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

The amount of sunlight that strikes the earth’s surface in an hour and a half is enough to handle the entire world’s energy consumption for a full year.

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.

Solar energy is a powerful source of energy that can be used to heat, cool, and light homes and businesses.

What is Solar Energy?

Solar energy is a form of renewable energy that is generated by harnessing the energy of the sun. It is a clean and abundant energy source that can be used to power homes, businesses, and communities.

Solar energy is created by using photovoltaic (PV) cells, which are made of semiconductor materials that convert sunlight into electricity.

These cells are usually installed on the roof or in a sunny location, and they are connected to an inverter that converts the direct current (DC) electricity generated by the cells into alternating current (AC) electricity, which can be used to power household appliances and other devices.

There are several benefits to using solar energy. It is a renewable and clean energy source that does not produce any greenhouse gases or other harmful pollutants. It is also a reliable energy source, as the sun is always shining somewhere on the earth.

Additionally, solar energy can be used to power homes and businesses in remote locations, where it may be difficult to access traditional energy sources.

Overall, solar energy is a promising technology that has the potential to significantly reduce our reliance on fossil fuels and help mitigate the impacts of climate change.

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.

How Does Weather Affect Solar Energy?

Weather can have a significant impact on the amount of solar energy that is generated by a solar panel system.

Solar panels are most effective at producing electricity when they are exposed to direct sunlight, so cloudy or overcast conditions can reduce the amount of electricity that is produced.

Similarly, heavy rain, snow, or ice can also obstruct sunlight and reduce the efficiency of solar panels.

However, solar panel systems are designed to be able to withstand a wide range of weather conditions and are generally durable enough to withstand normal weather patterns.

In fact, many solar panel systems are able to continue generating electricity even during cloudy or overcast conditions, although the amount of electricity produced may be reduced.

Overall, the impact of weather on solar energy generation can vary depending on the specific location and climate of the area where the solar panels are installed.

In general, solar energy is most effective in sunny, dry climates, but it can still be a reliable source of energy in other weather conditions as well.

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.

#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

The more we can capture the benefits of solar energy, the less we will rely on fossil fuels. Adding a solar energy system to your home allows you to tap into these solar energy advantages:

#1. Solar panels are increasingly affordable.

Residential solar is more affordable than ever, especially with the extension of the federal residential solar tax credit.

Taxpayers can claim a 30% tax credit on the cost of solar systems on their income taxes. But be sure to install before January 1, 2033, when the tax credit is set to decrease to 26%.

There are also a number of different financing options to make purchasing solar systems easier and with less money upfront.  The monthly amount owed on a solar loan is typically less than an average utility bill.

#2. You can save money by going solar.

Solar offers great potential to save money on your monthly utility bill, and with utility bills trending upward, solar is likely to remain a good money-saving option for years to come.

The amount you save depends upon how much electricity you consume, the size of your solar energy system, and how much power it is able to generate.

You may also opt for a leased, third-party owned system that allows a homeowner to host a solar energy system on their rooftop and purchase back the electricity generated at a discounted rate, which is not only is often less than utilities charge customers, but also allows electricity rates to be locked in for years.

#3. You can keep the lights on when the grid goes down.

Generating your own solar power can give you the freedom to keep the lights on if there’s a disruption in power.

Residential solar energy systems paired with battery storage—generally called solar-plus-storage systems—provide power regardless of the weather or the time of day without having to rely on backup power from the grid.

As battery technology improves and financial incentives for energy storage go into effect, deciding to invest in battery storage makes sense for more households across the nation.

#4. Solar will often increase the value of your home.

Buying a solar energy system will likely increase your home’s value.

A Berkeley National Laboratory study found that solar photovoltaic panels are viewed as upgrades, just like a renovated kitchen or a finished basement, and home buyers across the country have been willing to pay a premium for a home with an average-sized solar array.

As for third-party owned systems, it appears that the impact is largely neutral but can occasionally add value, especially for prepaid leases.

#5. Solar systems work in a variety of climates.

Solar panels only need one thing to generate electricity — sunshine! Even in the winter when there are fewer hours of daylight, there is still a sufficient amount to power the average American home. That makes solar viable even in Alaska with longer, colder winters.

The U.S. Department of Energy’s Solar Energy Technologies Office (SETO) is dedicated to ensuring solar panels can withstand the elements no matter your location. 

SETO funds five Regional Test Centers across the country — each in a different climate — to make sure panels perform as best they can, regardless of climate or weather.

Disadvantages of Solar Energy

The disadvantages of solar energy are becoming fewer as the industry advances and grows, creating economies of scale. Technological advances are helping solar go mainstream. Here are how the disadvantages of solar energy and the pros and cons stack up.

#1. The high initial costs of installing panels.

The most commonly cited solar energy disadvantage, cost, is declining as the industry expands. The initial cost to buy and install the equipment is not cheap. Still, if cost is an issue, leasing options may reduce the amount of your initial outlay.

If you do choose to buy, you will need to live in your home for a number of years before the system pays for itself. It’s a long-term investment better suited to property owners than renters.

#2. Solar energy storage is expensive.

Of the disadvantages of solar energy, the temporary decline in energy production during bad weather has been a major issue. Days with low solar energy, however, are having less of an effect due to advances in battery technology.

Old technology for storing solar energy, like lead acid batteries are being replaced by alternatives. Lithium ion batteries offer greater power at a lower cost.

Nickel-based batteries have an extremely long life. New technologies, like flow batteries, promise scale and durable power storage.

#3. Solar doesn’t work for every roof type.

Not every room will work well with solar panels. Orientation matters. If your roof doesn’t face the sun, you won’t be able to capture enough solar energy. Roofs that angle into the sun tend to work better than flat roofs.

Roofing materials like asphalt shingles, metal and tiles make installing solar panels easier. If your room is made with other materials, installation may be more expensive. Part of what makes energy-efficient roofs is their ability to support solar panels.

#4. Solar panels are dependent on sunlight.

It’s obvious that solar panels need sunlight to generate electricity. They won’t produce electricity at night when you need it for light and they can be inefficient during storms and gloomy days.

Your solar energy system needs batteries if you plan to fully depend on solar energy to power your home.

Batteries are one of the more expensive components of your system. Unlike solar panels, they do wear out and need careful maintenance to lengthen their lives.

Comparing wind power vs. solar power, wind will keep generating electricity at night and during storms, as long as there is enough wind. Many people use both in residential systems.

FAQs.