What is Solar Energy?- Definition, Types, & Working

What is Solar Energy?

Solar power is energy from the sun that is converted into thermal or electrical energy. Solar technologies can harness this energy for a variety of uses, including generating electricity, providing light or a comfortable interior environment, and heating water for domestic, commercial, or industrial use.

Solar energy is the cleanest and most abundant renewable energy source available, and the U.S. has some of the richest solar resources in the world. Solar energy is a powerful source of energy that can be used to heat, cool, and light homes and businesses.

More energy from the sun falls on the earth in one hour than is used by everyone in the world in one year. A variety of technologies convert sunlight to usable energy for buildings. The most commonly used solar technologies for homes and businesses are solar photovoltaics for electricity, passive solar design for space heating and cooling, and solar water heating.

Businesses and industries use solar technologies to diversify their energy sources, improve efficiency, and save money. Energy developers and utilities use solar photovoltaic and concentrating solar power technologies to produce electricity on a massive scale to power cities and small towns.

How does solar energy work?

When the sun shines onto a solar panel, energy from the sunlight is absorbed by the PV cells in the panel. This energy creates electrical charges that move in response to an internal electric field in the cell, causing electricity to flow.

Our sun is a natural nuclear reactor. It releases tiny packets of energy called photons, which travel 93 million miles from the sun to Earth in about 8.5 minutes. Every hour, enough photons impact our planet to generate enough solar energy to theoretically satisfy global energy needs for an entire year.

Currently, photovoltaic power accounts for only five-tenths of one percent of the energy consumed in the United States. But solar technology is improving and the cost of going solar is dropping rapidly, so our ability to harness the sun’s abundance of energy is on the rise.

In 2017, the International Energy Agency showed that solar had become the world’s fastest-growing source of power marking the first time that solar energy’s growth had surpassed that of all other fuels. Since then, solar has continued to grow and break records around the globe.

When the sun shines onto a solar panel, energy from the sunlight is absorbed by the PV cells in the panel. This energy creates electrical charges that move in response to an internal electric field in the cell, causing electricity to flow.

How Does Weather Affect Solar Energy?

Weather conditions can impact the amount of electricity a solar system produces, but not exactly in the way you might think.

Perfect conditions for producing solar energy include a clear sunny day, of course. But like most electronics, solar panels are actually more efficient in cold weather than warm weather. This allows the panel to produce more electricity in the same amount of time. As the temperature rises, the panel generates less voltage and produces less electricity.

But even though solar panels are more efficient in cold weather, they don’t necessarily produce more electricity in the winter than in summer. Sunnier weather often occurs in the warmer summer months. In addition to fewer clouds, the sun is usually out for more of the day. So even though your panels may be less efficient in warm weather, they’ll still likely produce more electricity in summer than in winter.

Solar Technologies

There are three ways to use solar energy: photovoltaics, solar heating and cooling, and concentration of solar energy. Photovoltaics generate electricity directly from sunlight through an electronic process and can be used to power everything from small electronic devices like calculators and traffic signs to households and large commercial operations.

Solar heating and cooling (SHC) and concentrating solar energy (CSP) applications both use the heat generated by the sun to provide space or water heating in SHC systems or to run conventional power generation turbines in CSP power plants.

Types of solar Energy

Photovoltaic technology directly converts sunlight into electricity. Solar thermal technology harnesses its heat. These different technologies both tap the Sun’s energy, locally and in large-scale solar farms.

Two major technologies have been developed to harness it:

  • Photovoltaic solar technology, which directly converts sunlight into electricity using panels made of semiconductor cells.
  • Solar thermal technology, which captures the sun’s heat. This heat is used directly or converted into mechanical energy and in turn electricity, known as concentrated solar power. This heat is used directly (low‑temperature solar thermal) or converted into mechanical energy and in turn electricity (concentrated solar power – CSP).

1. Photovoltaic Solar Power

The photovoltaic effect (or photoelectric effect) converts light into electricity. It was discovered by the French physicist Edmond Becquerel in 1839 and first used in industrial applications in 1954. The principle: an electric current is created when electrons are displaced. To do this, photons (light particles) stimulate the outermost electrons of the atoms of certain semiconductor elements.

In practice, light that hits a photovoltaic cell is converted into electricity by a semiconductor, generally silicon. A photovoltaic module consists of several cells that generate direct current, which is then converted into alternating current by an inverter. Panels can be used in small systems or large plants.

