5 Examples Of Green Technology

What Is Green Technology – Definition and Examples

The term green tech refers to technology that is considered environmentally friendly based on its production process or supply chain. Green tech–which is short for green technology–can also refer to clean energy production. 

Clean energy is the use of alternative fuels and technologies that are less harmful to the environment versus fossil fuels.

The main purpose of green technology is to slow down global warming and reduce the green house effect. The main idea is the creation of new technologies which do not damage the natural resources. This should result into less harm to people, species and the general health of our planet.

Contoh-contoh Teknologi Hijau

Green technology is used in many ways, including recycling, clean water production, clean air, energy and so on. In this write-up, we will explain further on how green technology is used in energy generation.

These are the five main different types of green energy:

1. Nuclear Power

Atoms are tiny particles that make up every object in the universe. The bonds that hold atoms together contain a huge amount of energy. When atoms are split apart, this energy can be used to make electricity. This process is called nuclear fission.

In a nuclear power plant, fission takes place inside a reactor. Most nuclear power plants use uranium as fuel because its atoms are easily split apart.

Uranium is a metal found in rocks all over the world. Although uranium is not a renewable resource, fairly large quantities of it still exist, and it only takes a small amount to produce a lot of energy.

Because nuclear power plants don't burn fossil fuels, they don't produce greenhouse gases. But mining and refining uranium requires large amounts of energy. In addition, nuclear power plants produce waste that is radioactive. This waste has to be handled and disposed of according to special regulations designed to protect people and the environment.

How It Works?

  1. In a nuclear reactor, fuel rods full of uranium pellets are placed in water.
  2. Inside the fuel rods, uranium atoms split, releasing energy.
  3. This energy heats water, creating steam.
  4. The steam moves through a turbine, which turns a generator to create electricity.
  5. The steam cools back into water, which can then be used over again. At some nuclear power plants, extra heat is released from a cooling tower.

Nuclear Energy Pros and Cons

Pros

  • Low Greenhouse Gas Emissions.
  • Doesn’t Rely on Fossil Fuels.
  • Electricity generated by nuclear reactors is cheaper than gas, coal, or any other fossil fuel plants.
  • A relatively small amount of uranium can be used to fuel a 1000 Megawatts electric plant,

Cons

  • Back-end Environmental Impact..
  • High Up-Front and End Stage Cost.

2. Offshore Wind Turbines

Three months after deployment, the world’s first floating wind farm surpassed performance expectations, according to its operator, Statoil. The five-turbine, 30-MW Hywind Scotland Pilot Park — situated 15 miles off the Aberdeenshire Coast — operated at 65% of its maximum theoretical capacity last November, December, and January, the Norwegian energy company said.

By comparison, the typical capacity factor during the winter season for a bottom-fixed offshore wind farm is 45 to 60%. The 65% capacity figure was achieved despite a hurricane and a severe winter storm with wave heights up to 27 feet.

How Are Offshore Wind Turbines Anchored At Sea?

In offshore wind farms, wind turbines are elevated over the sea level with different types of foundations, depending on the depth. Offshore wind power projects are used to exploit the potential of wind in open seas, where wind blows stronger than on land. 

There are different types of foundations, according to the depth at which the wind turbine will be installed. 

TurbinesMonopilesGravityJacket
Depth<15m≤30m >30m
StructureThick steel cylinder, buried down to a depth of 30m to support the towerConcrete or steel platform with an approximate diameter of 15mStructure with 3 or 4 anchoring points. Reaches a length of almost 60m
GroundSandy-clayeyRequires the previous preparation of the terrainDifferent types of soils (non-rocky)

How It Works?

Offshore Wind Power Advantages

  • Offshore wind energy is renewable, unlimited and non-polluting.
  • There are more wind resources offshore than onshore (up to twice as much as in a medium onshore wind farm).
  • When located offshore, the visual and acoustic impact is very small, so much larger areas can be used.
  • Offshore wind farms typically have several hundred megawatts of installed capacity.
  • The ease of maritime transport, which has few limitations with regard to cargo and dimensions in comparison with land transportation, has made it possible for offshore wind turbines to reach much larger unit capacities and sizes than onshore wind turbines.

