Photovoltaics offer consumers the ability to generate electricity cleanly, quietly and reliably. Photovoltaic systems are made up of photovoltaic cells, devices that convert light energy directly into electricity. Because the light source is usually the sun, they are often called solar cells. The word photovoltaic comes from “photo”, which means light, and “voltaic”, which refers to producing electricity.
Therefore, the photovoltaic process is “producing electricity directly from sunlight.” Photovoltaics is often referred to as PV. Photovoltaic systems are being installed by consumers who already have grid-supplied electricity but want to start living more independently or are concerned about the environment. For some applications where small amounts of electricity are required, such as emergency call boxes, photovoltaic systems are often cost-justified even when the power grid is not far away.
When applications require larger amounts of electricity and are located far from existing power lines, photovoltaic systems can, in many cases, offer the least expensive and most viable option.
In use today in street lighting, door openers, and other low-power tasks, photovoltaics are gaining popularity around the world as their price drops and their efficiency increases.
The total peak power of solar photovoltaic panels installed worldwide was about 5,300 MW at the end of 2005, with grid-connected systems representing the fastest growing area. Note that solar photovoltaic panels have capacity factors of around 20%, which is lower than many other industrial sources of electricity. Therefore, the 2005 maximum installed base production would have provided an average production of something like 1,060 MW (20% × 5,300). This represents 0.03 percent of global demand at the time.
Large-scale incentive programs, which offer financial incentives such as the ability to sell excess electricity to the public grid (“feed-in tariffs”), have greatly accelerated the pace of solar PV installations in many countries. , including Japan, Germany, and the United States. state
Although solar photovoltaic energy does not generate direct emissions during its operation, it can cause indirect pollution due to the industrial processes used in the manufacture and subsequent disposal of photovoltaic modules. Over the lifetime of a module, the years of clean energy produced will more than offset this initial pollution.
Photovoltaic cells convert sunlight directly into electricity without creating air or water pollution. Photovoltaic cells are made of at least two layers of semiconductor material. One layer is positively charged, the other negative. When light enters the cell, some of the light’s photons are absorbed by the semiconductor atoms, freeing electrons from the negative layer of the cell to flow through an external circuit and back to the positive layer. This flow of electrons produces electrical current.
To increase their usefulness, dozens of individual PV cells are interconnected in a sealed, weather-resistant package called a module. When two modules are connected in series, their voltage doubles while the current remains constant. When two modules are connected in parallel, their current doubles while the voltage remains constant. To achieve the desired voltage and current, modules are connected in series and parallel in what is called a PV array. The flexibility of the modular PV system allows designers to create solar energy systems that can meet a wide variety of electrical needs, no matter how large or small.
Unlike fossil fuel-based technologies, solar energy does not generate harmful emissions during operation, but the production of the panels does generate some amount of pollution.
While photovoltaic systems can require a substantial investment, they can be cheaper than paying the costs associated with extending the electrical grid.
