What are the main sources of renewable energy?


The continued use of nonrenewable fossil fuels is detrimental to our environment and the future of our planet. Fortunately, there are numerous types of renewable energy sources available to us. Many energy providers across the world are now offering renewable energy plans that allow you to use these renewable energy sources to power your home. (Change energy plans today with Inspire)

But what are the different types of renewable energy sources, how do they work, and are they really all that beneficial?

What are renewable energy sources?

Renewable energy sources are sustainable, meaning they will never run out. These are sometimes referred to as alternative energy sources (i.e. alternatives to fossil fuels) or green energy sources, though green energy sources are simply renewable energy sources that produce little-to-no emissions.

What are the five most common sources of renewable energy?

The 5 main sources of renewable energy are:

  1. Solar energy – energy produced by the sun’s light or thermal energy.
  2. Wind energy – energy generated via wind turbines.
  3. Hydro energy – energy generated by harnessing the natural flow of water and the tide.
  4. Geothermal energy – energy generated by harnessing heat produced by the Earth itself.
  5. Biomass energy – energy produced by burning biofuel, such as plant matter.

How do the different types of renewable energy work?

Solar energy

As one of Earth’s most abundant resources, it is no surprise that sunlight is commonly utilized to generate power, both commercially and domestically.

Photovoltaic (PV) systems capture the energy produced by solar rays within their cells which is then converted into electricity and heating.

The amount of solar energy that can be used depends largely on geographical location, the season of the year, and the time of day.

Wind energy

Wind is another plentiful clean energy resource, harnessed using turbines. When wind blows by the turbines, it causes the blades to rotate and in turn produce electricity.

Wind power is often used on a large scale to power a number of commercial properties or used on a smaller scale to supplement other energy sources. It can also be used on a domestic scale, although not every home will be suitable for this.

Hydro energy

Hydro energy, otherwise known as hydroelectric power, is the most commercially developed renewable energy source.

A large reservoir is created with a dam that can be used to control the flow of water. This flow of water causes a water wheel to turn, which leads to the generation of electricity.

Hydro energy can also be harnessed using the natural flow of a river, known as run-of-river hydropower. This method uses a narrow channel to funnel the flow toward a water wheel rather than needing to build a dam.

The electricity created can be stored for later use if demand has already been reached and hydro energy is generally more reliable than both solar and wind energy as it can be used 24/7 in any weather condition.

Tidal energy

Tidal energy is another form of hydro energy, using the ocean to generate power. The twice-daily tidal currents work to drive turbines connected to generators, which, although not constant, is very predictable. This means that the amount of energy produced during each tidal current can be easily estimated, and power stations can compensate for low tide currents when needed.

Tidal energy is particularly useful for towns and cities located near the coast as this energy can be harnessed for the local population without any trouble.

Geothermal energy

Geothermal energy is harnessed from heat that has been trapped underneath the Earth’s crust either since its formation or due to radioactive decay. Some of this heat will escape naturally in large quantities, typically in the form of a volcanic eruption or geyser, but it can also be captured manually to produce geothermal energy.

The heated water within a geothermal reservoir is pumped up to a geothermal power plant where it turns into steam, which is then used to operate a turbine to power a generator. This generator produces electricity for the grid and the steam is cooled back into water and fed back into the geothermal reservoir to be used again and again.

This type of energy can also be used on a smaller scale to heat homes directly using a geothermal heat pump.

Biomass energy

Biomass is organic matter that is typically a by-product of recently living organisms and plants, and can be converted into a solid fuel made of plant material or methane gas.

This solid fuel, not including wood, is burned in order to produce electricity, which may not be a particularly clean process, although it is cleaner and more energy-efficient than it has been in the past.

Methane gas is typically produced through anaerobic processes during the natural decomposition of organic matter. It occurs particularly in bodies of water and landfills.

Biomass energy can be produced at particularly low costs, both in an economical sense and an environmental sense, as it involves the conversion of agricultural, domestic, and industrial by-products that would otherwise be wasted.

What are the benefits of renewable energy sources?

The benefits of renewable energy sources include the following:

  • Clean sources – they do not produce air pollutants, such as carbon dioxide
  • No negative impact the environment or cause harm to human health
  • Can reduce energy bills, especially with regard to solar, and can eliminate energy costs completely in the long term
  • Provide many job opportunities – renewable energy sources need to be regularly serviced and maintained to ensure they are working to full efficiency
  • Can often be utilized on both a commercial scale and a domestic scale

What is the best source of renewable energy?

It is difficult to determine what is the best source of renewable energy as this largely depends on your geographical location. The most efficient sources of renewable energy are hydro energy, wind energy, and solar energy.

