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What is Solar Energy? How Does Solar Energy Work?

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    What is Solar Energy?

    Solar energy refers to the light and heat from the sun, which can be utilized in raw form or harnessed and converted into usable heat or electricity. Solar energy is captured using various technologies that include solar photovoltaics and solar thermal.

    How Does Solar Energy Work?

    An illustration of how solar energy works

    Solar energy involves an exciting process of capturing sunlight and then converting it into usable electricity or heat.

    There are three types of residential solar power systems that generate electricity from the sun. They are off-grid, grid-tied, and hybrid solar systems.

    Uses of Solar Energy

    Active Solar Energy

    Active solar systems refer to those designs that incorporate other additional electrical components. There are four categories of such systems, which are solar space heating, water heating, photovoltaic cells, and concentrated solar power. Based on this, the common uses of active solar energy are:

    • Indoor and Outdoor Lighting
    • Powering appliances such as TVs, freezers, and washing machines.
    • Water pumping
    • Space heating
    • Space cooling
    • Water heating
    • Powering transportation systems such as electric cars

    Passive Solar Energy

    In passive solar energy, the system does not make use of external mechanical or electrical devices, as is the case with active solar systems. Instead, it is dependent on the exterior and interior design of a house or building. The designs either expose or shield a given space from the sun. Based on this, applications of passive include:

    • Daylighting
    • Space cooling
    • Space heating

    Types of Solar Panel Systems

    Off-Grid

    In an off-grid system, the installed system is independent of any other source of energy. It means that such a system generates electricity from the sun, which is then used during production or stored for later use. The power generated is consumed within the house or business premises. If you rely on an off-grid system, you will stay without power when the stored energy runs out, and the system is unable to generate more.

    Grid-Tied

    In grid-tied, the solar power system in place is connected to the mains. The design allows homeowners to produce their energy, and also draw from the grid whenever the need arises. Grid-tied has an advantage over the off-grid system since the owner can switch to the mains when the solar system is not generating enough power. They can also sell energy to utility companies during hours when the solar system is producing excess.

    Hybrid

    A hybrid solar system combines some elements of both off-grid and grid-tied systems. Just like in an off-grid system, those with a hybrid system can choose to rely entirely on solar energy. The reason for this is that a hybrid system has a battery bank, which can store power for later use.

    However, a hybrid system also allows the owner to either switch to the grid or sell excess energy from the sun to utility companies. Such characteristics make hybrid solar systems the most preferred over both off-grid and grid-tied systems.

    Components Found in Solar Power Systems

    The whole process of capturing sunlight and using it to generate electricity requires the combination of various parts within a solar power system. 

    Depending on the design of the solar system, the components can include solar panels, charge controller, battery bank, inverters, and net meter. They are connected using electrical cables. However, the size of the electrical cable tends to vary, depending on the items that are being linked together.

    All the components are vital. Each plays a role in ensuring that the energy from the sun is converted into usable electricity capable of powering your home or business. To better understand the significance of the components in solar power systems and how they work, let’s analyze each of them individually.

    Solar Panels

    Solar panels or modules are crucial in any solar power system. They are, therefore, present in off-grid, grid-tied, and hybrid systems.

    Panels are vital because they are responsible for capturing the rays from the sun and then using them to generate electricity. The process is made possible by the presence of solar cells in the module and the photovoltaic effect.

    Related Article: How Do Solar Panels Work?

    When the sun’s energy in the form of protons hits the surface of a panel, they are absorbed by solar cells, which make up the module. Photons then loosen electrons from the atoms that make up these cells. The free particles are then able to move across the cells, a process that results in the production of direct current (DC) electricity. The generated power from each of the cells is usually small. That is why the many solar cells in a panel are connected in series to help sum up the produced electricity.

    The amount of power that can be produced by a single panel within a given time is dependent on its electrical rating. However, you can still increase the generated electricity by installing more solar panels, which are connected to form a solar array. The more the number of modules in a given solar system, the more electricity is generated within a short period

    Depending on the physical nature of the location, solar panels can be mounted on the roof, walls, poles, and on the ground where they are to be provided with supporting stands. The only requirement is that the modules should be fixed facing the sun. Alternatively, they can be fitted with trackers, which allows them to follow the direction of the sun. The positioning ensures that the modules capture the energy from the sun for most of the day.

    Battery Bank

    Battery banks are present in off-grid and hybrid residential solar power systems. But why are storage batteries essential? They are crucial because of the limitations that come with the generation of solar energy.

    Solar panels can only generate electricity during the day. Hence, homes or businesses that rely on solar energy can lack power during the night since the solar system is not active during such hours. It then becomes necessary to store the power generated by solar panels during the day for use during the night or during those days when there is no enough sunlight.

    The need is the reason why battery banks are essential for those that rely entirely on solar energy. Batteries ensure that the electricity produced by the panels during the day is stored for later use. This guarantee those with solar systems access to power during the night and days when there is unfavorable weather.

    Charge Controllers

    Charge controllers are present in a residential solar power system with a battery bank. Thus, you can only find the component in off-grid and hybrid solar power systems. Depending on its nature, a charge controller serves various purposes in a solar power system.

