- Uses of geothermal energy include (in order of importance):
- How is Geothermal Energy Created?
- Types of Geothermal Energy
- Advantages of Geothermal Energy – What are the pros?
- List the benefits and drawbacks
- Why is Geothermal Energy Not Used as Frequently as Other Forms of Energy?
- Who Uses Geothermal Energy and for What Purposes?
Uses of geothermal energy include (in order of importance):
- Generating electricity
- Home heating and cooling using ground-source heat-pumps
- Heating greenhouses directly
- Pasteurizing milk
- Heating water for fish farms
- Health uses (as in health spas)
- Drying food
How is Geothermal Energy Created?
Geothermal energy is created underground due to the pressure deep within the earth (which is one of the disadvantages), and is usually found in underground hot-water reservoirs. The steam can be used to turn a generator to produce electricity.
People can also capture this energy using energy conversion power plants and heat tubs, for example. The energy is generated at high temperatures ranging from 300 to 700F. Geothermal energy systems make the energy accessible to consumers for practical use.
Where is Geothermal Energy Found?
This energy is found in the earth’s sub-surface – which can be as deep as the earth’s magma (this is hot, molten lava). Most power plants use hydrothermal resources, which means they bring up hot water to the surface where heat is extracted for generating electrical power or heating purposes.
These resources come from dry steam or hot water wells. Some are close to the surface and don’t require much drilling, while others can be as deep as two miles.
Flash Steam Geothermal Power Plant
Flash steam is the most popular type of geothermal power plant. It uses straightforward technology. The hot water comes from beneath the earth’s surface at relatively high pressure.
The pressure reduces when it hits the ground, and the hot water vaporizes (this is where the term ‘flash’ comes from). If there is remaining liquid, it is recycled by injecting it back into the underground source to be heated up and ‘flashed’ again, continuing the process.
Types of Geothermal Energy
What are the 3 Types of Geothermal Power Plants?
The three types of geothermal power are:
- Binary cycle
- Flash steam
- Dry steam
1. Binary Cycle Geothermal Power Plants – How do binary cycle plants work?
Binary cycle plants use hot water to boil an organic compound (working fluid) with a low boiling point. The boiling fluid is fed to a heat exchanger, vaporized, and used to turn a turbine.
After this, the water is piped back underground and reheated. The low-temperature water (107-182°C or 225-360°F) and working fluid are never mixed to prevent polluting the underground source.
2. Flash Steam Geothermal Power Plants
These are the commonly used geothermal power plants because they use very hot geothermal water reservoirs (182°C or 360°F). The hot water uses its normally higher pressure to flow up the wells. As this process happens, some water turns to steam and turns the turbines. The condensed and remaining water is pumped back to the reservoir to avoid wastage.
3. Dry Steam Geothermal Power Plants
Unlike flash steam, dry steam power plants use steam that has been directly pumped from the wells to the turbine. In the United States, there are two resources of dry steam; the Geysers in CA and Yellowstone National Park. The latter is protected from development, so the Geysers in California are the only dry steam power plants operating currently.
Which is the Oldest Type of Geothermal Power Plant?
The first geothermal generator was developed in 1904 in Italy due to the demand for more electricity, and it lit four bulbs. In 1911, the first geothermal power plant was built at the exact location. It was invented by Prince Piero Ginori Conti in Tuscany. It was not until 1958 that another operating plant was successfully developed.
America has a total geothermal power generation of over 3676 MW; this was achieved between 2015-2019 when seven plants were installed. The oldest power plant and type of geothermal technology is dry steam. It is not often used because it needs dry steam resources. Otherwise, the plants have a simple yet efficient design.
Advantages of Geothermal Energy – What are the pros?
All energy sources have pros and cons, and the benefits should outweigh the drawbacks, if the resource if to be any use. Extracting natural underground heat has a lot going for it on the ecological front, while foremost among the negatives aspects is initial investment costs.
List the benefits and drawbacks
Advantages of Geothermal Energy
1. Renewable and sustainable
Geothermal energy is renewable, which means it will last for as long as the earth will be around (5 billion years+). Since geothermal energy can be used without getting replenished, it becomes a sustainable source of electricity. This type of true renewable energy is also readily available in the form of wind and solar.
With global warming and pollution rising, the need for environmentally-friendly energy sources keeps rising. Geothermal energy has more minor effects on the environment than most fuel sources. It also has a low carbon print and causes less pollution.
