Energy is power derived from physical or chemical resources with its main aim being to provide light and heat or work machinery. There are various sources of energy such as water, sunlight and a variety of chemicals. In this article we are mainly going to focus on sunlight as a source of energy.
What is solar energy?
Solar energy is power from the sun that is converted to thermal or electrical energy. Solar energy is the most abundant and cleanest source of power. A number of states have established some solar resources to cater for production of electricity. Nonetheless solar products i.e solar panels have been made available in markets for small scale production of home consumable electricity. Modern technology can harness this energy for a variety of reasons including electricity generation, provision of light, heat and humidity to provide a comfortable interior environment. Solar energy can also be used for commercial and industrial uses.
Solar energy is very flexible source of energy. Solar power plants can be located at or near the place of use.
Ways to harness solar energy
- Solar water heating– this is a process that uses solar thermal collectors which are usually rectangular chambers with small tubes which circulate water. The pipes are attached to a black painted surface where the top surface is transparent allowing sunlight in which is then trapped then transferred to the water. The hot water is stored in a tank and is used to heat water.
- Photovoltaic systems(PV systems)– these are systems made up of panels that consists of materials that use heat and light to shake electrons to loose and create electric current when exposed to the sun. This process is called the photovoltaic effect.
- Passive solar energy– this is where solar heating and lighting can be achieved indirectly or directly. To directly achieve solar heating and lighting materials that absorb heat from the sun are placed in locations where they receive sunlight and radiate it through the night. Most buildings harness solar power by building sun spaces which use the sun to heat an area and circulate air through it to the rest of the building.
- Solar thermal electricity– turbines are widely known to produce electricity. With the use of solar energy turbines can be run. This can be achieved in the following ways:
- Use of parabolic trough systems- these are U-shaped troughs lined together. They focus sunlight to heat a pipe circulating oil that is used to generate steam which turns he turbines
- Power tower- this is a large field with mirrors that reflect a huge area of sunlight onto a tower at the center to produce extreme heat that heats molten salt which is pumped to a boiler to produce steam.
Solar energy was very expensive, inefficient and often unreliable until recently. With the modern day technology and ways of utilizing it, it has become one of the easiest ways to gain friendly energy.
Efficient solar cells
A solar cell is an electrical device that converts the energy of light into electrical energy by the photovoltaic effect. Solar cells are the building block of solar panels. Efficient solar cells contains the parts responsible for conversion of sunlight to electricity then the solar panels combine and direct all of that electricity. Solar cell efficiency may be broken down into:
- reflectance efficiency
- conductive efficiency
- carrier separation efficiency
- thermodynamic efficiency
The overall efficiency is the product of the above specifics.
Improving the efficiency of solar cells can take up to years. However companies are working day and night to improve efficiency of solar cells. Specialists are persistently endeavoring to enhance the proficiency with which solar cells change light energy to electrical energy. The record right now remains at an efficiency of around 40%, utilizing multi connected cells (different layers of silicon).
Factors that affect the efficiency of solar cells
Reflection- efficiency of a solar cell can be increased by minimizing the amount of light reflected away from the cell’s surface. Anti reflection technologies such as coating cells, texturing the top of the cell increases the probability of the cell absorbing the reflected sunlight thus producing more energy. Other factors include temperature, electrical resistance, and wavelength of light.
Efficiency of solar panels Measurement
The efficiency of solar panels measures what percentage of the sunlight hitting the solar panel is getting turned to electricity that you can use. Most panels around the globe are 11-15% efficient. The higher the solar panel efficiency the lesser the surface area you need for your solar panels.
Some factors that affect how much power your solar panels will generate in addition to the efficiency of solar panels and their size include:
- Temperature- solar panels need to be installed a few inches above the roof to allow airflow to cool them down. Hot temperatures can lead to low efficiency of solar panels.
- Shade- shade is a great hindrance of efficient energy production. A little shad on one panel can shut down the power production of the entire system. Detailed analysis of patterns of the sunlight should be done before installing panels in a specific area.
- Slope of the roof- the tilt of the roof can affect the number of hours a panel is receiving sunlight large solar plants are fitted with systems that track the sun as it changes its position.
Scientists have developed solar panels that are up to 40% efficient, but manufacturers have not yet figured out how to produce these economic products. Panasonic built a record breaking prototype that was mass produced and was able to convert 22.5% of sunlight into electrical energy which will be easily commercialized and relatively cheap for customers.
Most consumers would opt to choose the more efficient solar panels since it sounds good however high efficiency does not mean better. Efficiency is not a major concern unless you are considering the factor of space. Consumers with small spaces can opt for the more efficient panels but that will of-course come with some extra charges. So they are less common among consumers.
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