Solar Energy

Solar Energy is a renewable resource that is free and supplies unlimited without pollution or damage the environment, and many technologies can be applied directly for use in homes, businesses, schools, and hospitals. The Solar Energy is an electromagnetic energy transmitted from the sun (solar radiation). Some Solar Energy technologies include solar heating, concentrated solar power (CSP), and solar architecture, and photovoltaic (PV) cells and panels. The potential of Solar Energy is 20,000 times more power than what is needed to supply the entire world, the surface of the earth receives 120,000 terawatts of solar radiation (sunlight). 

Solar Power Plant is to convert sunlight into electrical energy either through photovoltaic (PV) panels or through mirrors that concentrates solar radiation. Photovoltaic cells convert light into an electric current using the photovoltaic effect that utilises thermal energy from the sun and further transformed into electrical energy which feeds into the grid. Concentrated Solar Power (CSP) System uses the mirrors or lenses that are stationed in an organised way to concentrate collected heat to one specific position in which the heat is further utilised to a steam turbine power and to generate electricity.

Solar Resource is the amount of solar insolation a site receives, usually measured in kWh/m2/day, which is equivalent to the number of peak sun hours. The potential of Solar Energy is 20,000 times more power than what is needed to supply the entire world, the surface of the earth receives 120,000 terawatts of solar radiation (sunlight).

Solar PV generation increased by a record 270 TWh (up 26%) in 2022, reaching almost 1 300 TWh. It demonstrated the largest absolute generation growth of all renewable technologies in 2022, surpassing wind for the first time in history. This generation growth rate matches the level envisaged from 2023 to 2030 in the Net Zero Emissions by 2050 Scenario. Continuous growth in the economic attractiveness of PV, massive development in the supply chain and increasing policy support, especially in China, the United States, the European Union and India, are expected to further accelerate capacity growth in the coming years. The tracking status of solar PV has therefore been upgraded in 2023 from “more effort needed” to “on track”. (Source: IEA Tracking Solar PV)

Solar PV capacity additions are expected to increase 8% to over 145 GW in 2021. PV has become the lowest-cost option for electricity generation in many countries, especially those with good resource availability and affordable financing. As a result, corporations are increasingly opting for bilateral contracts with large-scale solar PV plants to meet their energy demand. Thanks to further cost reductions and continuous policy support from 120 governments globally, PV capacity additions are forecast to expand further to 162 GW in 2022. (Source: Renewable Energy Market Update - Outlook for 2021 and 2022)

Global solar PV capacity additions are expected to reach nearly 107 GW in 2020 in the main case, representing stable growth from 2019 (this forecast has been revised up by 18% from the market report update published in May). IEA monthly deployment data indicate that construction activity for utility-scale projects slowed from March through April, but rapidly regained speed in mid-May. Deployment of distributed PV applications remains sluggish in large markets such as China and the United States, although activity in most European markets, Australia and Brazil has not been hampered significantly. Still, the share of distributed applications in total PV deployment is expected to decline to 37% this year, the lowest since 2017. (Source: IEA Renewable 2020)

Concentrated Solar Power (CSP) technologies use mirrors to concentrate the sun's light energy and convert it into heat to create steam to drive a turbine that generates electrical power. A CSP technologies are 1) Parabolic Trough System uses trough-shaped mirrors that reflect and concentrate solar radiation onto receiver tubes containing heat transfer fluid; 2) Central Receiver uses an array of individually tracking mirrors to reflect and concentrate solar radiation onto an elevated central receiver which produces steam; 3) Linear Fresnel System uses an array of flat or slightly curved reflectors to concentrate solar radiation onto an elevated absorber tubes containing heat transfer fluid; 4) Dish Stirling System uses a parabolic dish to reflect and concentrate solar radiation onto a receiver filled with hydrogen or helium as a transfer gas.

Photovoltaic (PV) means the words photo (light), and volt (electricity) that is the conversion of sunlight (solar radiation) into electricity using semiconducting materials.

