4 Amazing Different Types of Solar Energy

Believe it or not, there are in fact quite a few different types of solar energy.

When you think about solar energy in general, the mind is usually drawn towards the thought of photovoltaic panels right?

This article aims to cover all those different types and spread the wonders of solar energy as a green investment into your future.

You might just be surprised by all the ways you could implement solar energy into your life.


What Is Solar Energy?

In simple terms, solar energy is the light and heat that come from the sun.

Interestingly, only about one one-billionth of the sun’s total energy output reaches our Earth.

Of the solar energy that does reach our earth, 66% is reflected back out to space by the earth itself.

When scientists discuss solar energy, they take into account the duality of sunlight as introduced in 1909 by Albert Einstein.

Sunlight is at the same time a wave and a particle: the photon.

Each photon carries an amount of energy that we calculate with the formula below:

E=h.v

Where h is the Plank constant and v is the frequency of the photon.

As you notice, the photon energy is dependent on its frequency. Indeed, pure sunlight is white, but if this light goes through a prism, you’ll see more colors similar to a rainbow. Each color corresponds to a specific photon frequency or wavelength.

The sunlight wavelength varies from 300nm (ultraviolet) to 2.5um (infrared), but the visible light wavelength is between 400nm (blue) to 700nm (red). As you can see in the chart below, solar energy is the highest at around 500nm (green/yellow color). Therefore, scientists are developing systems that harvest solar energy in the visible spectrum up to infrared.

Sunlight spectrum – visible light between 450nm and 700nm

Knowing this will come in handy later when we discuss the different types of solar energy later.


Types of Solar Energy

The 4 types of solar energy we will describe in the following parts take advantage of the amazing properties of sunlight to produce either electricity or heat for human use.

Photovoltaic Systems

One of the most common examples of solar energy, and the best way to utilize the sun’s energy is with photovoltaic systems – also known as solar panels.

A solar panel consists of many solar cells.

These systems transform solar energy into electricity.

Read our guide: How do solar panels work?

The winning ingredient inside a solar cell is silicon. This material has specific electronic properties that allow the element to convert sunlight into electricity.

When sunlight interacts with the silicon, it forces the electrons inside it to move, this movement then initiates a flow of electricity.

This whole process is known as the photovoltaic effect (‘photon – light, ‘Voltaic’ – electricity), discovered by Raymond Becquerel.

A fully functional photovoltaic home setup would include the following:

  • Solar Panels: These are often connected in an array to provide higher overall power outputs/DC voltages.
  • Solar batteries: The electricity generated by your solar panels is stored here.
  • Charge controller: These devices regulate the charge of the battery and prevent overcharging which could compromise your storage batteries health.
  • DC – AC inverter: Solar panels produce DC (direct current), most appliances utilize AC (alternating current). An inverter is used to convert DC power to AC power which we can then use in our homes or campervans.

Solar Water Heating Systems

Another type of solar energy is solar hot water, which as I’m sure you’ve already figured out, entails the heating up of water using the sun’s heat. This is called Solar Thermal energy.

Solar thermal energy is perhaps the easiest way to harvest solar energy. It doesn’t require complex set-up and manufacturing processes, as only a dark surface (black or deep blue) will do the job to soak the most heat from the sun.

Therefore, solar water heating systems are extremely popular and in many countries they are responsible for a large portion of water heating, such as in Israel with 85% of domestic hot water supply.

The concept of solar water heating comes directly from nature herself. Ever noticed how shallow pools of water seem to be much warmer than deeper ones?

This is because most of the sunlight energy is absorbed by the water in the first meters. The thinner the water layer, the hotter it will get.  

Humans created solar water heating systems which mimic the genius of nature.

Two parts make up this system – the solar collector and the storage tank.

The most common collector is called a flat-plate collector. It’s mounted onto your home’s roof and is angled to face the sun.

Solar water heater working principle

There are many small tubes that run through the plate and carry the fluid.

As the collector begins to heat up it warms the fluid passing through its tubes. This warm water then gets stored in the storage tank, ready to be used.


Solar Power Plants

The third way you can utilize the different types of solar energy is through the production of electricity generated by solar thermal power plants.  

As I am sure many of you are well aware, most power plants today use unsustainable forms of energy such as fossil fuels to boil water.

This boiling water creates high pressured steam which rotates large turbines, which in turn activates the generator that then produces electricity.

This conventional way of generating electricity is toxic to our health and is largely responsible for global warming.

However, there is light at the end of the tunnel. The good news is that new forms of power plants that rely solely on solar power are being introduced.

