What Is Solar Energy and How Does Solar Power Work?

Last Updated: 5 March, 2019 by Alexander Thomas

What Is Solar Energy and How Does Solar Power Work?

Going solar is the way of the future. Although, at present, only 0.5% of the power consumed in the United States comes from solar energy, the price of solar panels has decreased by more than 70% over the past decade to encourage more and more homeowners to develop a sustainable way of life.

Given the environmental challenges we face today, going solar has never been more crucial to the preservation of our entire planet. But what is solar power exactly? When was it first discovered and how does solar energy work today? Are you a good candidate for a solar power system? How does solar power work in your region of the world?

In what follows, we provide answers to these questions and more.

A Brief History of Solar Power

As early as 1876, Professor William Grylls Adams and one of his students, Richard Day, stumbled across a property of selenium that had never been observed before. They exposed the material to light and were surprised to notice that it produced electricity as a result.

Although the discovery was said to be “of the most far-reaching importance” by another electricity expert of the time, Werner von Siemens, selenium did not convert light into electricity effectively enough to present any practical applications.

Almost one century later, in 1953, Daryl Chapin, Gerald Pearson, and Calvin Fuller came up with the idea to replace selenium with silicone. Their silicone solar cell could actually power small devices, which promoted the New York Times to acknowledge the discovery as “the beginning of a new era.”

In 1956, the solar cell was first used for commercial purposes. It features in radios and toys and could also be purchased independently for the exorbitant price of $300 per Watt. It was only in the early 1970s that means to lower the production cost of solar cells were discovered in research spearheaded by Exxon. The cost of 1Watt gradually decreased to $100 and eventually to just $20, which made solar cells accessible to the wider public.

What Is Solar Power Like Today?

Since the late 1950s, solar power has been used to power satellites in the Soviet and USA space programs. In the 1970s, the application of solar cells was also extended to off-shore oil rigs, where solar electricity was used to run waning lights.

Finally, by the 1990s, solar cells were used for a variety of purposes: in railroad crossings, in remote homes, in Australia’s notorious microwave towers, and in irrigation systems throughout the desert. Today, we are witnessing the development of solar powered cars, of aircraft that run on solar energy, but also of evermore efficient solar cells for increasingly affordable prices.

Which brings us back to our initial question.

What is Solar Energy?

Our sun is a fascinating celestial object that exists in what is essentially a perpetual state of nuclear reaction. Made up of 70% hydrogen, 28% helium, and other gases, its dense plasma surface rests at temperatures of no less than 5,800 ºK. At its core, hydrogen is transformed into helium through fusion. The process releases blinding light and incredibly high levels of heat in all directions, including towards our planet.

In approximately 8½ minutes, this light travels 93 million miles to the Earth in the form of energy particles or photons. Provided the appropriate solar electricity system, photons that hit the surface of our planet for the duration of just one hour could provide enough solar energy to meet global needs for an entire year.

What is solar energy, then? In short, energy from the sun transformed into electricity.

How Does Solar Power Work?

Solar cells function in virtue of the “photovoltaic effect” first discovered in 1839 by Edmond Becquerel, a French physicist. The photovoltaic (or PV) effect refers to the fact that certain materials, like selenium or silicone, for instance, can absorb light and produce electrical voltage.

The typical contemporary solar cell is made of silicone and constructed with two layers, one of which is positively charged, and the other, negatively. Like in the case of a battery, when the two layers are put together, they create an electric field.

Next, the solar cell is exposed to sunlight. The photons in the light hit the solar cell and dislodge electrons from their atoms. Loose electrons now flow through the electric field and, when conductors are attached to the positive and negative ends of the cell, an electrical circuit is formed.

Of course, one solar cell can only produce negligible amounts of electricity on its own. That is why a solar panel consists of tens of cells wired together, while the array necessary to power a household often features more than ten panels.

The Components of a Solar Power System for Homes

Given the question “what is solar power?”, most people immediately visualize an array of solar panels harnessing the energy of the sun. Indeed, PV panels are an essential component of a solar power energy system, but they are not sufficient to generate and distribute electricity safely. In a complete system, batteries, a generator, a charge controller, and an inverter all play equally important roles.

Solar Panels

The most basic, recognizable feature of a solar power system, the solar panels are made of a material capable of absorbing sunlight and producing electricity in the form of DC current. Different types of solar panels come with different PV inputs and conversion efficiency coefficients. For instance, you’ll find that most commercial panels have a PV input of at least 100Watt and are capable of converting energy with an efficiency of at least 15%.

Rechargeable Battery Pack and Backup Generator

From the very beginning, one of the drawbacks of solar energy has been that solar power energy systems can only generate electricity during the day, when panels are exposed to sunlight. However, we also require electricity during the night, as well as throughout cloudy days and bad weather. Battery packs resolve this issue because they allow energy produced during the day to be stored for use at a different time. In addition, solar backup generators are employed when the solar system is not tied into the household electricity grid. They are capable of storing sufficient energy to power up appliances and small devices for up to several days.

