What is Renewable Energy?- Definition, and Types

Renewable energies are booming as innovations cut costs and deliver on the promise of a clean energy future. American solar and wind generation breaks records and is integrated into the national power grid without compromising reliability.

This means that renewables are increasingly displacing “dirty” fossil fuels in the electricity sector, offering the benefit of lower CO2 emissions and other types of pollution. But not all energy sources marketed as “renewable” are environmentally friendly.

Biomass and large hydropower plants make difficult tradeoffs when considering the impact on wildlife, climate change, and other issues. Here’s what you should know about the different types of renewable energy sources and how you can take advantage of these new technologies in your home.

What is Renewable Energy?

Renewable energy often referred to as clean energy, comes from natural sources or processes that are constantly replenished. For example, sunlight or wind keep shining and blowing, even if their availability depends on time and weather.

While renewable energy is often thought of as a new technology, harnessing nature’s power has long been used for heating, transportation, lighting, and more. The wind has powered boats to sail the seas and windmills to grind grain.

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The sun has provided warmth during the day and helped kindle fires to last into the evening. But over the past 500 years or so, humans increasingly turned to cheaper, dirtier energy sources such as coal and fracked gas.

Now that we have increasingly innovative and less expensive ways to capture and retain wind and solar energy, renewables are becoming a more important power source, accounting for more than one-eighth of the U.S. generation.

The expansion in renewables is also happening at scales large and small, from rooftop solar panels on homes that can sell power back to the grid to giant offshore wind farms. Even some entire rural communities rely on renewable energy for heating and lighting.

As renewable use continues to grow, a key goal will be to modernize America’s electricity grid, making it smarter, more secure, and better integrated across regions.

Types of Renewable Energy

Renewable energy is energy from sources that are naturally replenishing but flow-limited; renewable resources are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time.

Renewable energy often referred to as clean energy, comes from natural sources or processes that are constantly replenished. For example, sunlight or wind keep shining and blowing, even if their availability depends on time and weather.

The major types or sources of renewable energy are:

They are called renewable energy sources because they are naturally replenished. Day after day, the sun shines, plants grow, the wind blows, and rivers flow.

1. Solar Energy

Solar power is energy from the sun that is converted into thermal or electrical energy. Solar energy is the cleanest and most abundant renewable energy source available, and the U.S. has some of the richest solar resources in the world.

Solar technologies can harness this energy for a variety of uses, including generating electricity, providing light or a comfortable interior environment, and heating water for domestic, commercial, or industrial use.

There are three main ways to harness solar energy: photovoltaics, solar heating & cooling, and concentrating solar power. Photovoltaics generate electricity directly from sunlight via an electronic process and can be used to power anything from small electronics such as calculators and road signs up to homes and large commercial businesses.

Solar heating & cooling (SHC) and concentrating solar power (CSP) applications both use the heat generated by the sun to provide space or water heating in the case of SHC systems or to run traditional electricity-generating turbines in the case of CSP power plants.

2. Wind Energy

Wind power or wind energy describes the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or can be converted into electricity by a generator.

You can learn how wind turbines make electricity and see an illustration of the components inside a wind turbine, or view a wind power animation that shows how moving air rotates a wind turbine’s blades and how the internal components work to produce electricity.

3. Geothermal energy

Geothermal energy is the heat that comes from the sub-surface of the earth. It is contained in the rocks and fluids beneath the earth’s crust and can be found as far down as the earth’s hot molten rock, magma.

To produce power from geothermal energy, wells are dug a mile deep into underground reservoirs to access the steam and hot water there, which can then be used to drive turbines connected to electricity generators. There are three types of geothermal power plants; dry steam, flash, and binary.

Dry steam is the oldest form of geothermal technology and takes the steam out of the ground and uses it to directly drive a turbine. Flash plants use high-pressure hot water into cool, low-pressure water whilst binary plants pass hot water through a second liquid with a lower boiling point, which turns to vapor to drive the turbine.

4. Tidal Energy

Tidal energy is produced by the surge of ocean waters during the rise and fall of tides. Tidal energy is a renewable source of energy.

During the 20th century, engineers developed ways to use tidal movement to generate electricity in areas where there is a significant tidal range the difference in area between high tide and low tide. All methods use special generators to convert tidal energy into electricity.

Tidal energy production is still in its infancy. The amount of power produced so far has been small. There are very few commercial-sized tidal power plants operating in the world.

5. Hydroelectric Power

Hydroelectric energy, also called hydroelectric power or hydroelectricity, is a form of energy that harnesses the power of water in motion such as water flowing over a waterfall to generate electricity. People have used this force for millennia.

Over two thousand years ago, people in Greece used flowing water to turn the wheel of their mill to ground wheat into flour.

Most hydroelectric power plants have a reservoir of water, a gate or valve to control how much water flows out of the reservoir, and an outlet or place where the water ends up after flowing downward. Water gains potential energy just before it spills over the top of a dam or flows down a hill.