    First, the most crucial role of a charge controller is to regulate the voltage or current that is flowing from the solar panels to the battery bank. Hence, it is responsible for monitoring the charging process of the batteries. The process is crucial since it protects against overcharge, which can easily damage the cells, thereby affecting the performance of the whole system.

    Charge controllers also play an essential role in blocking reverse current. During the night, panels do not generate electricity. Thus, there is the risk of power flowing back that is from the battery to the modules. The process can lead to the loss of stored energy and even cause damage to solar panels. Charge controllers ensure this does not happen since they are designed in a way that allows current to flow in one direction only.

    It is was worth noting that panels can also block reverse current. However, charge controllers ensure that they are never required to do so by providing extra protection.

    Charge controllers also have DC output terminals that allow you to connect appliances while charging batteries. The terminals provide DC electricity, which means that they can only power up DC devices or machines such as DC lights.

    Inverter

    An inverter is a crucial component in any modern solar power system. In case you are still wondering why that is the case, here is the reason.

    Solar panels generate DC electricity. This type of power cannot be used directly by most of the appliances available in the market today. Hence, there is a need to convert the produced DC power into AC, which is the most commonly used type of electricity.

    An inverter is the only device that can change DC to AC, which makes it a necessary component of any solar power system. Hence, unlike charge controllers and batteries, inverters can be found in an off-grid, grid-tied, and hybrid systems.

    But how do inverters work in each of the three solar power systems?

    In an off-grid system, an inverter converts the DC electricity stored in the battery bank into AC power. The power is then utilized within the home or business premises in the same way as the mains.

    In a grid-tied system with no battery back-up, an inverter directly converts the DC electricity been produced by solar panels into AC power. It means that DC power is not stored first before it is changed, as is the case with off-grid systems. The AC electricity is then used within the home or business while the excess is fed into the national grid.

    In a hybrid solar system, installed inverters convert the DC electricity from the battery bank to AC. Similar to a grid-tied system, the power from the inverter is not only supplied within the house but can also be sold to utility companies.

    Net Meter

    A net meter is a component in a solar power system that measures the amount of energy consumed by a customer from the grid against what they have supplied to the network.

    As noted, residential solar power systems can sometimes generate more electricity than required. Under such circumstances, nations such as the United States have energy policies that permit the owner to sell the surplus energy to utilities by feeding it to the grid.

    If you are a homeowner and you decide to sell the excess, then you require a device to measure and show the amount of energy that you have fed to the grid. It is in such a case that net metering comes in. It measures the amount of energy supplied to the grid against what a house or business takes from the mains during hours when the solar system is not producing enough. Thus, the meter can sometimes run forward or in reverse.

    It should be noted that net metering only applies to grid-tied and hybrid solar systems. The main reason being that they are the only solar systems connected to the grid.

    Benefits of Solar Energy

    It Reduces Energy Bills

    Solar energy help reduces energy bills by helping you avoid or minimize dependence on the costly power from the grid.

    Individuals who do not own a solar power system but are supplied with electricity generated by solar plants also benefit from reduced energy costs. How?

    The cost of production is usually small compared to when traditional sources of energy are used. Thus, the price per unit of power supplied to the consumer also tend to reduce.

    Solar Energy is Renewable

    Solar energy is obtained from a free and inexhaustible source, which is the sun. Thus, unlike fossil fuels, solar energy cannot be depleted but will continue to provide power to future generations.

    Solar Energy is Generated from any Location

    Unlike other types of energy, solar power can be produced from any geographical location. The reason for this is that the sun shines across the world. It then becomes possible to harness solar energy from almost anywhere.

    The ability to generate solar energy from any location benefits those living in rural and remote areas, and far from the grid. Why? They can install off-grid solar systems that will provide them with the power they need.

    Solar Energy Creates Jobs

    Solar energy create jobs

    Solar energy benefits the community by creating employment opportunities. It increases the demand for solar-related products, which then leads to the emergence of new companies and the growth of existing ones. It also increases the need for solar technicians who are responsible for designing and installing solar power systems.

    All these contribute to an increase in job opportunities, which has a positive impact on communities. For instance, it can lead to improved standards of living and economic growth

    It Does Not Harm the Environment

    One of the main advantages of solar energy is that it is a renewable resource. Thus, unlike traditional energy sources such as coal, it does harm the environment by emitting toxic material into the surrounding. It is, therefore, one of the energies whose increased use contributes to a sustainable future.

    Solar Energy Has Low Running and Maintenance Costs

    Solar energy is a profitable long term investment due to the little maintenance costs associated with the systems.

    Many of the components that make up the systems are durable, with some such as solar panels having a warranty of even 20 years. Thus, once a solar power system is installed, the cost of running and maintaining it is usually small, making it a profitable long term investment.

    John Gathuita
    John Gathuita

    John is an electrical and solar technician, writer, and blogger who specializes in renewable energy, sustainability, and technology. He seeks to inspire more people to adopt solar energy and to work towards a sustainable future.