The Charge Controller

The charge controller or regulator ensures that the DC power coming from solar panels does not overcharge and therefore damage the batteries. Most batteries are tagged as 12V, which means that anything over 12-14V will wear them off in time. Panels are also generally tagged as 12V, but their output actually ranges from 16V to 20V. As such, a charge controller is necessary to avoid overcharging the system batteries and to prolong their lifespan.

The Solar Inverter

While solar panels produce DC power and batteries store it as such, appliances in your household require AC (alternating current) to run. The purpose of the solar inverter is to ensure the correct conversion from DC to AC, but also the conversion from 12V or 24V to 110/120V or 220/240V. The best solar inverters will sometimes come equipped with an in-built array DC disconnect, which, as its name suggests, is used to disconnect the array from the household electricity grid when maintenance is required. The inverter can also feature a power or utility meter to help the user monitor how much power is being used and, if this is the case, how much excess power is sent to the grid.

How Does Solar Power Work with Different Types of Solar Panels?

Now that the question of “what is solar energy?” is well out of the way, we can turn our attention to the way solar energy functions when harnessed through different types of panels. Solar panels currently on the market come in numerous forms. We describe the four most common and most effective below.

Monocrystalline Solar Panels

These solar panels are made of monocrystalline silicone and are widely considered to be the purest, most effective type for conventional use. They are easily recognizable due to their dark hue, uniform look, and round edges, while the purity of the silicone in their composition results in high efficiency rates of up to 20%. Overall, monocrystalline solar panels have a higher PV input, take up less space, but also last longer when exposed to the outdoors and high temperatures. Unlike other models, however, they are also pricier.

Polycrystalline Solar Panels

Polycrystalline solar panels are also considered to be 1st generation (or traditional) solar panels and, as such, they are very common for household and business applications. Unlike their monocrystalline counterparts, however, they only rise up to a maximum of 15% efficiency, take up slightly more space, and have shorter lifespans. To make them, manufacturers melt raw silicone, which is overall a faster and less expensive process. The panels themselves are therefore cheaper and can be distinguished by their blue color and speckled look.

Thin-Film Solar Panels

Primarily used in PV power stations, solar panels made of thin-film solar cells are even cheaper than polycrystalline solar panels, but take up significantly more space for the same PV input. They are made by overlapping one or several films of PV material (including cadmium, copper, or silicone) on a substrate, which makes them less expensive and much more flexible. Their lifespans are shorter than with mono- and polycrystalline solar panels, but they withstand high temperatures more effectively and are suited for solar electricity systems where large spaces are available.

Concentrating PV Solar Panels

These solar panels produce solar electricity like all others, but their efficiency can run up to 41%, which is the highest among all PV systems so far. What makes them perform so well is a combination of curved lenses and mirror surfaces that manage to bundle sun rays and enhance efficiency. Cooling systems are also sometimes used in order to prolong the lifespan of the panels. To reach peak effectiveness, concentrated PV solar panels must face the sun at a precise angle, which is why most of them are equipped with an in-built solar tracker that allows the entire unit to follow the sun. This type of panel is expensive to acquire and install, which is why it is not, as of yet, used in conventional applications.

How Does Solar Energy Work in Bad Weather?

It’s nothing more than a myth that solar panels no longer work during winter or bad weather days. Regardless of the climate, if a solar panel is exposed to sunlight (even through clouds or rain), it will produce electricity, albeit at a slower, less efficient rate.

There are actually four factors related to outdoor exposure that can affect the effectiveness of your solar panel array: sunlight, temperature, shade, and dirt. The more direct sunlight a panel is exposed to, the more electricity it will put out. On a bad day, a solar panel will be less effective, but it will still do at least 50% of the work it would do otherwise.

In addition, contrary to what you might be tempted to think, a solar panel works best at cold temperatures, because this keeps the solar cells from degrading due to heat. This is part of the reason why solar panels continue to function perfectly during the winter. On the other hand, shade cast by anything other than a cloud will decrease the effectiveness of the panel, which is why you want to make sure you position your array out of the way of trees and other tall landscaping features.

Finally, accumulated dirt is perhaps the worst obstacle in the way of your solar panels achieving peak performance. As such, the single best thing you can do to prolong the lifespan of your solar electricity system is to keep the panels clean and hire professional cleaners to remove any accumulated dirt.

How Does Solar Power Work during a Blackout?

The answer to this question depends largely on your specific solar power energy system and whether or not the latter is connected to the household electricity grid. If your solar system is not tied into the grid and you own a charged battery or backup generator, then the panels will continue to produce electricity even during a blackout.