3. Evolution and Potential
There has been rapid growth in the geothermal industry. Currently, global energy consumption is at 15 terawatts. It is predicted that geothermal energy can account for 0.0035 to 2 terawatts with growth. Furthermore, new technologies are being invented to promote worldwide energy distribution, and geothermal energy faces a lot of development.
4. Less Noise Pollution
Geothermal energy power plants produce ‘silent energy’. There is no noise pollution after the construction and excavation processes are over. The steam turns the turbines with negligible noise – this applies to domestic and industrial plants.
5. Reliability and Maintenance
Did you know that a geothermal power plant can last as long as 80 – 100 years? Since there is no need for fuel during production, risks like fire are reduced. In contrast, thermal and wind power plants reduce performance over time compared to hydroelectric plants.
When it comes to maintenance, little to no effort is required, especially for domestic heating systems.
Disadvantages of Geothermal Energy
1. Location Specificity
This is the biggest downfall geothermal energy is facing. Geothermal plants are location-specific, meaning they must be developed where the energy is accessible. If the energy is not accessible and the location cannot exploit the resources, the energy becomes useless.
Geothermal energy production has a small risk of causing earthquakes. This is because digging and excavation alter the earth’s natural structure. In large geothermal plants especially, water is forced into the earth, forcing it to open for exploitation. Luckily, most plants are away from populated areas, so these risks are considered to be almost neglible.
3. Greenhouse Emissions
Even though geothermal energy is among the safest, it still poses some minor environmental concerns due to greenhouse emissions. The production and development of geothermal power plants release greenhouse gases; ammonia, methane, hydrogen sulfide, and carbon dioxide.
4. Investment Costs
Since geothermal energy is not as common as most energy sources, the industry is not as advanced. As a result, the initial costs tend to be high. This is because complex systems have to be installed. However, the ROI for geothermal power plants is between 2 to 10 years, so it is mostly worthwhile.
Why is Geothermal Energy Not Used as Frequently as Other Forms of Energy?
Since 2015, only three countries have steadily been producing geothermal energy in large-scale plants; the U.S, Indonesia, Philippines – Kenya, and Turkey have slowly been building up.
Geothermal energy is undoubtedly more beneficial than fossil fuels, water, and solar energy. Yet, it is rarely used – and not much of it is mentioned in posts, papers, and blogs. But why is this?
There was not much of geothermal energy to start with. Other renewable sources of energy like wind and solar are exploitable to the lesser or greater. High-temperature geothermal sources are only accessible in areas with heat flow and satisfactory hydrology.
These areas are usually common in places with high energy consumption. While geothermal energy technology has been around for over a century, very few places in the world have the heat and water needed for production.
In addition, geothermal energy can’t be transported – it must be used on-site. Most geothermal resources are still unexploited because of the distance between the resources and places of consumption.
Finally, geothermal energy is simply hard to produce. The reason is, there is no ‘one-size-fits-all’ mechanism. The site must be drilled, dug, and excavated. All these tests take time, money, and resources before energy production succeeds.
Who Uses Geothermal Energy and for What Purposes?
Who Uses Geothermal Energy?
1. Direct Heating Systems
People use geothermal energy as direct heating systems. Direct use of the energy is through reservoirs or springs beneath the earth’s surface. In ancient Roman, Native American, and Chinese cultures, hot water springs were believed to have many benefits. Today, people use them for bathing because of the availability and advantageous hot-water minerals.
2. District/multiple buildings heating
District heating systems also use geothermal energy to heat single or multiple buildings. The hot water underground is piped to apartments via heat pumps to provide residents with warm water and heat. This technology is primarily found in Iceland.
3. Farming – heating greenhouses and drying food
In agriculture, farmers use the energy to heat greenhouses and dry food. It is also used to grow tropical fruits and foods during winter in countries like Italy and Hungary. Countries with cold weather and tropical fish also use geothermal energy to heat fish farms.
4. Infrastructure – keeping roads ice-free
Countries like the Netherlands have developed their geothermal technology production for infrastructure. In the Netherlands, it keeps the sidewalks, roads, and bike roads warm during winter. The roads do not freeze, and fewer accidents occur.
5. Industrial use – food processing
Geothermal energy production has advanced in some industries. It is used to dry fruits and vegetables (food dehydration), extract metals, milk pasteurizing, and gold mining.