Solar energy is energy emitted by the sun in the form of heat and light, which can be captured and utilized for various purposes.
This article discusses the following issues with respect to solar energy;
Solar Energy Definition
Solar energy may be simply described as radiation which is released by the sun in form of heat and light .
Solar energy is important due to its capacity to drive some important chemical processes and reactions that involve the production of electricity as well as heat. This implies that there are two main forms in which solar energy may occur: heat and electricity.
Is Solar Energy Renewable or Non-Renewable?
Unlike fossil fuels which are non-renewable, solar energy is a completely renewable form of energy. This is mainly because radiation from the sun is constant and cannot be exhausted from use.
If solar energy released from the Sun to the Earth, is well utilized or harnessed, it will be more than enough to meet the present and future energy needs of our society. Because of its unlimited supply and environment-friendly characteristics, solar energy has become one of the most attractive renewable energy options in the 21st century. As we may predict, this has led to much interest and efforts to see that it is developed and made available for use.
Solar energy is harnessed using different forms of technology, including photovoltaic systems, solar water heating, concentrating solar power plants, among others.
Quick Facts about Solar Energy and General Renewable Technology: Solar Energy Information
1). Solar energy is the most abundant form of renewable energy on Earth
2). In the year 2020, solar energy made up about 3.3 percent of overall energy supply in the United States. This makes it the renewable energy source with the fastest rate of growth for the year.
The overall use of renewable energy in the world, in 2020, was about 29 percent.
3). The cost of solar energy is currently much less than that of fossil fuels, with a fall in the price of solar panels by about 99 percent since the year 1977
4). In 2016, solar energy made up about 39 percent of all newly-installed electricity production capacity
5). China is the leading country in terms of solar energy deployment in the world. In the United States, (which itself is third largest producer and consumer of solar energy), the state of California leads in solar energy deployment, producing 38.9% of solar capacity as at 2018
6). Solar is one of the cleanest forms of renewable energy which can be used on Earth. It is also the fastest and easiest to deploy, and has been optimized due to the presence of more utilities
7). Solar power plants have an expectancy period of at least four decades
8). Solar radiation from the sun to the Earth, for a period of one hour, is capable of producing enough energy to be used on Earth for a whole year. At any moment, at least 174,000 terawatts of solar energy is incident on Earth from the Sun. Also, solar radiation reaches the Earth in about 10 minutes, from a distance of 90 million miles.
9). The use of solar energy saves at least 75 million barrels of crude oil and 35 tons of carbon dioxide (CO2) per year
10). Bell laboratories in New Jersey, United States, built the first solar cell comprised of silicon, in the year 1954 .
11). Solar energy demand in the United States, and all over the world, has risen dramatically in recent years. In 2008, about 1.2 gigawatts of solar power was installed in the U.S. This rose to about 27.4 gigawatts by 2015.
12). The space industry made use of solar energy to power the interior of its space crafts between 1956 and 1967.
An example of such space crafts is the Vanguard 1, launched on 17th March 1958; which is the first solar-powered artificial satellite, and the oldest one in orbit .
13). The largest solar thermal plant in the world, is the Ivanpah Solar Power Facility, which is located in Mojave Desert, California.
The facility operates using concentrating solar power technology (CSP), and has an overall capacity of 392 megawatts.
14). The drop in cost of installing solar energy has made it a very economical choice for power supply. However, the miscellaneous costs which include zoning, permitting and linking to the power grid, are relatively expensive.
As a result of this, different programs which are called ‘soft cost’ programs, have been implemented to reduce the time and cost of carrying out these miscellaneous functions.
15). In the United States, about 64 2 gigawatts of solar power had been installed by the end of 2018. This value was gotten after an addition of at least 10.6 gigawatts of solar during the year (2018).
16). Solar power in the U.S alone, replaces at least 70-100 million tons of carbon dioxide per year.
17). As at 2018, there were more than 242,000 workers in the solar energy sector in America. This number is above that of workers in the oil and gas sector.
18). The efficiency of solar panels has risen by at least 34% since the year 1954.
19). Most of the facilities used to set up solar power plants (at least 90%) can be recycled after the plant has been decommissioned.
Types of Solar Energy Technologies or Systems
1). Passive Solar Systems
Passive Solar Systems are systems which use solar energy only for cooling and hearing purposes .
Because they only make use of heat from the sun, passive systems do not require any complex external facilities.
They work by using collectors (also called ‘passive collectors’) to trap or capture solar rays. From these rays, they absorb heat, which is then used tor various purposes.
Passive Solar systems may also be called Solar Space Heating. They are a cost-effective and simple type of solar system, because they extract hear energy from the sun, and do not require any complex process of conversion to produce energy.
It is also important to not that passive solar systems do not directly produce electricity, but can be used for this purpose. However, such an approach will require a steam turbine, and is only used in large industries.
Passive solar energy can be used in residential buildings as well. Through strategic design, the windows and walls of such buildings can absorb heat in the daytime, and expel it slowly in the night. This method is used in areas which are prone to harsh winter and low temperature conditions.
Pros and Cons of Passive Solar Systems
1). Low Cost
2). Relatively Simple to Set Up
1). It depends directly on the Weather.
Provided the weather is excessively hot, it may cause overheating of the system and the building in which it is being used. In cold weather, the efficiency of the system will reduce
Examples of Passive Solar Energy Systems
-Solar Water Heater
The solar water heater may be in form of an active or passive system.
Passive solar water heaters make use of solar radiation to derive thermal (heat) energy, especially for commercial purposes.
