Renewable Energy Sources

Renewable Energy Sources

The fastest-growing energy source in the world is renewable energy. In 2016, renewable energy made up 24% of electricity generation. Of the 24%, hydro-power generated 16%. In 2017, 18% of the energy consumed globally for transportation, heating, and power was from renewable sources.

Sixty percent came from biomass, solar, geothermal, Hydro-power, Wind, and Bio-fuels. The remainder was from traditional biomass used in heating and cooking. During the first eight months of 2019, green energy solutions accounted for 18.49% of domestic electric generation.

Countries around the world are adopting the use of renewable energy sources to conserve the planet’s resources and combat climate change. Currently, one of the biggest problems ailing our planet is greenhouse gas emissions.

These gases trap heat and contribute to respiratory diseases from air pollution and smog. Due to the greenhouse effect, the world is experiencing food supply disruptions, extreme weather, and increased wildfires.

As a homeowner or entrepreneur, you can reduce your carbon footprint by using renewable energy sources. Want to know the types of renewable energy sources currently available in the market.

In this post, we discuss the types of renewable energy sources.

Types of Renewable Energy Sources

Energy conservation and efficiency are the best solutions to fighting global warming, climate change and save the planet’s resources for future generations. The good news is we are way ahead.

According to experts, the world doubled the amount of installed renewable power capacity in the past decade. In 2008, hydropower capacity was 1,058 GW, but in 2017, hydropower capacity was 2,179 GW. There are several types of renewable energy sources, each with its benefits.

  • Solar
  • Wind
  • Hydro-power
  • Biomass
  • Geothermal

1. Solar

The Earth receives 174 petawatts of solar radiation each day. Of these, 30% is usually reflected back into space, while landmasses, oceans, and clouds absorb the rest. The amount of solar energy radiated by the Sun each day can power homes and businesses for years. Get all the Solar Energy advantages here.

Bell Labs developed the first photovoltaic cell in 1954. Made of Silicon, the photovoltaic cell captured and converted solar energy into usable energy. The primary solar cells were able to convert solar energy into electricity at an efficiency of 4%. Today, solar cells can convert sunlight to solar power at 20% efficiency.

There are several ways to harness solar power.

  • Photovoltaic systems
  • Concentrated solar power
  • Solar water heating

Photovoltaic systems are a form of active solar technique. Composed of solar panels, battery packs, inverters, and system meter, they harness energy from sunlight converting it into solar power for use at home. In 2018, solar photovoltaics produced 100 GW of global capacity. This brought the total of power generated by solar PV systems to 505 GW, accounting for 2% of the world’s electricity.

Concentrated solar power systems generate solar power by using lenses or mirrors. The system concentrates the sunlight onto a receiver whereby the receiver generates electricity after converting the concentrated light into heat. How may you ask? The heat or solar thermal energy drives a steam turbine connected to a power generator.

Solar water heating is another form of active solar technique that converts the Sun’s radiation into heat for water heating. The system uses a solar thermal collector with dark-colored pipes enclosed in a simple glass-topped insulated box.

Apart from heating, cooling, and electricity production, solar has other applications too.

  • Solar heating of buildings
  • Solar distillation
  • Solar pumping
  • Solar cooking
  • Solar furnaces
  • Solar drying of animal and agricultural products

2. Wind Energy

Wind energy is another popular green energy-saving solutions. The process involves electricity production using wind, which occurs naturally in the Earth’s atmosphere. In 2015, the global wind energy market reached 945 MW, a 14% growth after installation of 1 million wind turbines. Come 2016, wind energy capacity rose to 486,661 MW after the addition of 54,846, representing a growth rate of 11.8%.

By 2018, wind power capacity reached 597 GW after the addition of 50.1 GW.

There are three types of wind energy:

  1. Distributed – also referred to as small wind energy, turbines used are below 100 kilowatts and can power a farm, home, or small business. This type of system is not connected to the grid.
  2. Utility-scale – wind turbines in this class range from 100 kilowatts to several megawatts. Electricity produced under utility-scale is distributed to the grid and end-users by power system operators
  3. Offshore –under offshore, wind turbines are usually installed in large bodies of water on the continental shelf. Offshore wind turbines are bigger than onshore wind turbines and generate more power.

To produce electricity, the blades of a wind turbine capture the wind’s kinetic energy as they rotate. The blades turn the kinetic energy into mechanical energy when they turn the low-speed shaft connected to a gearbox.

This low-speed shaft increases the speed of rotation by 100. Since the low-speed shaft is usually connected to a high-speed shaft, when they both spin, they also spin a generator producing electricity.

For a modern turbine to produce electricity, wind speeds must reach six to nine mph. This is also called the cut-in speed. If the wind blows hard (55 mph+), the turbine shuts down to prevent damage.

A modern 2 MW wind turbine is capable of producing 17,520 MWh. However, there are onshore models capable of producing 7,884 MWh in a year because the wind was not blowing too much.

3. Hydro-power

Hydro-power is one of the most efficient ways to generate clean energy. Unlike coal burned in a coal-fired plant to produce electricity or oil, hydro-power relies on a renewable resource – water. This is thanks to the water cycle.