3. Solar Thermal

There are two main ways of generating energy from the sun. Photovoltaic (PV) and concentrating solar thermal (CST), also known as concentrating solar power (CSP) technologies.

PV converts sunlight directly into electricity. These solar cells are usually found powering devices such as watches, sunglasses and backpacks, as well as providing power in remote areas.

Solar thermal technology is large-scale by comparison. One big difference from PV is that solar thermal power plants generate electricity indirectly. Heat from the sun's rays is collected and used to heat a fluid. The steam produced from the heated fluid powers a generator that produces electricity.

It's similar to the way fossil fuel-burning power plants work except the steam is produced by the collected heat rather than from the combustion of fossil fuels.

How It Works?

Plantar kuasa solar thermal merupakan penjanaan elektrik yang menggunakan tenaga dari matahari untuk memanaskan cecair pada suhu yang tinggi. Cecair ini kemudian menukar haba kepada air yang akan menjadi wap yang sangat panas.

Wap ini kemudian digunakan untuk menghidupkan turbin yang terdapat dalam plantar kuasa dan tenaga mekanikal ini akan ditukar menjadi elektrik oleh sebuah generator.

Types Of Plants

There are two types of systems to collect solar radiation and store it: passive systems and active systems. Solar thermal power plants are considered active systems.

Despite the fact that there are several different types of solar thermal power plants, they are all the same in that they utilize mirrors to reflect and concentrate sunlight on a point. At this point the solar energy is collected and converted to heat energy, which creates steam and runs a generator. This creates electricity.

  • Parabolic Troughs

These troughs, also known as line focus collectors, are composed of a long, parabolic shaped reflector that concentrates incident sunlight on a pipe that runs down the trough. The collectors sometimes utilize a single-axis Solar tracking system to track the Sun across the sky as it moves from east to west to ensure that there is always maximum solar energy incident on the mirrors. The receiver pipe in the center can reach temperatures upward of 400°C as the trough focuses Sun at 30-100 times its normal intensity.

These troughs are lined up in rows on a solar field. A heat transfer fluid is heated as it is run through the pipes in the parabolic trough. This fluid then returns to heat exchangers at a central location where the heat is transferred to water, generating high-pressure superheated steam. This steam then moves a turbine to power a generator and produce electricity. The heat transfer fluid is then cooled and run back through the solar field.

  • Parabolic Dishes

These are large parabolic dishes that use motors to track the Sun. This ensures that they always receive the highest possible amount of incoming solar radiation that they then concentrate at the focal point of the dish. These dishes can concentrate sunlight much better than parabolic troughs and the fluid run through them can reach temperatures upwards of 750°C.

In these systems, a Stirling engine coverts heat to mechanical energy by compressing working fluid when cold and allowing the heated fluid to expand outward in a piston or move through a turbine. A generator then converts this mechanical energy to electricity.

  • Solar Towers

Solar power towers are large towers that act as a central receiver for solar energy. Power towers rely on thousands of heliostats, which are large, flat sun-tracking mirrors, to focus and concentrate the sun's radiation onto a single tower-mounted receiver.

Like parabolic troughs, heat-transfer fluid or water/steam is heated in the receiver (power towers, though, are able to concentrate the sun's energy as much as 1,500 times), eventually converted to steam and used to produce electricity with a turbine and generator.

The Advantages Of Solar Thermal

  • Can Be Combined With Solar PV
  • Renewable
  • Reduces Fossil Fuel Dependency
  • Requires Little Space
  • Solar Thermal Reduces Heating Bills
  • Environmentally Friendly

4. Biomass Energy

Biomass is referred as organic matters derived from plants, animals, forestry and agriculture residues, and organic compounds of municipal and industrial wastes. 

Biomass technologies decompose organic matters to release their stored energy such as biofuels and bioenergy.

Examples of Biomass and Their Uses for Energy

  • Wood – burned to heat buildings, to produce process heat in industry, and to generate electricity
  • Crops – burned as a fuel or converted to liquid biofuels
  • Garbage – burned to generate electricity in power plants or converted to biogas in landfills
  • Animal manure and human sewage – converted to biogas, which can be burned as a fuel

Biomass Energy Technology Applications

  1. Biofuels: Converting biomass into liquid fuels for transportation.
  2. Biopower: Burning biomass directly, or converting it into a gaseous fuel or oil, to generate electricity.
  3. Bioproduk: Converting biomass into chemicals for making products that typically are made from petroleum.

