Solar panels work by absorbing sunlight and converting it into electricity. They are usually mounted on a south-facing roof and are angled to maximize the effect of the sun. The energy produced by the sun is stored in a battery to be used on cloudy days. A battery is frequently used in conjunction with solar panels to supply clean electricity for a home even when the sun is not shining, as is encouraged by New Jersey’s clean energy program.
Photovoltaic Effect
When sunlight strikes a material, the photovoltaic effect occurs. This physical and chemical process changes the material’s charge, which is converted into electricity. It is one of the most efficient ways to convert sunlight into electricity. It is also one of the safest and most environmentally-friendly alternatives to conventional power sources.
The output voltage and current of solar panels are directly proportional to the amount of electricity they generate. This voltage-current curve varies depending on the time of day and intensity of the sun. A solar panel is most effective at generating electricity when the voltage and current are equal. However, the efficiency of the conversion process will not remain constant under constant solar irradiation.
A solar panel’s photovoltaic cells are made up of two slices of semiconductor material. These are further doped with other materials, such as boron or phosphorus. Phosphorus increases the number of negatively charged electrons, while boron reduces these negative charges and increases the number of positively charged electrons. This creates an electric field at the junction of the two semiconductors.
Silicon is the most common semiconductor material used in solar cells. It accounts for over ninety-five percent of the solar modules sold today. Silicon is also the second-most abundant material on Earth after oxygen. It also plays a crucial role in computer chips.
Monocrystalline Cells
Monocrystalline solar cells work in a similar way to polycrystalline cells. The primary difference between the two is their production process. Monocrystalline cells are produced using molten silicon, which is pulled into a cylindrical crystal before being allowed to cool and fragment. These silicon crystals are then poured into cubic-shaped growth crucibles. The silicon crystals are then polished and improved before being cut into thin wafers. The panels are then assembled using these wafers.
When sunlight hits a monocrystalline cell, an electron is displaced from its orbit. This free electron tries to return to the P-Side but cannot cross the barrier between the two semiconductors. This energy is converted to electricity and is used to power electrical appliances. Solar cells made of crystalline silicon are being researched to improve their efficiency, and researchers have found that up to 25% of solar energy is converted into electricity.
In terms of efficiency, monocrystalline solar panels offer superior performance. They can produce more electricity in the same area, which makes them a popular choice for residential and commercial applications. They are also available in different wattage ranges, producing between 5 and 25 watts.
On the other hand, polycrystalline solar panels are less efficient than monocrystalline solar cells. Polycrystalline panels have power ratings of around 240 watts, and some panels are more powerful than 300 watts. New technology and manufacturing processes have improved the efficiency of polycrystalline solar cells.
Concentrating Solar-Thermal Power (CSP) Systems
Concentrating solar-thermal power systems (CSTs) capture the sun’s energy and use it to produce electricity. These systems use mirrors to gather solar energy and convert it into high-temperature steam that drives a turbine. This method is similar to nuclear fission plants in that it uses the heat energy in the sun’s rays to create electricity.
Concentrating solar-thermal power systems are often used in large utility projects. Utility-scale systems typically use a power tower that arranges mirrors around a central tower, which acts as the receiver for the energy. Smaller CSP systems are typically single-dish or single-engine systems. They can generate five to 25 kW of power per dish and can be used to generate electricity in distributed applications.
In addition to solar panels, CSP systems can use thermal energy storage to provide electricity. The heat can be stored in thermochemical or sensible systems, which can improve the dispatchability of the plant. Many CSP plants today use molten salts as a storage medium. The efficiency of CSP systems is still in its early stages, but research is underway to make them as efficient as fossil fuel power plants.
