What is Solar Energy? Everything You Need to Know

At no point in our species’s history has the human race relied on, obtained, and consumed more energy than we do today. 

Yet, even then, with all our machines, factories, and gadgets, the earth’s surface receives more energy from solar radiation in an hour than all seven billion of us collectively consume in an entire year. Simply put, that bright disk can provide us with a year’s worth of energy in less time than it takes to get a tan on your favorite summer beach.  

Harnessing the power of the Sun

Fortunately, not all that power goes to waste. Advances in technology have allowed us to harness the sun’s energy, albeit a tiny fraction, and use it in our day-to-day lives. This is what is solar power; usable energy (electric or thermal) generated from the sun. In our world, it is usually harnessed using solar panels, ovens, water heaters, and cookers. 

Table of Contents

A history of solar energy

Solar energy has been around since the big bang. However, our species started utilizing it around the 7th century BC, when humans used magnifying glass materials to light fires. Four centuries later, the Greeks and Romans were using mirrors to light torches during religious ceremonies. This practice was adopted by ancient civilizations, among them the Chinese, in 20 A.D.   

From Solar Death Ray to Power Tower, Solar Energy has come a long way since 3rd Century BC

Sunrooms are another example of early uses of solar energy, and unlike the rest, they are still common today. These were made popular by the Roman bathhouses, which were typically south-facing rooms with massive windows that concentrate sunlight in one area. 

In the 18th and 19th centuries, harnessing solar radiation became a little more sophisticated. Researchers and scientists successfully created solar-powered ovens for sailors during long voyages and, later on, harnessed sunlight to fuel solar-powered steamboats. 

But the most significant strides took place with the discovery of the photovoltaic (PV) effect and the development of solar panel technology between the mid 19th and the mid 20th centuries. Of course, there is plenty of debate over when exactly the invention took place and who takes the credit for it. But it’s pretty safe to say that it all came together thanks to the cumulative efforts of curious and brilliant scientists from Europe and America. 

The most notable include the French scientist Edmond Becquerel, who discovered the photovoltaic effect in the 1800s. He determined that sunlight could create an electric current when shone upon an electrode submerged in a conductive solution. While this hypothesis was true, early PV technology was extremely inefficient.  

This remained the case until Daryl Chapin, Gerald Pearson, and Calvin Fuller of Bell Labs created the first silicon PV cell in 1954. Then, for the first time in history, solar energy could power an electric device for several hours despite the first silicon solar cell converting only 4% of the solar energy. 

Today, the technology has improved, with the average modern PV cell achieving well over 20% efficiency. Still, solar panels have a long way to go before we can fully harness the sun’s energy to generate electricity for all our needs. 

How is solar energy used today?

Utilizing considerably better PV technologies, solar energy has several applications in our modern world. 

Solar Electricity

There are several uses of Solar Energy at the moment and here are only a few

This is the most popular and fastest-growing application of solar technologies in the United States and the world.  Therefore, the bulk of this article will center around solar electricity tips, statistics, usage, and trends in the country. 

Solar water heating

Solar energy systems are also used to provide water heating solutions in homes across the country. This technique uses rooftop cells to absorb and transfer the sun’s heat to the water tank. 

Though quite common in the southern and southwestern US, warming swimming pools is a less popular application of solar heating solutions. It usually involves circulating water in a collector heated by sunlight, then pumping it back to the pool. 

Solar lighting

Solar lights are probably the most common and readily available forms of solar technology in the country. They are typically used in home landscaping and road signs and can be found as security lights, street lights, and torches.   

Solar lighting equipment is relatively inexpensive and easy to purchase from online shopping websites and hardware stores. 

Portable solars

Portable PV chargers have also been developed to assist those always on the go manage their electric-powered gadgets better. There are also watches with in-built solar cells, and it’s the technology needed to integrate PV cells into modern phones already exists. 

Solar thermal energy

Modern solar heating systems for homes already exist in the market. However, these are quite sophisticated and not as popular as most other items on the list. 

A much older technique includes implementing a passive solar home design by carefully selecting building materials and considering the placement of windows. If done right, it’s the cheapest and easiest way to heat homes and business spaces since it uses passive solar energy. 

Solar ventilation

 There are also solar ventilation technologies that can help cool homes and businesses during the summer.  

Solar transportation

Fully solar-powered transportation is the least popular application of solar energy, probably due to the technology still being in its infancy and the costs of development remaining quite high.  

However, solar-powered airplanes, buses, cars, and trains exist. In addition, many EVs and electric cars can also be charged using solar panels. 

Solar electricity by the numbers

The solar industry has experienced rapid growth over the past decade, making solar energy the fastest-growing electricity source in the United States.  In fact, it is expected to account for half of all renewable energy generation in the US by 2050.

Just how fast is solar power growing? Consider this: It took the industry 40 years to complete its one-millionth installation. Just three years later, in 2019, the Solar energy Industry Association (SEIA) and Wood Mackenzie Power & Renewables announced that the country was now home to more than 2 million solar installations. 

