Renewable Energy Sources 101: Overview and Comparison

There’s a lot of talk going around about renewable energy sources, due to the alarming state of current environmental issues. Sources of renewable energy may very well be our ticket, as mankind, to continue enjoying our planet and all that it offers us. However, there is still a widespread lack of knowledge regarding renewable sources of energy and even examples of renewable energy sources to work with in the first place. The questions surrounding renewable energy sources are numerous:

  • What are renewable energy sources?
  • Which energy source is renewable? Which isn’t?
  • Which of the following is a renewable source of energy: solar power or coal?
  • How can we use a renewable energy source to create a healthy future?

We’ll explore all of the facts and significant details about new renewable energy sources in our Renewable Energy Sources 101: Overview and Comparison guide, so you can understand what they are, how they work and how to benefit from them.

renewable energy sources

The Importance of Renewable Energy Sources

If you’re new to the concept, you’re probably wondering: what is a renewable energy source? Before you think it’s a complicated notion and that the renewable energy source definition is difficult to comprehend, you should know that it’s pretty much as easy as it gets. So, what is renewable energy sources? To put it simply, renewable energy sources are basically alternative energy sources come from renewable processes. A renewable source of energy is defined by its ability to replenish in a natural manner. In a world where non renewable energy sources are slowly but surely taking hold of our lives, these natural resources are becoming more and more of a necessity.

Prior to expanding on which is a renewable source of energy and which is not and offering a renewable energy sources list, take a look at some reasons why they are critical for both man and Earth:

  • While ‘traditional’ sources of energy are only available in a few locations across the globe, renewable energy sources can be found everywhere in the world.
  • The aforementioned sources have caused global disputes and wars leading in the loss of countless lives.
  • Fossil fuels are not only concentrated in certain areas on the planet, but they are also incredibly harmful for the environment.
  • There will never be a lack of renewable energy sources, hence their name. All future generations will benefit from them, provided we create a habit of using renewable energy sources.

List of Renewable Energy Sources

Now that we understand the basics, we’ll get into the next big question: what are some renewable energy sources? Which is a renewable energy source that we can count on in the long run? When identifying which are renewable energy sources, all we have to do is keep in mind the energy sources that are natural and limitless. Here are the best examples of renewable energy sources.

solar power panels

Solar Power

One of the most popular options is solar power, also known as energy from the sun. Fortunately, we already have multiple options for using solar power, through methods like:

  • Photovoltaic systems (commonly abbreviated as PV systems)
  • Concentrated Solar Power (CSP), which involves
    • Mirrors
    • Lenses
    • Tracking systems

With the help of solar power, the rays from the sun will be transformed into electricity without increasing pollution or harming the environment in any way. At the moment, one of the greatest issues regarding solar power as a permanent replacement for traditional electricity is the high cost of panels. Nevertheless, this is a problem that will most likely be solved in time.

wind energy farm photo

Wind Power

In countries like Denmark, Germany, Portugal or Spain, wind power has already become quite a normal part of day to day life. Wind farms can be seen more and more often and they act as a source of clean energy that won’t harm our planet. An advantage that wind power has over solar power is the reduced costs. The only reason why wind power seems to not have become a primary source of energy yet is because many individuals still have doubts about how turbines and towers would affect natural surroundings. Nonetheless, it is one of the renewable energy sources with the largest increase in popularity lately.

Hydro Power

It is estimated that roughly 20% of the energy used on Earth is powered by water. In a nutshell, hydroelectric power works by using water to power turbines. The turbines, in turn, produce electricity. The process is quite simple and is already widely used in all corners of the world. In fact, using water to generate electricity is a process that dates back to the second half of the nineteenth century. Nowadays, hydroelectric power is both praised and frowned upon, depending on perspective. While it can aid in stopping pollution from fossil fuels, it might affect the fauna and flora in the specific areas where it’s used.

Geothermal Power

Another widely embraced option for renewable energy sources is geothermal power. To briefly describe it, geothermal energy is obtained in three main steps:

  1. Accessing the hot water (‘thermal energy’) in our planet.
  2. Using the steam for running power stations.
  3. Transforming the steam in electricity.

As for classification, there are three distinct types of geothermal energy:

  • Vapor dominated forms (i.e. geysers)
  • Liquid dominated plants (i.e. Cerro Prieto, Mexico)
  • Enhanced Geothermal Systems (EGS)

As a final note for this source of renewable energy, costs continue to fall considerably for producing geothermal power.


Certain types of plants and waste can be used to produce electricity, generating heat, or it can be converted into biofuel. The biggest source of biomass energy at the moment is wood waste. Biomass clearly isn’t a cause of pollution and is one of the most reliable renewable energy sources we have. Unfortunately, quite a lot of research needs to continue to be carried out on this topic. This is one of the reasons why biomass is currently one of the priciest renewable energy sources. However, it is expected to experience a substantial increase by 2020, according to the U.S. Energy Information Administration.

infographic of renewable and non-renewable energy sources

Renewable energy sources (on the left) vs. Non-renewable energy sources (on the right).

Non Renewable Energy Sources

We can now understand how renewable energy sources work and how they can help us create a bright and happy future for the generations to come. However, it still seems that non renewable energy sources are still the most used around the world. Which are these? To sum up, it is easiest to identify which of the following is a renewable energy source by looking at the image we have provided above. As you can see, the main non renewable energy sources are fossil fuels, namely:

  • Oil
  • Coal
  • Nuclear energy
  • Natural gas

By comparison, these sources are finite – meaning that we will run out of them eventually. Not only are they limited from a long-term perspective, but they are also the reason why pollution has got so out of control. In addition to this, the cost of harvesting non renewable energy sources will surpass those for wind power or solar power in the future, just to name a few.

We can all contribute to protecting our planet just by spreading awareness and adopting these renewable energy sources. How are you doing your part for saving future generations?

Image sources: 1, 2, 3, 4.


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  • Anything that’s alive works on bioelectric systems like the (heart, brain) for living tissue assemblies, as well as trees,
    flowers, weeds and grasses. These included insects and bacteria as well. The key question is to how to harness it,
    through electronic circuitry and store it for either current usage or later by charging batteries. This presents a
    challenge to overcome the fossil fuel industry.