In general, there are two main components which make up a typical, passive solar water heater. These are; the solar collector, and a storage vessel (usually a tank).
For the sake of simplicity, we can describe passive solar water heaters, as solar systems which make use of freely-available solar thermal energy to transfer heat across fluids. Because of their reliable and simple nature, solar water heaters are the most common passive solar-energy systems .
The main feature which we can use to differentiate between passive and active solar water heaters, is the absence of any external source of energy for circulating the heated fluid in the passive solar water heater.
In place of an external fluid-circulating force, passive solar water heaters, make use of the natural, physical principle of Convection. As a result of convection, the heated fluid naturally circulates in the storage tank, as it heats. Although the simplicity of passive solar water heaters is an advantage, it makes them less efficient than active solar water heaters.
There are different types of passive solar water heater systems, such as the Thermo-syphon solar heater system, and the integral collector storage system.
2). Active Systems
We have mentioned in our discussion of solar water heaters, that passive solar systems have less efficiency than active solar systems.
The active solar systems make use of external devices to pump and circulate the heated fluid, or to convert solar energy to electricity, as well as to other forms of energy. The benefit of these external devices used in active solar systems, lies in their ability to increase the effectiveness of the solar system .
The main disadvantage of active solar systems is their relative cost. Compared to passive systems, active solar systems and their required maintenance as well as equipment, are expensive.
Examples of Active Solar Energy Systems
-Photovoltaic (PV) Systems
The major component of a photovoltaic system is the photovoltaic cell or PV Cell. Also known as solar cells, these cells are a very simple set-up, for capturing solar radiation and converting it to electricity.
Photovoltaic cells are usually made using silicon (or similar polycrystalline materials) and produce electric current when solar radiation strikes the (solar) panel. The generation of electric current in PV cells is based on the photoelectric effect. So far, PV cells have been very useful in many parts of the world, which includes all regions of the United States .
PV cells are usually installed at strategic positions where they can have full access to sunlight, including roofs and windows of buildings . They can be designed to meet the needs of any building or facility in which they are installed. This can be done either by adding batteries for energy storage, DC-AC converters, and solar concentrating devices.
In cases where they are being used as a supplementary source of power, we may connect PV systems to the electric grid. In other cases, however, these systems can be allowed to function independently. PV systems so far have been used to power different devices and units, including streetlights, calculators, remote buildings and water pumps .
Asides the PV cells themselves, photovoltaic systems are comprised of various components. These include; battery bank, DC-AC power inverter, and battery controller.
-Concentrated Solar Power (CSP)
The CSP system is yet another type of active solar system. It is unique due to its capability to function at a large scale, by generating relatively large amounts of power.
CSP systems work mainly by a mechanism which helps to capture and concentrate a large amount of solar radiation upon a relatively small surface area. This is done by the use of mirrors which are inclined so as to deflect the sunlight or solar radiation, in the desired direction.
In Concentrated Solar Power Systems, the solar energy which is concentrated by the fixed mirrors, is often used to heat a fluid. This fluid, when heated, is excited to a state of mobility, such that it is used to drive a steam engine or a turbine, and in turn is used to power an electric generator.
The thermal energy produced in CSP systems may be stored in thermos tanks, especially provided the heat-transfer medium is a fluid like molten salt or oil (that can retain heat for long periods). In some configurations, natural gas boilers can be used to substitute for solar thermal energy when there is not sufficient sunlight to heat the fluid.
There are various forms of CSP systems, based on the geometry and arrangement of the system components. These forms include;
The main disadvantage of CSP systems is its cost. In general, Concentrating Solar Power Systems are capital-intensive and require huge financing for their maintenance. The resources needed by CSP plants include large amounts of water and space (land).
-Active Solar Space Heating
An active solar space hearing system, typically comprises of a solar collector, which holds a fluid or an other medium for heat-transfer.
The system works simply by circulating the fluid, which has captured thermal energy from the sun, through a building or any other facility where the system is installed. It is called an ‘active’ system because it makes use of pumps and other similar devices to provide the force for circulating the thermal fluid.
For a simple description, the basic principle behind solar energy is the capture of solar radiation, which is composed of light and heat.
The captured solar radiation may be used in by of different ways, depending on the existing need. Solar thermal systems use the heat energy from solar radiation, while other solar systems may convert solar radiation to electricity.
In order to convert solar energy to electricity, photovoltaic (PV) cells are used. An array of such cells forms what is generally known as a solar panel. The energy from solar panels can be stored in batteries for subsequent use.
The electricity generated by solar panels is Direct Current (DC). It is usually converted to Alternating Current (AC) using an inverter.
Typically, solar panels absorb solar radiation when it cones in contact with the silicon photovoltaic cells. Using this radiation, electricity is produced through a mechanism and process known as the photoelectric effect.
After converting the direct current (DC) produced by the solar panel, to alternating current (AC), the AC is channeled to the switchboard, which helps to send this current to the different points and appliances where it is needed . The switchboard also helps to balance the electricity supply between the electricity grid and the solar panel (in cases where the building/facility is also connected to the electricity grid).
Buildings which are equipped with solar power, usually require a bi-directional electric meter which helps to record the amount of electricity from the grid which has been saved by using the solar system. This measurement and recording is known as ‘Net-Metering’.
In any set-up where a solar-powered building is also connected go the grid, all unused electricity from the solar panel, is usually sent back to the grid . This reduces the cost charged on electricity, as it results in credits on the electricity bill, also known as Feed-in Tariff (FiT). The cost of the electricity sent to the grid from the solar panel, is simply subtracted from the electricity bill in such cases.