By the end of the year, experts forecast that there will be 3 million installations, and the number would have grown to 4 million in 2023. In 2024, experts predict that, on average, there will be one solar installation per minute, up from one installation every 10 minutes in 2010.  

This explosion is largely due to the evolving solar energy technologies that have made solar panels more efficient and contributed to their increasingly falling prices. In the past ten years alone, the average cost of installing a solar panel has fallen by 60%, with experts predicting that these prices will continue to fall. Also, more people are becoming conscious of preserving the earth’s valuable resources by resorting to renewable energy sources whenever possible.  

For now, though, solar energy accounts for 1.6% of the country’s total electricity generation. Cumulatively, the U.S has around 81.4 GW of solar power installed in more than 2 million commercial, residential, and utility-scale establishments. This energy is enough to power 15.7 million of the 126 million households in the country. 

Solar panels and how they work

Solar panels are the equipment used to convert light from the sun into electricity for use in commercial and residential settings. They typically consist of photovoltaic cells, each of which is contained within a larger silicon cell. The silicon cell is in turn encased in glass and metal to protect it from the elements. 

Several layers form a single panel that produces energy coming from the Sun.

The photovoltaic cell is the most crucial component of a solar panel. How does it work? Typically, a PV cell is made of semiconductor material, usually silicon, that absorbs photons emitted by the sun. These tiny packets of energy carry solar radiation, and once they strike the semiconductor material, they release electrons from the silicon atoms. 

The surface of the PV cell is usually coated by anti-reflective material to minimize photon loss during reflection. 

Usually, the silicon layer on top is doped with phosphorus atoms (has one more electron than silicon), and the other layer is doped with boron atoms (has one less electron than silicon). As a result, the cell creates an electric field when the electrons are excited by light photons, pulling those displaced electrons into a directional current. 

Wires then feed the direct current (DC) to a solar inverter which converts it to alternating current (AC), which is what you need to turn on and run your home appliances. Normally, inverters are placed as close as possible to the solar panels. However, they usually make some noise when generating electricity, so consult your solar installer for the best position to put your inverter. 

From here, the AC flows to your fuse box, from where it’s distributed throughout your home.   

Types of solar installations

Most solar panel installations use the same technology but differ in purpose, size, location, and price. Installations are generally categorized into four groups; residential, commercial, community solar, and utility solar. 

The initial cost of a residential installation can go up to thousands of dollars but will save you money in the long run

Residential solar

These are installations typically found in homes and residences. Most residential solar systems are rooftop installations, although it’s possible to have ground installations. Also, most of them send their electricity directly to your home and transfer any excess to the grid. This offsets your electricity bill in a process called net metering

Commercial and industrial solar

These are the solar energy systems installed in any business, regardless of the size. You can see such installations on rooftops in small businesses to parking lot canopies and wide-open fields in larger establishments. 

Utility-scale solar

Today, power plants are increasingly incorporating large-scale establishments of renewable energy resources like solar energy to provide electricity. Utility-scale solar installations can get massive, ranging anywhere from 500 to 30,000 times the size of residential solar installations. 

Community solar

These are large-scale solar farms designed to make solar power accessible to people and sometimes businesses that can’t install solar panels on their premises. The farm is usually situated in an open area around the neighborhood where the solar energy is directed. 

To go off-grid or stay on-grid

Many homeowners often wonder whether their solar installations can allow them to go completely off-grid. After all, the more disconnected you are from the grid, the less your monthly utility bills. 

Off-grid solar

Off-grid generally means you get all your power from your home’s solar system, even at night and during bad weather. For it to happen, you need to connect a solar battery bank to your home installation. That way,  surplus energy generated during the day is stored in the battery for use at night. And since you don’t rely on the grid for electricity, you don’t have to pay electricity bills. 

While this sounds great, it’s not as easy as it sounds. First, you have to find a reliable battery with enough capacity to cater to your daily energy needs, plus any surplus demands. Even then, city zoning laws have restrictions that prevent homes from going completely off-grid. So, you’ll still be paying that bill, even with a battery installed. 

On-grid solar

On-grid solar is probably what you already have or will have when you decide to install solar energy equipment. Such systems are designed to supplement the home’s electricity demand. They don’t necessarily require a battery bank as surplus electricity is sent to the grid, allowing you to enjoy the cost-saving benefits of net metering.

 In the case of a battery bank, the generated electricity first fills the battery before sending any excess electricity back to the grid for net metering. 

Is solar energy renewable?

Perhaps the biggest appeal to solar energy lies in the fact that it’s a renewable source. The sun provides more than a year’s worth of the earth’s energy in one hour and will continue shining for the next 5 billion years. 

See our related article where we explain the 5 Renewalable Energies of the Future.

Even if we wanted to, there doesn’t exist a world out where we completely exhaust solar energy.  And by the time the sun dies and can no longer be harnessed for power, the human would probably have moved on to a new solar system in an Earth-like planet with a sun-like star. 

Fortunately, the same can’t be said about fossil fuels. Why fortunately? Well, who would want to have an infinite supply of fuel sources already killing the earth just a few centuries into their widespread use? 

Should we go solar?

