During the first eight months of 2019, green energy solutions accounted for 18.49% of domestic electric generation. Sixty per cent came from biomass, solar, geothermal, Hydro-power, Wind, and Biofuels. The remainder was from traditional biomass used in heating and cooking.
Countries worldwide are adopting renewable energy sources to conserve the planet’s resources and combat climate change. One of the biggest problems ailing our planet is greenhouse gas emissions.
These gases trap heat and contribute to air pollution and smog respiratory diseases. 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 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 saving the planet’s resources for future generations. The good news is we are way ahead.
There are several types of renewable energy sources, each with its benefits. According to experts, the world doubled its installed renewable power capacity in the past decade. In 2008, the hydropower capacity was 1,058 GW, but in 2017, the hydropower capacity was 2,179 GW.
- Solar
- Wind
- Hydropower
- Biomass
- Geothermal
1. Solar
The Earth receives 174 petawatts of solar radiation each day. Of these, 30% is usually reflected in space, while landmasses, oceans, and clouds absorb the rest. The amount of solar energy the Sun radiates daily 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. Primary solar cells can convert solar energy into electricity at an efficiency of 4%. 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 meters, 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 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, which generates electricity after converting the concentrated light into heat. The heat or solar thermal energy drives a steam turbine connected to a power generator. How, may you ask?
Solar water heating is another active solar technique that converts the Sun’s radiation into heat for water heating. The system uses a solar thermal collector with dark-coloured pipes enclosed in a simple glass-topped insulated box.
Besides heating, cooling, and electricity production, solar has other applications.
- 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 solution. 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 installing 1 million wind turbines. Come 2016, wind energy capacity rose to 486,661 MW after adding 54,846, representing a growth rate of 11.8%.
By 2018, wind power capacity reached 597 GW after 50.1 GW.
There are three types of wind energy:
- Distributed – also called small wind energy- turbines that are used below 100 kilowatts and can power a farm, home, or small business. This type of system is not connected to the grid.
- Utility-scale – wind turbines in this class range from 100 kilowatts to several megawatts. Power system operators distribute electricity produced on a utility scale to the grid and end-users.
- Offshore –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, they also spin a generator, producing electricity when they both spin.
Wind speeds must reach six to nine mph for a modern turbine to produce electricity. This is also called cut-in speed. To prevent damage, the turbine shuts down if the wind blows hard (55 mph+).
A modern 2 MW wind turbine is capable of producing 17,520 MWh. However, onshore models can produce 7,884 MWh in a year because the wind is not blowing too much.
3. Hydropower
Hydropower is one of the most efficient ways to generate clean energy. Unlike coal burned in a coal-fired plant to produce electricity or oil, hydropower relies on a renewable resource – water. This is thanks to the water cycle.
The water cycle is a natural process whereby the Sun heats large and small masses of water, such as lakes, rivers, streams, seas, and oceans. The vapour rises 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 form small streams and rivers that flow into lakes and oceans. To harness hydropower, engineers dam a river creating a reservoir. They also make a diversion tunnel to allow the river to continue flowing.
After completing and installing generators/turbines, water flows from the reservoir through the turbine. The water spins the turbine activating the generators, which produce electricity.
The largest hydropower 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, hydropower generated 16% of global electricity from over 45,000 large dams. Today, thanks to the introduction of other renewable energy sources, hydropower generation stands at 16%.
While hydropower 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 nature when it plans to build a hydropower 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. Its growth in the past few decades is greater or similar to solar and wind energy in most countries. During the Industrial Revolution, European industrialised nations started using wood as fuel.
After discovering coal and oil, industries began using energy produced by coal-fired power plants. By the mid-18th century, England’s primary fuel source was coal; 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
A report from the International Energy Agency shows that biomass accounts for 10% of the global energy supply. Biomass can power vehicles, produce electricity, heat, and cool buildings. Other applications include cooking and water heating.
Two-thirds of the power is used 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 are rising, there are a few issues. First, many people think corn-based ethanol is not sustainable even though it’s renewable. The reason for this is simple: farmers may 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 develop policies that promote the sustainable production of ethanol and food.
5. Geothermal
Geothermal is a cost-effective way of producing electricity. It’s renewable, like hydropower, as a natural power source below the Earth’s surface. 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, it’s piped directly into turbines. The high-pressure 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 – Hot steam from underground is usually pipped directly into turbines in dry steam power plants. The turbines power generators to generate electricity. After powering the turbines, the steam condenses into water and is piped back into the Earth.
- Flash steam power plant – The turbines use hot water, not steam in a flash steam power plant. 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. Hot water passes through a binary cycle power plant 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 worldwide to produce 8.3% of the entire 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 in technology, the rewards are great. First, they will reduce the carbon footprint and the use of fossil fuels.
This helps to lower the greenhouse effect and climate change. 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 water heating systems in your home or business. This will help lower your carbon footprint and save the planet’s resources.
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