There are various ways to convert solar energy into electricity. Some of these methods use individual modules to imitate the photosynthesis process. While others use concentrated solar-thermal power (CSP) towers. In this article, we will look at concentrating solar-thermal power (CSP) and photovoltaic cells.
Photovoltaic cells
Solar cells collect light energy from the sun and convert it into electricity. This process is called photovoltaic, and involves two layers of silicon – one positively charged and the other negatively charged. These layers interact with the light that strikes them, causing electrons to become loose. The electrons are then set in motion by an electric field surrounding the wafer, creating a flow of electricity.
The first step in the process is to build a solar cell using a material known as photovoltaic (PV) or semiconductor (PV). PV semiconductors absorb a wide range of wavelengths, and solar cells can be made from different materials to increase their efficiency. Some solar cells use several different layers of semiconductor, called multijunction cells. This improves the efficiency of the solar cell and allows it to absorb more sunlight.
Photovoltaic cells are made up of silicon crystals, a metal frame, and glass casing surrounded by a special film. These photovoltaic cells can generate direct current electricity, which can be used to power devices such as phones, lights, or refrigerators. In contrast, most electricity is provided as alternating current in distribution and transmission systems. To convert DC electricity into AC electricity, photovoltaic cells need an inverter.
Concentrating solar-thermal power (CSP)
CSP is a renewable energy source that uses concentrated sunlight to generate electricity. It converts solar energy into electricity by using a turbine. It can also be used to generate heat for industrial applications such as water desalination, enhanced oil recovery, chemical production, and mineral processing.
CSP plants are typically built in utility-scale projects. They have multiple components and require high-voltage transmission lines to transfer the electricity from the solar plant to the end-user. Unfortunately, the existing transmission infrastructure in the Southwest is at capacity and new construction is urgently needed.
The annual power generation capacity of a CSP plant is based on its efficiency and the amount of solar irradiance collected at the site. The efficiency of a CSP plant depends on several factors, including the amount of sunlight available on the site and the efficiency of the thermal engine.
Cost reduction is an important goal for CSP. Cost reductions are expected to be significant as new technologies and operating concepts are developed. CSP plants are currently very expensive, and cost reduction will be critical to reaching the seven to ten euro cents per kWh target within the next ten to fifteen years.
Liquid sodium
Solar panels that use liquid sodium as the heat transfer fluid (HTF) can transform concentrated sunlight into electricity. This process can replace fossil fuels. The liquid sodium can be used for desalination and district heating. It can also be used to produce hydrogen, petrochemicals, and steel.
This process is very efficient. This type of battery can be used to store excess solar energy. Solar cells made of sodium can be used to power solar lights. The sodium in the battery can absorb up to eight times more solar energy than the other materials in the system. Moreover, the device can operate indefinitely without running out of power.
In addition, it can also be used as a thermal energy storage device. Liquid sodium is an excellent thermal conductor. Its thermal conductivity is about three times greater than that of stainless steel. This makes it possible to reduce the size of heat supply and removal systems. In addition, the high heat transfer properties of sodium allow the device to operate at atmospheric pressure, eliminating the need for large pressure-retaining equipment and structures.
Concentrating solar-thermal power towers
Concentrating solar-thermal power towers use massive mirrors to track the sun and focus its heat on a receiver at the top of the tower. This heat then turns into steam that drives a conventional turbine generator to produce electricity. Some power towers use water or steam as heat-transfer fluid, but more advanced designs are experimenting with molten nitrate salt, which has superior heat-transfer and energy-storage properties. During cloudy days, thermal storage allows the power tower to continue delivering electricity.
The technology behind these systems is becoming more widespread. One major advantage of CSP is its high energy density. This means that less land is required per megawatt. In Spain, for example, a single megawatt-watt CSP plant requires only 6.86 acres. Additionally, CSP systems are now capable of operating at higher efficiencies, and can power a range of utility-scale projects.
These solar power towers have an enormous array of mirrored heliostats that focus sunlight. The towers are fitted with a mounted heat exchanger. This heat exchanger heats the fluid, which is used to run a turbine. This steam is then converted into electricity.