, a process called photo-tropism in biology. This is the natural equivalent of the charge controller: it regulates the degree of solar exposure by orienting the flower and leaves to face the sun.

The energy absorbed through the leaves is converted for storage by the process of photosynthesis. This is the flower's equivalent of an inverter; energy is used to create sugar, which acts as a storage battery for the plant. The sugar is transported from the leaves – where it is generated – to the various parts of the flower requiring energy.

This is a very basic and primitive process which has been perfected over a very long time.

Today's engineers and scientists have tried to duplicate or replicate the process; however, they are constrained by having to work on a very large scale, as opposed to operating at the molecular level.

Most people are familiar with the concepts of plant photosynthesis from biology class in high school. On the other hand, many more people are confused about man-made solar power collection and how it actually works.

The primary solar collection subsystem is the photovoltaic array, commonly known as “solar panels”. Without getting technical, a solar panel is a power generation and conversion process that takes one form of energy – light – and converts it to electricity. The electricity can then be sent to an electrical storage subsystem – a rechargeable battery. Several batteries together form an array that is capable of creating relatively small amounts of electricity collected at the solar panel and sends the composite result to a converter that is designed to make usable house current from stored battery current.

Because of the nature of electricity and how it is used in normal day-to-day living, the same type of electricity that is practical to store is unfortunately impractical and not compatible with the type of electricity used to power an appliance. On the plus side, there is an easy way to convert from battery direct current – DC – to household alternating current – AC. It is called a DC-to-AC inverter. This is generally a solid-state device with no moving parts, excepting perhaps a fan to cool it as required under heavy load conditions.

There is a subsystem that is critical to the efficient functioning of the battery array. It is called a charge controller. It functions as a regulator to prevent the batteries from overcharging, and charging batteries that have been discharged that can now store more electricity.

The deep discharge, deep cycle battery is the preferred storage solution and forms the heart of the battery array. Deep cycle batteries are specifically engineered to be constantly charged and discharged and deep discharge batteries provide long battery power duration. This is to provide an ample amount of stored electricity to power devices during the hours of darkness or relatively diminished exposure of the solar panels to direct sunlight. The ideal is have both characteristics in a single battery, however, as with most other technology, the advantages of one characteristic must be compromised with the other.

Solar power is totally dependent on direct sunlight. It's the source of power used to create electricity. In order to take advantage of this technology, refer to the analogy of the flower. Proper orientation of the solar panels is a fundamental requirement. The flower uses its photo-tropism to constantly and continuously reposition the flower and its leaves to provide maximum exposure to sunlight. This may be impractical in a consumer application, as moveable solar arrays are problematic for a number of reasons: expense, moving mechanical parts and mounting are but a few of the complications. For this reason, stationary arrays are desirable. In the northern hemisphere, orienting the collection array to face south provides the longest duration of exposure. The other consideration is the angle of the array; however, this is not as critical, as the position of the sun in relationship to the horizon is dependent on the time of year. Still, this angle is ideally set at the midpoint of the angle to the sun from where the array is located.

From a consumer's point of view, the amount and duration of available direct sunlight will guide the engineer to select a specific optimal solution for each unique application.