The switchboard relieves users of the responsibility of switching between the grid and the solar panel. In general, the maintenance requirements of a solar system are low. The system also lasts for a fairly long period of time, especially due to its simplicity.
Solar inverters usually give information on the amount of electricity produced and consumed by the solar system at any point in time.
Based on the information which we have read so far, we can simplify the process of electricity generation by solar systems, into a number of definite steps, as follows;
1). Solar Radiation or Sunlight, comes in Contact with the Panels
The design of a typical solar panel will include the silicon cells, arranged in arrays and embedded in a metal frame, with a glass casing and a surface film. This configuration is connected with wires to transfer any electricity produced.
Solar panels are placed in outdoor locations like rooftops, where they are exposed to sunlight.
2). Electric Current is Produced by the Cells
In each photovoltaic cell, two thin layers of silicon or any suitable semiconductor, are placed parallel to each other . One of these layers is positively charged and acts as an anode, while the other is negatively charged and acts as the cathode. These two components make up an electric circuit.
When solar radiation comes into contact with the PV cell, it excites electrons in the cell, causing them to move freely. The flow of these electrons between the anode and cathode silicon sheets produces an electric current.
3). Conversion of DC to AC
As we have mentioned before, solar panels produce direct current (DC), which must be converted to alternating current (AC) in order for it to be suitable for use .
An inverter does the job of carrying out this conversion, in a rather simple manner. Therefore, inverters are usually installed as one of the core components of a solar system.
4). The AC is Channeled to the Point of Use
After converting DC to AC, the current is transferred using wires, to the building or other facilities where it is needed.
As we have mentioned earlier, a switchboard is usually required in order for the electricity to be balanced and switched efficiently, between the solar system and the grid.
5). A Bi-Electric Meter is used to Gauge the Electricity Usage
Also simply referred to as a ‘Smart meter,’ the bi-electric meter helps to measure the amount of electricity which flows in from the grid, and that which flows to the grid. It is very useful to provide information on how much energy has been saved using the solar system.
How is Solar Energy Used? Uses of Solar Energy
Electricity is one of the most common uses of solar energy. The factors which have made solar electricity prominent, include;
i). Low Cost
iii). Environmental Benefits
iv). Ease of Maintenance
The reduction of the cost of solar panels in recent years has made them to be much more accessible. They are also easy to install on rooftops or any other exposed structure, and are easy to maintain.
Most users of solar electricity, utilize it in order to reduce or supplement the need for other sources of electricity like generators and the electric grid.
In other cases. solar energy can be used in large-scale solar farms. These are large areas of land in which solar panels and other devices are installed, and they typically generate enough solar electricity to power entire cities and large settlements.
2). Space Heating
Solar Space Heating, which we have earlier discussed, makes use of heat from solar radiation to warm a given space (usually the interior of a building). This is done using a fluid which serves as a medium for carrying and transferring thermal energy.
3). Water Heating
Solar water heating systems make use of solar energy to directly heat water, usually for domestic purposes.
As we have earlier mentioned, these systems comprise mainly of a solar thermal collector, and a storage tank. The water is circulated to the collector, where it becomes heated, before flowing into the storage tank.
Also as earlier mentioned, solar water heaters may be of either the passive or active types. Passive solar water heaters do not use any external device to circulate the thermal fluid while it is being heated. The circulation of heated fluid is rather carried out solely by convection, which is a natural process.
Solar energy can be used to provide ventilation, in the form of solar attic fans .
These devices are driven by solar energy and can help to support the existing HVAC (Heating, Ventilation and Cooling) system in a building, while saving energy costs.
At the present, we already have a number of transport systems powered by solar energy. They include solar-powered trains and buses. Academic research projects have also included the building of solar-powered cars.
This is perhaps one of the most common uses of solar power.
The applications of solar lighting technology include street lights, security lights, road signs and landscaping.
7). Wearables and Portable Solar
These include torchlights, power-ports and solar-powered chargers. These devices make solar energy to be more flexible and portable, so that it can be used for simple purposes like charging of mobile phones and accessories.
Solar Energy Advantages and Disadvantages: Pros and Cons of Solar Energy
-Advantages of Solar Energy
1). Solar Energy is Renewable
This is the most important advantage of solar energy. The fact that it is renewable makes it easy to access and unlimited in available quantity, in all parts of the world.
2). Solar Energy is Good for the Environment
The environment-friendly nature of solar energy is a great advantage. While using this form of energy, there is no potential damage to the environment.
This is unlike some known sources of energy like fossil fuels, which release greenhouse gases and toxins into the environment and the atmosphere in the process of using them. Solar energy is often referred to as ‘clean’, due to the fact that it is not associated with gaseous emissions or environmental pollution of any kind.
3). Reduction of Energy Cost
As we earlier stated in this article, solar energy, being renewable, reduces the cost of energy consumption.
In addition to reducing the electricity consumed from the electric grid (and the associated cost), solar energy may enable the user receive credits on the electricity bill when unused power is sent to the grid.
To set up a solar system requires different components including inverters, panels, switchboards and batteries. Although these components (along with their installation) may incur substantial cost, this is usually offset by the electricity bill-savings from using the system.
4). Solar Energy can be Stored using Batteries and Capacitors
Solar panels can be paired with batteries for energy storage. This is a particularly good combination as it helps the user to store solar power while it is being generated in the day time, for use at other periods when it may be needed.