Solar energy is particularly popular for both commercial and domestic use as it is efficient and effective, with an efficiency of 15% to 20%, and it can significantly lower your electric bills.

Wind energy is even more efficient than solar energy, averaging around 35%, although this can reach up to 50%. The main issue with wind energy, however, is that you need enough space to be able to erect one or more turbines and somewhere that gets a good, regular flow of wind.

How to use renewable energy at home

As mentioned above, there are a number of renewable energy sources that can be utilized at home, although they may not all be a viable option for your property.

In order to use solar energy for electricity and/or heating, you can purchase PV panels that can be installed on your roof or another suitable location of your property. These will work to generate electricity during all daylight hours, although they are more effective during sunnier weather. Any surplus power can be stored in batteries for later use, although these batteries can be pretty expensive. Solar energy will work to improve the sustainability of your home and cut down your electric bills, but the initial installation can come at a very high cost.

You could opt to install a small wind turbine on your property to generate a percentage of your electricity, either installed on the roof of your home or as a free-standing pole. This will help to reduce your electricity bills, although you will find wind energy more beneficial if your geographical location is more susceptible to high winds.

If you are looking for a renewable energy source to provide heating and hot water for your home, you could choose to have a biomass system installed. This burns organic materials, such as wood pellets, so it is not a totally clean energy source, although it does produce lower levels of carbon than fossil fuels.

While these are all great options, the easiest way to support renewable energy in your home is by switching to a green energy plan, such as our unlimited renewable energy plan. Inspire members get all the benefits of using renewable energy sources, but without the need for a huge amount of space, upfront cost, or potential unknown costs.

Why are renewable energy sources important?

The continued development of renewable energy sources is crucial to combating climate change and working to reverse the effects of global warming as much as possible. Working toward a completely renewable power market is the most reliable way to ensure that our environment is protected for the future.

What isn’t a renewable energy source?

Fossil fuels (i.e., coal, oil, and natural gas) are not a renewable energy source as they will eventually run out. These energy sources will eventually replenish, but this typically takes hundreds of thousands of years. Fossil fuels also release harmful gases and particulate matter into our atmosphere when burned, which results in global warming.

Which renewable energy is growing the fastest?

The fastest-growing renewable energy source in the U.S. is solar energy. In the last three to four years, the entire solar energy industry doubled, surpassing 100 gigawatts of installed electric generating capacity. Each gigawatt is the equivalent of 1-billion watts, so one gigawatt or 1-billion watts is enough energy to power more than 200,000 to 300,000 homes in the U.S1.

In the first quarter of 2021, solar energy accounted for 58% of all new electric energy capacity additions in the U.S., with almost all new electric capacity additions being renewable energy sources.

But it’s important to recognize that this trend has been going on for about a decade now. Since 2011, solar energy has seen an average annual increase of around 42%. Much of this can be attributed to the declining costs associated with solar panel manufacturing and solar installation. The bottom line is that solar has gotten considerably cheaper. Consumers are now more willing to take on solar panel installations on their homes since the costs are more realistic for the average middle-class family. Combine rapidly declining prices with federal, state, and local tax incentives, you have a clear idea of how solar energy has been able to grow around 42% each year for the past ten years.

In 2010, the average-sized residential solar project had a $40,000 price tag before any tax credits or rebates. At the end of 2020 and 2021, the average-sized residential solar project costs around $20,000. That 50% decrease in prices over the last ten years has significantly contributed to the rise in the use of solar energy2.

What renewable energy is the most efficient?

When considering the three main sources of renewable energy, wind, solar, and water, which is the most efficient? The most efficient of the three is hydroelectric power. Solar is said to be on average 15% to 20% efficient, where wind averages around 30% but can sometimes reach peaks in the 50% range. A hydroelectric power plant can have an efficiency rating of about 90%. Thus, there is a large gap in the efficiency ratings between hydroelectric power and wind and solar3.

Aside from the higher efficiency rating, there are other benefits to using hydroelectric power. Hydropower is fueled by water, a clean fuel source that does not create pollutants during energy production. Hydropower is a localized power source allowing each state to construct its dams and supply power to its residences rather than relying on power plants in other regions supplying electricity to the primary power grid. Hydropower plants not only provide a renewable energy source, but they can provide additional benefits like flood control, irrigation, and local drinking water supply4.

What is the most reliable energy source?