Solar Cell Efficiency is the performance measurement of the solar panel that is a rate of converting the sun’s lighting (the portion of energy) to electricity through the Photovoltaic (PV). The most efficient solar panels in the world are capable of 40 to 50% efficiency. Most domestic solar panels are around 10 to 20% efficient. Monocrystalline efficiency is higher, approximately 13-17%. Polycrystalline units are cheaper to make, but have lower efficiency, usually 11-15%. A third system combines one of these two panel types with a thin-film PV system, again more expensive, but capable of efficiencies exceeding 17%.

Crystalline silicon (c-Si) is the crystalline forms of silicon. The types of Crystalline Silicon (c-Si) are: Monocrystalline Silicon Solar Cells (mono-Si); Polycrystalline Silicon Solar Cells (p-Si) or multi-crystalline silicon (multi-Si), or Thin-Film Solar Cell (TFSC) or Thin-Film Photovoltaic Cells (TFPV). The Crystalline Silicon (c-Si) is the dominant semiconducting material used in photovoltaic (PV) technology for the production of solar cells. 

Monocrystalline Silicon Solar Cell (mono-Si) is made out of silicon ingots, which are cylindrical in shape. To optimize performance and lower costs of a single monocrystalline solar cell, four sides are cut out of the cylindrical ingots to make silicon wafers, which is what gives monocrystalline solar panels their characteristic look. Monocrystalline solar panels have the highest efficiency rates since they are made out of the highest-grade silicon. The efficiency rates of monocrystalline solar panels are typically 15 ~ 20%. Monocrystalline solar panels are the most expensive.  

Polycrystalline Silicon Solar Cell (p-Si) or Multi-Crystalline Silicon Solar Cell (mc-Si) is a material comprising multiple small silicon crystals. For this solar panel, the Polycrystalline Silicon is made by melting raw silicon and pouring it into square mold, which is cooled and cut into perfectly square wafers. The process used to make polycrystalline silicon is simpler and cost less. The efficiency of Polycrystalline-based solar panels is typically 13 ~ 16%.

Thin-Film Solar Cell (TFSC) or Thin-Film Photovoltaic Cells (TFPV) technology is made by depositing one or several thin layers of photovoltaic material in a substrate. Photovoltaic material is deposited into the substrate with the help of these different types of solar cells Amorphous silicon (a-Si), Cadmium telluride (CdTe), and Copper indium gallium selenide (CIS/CIGS). Thin-Film module prototypes of the Solar Cell Efficiency are approximately 7 ~ 13% and production modules operate at about 9%. A TFSC or TFPV can be applied a mass production. Many thin-film solar cell types are still early in the research and testing stages.

Amorphous Silicon (a-Si) Solar Cell

Absorption Coefficient is the value of the change in energy as the solar photons passes through substances that is the constant of the material for a given wavelength. The higher Absorption Coefficients means more readily absorb photons.

Active Solar Heater is a solar space-heating system that uses electricity to circulate air or a liquid through a solar collector and then distributes the heat throughout the house.

Annual Solar Saving is the yearly energy savings that is the amount of energy provided by the solar technology attributed to a solar feature relative to the total energy requirements.

Antireflection Coating is a type of optical coating applied to the surface of lenses and other optical elements to reduces the light reflection and increases light transmission including a thin coating of a material applied to a solar cell surface.

Array Current is the electrical current produced by a photovoltaic (PV) array under the sunlight.

Azimuth Angle is an angular measurement in a spherical coordinate system that is the angle between a celestial body (sun, moon) and the North, measured clockwise around the observer's horizon.

Bypass Diode is a standard addition to any crystalline PV module that connects across one or more solar cells in a photovoltaic module.

Central Receiver

Solar Energy Industries Association (SEIA®) is the driving force behind solar energy and is building a strong solar industry to power America through advocacy and education. As the national trade association of the U.S. solar energy industry, which now employs more than 260,000 Americans, we represent all organizations that promote, manufacture, install and support the development of solar energy. SEIA works with its 1,000 member companies to build jobs and diversity, champion the use of cost-competitive solar in America, remove market barriers and educate the public on the benefits of solar energy. (Source: www.seia.org/)

Solar Energy Research Institute (SERI) is a federally funded institute, created by the Solar Energy Research, Development and Demonstration Act of 1974, that conducted research and development of solar energy technologies. Became the National Renewable Energy Laboratory (NREL) in 1991. (Source: https://energy.gov/eere/)