Different Types of Solar Energy Systems
Solar energy systems convert sunlight into electricity or heat. These systems can be grid-tied or off-grid. They can also be used to generate electricity for other areas if the system is large enough.
Solar energy technologies must be integrated into complex modern grids with varying mixtures of traditional and renewable generation. These systems must be able to respond quickly to abnormal situations, like storms or blackouts.
Photovoltaics
Photovoltaics is the direct conversion of sunlight into electricity. It uses semiconducting materials like silicon to generate clean, renewable energy. The name is derived from the Greek words “photo,” meaning light, and “voltaic,” which refers to electricity. The technology is used in solar panels, which are usually mounted on rooftops or walls. They can also be found in large solar farms and other industrial applications.
When sunlight strikes a PV solar panel, it ionizes the semiconductor material inside. This causes outer electrons to break free of their atomic bonds, creating an electric current. This current is then converted into electricity by the panel’s inverter. The resulting electricity is used to power appliances and lights in homes and businesses.
Each PV solar panel consists of many individual cells that are strung together to form solar modules. These are then connected to an inverter and the grid. A typical home PV system consists of 60 or more solar cells. A commercial solar system will have even more.
Concentrating solar-thermal power
Concentrated solar-thermal power (CSP) plants use mirrors to focus sunlight into a receiver that is heated to high temperatures. This heat can be used to produce steam, which in turn drives a turbine to generate electricity. The solar thermal energy can also be stored for later use, allowing plants to operate even when the sun is not shining.
There are a number of different types of CSP plants. One of the most common uses parabolically-curved trough systems. These have long rows of mirrors that focus sunlight into a solar-energy-systems linear absorber tube. Other CSP plants use heliostats that track the sun throughout the day and concentrate it into a central receiver.
Another type of CSP plant uses molten salt as a heat transfer medium. This can be stored in tanks for later use, enabling plants to generate electricity even after the sun has set. However, these storage systems are not cheap to build and require materials that can withstand very high temperatures. They are also not as efficient at producing electricity as other CSP technologies.
Solar furnaces
There are many different ways that solar energy can be harnessed, including for power generation and cooking. The technology uses a variety of hardware to concentrate the sun’s rays into a central point. This heat can then be used to create electricity, melt metals, or make fuel by turning water into steam.
Solar furnaces use parabolic mirrors to focus sunlight onto a central point. They can reach temperatures of up to 3,500 degrees Celsius, which is enough to generate power or produce hydrogen fuel.
However, they suffer from a number of practical problems, including the need for large mirrors that are expensive to produce and maintain. Using techniques like nonimaging optics, it is possible to build more efficient solar furnaces.
One such solar furnace is located at Odeillo, France, where clear skies are available 300 days a year. It is surrounded by 63 heliostats, plane mirrors that automatically track the sun. Another large solar furnace is located in Uzbekistan near Tashkent and has a larger mirror surface area than the Odeillo solar furnace. Using a similar configuration, this solar furnace is able to generate up to 10 kW of electricity.
Solar power towers
Solar towers, also known as central receiver systems, are a type of concentrated solar power (CSP). They use thousands of sun-tracking mirrors called heliostats to concentrate sunlight onto a receiver at the top of a tall tower. This heats a heat transfer fluid, which generates steam that drives a conventional turbine-generator to produce electricity.
The heliostats track the sun, using sophisticated computer software to focus on the absorber at the top of the tower. This is a crucial Energy storage brick step to maximizing solar energy collection. Solar towers can also store the energy for later use, as they are able to operate at night or on cloudy days.
Solar power towers require a large area for the mirrors, as well as access to water for cooling and cleaning. The heliostats must be kept clean, as the reflected sunlight is most effective when not covered with dust. Also, solar tower plants use potentially hazardous fluids to transfer the heat, so their location should be in a region with few rainy days and good air quality. This includes regions of the U.S. Southwest, Chile, southern Spain, and India.
Photovoltaic power stations
Photovoltaic solar power stations use the photoelectric effect to transform sunlight into electricity. They consist of a number of large-scale PV panels and can have capacities of many megawatts (MW). These plants need large areas for their installation and require complex technical equipment. Their development is subject to the approval of a government agency and may involve extensive environmental impact assessments. They are also prone to public criticism.
The movement of electrons, carrying negative electric charges, on the front and back surfaces of a photovoltaic cell generates an imbalance of electrical potential like the negative and positive terminals of a battery. Conductors on the cell absorb these electrons to produce direct current electricity. This electricity is converted to alternating current by an inverter and raised to medium voltage by transformers. It is then transported to consumers via transmission lines.
Unlike conventional diesel generators, PV systems have no harmful emissions and do not need to be refueled. They are therefore ideal for remote health facilities without access to grid power. They can be designed as either stand alone systems or hybrids with batteries to ensure energy continuity when the level of solar irradiation is low.