Battery storage of solar energy is helpful to users who do not rely on the electricity grid at all. This is especially the case in very remote areas and settlements where buildings and facilities may rely solely on solar energy.
5). Continuous Innovation and Technological Advancement
Solar energy technology is constantly being improved. These improvements help to make it more suitable and capable of meeting the existing needs in our society.
Technological innovation and development in solar technology, also help increase the effectiveness and efficiency of solar systems, while reducing their cost. Through research in fields such as nanotechnology and quantum physics, new, better and simpler ways of harnessing solar energy are being developed.
6). Low Cost of Maintenance
After they have been purchased and installed, solar energy systems do not usually require much maintenance.
Basically, solar panels may require periodic cleaning. Because there are no moving components, solar systems do not generally experience any wear or tear problems.
The only components which may need to be repaired or changed once in a while include the batteries and inverters. For these reasons, solar systems usually have a long, average period of usage.
7). Solar Energy has Various Areas of Application
There are diverse ways in which solar energy can be applied.
Based on our discussions in this article so far, these applications include electricity generation, space heating and water heating, transport, wearable solar technologies, among others.
-Disadvantages of Solar Energy
1). High Initial Cost
While we have acknowledged that solar systems save cost of energy consumption, the initial purchase and installation of these systems often requires fairly huge investments, especially in large scale utilities.
The initial cost of solar means that not all individuals or corporate entities are usually able to afford it. Also, the system includes other components aside the solar panels; like the wiring, batteries and inverters. These components must all be coupled, and installed, adding to the overall cost.
2). Solar Energy may Require large amounts of Space
Especially in large-scale projects like solar farms, large expanses of land may be required.
The main reason behind the need for large amounts of space for solar systems, is the fact that solar panels and collectors must be able capture as much sunlight or solar radiation as possible, in order for them to be able to produce sufficiently-large amounts of energy.
3). Need for Strategic Positioning
More than any other form of renewable technology, solar energy systems require placement in very strategic positions, before they can function effectively.
As a result of the fact that solar systems require strategic positioning, there are numerous factors which we always have to consider when installing solar panels and collectors. These factors include the orientation and size of the surface or structure (such as a roof) on which we are to install the panels.
The orientation of a roof, for example, determines how much sunlight can be captured when a solar panel is installed. This orientation must also vary with geographical location, since the sun is not equally inclined at all locations on the Earth.
The following points describe how solar panels should be oriented according to geographic location;
1). The surfaces of solar panels in the Southern hemisphere are required to face the true North direction in their orientation
2). Those in the Northern Hemisphere must be inclined to face the true South direction
3). Solar panels in the Equatorial regions should be horizontal in their orientation 
Also, obstructions like trees, buildings and electric poles can seriously affect the use of solar panels. These issues make it fairly complex to utilize solar energy in many regions, and in various circumstances.
4). Dependence on Weather Condition
While it is still possible for a panel or solar collector to capture solar radiation in any weather, rainy and cloudy conditions reduce the amount of available radiation significantly. This implies that solar systems are optimal and function efficiently in sunny weather. Such a requirement is problematic, because it means that users of solar energy systems mat not be able to depend solely on them for power.
There are some measures and technological devices which have been developed to reduce the limitation of weather-dependence, including solar batteries and capacitors. These devices help store solar energy to be used at night or in unfavorable weather. However, they have limited capacity and add to the cost and complexity of solar technology.
5). Legal Requirements
In most parts of the world, a user is required to have legal permission to install a solar system in any building or facility.
Government and environmental agencies have regulations and specifications for the use of solar energy, and these factors usually make solar installation more cumbersome. The level of legal involvement in solar installation projects (at a small or large scale) depends solely on the strictness of existing regulations, and the level of compliance with them.
The table below outlines advantages and disadvantages of Solar Energy in a simplified manner;
|Is clean and pollution-free||Initial costs are usually high|
|No greenhouse emissions||Is less efficient than some other sources of energy|
|Reduces the dependence on fossil fuels||Solar technology usually requires large amounts of space|
|Is available in unlimited supply||It is highly dependent on the weather and is not usable at night|
|Is relatively cheap and helps save cost of electricity from the gird||Efficiency varies with geographic location and season or period of the year|
|Requires little to no maintenance and lasts for a long period of time||It is not yet developed sufficiently for mass production and usage|
|Can store residual energy in batteries for future use|
|Is very versatile and can be installed in any part of the world|
|Can be used for various purposes, from heating and cooling, to wearables and electricity generation|
|It is relatively safe to use|
|Continuous innovation and development is improving the efficiency of solar technology|
|Tax incentives and grants are often available to support user with the initial cost of solar installation|
|Solar energy has led to creation of numerous jobs|
Solar Energy Benefits
Based on our discussions so far, we can derive the following benefits of solar energy usage;
1). Reduces the Need for Fossil Fuels
Fossil fuels are currently the most used non-renewable energy resources. The development of solar technology has reduced, and will further reduce the level of dependence on fossil fuels and non-renewable energy in general.
There are many ways in which this is of benefit to our society. One of these is the fact that non-renewable energy generation and usage, often causes significant levels of environmental pollution.
Also, it is very important for us to reduce our dependence on non-renewable energy resources, since they are not available in unlimited supply, and will therefore eventually be exhausted. On the other hand, solar (like all other forms of renewable energy) is available in unlimited supply.
2). Reduces Environmental Pollution
The environment, as we know it, consists of land (lithosphere) air (atmosphere) and water (hydrosphere).
Non-renewable energy resources are well-known for their potential harm to the environment. There are numerous examples of instances where the extraction or usage of coal, oil or gas, have had bad effects on land, water and air.
