Introduction
One of the most serious challenges in the world today is the scarcity of energy resources. For example, oil prices have been on the upward trend in the last few decades, due to the decrease in the number of oil deposits. Electricity is another important source of energy and its level of production has gone down considerably in many countries due to environmental degradation that has affected water resources. As the world grapples with the scarcity of energy resources, scientists are now focusing on other energy sources such as solar energy which has not been properly exploited.
The scarcity of energy resources has led to changes in technological trends such that electronic gadgets that are now being invented are designed in a manner that makes them consume little energy. Apart from using electricity to power electronics, solar energy may be used as an alternative source of energy for electronics. Most machines can now use solar energy and traffic lights are not an exception. This paper discusses the use of solar energy in traffic lights. “Traffic lights refer to signaling devices positioned at road intersections, pedestrian crossings, and other locations to control competing flows of traffic” (Orcuitt 12). These lights are commonly utilized to control and coordinate traffic in cities and big towns which have busy road and railway networks.
Traffic Lights
Traffic lights were probably introduced in 1868 in Britain and they were introduced by an engineer called P. Knight. These lights were used within the parliament in the city of London. However, the present traffic lights were indeed invented by Americans. The Americans started using traffic lights in 1912. “Salt Lake City is where the traffic lights were first used to manage the flow of traffic” (Orcuitt 56). Automatic traffic lights were first used in Houston and Texas. As the use of traffic lights gained prominence, various designs of traffic lights were invented to meet the road safety needs of various countries. Today many countries are using traffic lights on their major roads.
Solar Technology
Solar energy was introduced several centuries ago and it is still being used even now. “The earliest evidence of Passive Solar Design can be seen in Architecture of the early civilizations of Egypt, Mesopotamia, and the highly developed ancient cultures of South America. (Solar Energy International 68)” The photoelectric effect was first discovered and used by Henry Becquerel. This marked the origin of solar cells which are used today.
Charles Fritts later on in the nineteenth century applied metalized selenium to make vacuum photocells. After this photovoltaic technology was introduced and it has been improved and utilized in some aerospace industries. “Photovoltaic technology is referred to as the process by which electric power is generated from sunlight” (Dunlop 268). Further modifications on photovoltaic cells have been made by engineers and they are today widely recognized and used.
How a Solar Traffic Light Works
Photovoltaic System
Photovoltaic cells function using the following mechanisms. First, “Photovoltaic modules(solar panels) often have a sheet of glass on the front (sun up) side, allowing light to pass while protecting the semiconductor wafers from abrasion and impact due to wind-driven debris, rain, hail, et cetera” (Messenger 357). Second, “series or module connection is always used in connecting the solar cells and this type of connection helps in up stepping the voltage of the cells” (Messenger 390). The parallel joining of the cells generates a high current. After this, linking of the modules is done using either series or parallel methods.
However, both of them can be used in connecting these modules. This is done to generate the needed DC voltage. Finally, the energy that has been generated from solar is channeled to the electricity grid using power inverters. There is a cable connection between the photovoltaic unit and the grid. In small-scale use of solar energy for example at home, “batteries can be used to store the energy that is not needed immediately, and solar panels can also be used to power or recharge portable devices” (Nise 678).
The following theories give details of how solar cells function
- When a solar panel is hit by photons which are found in the sunlight, they are attracted by, “semiconducting substances such as silicon found in the panels” (Messenger 450).
- The electrons which are negatively charged are separated from their atoms and this makes them move through the panel and in this process they generate solar power. This is because the solar cells are designed to allow electrons to move in only one direction.
- Solar energy is then converted to direct current using solar cells.
After tapping solar through the process described above, the electric current is then used to power the solar traffic light equipment that is connected or attached to solar panels. The voltage that is channeled down from the solar panel is controlled with the solar charger. This solar charger maintains the battery by charging it continuously. Light Emitting Diodes also commonly referred to as (LED) are usually utilized in the lighting of the traffic lights. “In addition to being significantly brighter than conventional bulbs, these LEDs are far longer lasting and extremely energy efficient” (Solar Energy International 139). Single traffic lights can often be used in busy construction sites. In such a case, a timer is used in coordinating the lights and this happens at preset
intervals. Alternatively, radar sensors can be installed and used in controlling the lights. “When using a series of traffic lights, it is advisable to coordinate them using radio” (Dunlop 169). This ensures that there is a smooth flow of signals among traffic lights. This coordination is governed by a major traffic light that is programmed through a computer system.
Advantages of Solar Traffic Lights
The use of solar traffic lights is gaining much popularity in various countries and this is attributed to the following factors. They are more economical as compared to the normal traffic lights that are run by electricity. This is because they produce power independently hence they are cheap. The people who are concerned with the conservation of our environment have strongly criticized the use of fossil fuels which have always destroyed the environment through air pollution.
However, they support the exploitation of solar energy because it is very clean and it does not affect the environment. They, therefore, support the application of this energy in traffic lights. In addition to these advantages, it is also very simple to install solar traffic lights because it requires very minimal wiring as compared to other traffic lights which need to be connected to power lines. “Since they generate power independently, they are not prone to disruptions caused by outages” (Solar Energy International 132). This ensures that traffic is monitored consistently without any disruption.
Disadvantages of Solar Traffic Lights
Even though solar traffic lights are advantageous, they do have some challenges which can be discussed as follows. The fact that they depend on solar energy can be a limiting factor in the sense that they can only be effective in the tropics which receive enough sun. But not in polar countries which are not receiving enough sunlight during some seasons. Apart from these, solar panel installations may be subjected to vandalism in places that have poor security.
There are also many types of solar panels and they do have different life spans, hence if poor quality solar panels are used, they might not give the desired performance and this can cause serious inconvenience. It is also quite difficult to regularly maintain solar batteries. If the solar chargers experience some electric hitches, they can fail to charge the batteries.
Conclusion
The invention of solar energy has not only provided a solution to traffic lights but has also revolutionized the use of electric appliances especially in domestic lighting systems in rural areas which do not have access to electricity. Solar is also currently being used in providing energy for street lights. “Consequently, is likely to reduce the electricity demand” (Solar Energy International 145). Owing to the inventions of the new solar traffic lights, I, therefore, envisage better traffic control in many cities and towns. I would also like to encourage more countries to adopt this technology because of the advantages that have been described above.
Works Cited
Dunlop, James. Photovoltaic systems. New York: Amer Technical Pub, 2009.
Messenger, Roger. Photovoltaic systems engineering. New York: CRC Press, 2010.
Nise, Norman. Control systems engineering. New York: Wiley, 2010.
Orcuitt, Fred. The traffic signal book. New York: Prentice-Hall, 1992.
Solar Energy International. Photovoltaics: Design and installation manual. London: New Society, 2004.
Appendix
The above picture is an example of a solar traffic light.