If, on the other hand, your solar electricity system is connected to the grid, it is very likely that it will be automatically shut down during a blackout for reasons of safety. Indeed, when a power shortage takes place, specialists are sent out to fix the problem and may be injured if electricity is leaked into the grid from various homes.

As such, if you want to rely on solar power during blackouts, you need to invest in a battery or backup generator and ensure that the latter are at least temporarily disconnected from the grid.

Applications of Solar Electricity outside the Home

So far, we’ve looked at solar energy from the perspective of household applications, but what is solar power like outside the home? At present, some applications of solar energy are more viable than others, but there is reason to believe that progress is on the horizon and fast approaching.

Concentrating Solar Power Plants

When researchers and engineers asked “how does solar energy work for wider applications?”, this is the answer they came up with. Concentrating solar power plants use new technologies such as concentrating PV systems in order to increase the efficiency of solar arrays and power utility-scale generators. They are oriented towards sustainability and, with improvement, will likely replace many traditional, environmentally hazardous power plants. What is solar energy, after all, if not a way to preserve our planet for future generations? To achieve this, we require the means to effect society-wide changes in terms of power and fuel. Concentrating solar power plants are one such means.

Solar Power for Businesses

Moving from broad change to smaller adjustments at the hands of individual people, solar power can be employed successfully both in the household and in small businesses. The advantages of a business gone solar are not only environmental, but also financial. Indeed, a business switching to solar energy can save up to 75% in electricity bills, which means that they will pay off the initial investment in no more than 7-8 years. In addition, in the United States, business owners can access the Federal Investment Tax Credit (or ITC) to cover up to 30% (and sometimes more) of the initial cost of installing a solar power system.

Solar Vehicles

In the United States alone, 75% of carbon monoxide pollution is due to the cumulative effect of motor vehicles. What is solar energy to people who own cars, then? A potential way to decrease their carbon footprint decisively. Unfortunately, because rechargeable batteries are not yet powerful enough to store sufficient energy to run a car for long periods of time, vehicles featuring solar panels installed on the roof remain at an early development stage.

Camping, Hunting, and Fishing

Perhaps the most reliable application of solar energy at present has to do with off-grid travel. Instead of picking up a traditional electric generator that works on gas and emits unpleasant fumes, you can now acquire an affordable, portable solar generator to charge your devices on the go. Rechargeable batteries are perfectly suited to power up small to medium devices for extensive periods of time and, so long as your solar panels are exposed to sufficient sunlight, you don’t have to worry about running out of electricity.

How Does Solar Energy Work in Remote Locations?

Solar power systems are ideally suited to function in remote locations such as cabins, RVs, and yachts, but also in emergency camps, construction sites, mining operations, and more. Unlike traditional sources of electricity, solar systems are highly portable and require only a few minutes to be set up. While an initial cost is associated with their acquisition, relatively no additional funds are required when the system is re-deployed at different locations.

If you own a far-flung cabin or farm, for instance, it can cost upwards of $15,000 per mile of power line, in addition to construction and installation fees, in order to get your place tied into the nearest electricity grid. Solar energy provides a neat and sustainable alternative to such considerable costs. With the right solar kit, you can install the entire system yourself with minimal further interventions for maintenance. If you ever decide to re-locate, you’ll likely be able to bring the solar energy system with you for little to no additional cost.

How Does Solar Power Work for Developing Countries?

Solar power is in a unique position to assist people in developing countries in at least two important ways. First, due to rapid population growth, but also due to extreme poverty, developing countries have seen a drastic increase in the use of conventional fuels over the previous decades. In turn, this has increased CO2 emissions, as well as the total level of greenhouse gases, turning pollution of the air, soil, and water into a pressing issue. The installation of permanent solar power systems in these countries can significantly decrease the use of environmentally hazardous fuel, but also the long-term costs of electricity.

Secondly, in certain regions of the world, households do not have access to a power grid and must therefore survive without electricity. Connecting such a household to the nearest grid is often much too expensive for its inhabitants, which makes traditional power sources an unlikely solution. Solar power, on the other hand, can be easily installed and maintained with little to no further costs. While the initial cost of such an electricity system can be high, the latter might be covered by non-profit organizations around the world.

Solar Energy: Takeaway

From sustainability to energy independence, portability, and financial convenience, solar power offers ideal solutions to a myriad of global, social and environmental problems. Indeed, as it turns out, the New York Times correctly anticipated the importance of solar energy when they portrayed the invention of the silicone solar cell in 1953 as the “beginning of a new era.”

Since then, the solar cell has been constantly improved upon to the point where, at present, solar power has become and affordable alternative for most households and businesses. What is solar energy for us and for our society today? It is one of the best ways to prepare for the future.