Such examples can be seen in cases of land wastage and degradation in active or abandoned coal-mining sites. Others include gas leaks and oil spillage, such as the devastation and degradation of Ogoniland in the Niger Delta.
Compared to these forms of energy, solar does not have any significant effects on the environment at all . It does not cause any form of pollution (land, air, water, noise) and does not produce any wastes or by-products. It also lasts long compared to other energy technologies.
3). Is Not Resource-Demanding
By ‘resource-demanding’, we are referring to the need for tangible materials in order to produce energy. Unlike other forms of energy (both renewable and non-renewable) solar energy does not require or consume any material form of resources.
In the case of other energy sources, this is not so. For example, hydro-energy (which is renewable), makes use of large volumes of water to generate power or electricity. This often leads to flooding in cases where a dam may be overflown or damaged. Wind energy makes use of large amounts of air or atmospheric gas, while fossil fuels are required in combustion engines.
The fact that solar energy does not require any tangible supply of resources asides solar radiation or sunlight, makes it relatively simple and cheap to use.
4). Easy and Versatile to Install
We have already mentioned numerous times the fact that solar systems are relatively easy to install.
The simple nature of solar energy technology makes it possible to install a solar system (panel or collector) in almost any location. Also, solar technology is fairly flexible, and may vary n size and complexity, depending on the existing conditions and needs. These characteristics make solar to be the most feasible choice or energy source in remote locations.
5). Improves Climate Change and Human Health
Because solar energy does not produce greenhouse gases of pollutants, it is a good means by which we can tackle the problem of climate change in our society.
Unlike solar, most other sources of energy have potential impacts on the environment. These energy sources may either release greenhouse emissions, or may lead to environmental degradation.
In addition to affecting the environment and causing climate change, pollution and gaseous emissions can also affect human health . This implies that the use of solar energy can help to improve public health for the human population, in the long run.
6). The Use of Solar Energy is Economical
Like most of the other benefits which have been highlighted in this section, we have earlier mentioned the cost-saving nature of solar energy.
Being a clean, pollution-free source of energy, solar is not accompanied by any significant need for maintenance. The fact that it is a renewable source of energy also reduces the cost of use. In addition to these, continuous improvements so far, have made solar panels and their installation, to be much cheaper than before.
Employment opportunities are another economic benefit of solar energy . The solar technological industry is responsible for thousands of jobs in the United States alone, and millions of jobs around the world.
7). Produces Energy at the time of Peak Demand
We can choose to see this as the benefit of the weather-dependent nature of solar energy. Because solar energy is produced from sunlight, its production
basically occurs during the day.
At the same time, peak energy demand usually occurs during the day as will, especially between the late hours of the morning and the late hours of the evening.
This is the period during which solar radiation is mostly available. Unused energy may then be stored in batteries, for use at night or at other times when there is less sunlight available.
8). Energy Losses are Usually Small
In most energy systems, losses occur usually in the process of transporting energy from the point of production to the point of use.
Because solar energy is produced close to the point of use, transport of the energy is done over a relatively short distance. The simple configuration and design of solar systems also helps to reduce the places from which energy can be lost.
How to Improve Solar Energy: New Developments and Innovations in Solar Technology
1). Organic Solar Cells
Most solar cells (or PV cells) are made from silicon. This is because the semiconductor is very effective in its ability to convert solar radiation to produce energy. The maximum efficiency with which a silicon PV cell can convert solar energy to electricity or any other form of energy, is approximately 27-30%.
Organic solar cells are different from the typical silicon PV cells in terms of their composition. Mainly, these cells are composed of carbon polymer materials. Developments are still ongoing, to produce suitable organic solar cells with high efficiency.
The advantages of organic solar cells over silicon solar cells, include their flexibility, ease of handling, and light weight.
2). Crystalline Silicon Solar Cells
Presently, crystalline silicon PV cells are the mist commonly-used types of solar cells. They are used mainly due to their relatively low cost and fair degree of efficiency.
Recent developments in solar technology include the production of high-efficiency crystalline silicon PV cells, including hybrid tandem III-V/Si solar cells, and III-V multi-junction silicon cells. Some of these products have achieved efficiencies of up to 47% compared to the conventional silicon PV cells whose efficiencies are less than 30%.
Two important forms in which we may encounter enhanced silicon sola cells, include the bifacial cells and the multi-junction cells. Both of these types will be discussed shortly.
3). Solar Windows
Solar windows refer to a relatively new form of solar technology, by which windows in any building could be coated with transparent semiconductor sheets that generate electricity from sunlight.
We may choose to view the coating on most solar windows as a form of solar cells. These cells are able to function with a very simple setup.
4). Thin-Film Solar Cells
The unique design of thin-film solar cells presents them as one of the most potentially favorable developments in solar technology.
These cells provide the advantage of smaller size with a fair degree of efficiency as well. Typically, a thin-film solar cell is up to 350-times less than the size and thickness of the conventional silicon solar cells.
In addition to the light weight of thin-film cells, they are known to be flexible, making them relatively easy to install and maintain.
Different materials cam be used to produce thin-film solar cells. These include amorphous silicon, cadmium-telluride (CdTe), gallium-arsenide (GaAs), and copper-indium-gallium-selenide (CIGS) . So far, the CIGS thin-film solar cells have been found to have many desirable characteristics compared to other materials, in terms of cost and efficiency.
5). Passivated Emitter Rear Cell (PERC)
The PERC solar cell is simply a modification and improvement on the thin-film solar cell.