The water cycle is a natural process whereby the Sun heats up large and small masses of water, such as lakes, rivers, streams, seas, and oceans. The vapor rises up into the atmosphere and condenses to form clouds. Due to changes in pressure, rain starts to fall.

Once the raindrops hit the Earth’s surface, they flow to form small streams and rivers that flow into lakes and oceans. To harness hydro-power, engineers dam a river creating a reservoir. They also create a diversion tunnel to allow the river to continue flowing.

After completion and installation of generators/turbines, water flows from the reservoir through the turbine. The water spins the turbine activating the generators, which in turn produce electricity.

The largest hydro-power dams in the world are:

  • Three Gorges, Yangtze River, China – 87 TWh (annual generation)
  • Itaipu Dam, Parana River, Brazil/Paraguay – 96.586 TWh
  • Xiluodu, Jinsha River, China – 55.2 TWh
  • Guri, Caroni River, Venezuela – 47 TWh
  • Tucurui, Tocantins River, Brazil – 21.4 TWh

In 2011, hydro-power generation accounted for 16% of global electricity generation from over 45,000 large dams. Today, thanks to the introduction of other renewable energy sources, hydropower generation stands at 16%.

While hydro-power is a clean energy source, it has a few drawbacks. First off, it disrupts wildlife, surrounding communities, and river ecosystems. Studies show that governments displace people and wildlife when it plans to build a hydro-power plant across a river.

The dam disrupts the migratory routes and patterns of fish and other marine animals. It also kills breeding grounds for fish, which leads to a decline in fish numbers. Hydropower dams can cause silt buildup. This compromises the reservoir capacity and may harm equipment.

4. Biomass

Biomass is becoming the world’s biggest renewable energy source. In fact, its growth in the past few decades is greater or similar to solar and wind energy in most countries. During the Industrial Revolution, industrialized nations in Europe started using wood as fuel.

After the discovery of coal and oil, industries began using energy produced by coal-fired power plants. By the mid 18th century, England’s primary source of fuel was coal, and by the mid 19th century, biomass use as fuel declined in Western Europe.

Biomass use did not begin again until the mid 20th century. Countries like China and India remained biomass powered until the 1950s and 1960s when they turned to hydropower.

In Europe, America, Asia, and Africa, biomass is now seeing some form of a renaissance. The reason is simple – fight climate change and global warming, save the planet’s resources, and meet renewable energy goals.

Biomass energy includes:

  • Wood
  • Wood waste
  • Bio-diesel
  • Ethanol
  • Bio-gas

Biomass can power vehicles, produce electricity, heat, and cool buildings. Other applications include cooking and water heating. A report from the International Energy Agency shows that biomass accounts for 10% of the global energy supply.

Two-thirds of the power is in use in developing countries for heating and cooking. In 2009, 13% of biomass use was for power generation and heating, while industries and transportation consumed 15% and 4%, respectively.

Even though biomass use and popularity is on the rise, there are a few issues. First off, many people think that corn-based ethanol is not sustainable even though it’s renewable. The reason for this is simple – farmers may opt to grow corn for fuel rather than food. This will drive the cost of animal food up, and an increase passed along to poultry and beef consumers.

To resolve this, leaders must come up with policies that promote the sustainable production of ethanol and food.

5. Geothermal

Geothermal is a cost-effective way of producing electricity. As a natural source of power below the Earth’s surface, it’s renewable, just like hydropower. Below the Earth’s surface, there are pools of water. Magma or molten rocks heat these pools of water, creating geothermal reservoirs.

When the steam from these pools’ escapes, its piped directly into turbines. The high-pressured steam spins the turbines and generators, creating electricity. Other geothermal plants use hot water from underground to produce electricity.

There are three main types of geothermal power plants:

  • Dry steam power plant – in dry steam power plants, hot steam from underground is usually pipped directly into turbines. The turbines power generators to generate electricity. After powering the turbines, the steam condenses into water and piped back into the Earth.
  • Flash steam power plant – in a flash steam power plant, the turbines use hot water and not steam. Hot water from the underground is usually pumped into a flash tank on the surface. This flash tank is at a lower temperature. Pumping hot water into the flash tank causes the fluid to steam. The steam powers the turbines producing electricity.
  • Binary cycle power plant – unlike dry or flash steam power plants where hot steam or water comes in direct contact with the turbine. In binary cycle power plant, hot water passes through a heat exchanger and heats another liquid like isobutene. This liquid turns into steam spinning the turbine, which drives the generator to produce electricity.

Today, it’s considered possible for geothermal power plants around the world to produce 8.3% of the total world’s electricity, supplying 17% of the global population.

Can the World Achieve 100% Renewable Energy?

Yes, the world can achieve 100% renewable energy. While countries will have to invest a lot in technology, the rewards are great. First off, they will contribute to reducing the carbon footprint and the use of fossil fuels.

This helps to lower the greenhouse effect and climate changes. Basically, transitioning from non-renewable to renewable will aid in avoiding a monumental crisis when the end of fossil fuels comes.

The time is now, and we all have a part to play. Start by installing solar PV and solar water heating systems in your home or business. This will help you lower your carbon footprint and save the planet’s resources.