Fossil fuels are a non-renewable resource, unable to replenish themselves in meaningful human timeframes at a sufficient rate. As they are also the main source of energy for the entire world, scientists have worked tirelessly to find cost-effective alternatives to these fossil fuels as a way to generate electricity. In recent years almost twenty percent of the global energy consumption could be attributed to these renewable resources. However, despite the potential it has as a replacement for oil and natural gas, solar energy only accounts for a fraction of that percentage.
In simple terms, solar power is conversion of energy from light emitted by the sun into electricity we can use. This can be done in two primary ways. The first method to convert solar energy into electric energy is the use of the photovoltaic effect. The photovoltaic effect is the process by which certain materials, when exposed to light, begin to channel an electric current. This happens when the material (usually a metal) absorbs light, causing an electron within it to reach a higher-energy state. This causes different parts of the metal to have different amounts of electrical energy. This difference in energy levels, known as a gradient, leads to the flow of energy from areas where there is more of it to those where it is lacking. The devices that take advantage of this effect to produce and store electricity are known as photovoltaic cells.
The second way that the energy of sunlight is converted into electricity is called concentrated solar power or CSP. Concentrated solar power is the process by which mirrors and lenses are used to focus gathered sunlight on a limited area, producing large amounts of heat. This gathered thermal energy causes water in the area to boil, creating steam that moves a traditional turbine engine. The engine is then used to generate electricity.
Both of these methods have unique benefits and downsides to their use, and as a result there is a lot of work being done to perfect hybrid systems. These hybrid systems would use both methods of gathering solar energy, increasing efficiency and energy storage alike. Photovoltaic cells take up significantly less amounts of space than their CSP counterparts, and are in many ways simpler to construct. Furthermore, they do not require moving parts or frequent maintenance. They are commonly used on spacecraft for these reasons.
On the other hand, concentrated solar power is in some ways superior to photovoltaic cells. They convert sunlight into usable energy with significantly more efficiency and have longer lifetimes. Also, they are able to store thermal energy very well, which allows them to keep producing electricity for twenty-four hours a day. Photovoltaics are only effective during daylight hours.
Advances in the technology used to produce solar energy are causing the price of creating and operating these devices to go down. As a result, solar energy is swiftly gaining popularity across the globe. Someday soon, every building will have solar panels on the roof. As the technology improves and prices lower, many experts expect solar energy to become the primary source of electricity for the global population.