It combines the thin and flexible attributes of thin-film cells, with a more elaborate and efficient design.
PERC solar cells include two additional, thin layers attached behind the main silicon layer. These layers serve the basic purpose of improving the speed and effectiveness with which electrons travel through the solar cell.
The two additional layers also prevent solar radiation from penetrating through the PERC solar cell, rather reflecting such radiation back to the surface of the cell, where they are converted to electricity. Such a mechanisms helps by conserving solar radiation and preventing losses, while leading to greater efficiency.
However, the composition and design of PERC solar cells make them vulnerable to gradual degradation. This degradation is generally caused by exposure to light and extreme, unstable temperature, and it is referred to as; Light and elevated Temperature-induced Degradation,” (LeTID). Degradation ultimately reduces the efficiency of the cell and shortens its period of use.
For PERC cells, optimum performance will be equivalent to at most 17% loss of efficiency within a period of 25 years. It is likely, and hopeful, that recent advancements and researches in technology will help address the efficiency problem.
6). Perovskite Solar Cells
Perovskite solar cells are primarily composed of metallic halides . There are many advantages of this form of solar technology. They include low thickness, efficient absorption of sola radiation under all conditions, relatively-low cost, and temperature-tolerant characteristics.
Perovskites are a group of chemical compounds which have a similar structure to calcium titanate, and photovoltaic properties . Perovskite cells are very flexible and light-weighted. They can be printed as thin films, having efficiencies of up to 12.2%.
Another innovative method of using perovskite solar cells is by combining perovskite (metallic halide) with silicon. Such hybrid solar cells have been found to reach efficiencies above 27% (which is the maximum average efficiency of silicon PV cells).
As at 202z, perovskite cells are yet to be commercialized because more research and development is required to improve their resilience and practical usability.
7). Solar Balloons
The technology behind solar balloons can be described in a simple way.
Solar balloons are simply a globular-shaped design of solar PV cells, which usually takes the form of an array of balloons, made out of semiconductor material. In other cases, the ‘balloons’ act as solar concentrators/collectors, by helping to deflect solar radiation to the panels where it is converted to electricity
8). Half-Cell Solar Technology
The principle behind half-cell solar technology, is also a very simple one. It is built based on the observation that the efficiency and output of solar technology is proportional to the number of individual solar units (or solar cells) available in a system.
With half-cell technology, a solar panel is made to have at least twice the usual number of PV cells. This in turn requires each cell to be half the size of a conventional one; hence the name ‘Half-Cell.’ In most cases, half-cell solar panels provide at least 2-3% more efficiency than conventional solar panels.
9). Bi-facial Solar Panels
As the name implies, bi-facial solar cells provide two PV surfaces for capturing and converting solar radiation to electricity.
There has been much research on the development and use of bi-facial solar panels for several decades so far. In general, these panels provide a potential increase in efficiency by 6-9% n the average.
The concept behind bi-facial solar panels is very similar to that of the PERC panels. It includes a design to prevent loss of solar radiation which is reflected back to the PV surface when it penetrates the panel. Also, developments have helped to reduce the cost of producing, purchasing and installing bi-facial solar panels.
10). Building-integrated Photovoltaics (BIPV)
These solar systems are incorporated into a building, so that they essentially become a part of the building, rather than an external component or fixture.
An example of BIPVs is solar shingles, which are used in place of asphalt shingles in the roofs of buildings.
While these systems may reduce complexity, they often go along with high costs and maintenance requirements.
11). Heterojunction Technology (HJT)
HJT solar technology was introduced in the 1980s by Sanyo; a Japanese electrical company (later acquired by Panasonic) in a bid to improve the output and efficiency of solar PV cells .
The concept behind this solar technology, is simply an addition of a thin layer of amorphous silicon (a-Si) on either side of a poly silicon (poly-Si) or mono silicon (mono-Si) layer. These layers on either side help to absorb all solar radiation which is not absorbed by the middle layer. The setup thus described, increases the energy output of solar panels.
Whereas the typical efficiency of thin-film solar cells is about 12%, the addition of amorphous silicon in HJT solar cells increases this efficiency to above 20%. Also, the simple structure of HJT cells makes them much easier and cheaper to produce than many other solar panel types.
Another great advantage is their ability to perform well in extreme light and heat conditions. This is an improvement compared to technologies like the PERC solar cells (which we have discussed) that can be degraded over time due to heat and light exposure.
12). Concentration Photovoltaic cell (CPV)
Concentration photovoltaic cells make use of mirrors and lenses to capture and focus sunlight in a desired direction, which is often toward the surface of a solar cell or panel.
The setup is often used when large amount of solar radiation and energy output are needed. Because of the high levels of heat involved, CPV systems are not generally used in residential or corporate facilities. Rather, they are more often used in space and military operations, where the equipment involved are resilient and heat-resistant .
In some cases, also, active cooling functions are included in the solar tracking (concentration) device, to minimize potential heat damages.
Asides the heat challenges, CPV technology is relatively costly to develop and install. They also require more space and maintenance, than the more conventional solar technologies.
Careers and Companies in Solar Energy Technology
Solar Energy Careers
1). Materials Scientist/Engineer
Materials scientists and engineers are needed b by the solar energy sector, because of the continuous efforts being made to develop the most efficient, effective and resilient materials for producing solar cells and panels.
The duties of a materials scientist/engineer mainly include testing and improving on the materials used in making solar cells, batteries, inverters and wiring systems. By studying the chemical properties of various materials, these professionals are able to design and combine the best available chemical compounds to form efficient solar systems.