The most reliable energy source is nuclear power, which is not only efficient, but it also has the highest energy production capacity. For almost 93% of the time during any given year, a nuclear power plant is running at and producing its maximum energy output level. That is a far leap ahead of other energy sources that spend much less time operating at full capacity. Here is just a quick breakdown of what percent of the time a particular energy source runs at maximum capacity during any given year:

  1. Nuclear Power: 92% to 93%
  2. Geothermal: 74% to 75%
  3. Natural Gas: 56 % to 57%
  4. Hydropower: 41% to 42%
  5. Coal: 40% to 41%
  6. Wind: 35% to 36%
  7. Solar: 24% to 25%

In addition to providing a maximum power output the majority of the year, nuclear plants require less maintenance. They are designed to operate for long periods before needing to be refueled. Also, nuclear power plants are not intermittent sources of energy like wind and solar, and they do not rely on patterns in the weather to generate electricity.

Large-scale nuclear energy plants have been in operation for over 60-years in the U.S. They have been proven reliable through our ability to rely on them for roughly 20% of all of the energy needs of the entire U.S. since 19905.

What is the cleanest renewable energy source?

The cleanest renewable energy source is arguably wind energy. Wind energy is one of the cleanest and most sustainable ways to generate electricity with no production of toxic pollutants and no creation of global warming emissions. The most significant complaints about wind energy include:

  • Impact on the land used
  • Increased deaths of birds and bats
  • A visual and/or sound annoyance

Wind farms have become more efficient with how they use their space, and they have been able to get land usage down to 1 acre per megawatt produced. Once a wind farm has completed construction, the land can be repurposed to provide grazing ground for cattle and farmland for agriculture production. Some wind farms may see the construction of hiking trails and other outdoor recreational infrastructure.

Engineers are also working on improving the overall design of wind turbines to decrease further the sound it produces when in operation. In addition to creating the turbines, manufacturers minimize blade surface imperfections and use more sound-absorbent materials to reduce wind turbine noise.

To combat the visual annoyances of wind turbines, nothing can be done about the turbine itself. However, there is the issue of “shadow flicker,” when the sun shines through the rotating blades under certain lighting conditions, casting a moving shadow that many can find distracting and/or annoying. By planting trees on the parameters of wind farms and working with the natural landscape, engineers have been working on ways to decrease the visual annoyances that wind turbines may present. Scientists are also working to reduce bird and bat deaths by monitoring bird migrations and operating more frequently when bats and bird migrations are not present6.

What is the cheapest renewable energy source?

The cheapest renewable energy source available for consumption is hydroelectric power, simply because it produces electricity consistently, and the infrastructure needed to make hydroelectric power is long-lasting and has been in place for a long time. Currently, it costs an estimated 5-cents per kilowatt-hour to produce electricity using hydroelectric power. This is the cheapest compared to wind and solar, which can see a cost of 6-cents per kilowatt-hour for wind turbines and 10-cents per kilowatt-hour with solar.

IRENA, however, predicts that the cost to produce energy using both wind and solar will continue to drop and that it is possible to see prices as low as 3-cents per kilowatt for both wind and solar in the next few years. If that should happen, hydroelectricity will no longer be the cheapest renewable energy option making way for continued exponential growth in the wind and solar energy industries. This drop in price in both wind and solar energy would contribute to a continued rise in usage for both wind and solar. At the moment, hydropower is the world’s largest renewable energy source, however, wind and solar continue to close the gap in overall energy production capacity.

What is the most powerful renewable energy source?

When comparing the three primary renewable energy sources of wind, water, and solar, it is easy to see that at the moment, hydropower is the most powerful renewable energy source7. Although wind and solar have seen dramatic growth in energy capacity during recent years, hydropower is still number one, with a total energy production capacity of 1,311 gigawatts at the end of 2019. Wind energy has a full energy production capacity of 622.7 gigawatts, and solar is sitting at 583.5 gigawatts8.

Throughout 2020, both wind and solar had added enormous amounts of capacity to their industries. Solar alone added 139.4 gigawatts of new capacity, while wind power added somewhere around 120 additional gigawatts of global capacity9.

At the rate of growth that we see in both the solar and wind energy sectors, it is only a matter of a few years that it will be possible for both wind and solar to surpass hydropower as the most powerful sources of renewable energy on the planet.

Renewable energy sources are important for providing us with the power we need without causing harm to the environment. A renewable energy company allows you to sign up for 100% clean, renewable energy for a flat monthly rate so that you can help in the fight against climate change, without having to cut back on your usage. Visit Inspire to find out more about changing energy plans in less than a few minutes.


  1. seia.org/us-solar-market-insight 

  2. seia.org/solar-industry-research-data 

  3. usbr.gov/power/edu/pamphlet.pdf 

  4. energy.gov/eere/water/benefits-hydropower 

  5. energy.gov/ne/articles/nuclear-power-most-reliable-energy-source-and-its-not-even-close 

  6. triglobalenergy.com/environment 

  7. hydropower.org/status-report 

  8. pv-magazine.com/2020/04/06/world-now-has-583-5-gw-of-operational-pv 

  9. gwec.net/global-wind-report-2021