Geothermal Energy and Examples
Geothermal Energy and Examples
Contents
Geothermal energy refers to the use of thermal energy stored within the Earth. A distinction is made between shallow and deep geothermal systems. Geothermal energy is used for heating as well as for generating electricity.
Explanation
Shallow Geothermal Energy
- Utilizes layers up to 400 meters deep.
- Employs groundwater wells, geothermal probes, and ground source heat collectors.
- Provides constant, year-round temperatures starting at just 15 meters deep.
- Temperatures are relatively low.
- Energy is harnessed using thermal groundwater systems and/or heat pumps.
Deep Geothermal Energy
- The geothermal gradient means the temperature increases by approximately 3°C for every 100 meters of depth.
- Taps into resources deeper than 400 meters.
- Utilizes steam and hot water from underground reservoirs.
- This is known as a hydrothermal system.
- Reservoirs are accessed by drilling into the surrounding rock.
- Natural pressure often causes the hot water or steam to rise to the surface on its own.
Advantages and Disadvantages
| Advantages | Disadvantages |
| Renewable energy source | High initial exploration and drilling costs |
| Minimal land footprint for deep geothermal plants | Dependent on the availability of suitable hydrothermal reservoirs |
| High potential in geologically suitable regions | In rare cases, can cause surface subsidence or affect groundwater |
| Can be used for thermal energy storage | Shallow systems require significant surface area and preparatory work (e.g., trenching) |
| On-site energy generation | |
| Reliable and consistent, independent of weather or time of day | |
| Excellent carbon footprint (very low CO2 emissions) | |
| Can produce both electricity and heat (cogeneration) |
Example: Geothermal Energy in Iceland
Iceland is a world leader in the utilization of geothermal energy.
- It has 6 major geothermal power plants.
- They supply over 26% of the country’s electricity.
- They provide heating for approximately 90% of all households.
- The abundance of geothermal heat is even used for heating sidewalks and streets to melt snow and ice.