A job in this area requires a minimum of Bachelors’ degree in material science, engineering, or any related field. Average salaries typically range between $80,000 and $95,000 per annum.
2). Solar Sales Representative
As the title implies, this career is related solely to marketing and sales of solar technology devices and products.
Because of the technical nature of solar products, it is often necessary for solar sales representatives to be enrolled in basic technical training before taking up their responsibilities. Such training must cover the engineering capabilities, components and specifications of products, while providing the sales representative with knowledge on the important factors to consider for marketing the products.
Responsibilities of solar sales representatives vary, including assessment of potential solar installation locations, drafting of queries and proposals, as well as quotes, presentations and contract statements. Solar sales careers are lucrative in areas where renewable energy development is supported and driven by the government and related agencies.
A Bachelors’ degree is often required for this role. The degree may be in marketing, commerce, engineering or a related science field. Networking and communication are very important skills for the job, as they help in communicating effectively with prospective clients. Average salaries range broadly from $65,000-$100,000 on the average, per annum.
3). Solar Service Field Technician
Although we have mentioned severally, in this article, that solar technologies do not require much maintenance, it is yet important to have professionals dedicated to addressing the occasional maintenance issues that may arise.
The duties of a field technician in the solar energy sector, involve response and repairs of malfunctioning solar energy devices. A very common example of such issues is a faulty inverter. In such a case, either a repair or replacement will be required.
It is also the job of a service technician to consistently monitor the hardware systems of solar technologies in order to ensure that they continue functioning efficiently and effectively. Technicians may also diagnose potential problems and give recommendations on how best to minimize them.
A Bachelors’ degree is not always required, to work as a solar service technician. However, in order to fill this role, an individual must possess good skills in electrical and electronic systems management. Training programs are often available for learning these skills. The average salaries typically range between $60,000-$62,000 per annum.
4). Software Engineer
In the solar energy sector, software engineers are needed, to help with the programming aspects of solar technology.
These programming aspects include control functions and software applications for handling PV solar systems. Software engineers also help with modelling, designing and evaluating solar technologies. They may develop or make use programs that help to simulate and estimate the cost requirements and potential output of solar devices.
Based on the designs, models and simulations carried out by software engineers, training and guidance modules ate usually developed to help employees and users in handling solar technologies.
The average salary range for this role falls between $100,000 and $110,000 per annum. Very often, a degree in computer science or any related field is required. In other cases, training programs can provide the skills and certifications needed.
5). Solar Site Assessor
As the title already implies. the duties of a solar site assessor include visiting and assessing potential solar installation sites.
The purpose of assessing potential installation sites, is to determine how suitable a site is for solar energy production, and the level of efficiency and output which may be expected from such a site. While assessing sites, the solar site assessor makes very important decisions such as the best point of installation of solar panels, and the best size, type and design of solar system to be used.
From the assessment of the site, the solar site assessor then drafts recommendations which will be given to the engineers and installers to follow. This helps to ensure that users get the most suited solar technologies for their location, needs and financial capacity.
A two-year associate degree or a certification program can make one eligible for the role of a solar site assessor. The average annual salaries range between $40,000-$70,000.
6). Solar Installer
The role of a solar installer has experienced significant growth in and beyond the United of recent, because of the increase in demand for solar panels and related devices. This growth will continue in the years to come, as developments in solar technology make it more efficient, accessible and affordable.
The duty of a a solar installer is simply to transport the solar system components (panel, inverter, wiring) to the installation site, and set-up or mount them appropriately. This duty is carried out based on recommendations of the solar site assessor.
Training for this role can be received on the job, as there is usually no need for formal education or certification. The average annual salary ranges between $40,000 to $45,000.
7). Solar Engineering Technician
While the service technicians are responsible for monitoring. repair and maintenance, engineering technicians work to improve the performance, efficiency and overall output of solar systems.
The work carried out by a solar engineering technician is usually based on recommendations from the materials engineer and software engineer, who evaluate the solar devices and decide on the changes and improvements which should be made.
Skills in electrical systems operations (especially for solar technology) are needed for this role. Such skills can be acquired through training and certification programs. The average annual salary of a solar engineering technician ranges from $40,000 to $70,000.
8). Quality Assurance Personnel
This role involves assessing solar system components and identifying faults or shortcomings in the quality of their design or performance. These assessments are usually done at the same time as production is being carried out, so as to ensure that any identified problems may be solved promptly, in subsequent products.
Analysis for quality often involves the raw materials and equipment used in production, as well as the finished products themselves. Also. quality assurance personnel help to ensure that the quality of production remains consistent throughout the production process.
Average salaries range between $75,000 and $81,000 per annum. While training and certification is often used, a degree in material science, engineering and related fields may apply as well.
Quality assurance personnel usually present their recommendations in the form of detailed reports that are used to assess the quality of solar products.
9). Solar Fleet Manager
The core duty of a solar fleet manager, is to manage the logistic aspects of solar installations. These include the procurement and transport of solar equipment, and the actual process of installation.
Solar fleet managers also oversee the operations of service technicians and assess the quality of solar system output. Asides these functions, they help monitor the installed solar systems and oversee the scheduling of maintenance and repairs.
The average salary range for this role is $55,000 tp $65,000 per annum.
10). Company Lawyer
Also referred to as ‘environmental lawyers,’ solar company lawyers are responsible for representing these establishments in legal matters. Such legal matters include regulatory concerns, permits, taxes, contracts and governmental co-operations or agreements. Environment lawyers also advice the management of solar companies, on the approach to take in legal-related issues.