There is a lot of encouragement to go solar, whether from the millions joining the movement each year or from the regular recommendations we get from environmentalists. But should you give in and call your local installer? To answer that, let’s look at the pros and cons of solar energy. 

The pros of Solar Energy

It’s a renewable energy source

As long as humanity can produce working solar panels, we will never run out of solar energy.  

It can be harnessed anywhere

Solar energy can be harnessed at any point where sunlight hits the surface of the earth. That pretty much describes anywhere with humans; deserts, cities, villages, colleges, towns, even if you live in the middle of nowhere.

It is a clean energy source

In a world that is consistently scarred by our growing energy demands, we urgently need to transition to a clean source(s) of energy or wave our home goodbye. Fortunately, the sun has been proven to be the cleanest energy source, even beating alternatives like nuclear energy. 

Cost-saving benefits

Going solar reduces your electricity bills as it allows you to meet some of your energy needs with electricity from your home’s or business’ solar system. Depending on the size of your system, using solar power takes away huge chunks from your monthly energy bill. 

Low maintenance costs

No moving parts mean no wear and tear for solar panels, but you may need to clean them a couple of times a year. You don’t necessarily need professional cleaners for this task; it’s a relatively easy DIY project that you can complete with the help of a solar panel’s cleaning guide. 

The technology is getting better

Governments and energy corporations are investing in research to drive innovations that will advance and improve solar technology. 

See our Related Article where we break down the Advantages of Solar Energy in greater detail. Some of the pros may surprise you.

The cons of Solar Energy

Up-front solar costs are relatively high

The total cost of purchasing solar systems is still relatively high. The average cost of a standard solar panel in the United States is 12,000 dollars. Some low-end models come as cheap as $5,000, but these are probably not the best long-term options. On the other hand, most high-end panels cost $28,000, some even going for as high as $42,000.   

It doesn’t work at night

Solar energy is virtually non-existent at night. Therefore, going completely off-grid isn’t exactly realistic, and you usually have to switch back to grid electricity at night.

Solar energy is also reliant on the weather. Cloudy and rainy days may still allow the panels to collect sunlight, but the system’s efficiency significantly drops. 

It takes up space

Solar PV panels typically require a lot of space, especially if your energy demands are high. Unfortunately, some roofs are not big enough, and fit the desired number of panels is easier said than done. 

Environmental damage

The manufacture of solar panels takes place in industries and plants associated with the emission of greenhouse gases. There are also toxic materials used and released during the manufacturing process. 

See our related article where we break down the Disadvantages of Solar Energy in greater detail. See what our future looks like.

Since solar technology is getting better with time, are there any exciting innovations to look forward to? Yeah, here are some big solar technologies we may see in the coming decade. 

Floating solar farms

Floating solar farms refer (floatovoltaics) to solar stations constructed in water instead of on land. They’re an innovative solution that will allow countries with limited open spaces to construct farms of enormous magnitude if done right.

Using floatovoltaics also carries a couple of benefits;

  • There’s no money spent on buying land. This reduces the opportunity cost of establishing solar farms on real estate and lowers the total energy cost. 
  • The water also helps cool the solar panels, reducing fluctuations in the PV cell’s efficiency.

This concept has been around for a while. The world’s first floatovoltaic system was installed in California in 2008. Today, there are over 100 such installations globally, seven of which are in the U.S. and around 80 in Japan. As this technology becomes more mainstream, don’t be surprised if you see a floating solar farm on a lake near you. 

Integrated photovoltaics

Solar panels are typically placed on the rooftops of buildings, which often have limited space. Therefore, researchers are developing building-integrated photovoltaics (BIPV) to use the vertical space of skyscrapers. This technology has the potential to be used on windows without blocking natural light from passing through the glass.

We may also see an extension of BIPV technology on solar skins; cheap and efficient paper-thin panels applicable on almost any surface. 

Harvesting solar power at night

Unavailability at night is probably solar’s biggest disadvantage. Fortunately, some people believe that this should change. Researchers from the University of California are developing new solar technology that can generate power 24/7. How will it work?

Solar energy received by the earth during the day escapes as solar radiation at night. This technology seeks to capture that radiation and convert it into usable energy. 

Perovskite crystal

There may be a chance that we’ve reached the peak efficiency of silicon PV cells. Therefore, scientists are working on perovskites as the next evolution of solar panels. Currently, they’re being used to enhance the efficiency of silicon cells so panels can convert more solar energy into electricity. However, if the technology advances well enough, there is potential for perovskites to be used independently in PV cells. 

Final word

It’s quite clear that the benefits of solar energy far outweigh the disadvantages. The long-term cost-saving benefits also beat the up-front costs of purchasing and installing solar panels. Experts estimate that over the lifespan of their solar panels (usually 15 to 20 years), homeowners would have saved an average of $78,000 through reduced electricity bills and the net metering system. 

The manufacturing process may also not be 100% fair to the environment, but solar is still far less of a pollutant than fossil fuels and other energy sources. This is the most important aspect of solar energy and why so many people in the world are eager to adopt the resource. As more people, corporations, and governments join in the movement, solar technology keeps getting better and cheaper, moving earth closer to a sustainable and emission-free future.

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