These power plants use the sun as a heat source and can do so in 3 different ways:

  • Parabolic-trough systems capture the sun’s energy via long rectangular, curved mirrors that are angled towards the sun. This enables sunlight to focus its super rays onto a pipe that contains oil. This oil is heated and then used to boil water in a conventional steam generator to produce electricity.
  • A dish/engine system uses large, mirrored dish which resembles your household satellite dish (except 1000 times bigger). This dish concentrates the sun’s heat onto a receiver. This receiver absorbs the heat and transfers it to the fluid within an engine. Heat causes this fluid to expand which then pushes against a piston or turbine and produces mechanical power. This mechanical power is then used to run a generator or alternator to generate electricity.
  • Power tower systems use large fields of mirrors that concentrate the sun’s sunlight onto the top of the tower. On top of the tower there is a receiver containing molten salt. The salts heat can be used to generate electricity through a conventional steam generator (minus all the pollution). Molten salt is really effective at retaining heat efficiently and can be stored for days until it needs to be converted into electricity. This means electricity can still be produced on cloudy days or even during the night.

Passive Solar Heating

Passive solar heating in a house

Another different type of solar energy takes the form of passive solar heating. Though you would be mistaken to think this is a new concept.

In fact, ancient civilizations such as the Anasazi Indians used passive solar heating in their household designs.

The impact the sun’s energy has on our planet is quite easy to understand.

If it’s a hot sunny day where you live, take a break from your computer, go outside and just stand in the sun for a moment.

Back? Ok, what did you feel? Heat, right?

Well, with the proper design, many buildings can also “feel” the sun’s energy.

Buildings, for example, can install materials such as sunlit floors and walls that will actively absorb and store the sun’s heat.

These materials heat up during the day, and at a slow pace release the heat during the colder nights.

Other home designs include features such as a sunspace. These “spaces” resemble greenhouses, which concentrate a lot of heat. With the right ventilation, an entire space can be warmed up.

These different types of features maximize the sun’s energy.

Interestingly, on particularly hot day’s you’d imagine these designs to overheat entire buildings, right?

Wrong! In fact, there are ways to ensure these features do not overheat households.


How Is Solar Energy Classified?

Solar energy is classified as a renewable energy source. A renewable energy source is any source of energy that can replenish itself naturally, on a human timescale.

Energy sources like coal are considered non-renewable due to the fact it takes them over a hundred thousand years to reform.

This makes them unable to replenish at the rate at which humans use them today.

Solar energy is therefore classified as a renewable energy source that will never run out or be in short supply (at least in a human’s lifetime).

In addition, to produce solar panels, we are using large quantities of silicon. Silicon by itself is not renewable, however it is extremely abundant and easily accessible (sand) on earth. In addition, when recycling solar panels, we can recover almost all the silicon used to manufacture the panel.  

All we need to do is continue developing different types of solar energy to capture it!


What Are 4 Advantages Of Solar Energy?

pollution free

Pollution Free

Solar energy is pollution-free and causes no greenhouse gases to be emitted after installation. Also, a study done by the National Renewable Energy Laboratory shows that pollution created by solar panel production is generally recouped in clean energy within 4 to 5 years of a solar panel’s life span (+- 30 years).

Solar energy return on investment

Return on investment

Solar panel installation does have a somewhat higher initial investment (reducing every year, with technological advancements). However, unlike utility bills, you’ll receive a return on your once-off investment, within 6 to 8 years depending on the cost of electricity and subsidies for solar equipment. On top of that, in many states you can sell or offset your excess of solar energy, further reducing your energy bill.

Diverse Applications for solar energy

Diverse Applications

As has already been discussed in this article, there are many different types of solar energy and they can all be used for multiple purposes. It can be used to produce electricity or heat. In some locations, it’s even used to distill water.

low maintenance costs

Low Maintenance Costs

Photovoltaic systems require very little maintenance. Basically, all you’ll need to do is wipe the glass free from dust every few months or so. Because there are no moving parts, there is no wear and tear. For this reason among other solar panels can last up to 25 – 30 years.


Final Thoughts

Solar energy is amazing! Our sun is shining everyday and everywhere on our planet. Thanks to decades of scientific research, we can now harvest solar energy with reliable, simple and cheap systems.

As we demonstrate in our article, solar energy has many different uses from electricity production to heat generation. In 2022, it is even the cheapest way to produce heat and electricity. There is no doubt that in the coming years solar energy, coupled with storage systems and smart electricity grids will take an even bigger place among all energy production systems.

Romain Metaye

Romain Metaye

Dr Metaye has a Ph.D. in chemistry from Ecole Polytechnique, France. He is a renewable energy expert with more than 11 years of experience within the research world. During his career, he supervised more than 150 projects on clean energy. Off-grid smart systems, solar energy, battery and the hydrogen economy are among his specialties.

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