How do bore holes in Iceland create electricity from the steam produced by the earth?
Boreholes in Iceland, specifically geothermal boreholes, are used to tap into the Earth's geothermal energy and convert it into electricity. Here's how the process generally works:
1. Identifying the Resource: Firstly, areas with high geothermal activity are identified, such as regions with active volcanoes or hot springs. Iceland, for instance, lies on the Mid-Atlantic Ridge, where tectonic plates diverge, creating a geothermal hotspot.
2. Drilling Boreholes: Once a suitable location is determined, deep wells called boreholes are drilled into the Earth's crust. The depth of these boreholes can range from 1,500 to 3,000 meters (4,900 to 9,800 feet) in Iceland. The process of drilling is similar to drilling for oil or gas wells.
3. Tapping Geothermal Reservoirs: By drilling, the boreholes reach the geothermal reservoirs, which consist of superheated water and steam trapped deep underground. These reservoirs are formed by the heated rocks and water interacting with each other.
4. Extracting Hot Water and Steam: High-pressure pumps are used to extract the hot water and steam from the geothermal reservoirs. The extracted hot water and steam are separated in a separator, where the steam is separated from the water.
5. Power Generation: The separated steam is then directed to a turbine, which converts the thermal energy of the steam into mechanical energy by spinning the turbine blades. As the steam expands and pushes the turbine, the turbine's shaft is also turned.
6. Electric Generator: Connected to the turbine is an electric generator, which consists of a rotor and stator. As the turbine spins the rotor, it induces a magnetic field in the stator, producing an electric current.
7. Transmission: The electricity generated by the geothermal power plant is then transmitted through power lines to be distributed to homes, businesses, and industries.
8. Cooling the Steam: After the steam passes through the turbine, it is condensed back into water using cooling towers or by utilizing cold water sources (such as rivers). This condensed water is then injected back into the boreholes to be reheated by the Earth, completing the cycle.
By utilizing the natural heat from the Earth's interior, boreholes in Iceland leverage geothermal energy to produce clean and sustainable electricity, reducing the country's reliance on fossil fuels and contributing to a greener energy mix.