2. Solar Thermal

Solar thermal is a well-proven technology delivering energy and carbon savings. A solar thermal system works by harnessing is the sun’s energy and converting it into heat which is then transferred into your home or business’s heating system as hot water or space heating.

Solar thermal panels are used in conjunction with a boiler, collector, or immersion heater. The solar collector will use the sun’s rays to heat a transfer fluid which is a mixture of water and glycol, to prevent the water from freezing in the winter. The heated water from the collectors is pumped to a heat exchanger inside a water cylinder. The heat from the exchanger will then heat the water inside the cylinder.

After the liquid releases its heat, the water will flow back to the collectors for reheating. A controller will ensure that the fluid will circulate to the collector when there is sufficient heat available. Solar thermal technology is proven reliable and low maintenance.

Solar Thermal Technology

3. Concentrated Solar Power

This second type of thermal solar energy technology concentrates the heat of the sun’s rays with the help of collectors in order to heat a transmission fluid (e.g. gas, oil or molten salt) to a high temperature. The liquid heats a network of water that creates steam and drives a turbine (mechanical energy), which generates electricity.

The heat from the sun’s rays is collected in large power plants in which flat or curved mirrors are installed over large areas. The technology is best suited to countries where sunlight is intense, such as desert regions.

4. Solar power plants

In the Solar power plant that we can use the solar energy of the sun for energy commonly used in industrial applications. As we all know that most power plants use non-renewable fossil fuels to boil water.

The steam from boiling water rotates a large turbine which in turn activates the generator to produce electricity. This method of generating electricity is bad for both the environment and our health as the burning of fossil fuels emits greenhouse gases and air pollutants.

However, the good news is that a new generation of power plants is launching which relies on solar energy.

These plants use the sun as a heat source, and they can do this in three different ways:

  • Parabolic-trough systems capture the sun’s energy throughout long rectangular, curved mirrors that tip toward the sun. In this way, they help to concentrate sunlight on a pipe that contains oil. Oil is heated and used and used to boil water in a conventional steam generator to generate electricity.
  • A dish/engine system uses a mirrored dish the size of a very large satellite dish that receives and focuses the sun’s heat on a receiver. This receiver consumes heat and transfers it to the fluid within an engine. The heat causes the fluid to circulate against the piston or turbine and produces mechanical strength. This electricity is used to run a generator or alternator to generate electricity.
  • A power tower system uses a large area of mirrors to focus sunlight on top of a tower, where a receiver containing molten salt sits. Salt heat is used to generate electricity through conventional steam generators. The molten salt efficiently retains heat, so it can be stored for days before being converted into electricity. This means that electricity can be produced even on cloudy days or several hours after sunset.

5. Solar Water Heating System

The idea behind the Solar water system comes directly from nature: the shallow water of a lake or the water at the shallow end of a beach is generally warmer than deep water. This is because sunlight can heat the lake or sea floor in shallow areas, which in turn heats the water.

Therefore, a system has been developed to mimic this: the solar water heating system for buildings compose of two parts, a solar collector and a storage tank.

The most common collector is calling a flat-plate collector mount on the roof and facing the sun. Small tubes run through the box and carry fluid – either water or other liquids, such as an anti-freeze solution – to heat. As the heat increases in the collector, it heats the fluid passing through the tubes. The storage tank then contains the hot liquid.

A similar technique is often used to heat swimming pools.

6. Passive Solar Heating

Another method that solar energy can be used is through passive solar heating and the daylight method. This is not a new concept – in fact, ancient civilizations such as the Anasazi Indians in Colorado developed the passive solar design in their habitats.

It is easy to understand the effect of the sun: step outside on a hot sunny day and you can feel the sun. With a decent design, buildings can also “feel” the sun’s energy.

For example, south-facing windows will receive more sunlight, while buildings can also contain the heat and absorb materials of the sun, such as sun floors and walls.

These materials heat up during the day and gradually release heat at night when the heat is most needed. Other design features, such as a sunspace that resembles a greenhouse, concentrate too much heat that can use to heat an entire building with the right ventilation.

Such features maximize the direct benefit from the sun’s heat, but also the sunlight itself. The even better news is that especially on hot days, there are ways to ensure that these facilities do not overheat buildings.