The potential energy is converted into kinetic energy as water flows downhill. The water can be used to turn the blades of a turbine to generate electricity, which is distributed to the power plant’s customers.

6. Biomass Energy

Biomass energy is energy generated or produced by living or once-living organisms. The most common biomass materials used for energy are plants, such as corn and soy, above. The energy from these organisms can be burned to create heat or converted into electricity.

People have used biomass energy from living things since the earliest “cavemen” first made wood fires for cooking or keeping warm.

Biomass is organic, meaning it is made of material that comes from living organisms, such as plants and animals. The most common biomass materials used for energy are plants, wood, and waste. These are called biomass feedstocks. Biomass energy can also be a non-renewable energy source.

Biomass contains energy first derived from the sun: Plants absorb the sun’s energy through photosynthesis, and convert carbon dioxide and water into nutrients (carbohydrates).

Benefits of Renewable Energy

Environmental and economic benefits of using renewable energy include:

  • Generating energy that produces no greenhouse gas emissions from fossil fuels and reduces some types of air pollution
  • Diversifying energy supply and reducing dependence on imported fuels
  • Creating economic development and jobs in manufacturing, installation, and more
  • Renewable energy won’t run out
  • Renewable energy has lower maintenance requirements
  • Renewables save money
  • Renewable energy has numerous environmental benefits
  • Renewables lower reliance on foreign energy sources
  • Renewable energy leads to cleaner water and air
  • Renewable energy creates jobs
  • Renewable energy can cut down on waste
  • Renewable energy can cut down on waste

Here are some of the top benefits of going green:

1. Renewable energy won’t run out

Renewable energy technologies use resources directly from the environment to generate electricity. These energy sources include sunshine, wind, tides, and biomass to name a few of the most popular options.

Renewable resources are not running out, which cannot be said for many types of fossil fuels. As we use fossil fuel resources, they are becoming increasingly difficult to obtain, which is likely to increase both the cost and the environmental impact of extraction.

2. Maintenance requirements are lower

In most cases, renewable energy technologies require less overall maintenance than generators that use traditional fuel sources. This is because generation technology like solar panels and wind turbines have either few or no moving parts and do not rely on combustible, combustible fuel sources to operate. Fewer maintenance requirements mean more time and cost savings.

3. Renewables save money

By using renewable energies, you can save money in the long term. You not only save maintenance costs but also operating costs. If you’re using technology that generates electricity from the sun, wind, steam, or natural processes, you don’t have to pay to refuel.

The amount of money you save from renewable energy can depend on a number of factors, including the technology itself. In most cases, switching to renewable energy means savings of between hundreds and thousands of dollars.

4. Renewable energy has numerous health and environmental benefits

  • Generating energy that produces no greenhouse gas emissions from fossil fuels and reduces some types of air pollution
  • Diversifying energy supply and reducing dependence on imported fuels
  • Creating economic development and jobs in manufacturing, installation, and more

The use of fossil fuels not only emits greenhouse gases, but also other harmful pollutants that lead to respiratory and heart health problems. With renewable energies, you are helping to reduce the spread of these pollutants and contribute to an overall healthier atmosphere.

5. Renewables lower reliance on foreign energy sources

Renewable energy technologies allow you to produce energy locally. The more renewable energy you use for your electricity needs, the less you rely on imported energy and the more you contribute to the overall US energy independence.

Disadvantages of renewable energy

Renewable energy has many benefits, but it’s not always sunny when it comes to renewable energy. Here are some disadvantages to using renewables over traditional fuel sources:

  • High upfront costs
  • Intermittency
  • Storage capabilities
  • Geographic limitations
  • Renewables aren’t always 100% carbon-free

1. Higher upfront cost

While you can save money by using renewable energy, the technologies are usually more expensive upfront than traditional energy producers. To counter this, financial incentives such as tax credits and discounts are often available to help lower your initial renewable technology costs.

2. Intermittency

Although renewable energy sources are available worldwide, many of these resources are not available 24/7 all year round. Some days may be windier than others, the sun does not shine at night, and droughts can occur for some time. There can be unpredictable weather events that disrupt these technologies. Fossil fuels are non-intermittent and can be turned on or off at any time.

3. Storage capabilities

Due to the interruption of some renewable energy sources, there is a high demand for energy storage. Although storage technologies are available today, they can be expensive, especially for large renewable energy systems. It’s worth noting that energy storage capacity grows as technology advances, and batteries become more affordable over time.

4. Geographic limitations

The United States has a diverse geography with different climates, topographies, vegetation, and much more. This creates a nice melting pot of landscapes, but it also means that there are some regions that are better suited to renewable technologies than others.

For example, a large open space farm can be a great place for a residential wind turbine or solar system, while a townhouse in a city shaded by taller buildings cannot take advantage of either technology on their property. If your property is not eligible for personal renewable energy technology, there are other options.

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Reference

Renewable energy sources: Solar Schools