Electricity production using geothermal energy is based on conventional steam turbine and generator equipment, in which expanding steam powers the turbine/generator to produce electricity. Geothermal energy is tapped by drilling wells into the reservoirs and piping the hot water or steam into a power plant for electricity production. The type of power plant depends on a reservoir’s temperature, pressure, and fluid content. There are four main types of geothermal power plants: dry-steam, flashed-steam, binary-cycle and combined cycle (hybrid). Such projects
- Are technically simple;
- Contain significant equipment and material which may need to be imported;
- Usually base load;
- May produce a very small amount of CO2 greenhouse gas;
- Need a relatively shallow source of hot steam/water. Often located in areas of volcanic activity evidenced by hot springs and/or geysers;
- Have high capital costs and low running costs;
- Have capital costs which are highly site specific and the location of the site needs to be reasonable close to consumers;
- May be risky due to unpredictable geology;
- May require enhanced steam production by using fracking techniques;
- Will typically replace wells and pipework every 15 years or so;
- Need a larger number of operating and maintenance personnel than some other renewable energy projects such as solar (PV cells) and wind farms
How Promoter handles Geothermal power projects
Promoter can handle the above four types of geothermal power generation.
Typical Project Cash Flows
The following diagram illustrates the cash flows on a geothermal power project.
Note that the performance declines gradually until the pipework and wells are replaced at regular intervals.