Advantages of Solar Energy

Solar energy offers considerable advantages over conventional energy systems by nullifying flaws in those systems long considered to be unchangeable. Solar power for home energy production has its flaws, too, which are outlined in another article, but they’re dwarfed by the advantages listed below.

The following are advantages of solar energy:

  • Raw materials are renewable and unlimited. The amount of available solar energy is staggering roughly 10,000 times that currently required by humans and it’s constantly replaced. A mere 0.02% of incoming sunlight, if captured correctly, would be sufficient to replace every other fuel source currently used.
  • Solar power is low-emission. Solar panels produce no pollution, although they impose environmental costs through manufacture and construction.
  • Solar power is suitable for remote areas that are not connected to energy grids.
  • Solar power provides green jobs. Production of solar panels for domestic use is becoming a growing source of employment in research, manufacture, sales and installation.
  • Solar panels contain no moving parts and thus produce no noise. Wind turbines, by contrast, require noisy gearboxes and blades.
  • In the long run, solar power is economical. Solar panels and installation involve high initial expenses, but this cost is soon offset by savings on energy bills.  Eventually, they may even produce a profit on their use.
  • Solar power takes advantage of net metering, which is the practice of crediting homeowners for electricity they produce and return to the power grid.
  • Solar power can mean government tax credits. U.S. federal subsidies credit up to 30% of system costs, and each state offers its own incentives. California, blessed with abundant sunshine and plagued by high electric rates and an over-taxed grid, was the first state to offer generous renewable-energy incentives for homes and businesses.
  • Solar power is reliable. Many homeowners favor solar energy because it is virtually immune to potential failings of utility companies, mainly in the form of political or economic turmoil, terrorism, natural disasters, or brownouts due to overuse. The Northeast Blackout of 2003 unplugged 55 million people across two countries, while rolling blackouts are a part of regular life in some South Asian countries, and occasionally in California and Texas.
  • Solar power conserves foreign energy expenditures. In many countries, a large percentage of earnings is used to pay for imported oil for power generation.

Disadvantages of Solar Energy

While the considerable advantages offered by solar energy move some proponents to ignore the budding technology’s comparatively minor flaws, these imperfections must be acknowledged, lest their resolutions are stalled. We should take an honest look at the system’s disadvantages and seek to refine solar energy systems into truly environmentally friendly alternatives.

The most significant complaints with solar energy are:

  • lack of consistency and reliability. Solar systems rely on the steady absorption of sunlight particularly, subatomic particles called photons, which can be easily deterred.
  • Size. To power an entire building, a large solar array is required. It’s unfortunate that photovoltaic technology is still in its infancy but, for now, we must build large arrays to compensate for the inefficiencies of single panels. A bulky mechanical orientation system may also be required to turn the panels as they follow the sun across the sky. Batteries, too, can take up a fair amount of space.
  • Panel deterioration. Like anything else left out in the sun, solar panels gradually become damaged by ultraviolet radiation. Rain, snow, dirt, temperature fluctuations, hail and wind also pose serious hazards.
  • Cost. The number of solar array panels needed to capture energy for an entire home typically costs tens of thousands of dollars, making the electricity they produce cost substantially more than that provided by conventional power sources.
  • Environmental pollutants. A few of the more notorious substances contained in panels and associated equipment include. Cadmium. When sealed inside solar panels, cadmium is harmless. If leaked from the panel, cadmium can inflict serious environmental damage. Lead. Batteries, specifically deep-cycle, lead-acid batteries, are required by solar arrays to ensure a constant supply of electricity. They contain lead and sulfuric acid, which are both highly toxic, especially to marine creatures.
  • Roof considerations. Solar arrays are often installed on building roofs to make use of the large, empty, sunny space. As a consequence, repairs to the underlying roof become quite tricky and often require disassembly of the solar installation before even routine roof maintenance can be performed.
  • Appearance. Like it or not, solar arrays speak loudly, and neighbors and passersby will take notice of the systems. Many homeowners are understandably reluctant to install a large solar array on an otherwise attractive tile roof. This issue is being addressed through the development of photovoltaic shingles, windows, and other technologies that blend more seamlessly with existing roof surfaces.


What is Solar Energy?

Solar energy is the radiation from the Sun capable of producing heat, causing chemical reactions, or generating electricity. The total amount of solar energy received on Earth is vastly more than the world’s current and anticipated energy requirements.