Companies in the Solar Energy Sector
1). JinkoSolar Holding Company Limited (JKS)
With its headquarters located in China, JinkoSolar is involved in the production of modules, and solar cells, as well as other solar energy products.
The company is a globally prominent solar panel producer, with services extending beyond China to Europe, South America, the United States, and the Middle East.
2). First Solar Inc. (FSLR)
Based in Tempe, Arizona , United States; First Solar was founded in 1999, with a dealership in photovoltaics.
Services offered by the company include solar power plant production, construction, recycling, maintenance and installation. In its production of solar panels, First Solar makes use of thin-film semiconductor technology. This enables them to produce highly efficient and resilient solar panels.
3). Azuri Technologies Ltd
Azuri Technologies was founded in the year 2012, in Cambridge, United Kingdom. The company specializes in providing pay-as-you-go solar services for off-grid buildings.
Through its services, Azuri technologies provides solar power to homes and facilities which would otherwise have no access to electricity at all.
The company offers flexible and affordable payment plans and management schedules to its customers. Components which are installed for users include television, rechargeable radio and LED lights. In addition to being a clean, renewable alternative to the grid, payment can be done in installments, making the services affordable to most potential users.
4). Canadian Solar Inc. (CSIQ)
The services offered by Canadian Solar Inc., include solar panel construction, design, and marketing. In addition to solar panels, the company produces solar inverters. system kits and solar modules.
5). UKSOL Ltd
Based in the United Kingdom. UKSOL operates with a wide geographical span that extends to other parts of the world. Its services include the delivery of affordable and high-quality solar technologies.
Its products are generally secured with a warranty of 30 years, and the company also provides monitoring, repair and maintenance services.
6). GCL-Poly Energy Holdings Ltd. (GCPEF)
Based in Hong Kong, GCL-Poly specializes in the manufacture of polysilicon PV cells, which it incorporates into most of its solar products.
7). Macro-Solar Technology Co., Ltd.
Founded in 2006, and based in Zhejiang, China, Marro-Solar Technology deals in the manufacture of solar panels. Research and Development is continuously ongoing, to improve the quality and efficiency of these products, and other services offered by the company include sale, delivery and installation of solar system components.
The company also operates in various countries in Africa, including Lebanon, South Africa, Kenya and Congo.
8). Xinyi Solar Holdings Ltd.
Xinyi Solar Holdings is a Chinese company involved in the manufacture of solar panel glass. It also offers services in delivery and marketing of solar products.
9). Haining Sunfull Solar Technology Co., Ltd.
Sunfull is a solar technology company based in Zhejiang, China. Its services include manufacture and modification of solar collectors, concentrators, water heaters, and vacuum tubes.
10). SunPower Corp. (SPWR)
Sunpower Corporation specializes in designing and building silicon PV cells among other solar products, which they market and distribute globally.
11). Elsol – Solar Energy Systems Ltd.
With headquarters in Israel, Elsol company actively produces, designs, markets and installs solar water heaters, cogeneration facilities, capacitors and solar thermal systems.
Its specialty is restricted mainly to thermal solar applications, and its services are provided to mainly industries, hospitals, and other corporate facilities. So far, it has been able to serve customers in various countries, especially within Asia and Africa.
12). GTC Solar Industry and Trade Inc.
Based in Instanbul, Turkey, GTC Solar was founded in 1995 for the sole purpose of manufacturing high-efficiency solar PV modules.
The company’s products are generally of high quality and relatively low cost. These include thin-film silicon panels and bi-facial panels.
13). Atlantica Sustainable Infrastructure PLC (AY)
With headquarters located in the United Kingdom, Atlantica Sustainable Infrastructure Plc. specializes in the marketing and distribution of solar products, alongside other renewable energy systems.
14). Yingli Green Energy Holding Co. Ltd. (YGEHY)
Based in China, Yingli Green Energy Holding Company specialises in carrying out the modification, improvement, design and building of photovoltaic system components.
15). SolarEdge Technologies Inc. (SEDG)
SolarEdge Technologies is an Israel-based, active distributor and producer of solar cell array systems and solar panels.
In addition to these services, the company carries out repair, monitoring and management of solar systems in various locations.
16). SMA Solar Technology
SMA Solar Technology is based in Germany, and offers services in production and installation of solar panels, converters, batteries and inverters.
From the discussion in this article, we have been able to understand that solar energy is derived from sunlight, which is an abundant resource on Earth. It is therefore a renewable energy.
Asides being renewable; it has been show that solar energy is one of the cleanest and pollution-free sources of energy in the world today.
The development of solar energy may be traced back to 1954, when the first PV cell was produced in Bell Laboratories
Modifications and improvements in solar technology have provided us with many new and efficient options for harnessing solar energy, along with lower costs
We have also seen that the disadvantages of solar energy are relatively minor, and include initial cost, need for space, geographical constraints, efficiency challenges. and periodic maintenance issues
Examples of developments in the solar energy sector include bi-facial solar panels, heterojunction solar cells, thin-film technology, organic PV cells, among others.
We have also reviewed some very essential career opportunities in the solar energy sector. These include jobs as a maintenance technician, software engineer, material scientist, solar site assessor, solar installer, solar fleet manager, among others. We have noted that the available opportunities in the solar sector are increasing and will continue to increase in the coming years.
Lastly, some of the leading companies in the solar energy industry have been discussed briefly, along with the specific services and products which they offer. These different subheadings make up a good, essential representation of solar energy as a concept and a practical field.
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