How Biomass Energy Created?

1. Dirict firing

Most briquettes are burned directly. The steam produced during the firing process powers a turbine, which turns a generator and produces electricity. This electricity can be used for manufacturing or to heat buildings.

2. Pyrolysis

Pyrolysis is a related method of heating biomass. During pyrolysis, biomass is heated to 200° to 300° C (390° to 570° F) without the presence of oxygen. This keeps it from combusting and causes the biomass to be chemically altered.

Pyrolysis produces a dark liquid called pyrolysis oil, a synthetic gas called syngas, and a solid residue called biochar. All of these components can be used for energy.

3. Gasification

Biomass can also be directly converted to energy through gasification. During the gasification process, a biomass feedstock (usually MSW) is heated to more than 700° C (1,300° F) with a controlled amount of oxygen. The molecules break down, and produce syngas and slag.

Syngas is a combination of hydrogen and carbon monoxide. During gasification, syngas is cleaned of sulfur, particulates, mercury, and other pollutants. The clean syngas can be combusted for heat or electricity, or processed into transportation biofuels, chemicals, and fertilizers.

4. Anaerobic Decomposition

Anaerobic decomposition is the process where microorganisms, usually bacteria, break down material in the absense of oxygen. Anaerobic decomposition is an important process in landfills, where biomass is crushed and compressed, creating an anaerobic (or oxygen-poor) environment

In an anaerobic environment, biomass decays and produces methane, which is a valuable energy source. This methane can replace fossil fuels.

In addition to landfills, anaerobic decomposition can also be implemented on ranches and livestock farms. Manure and other animal waste can be converted to sustainably meet the energy needs of the farm.

List of Pros of Biomass Energy

  • It is renewable
  • It doesn’t produce carbon
  • It is widely available
  • It can be used in many forms

List of Cons of Biomass Energy

  • It is not 100% clean when burned
  • It needs a lot of space
  • It is expensive

5. Artificial Geothermal Energy

If you were to dig a big hole straight down into the Earth, you would notice the temperature getting warmer the deeper you go. That's because the inside of the Earth is full of heat. This heat is called geothermal energy.

How To Capture It?

People can capture geothermal energy through:

  • Geothermal power plants, which use heat from deep inside the Earth to generate steam to make electricity.
  • Geothermal heat pumps, which tap into heat close to the Earth's surface to heat water or provide heat for buildings.

How It Works?

1. Geothermal Power Plants

  1. Hot water is pumped from deep underground through a well under high pressure.
  2. When the water reaches the surface, the pressure is dropped, which causes the water to turn into steam.
  3. The steam spins a turbine, which is connected to a generator that produces electricity.
  4. The steam cools off in a cooling tower and condenses back to water.
  5. The cooled water is pumped back into the Earth to begin the process again.

2. Geothermal Heat Pumps

  1. Water or a refrigerant moves through a loop of pipes.
  2. When the weather is cold, the water or refrigerant heats up as it travels through the part of the loop that's buried underground.
  3. Once it gets back above ground, the warmed water or refrigerant transfers heat into the building.
  4. The water or refrigerant cools down after its heat is transferred. It is pumped back underground where it heats up once more, starting the process again.
  5. On a hot day, the system can run in reverse. The water or refrigerant cools the building and then is pumped underground where extra heat is transferred to the ground around the pipes.

Pros And Cons

Pros

  • Environmentally friendly compared to gas or oil furnaces (no combustion).
  • Not weather dependent like solar or wind power; geothermal heat pumps work year-round.
  • Quieter operation because of no outdoor compressor or fan.
  • Fewer moving parts mean minimal maintenance issues.

Cons

  • Electricity is still needed to operate heat pumps.
  • Geothermal energy using wells requires an incredible usage of water.
  • Damage to underground loops (tree roots, rodents, etc.) can be difficult and costly to repair.

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