What is solar energy in simple words?

The answer is simple: solar energy. Solar energy is simply the light and heat that come from the sun. People can harness the sun’s energy in a few different ways: Photovoltaic cells, which convert sunlight into electricity.

What are 5 advantages of solar energy?

Advantages of Solar Energy:

  • Renewable Energy Source. Among all the benefits of solar panels, the most important thing is that solar energy is a truly renewable energy source.
  • Reduces Electricity Bills.
  • Diverse Applications.
  • Low Maintenance Costs.

How does the solar energy work?

Essentially what happens is that solar panels record the sun’s energy and then work to convert that energy into power for your home. After sunlight hits solar panels, it’s captured within photovoltaic cells and transported to an inverter where it’s converted from direct current DC electricity to usable AC electricity.

What are the 2 main disadvantages to solar energy?

The main drawbacks to solar energy are:

  • Reduced power output in cloudy weather.
  • Zero output at night.
  • Solar panels can’t store electricity.
  • Solar energy is direct current and needs converting for a.c. Appliances.
  • Solar panels are inefficient, 20% maximum.

How do you explain solar energy to a child?

Solar power is power generated directly from sunlight. Solar power can be used for heat energy or converted into electric energy. When we use solar power, we don’t use any of the Earth’s resources like coal or oil. This makes solar power a renewable energy source.

What are the two uses of solar energy?

Solar energy is commonly used for solar water heaters and house heating. The heat from solar ponds enables the production of chemicals, food, textiles, warm greenhouses, swimming pools, and livestock buildings. Cooking and providing a power source for electronic devices can also be achieved by using solar energy.

Why do we need solar power?

Solar power systems derive clean, pure energy from the sun. Installing solar panels on your home helps combat greenhouse gas emissions and reduces our collective dependence on fossil fuel. Traditional electricity is sourced from fossil fuels such as coal and natural gas. Renewable energy also improves public health.

Why is solar power important?

Solar energy is energy derived from sunlight. Whether you realize it or not, the sun already powers our planet, providing the necessary energy to keep our environment and population growing. Solar energy can be used to provide heat, light, and other electricity-dependent needs in homes and buildings.

Does solar energy work at night?

Do Solar Panels Produce Energy at Night? Technically, no. Solar panels do not produce energy at night. The photovoltaic cells in solar panels must have sunlight to create electricity.

What is the biggest problem with solar energy?

One of the biggest problems that solar energy technology poses is that energy is only generated while the sun is shining. That means nighttime and overcast days can interrupt the supply.

Who invented solar energy?

In 1939, Russell Ohl created the solar cell design that is used in many modern solar panels. He patented his design in 1941. In 1954, this design was first used by Bell Labs to create the first commercially viable silicon solar cell.

How does solar energy affect the environment?

Solar energy technologies and power plants do not produce air pollution or greenhouse gases when operating. Using solar energy can have a positive, indirect effect on the environment when solar energy replaces or reduces the use of other energy sources that have larger effects on the environment.

How is solar energy produced?

Solar technologies convert sunlight into electrical energy either through photovoltaic (PV) panels or through mirrors that concentrate solar radiation. This energy can be used to generate electricity or be stored in batteries or thermal storage.

Why solar energy is the future?

Solar can be considered the way of the future due to its versatility. This means that wherever people choose to live their lives, solar energy will always be there to help. In other words, people can rely on the sun for energy. Unlike fossil fuels, sunlight can be a guaranteed resource of energy.

Is solar electricity safe will it burn us?

Overall, the small risk of your solar system causing a fire is, for most people, not enough to turn them off to installing solar altogether. It’s no riskier than any other electrical system within your building.

Do solar panels work in rainy season?

Absolutely yes. Solar panels generate 30 % – 50 % of their optimum generation during cloudy weather and 10 % – 20 % of optimum generation in heavy rain.

Can a house run on solar power alone?

It is possible to run a house on solar power alone. However, going completely off-grid requires a considerable financial and time investment. The higher your energy requirements, the more solar panels you’ll need.

Why solar energy is not popular?

The sun offers the most abundant, reliable, and pollution-free power in the world. However, problems with solar energy, namely the expensive cost and inconsistent availability, have prevented it from becoming a more utilized energy source.

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