Geothermal

The development of geothermal power generation is nowadays based on the exploitation of water-dominated fields, by far more common than steam-dominated ones. An increasing share of generating capacity installed in water dominated fields is made up of binary units (based on the adoption of an Organic Rankine Cycle turbogenerator), particularly suited for low and medium temperature resources.

Advantages of ORC plants in Geothermal Applications

Binary power plants feature many advantages:

  • They are environmentally more acceptable than any other kind of geothermal power plant because the geothermal fluid can be segregated throughout the whole process. In this way the release of gases or other substances to the environment can be prevented, thus virtually eliminating pollution problems;
  • They have a definite thermodynamic advantage, in terms of power production, compared to the conventional flashed steam cycles, for resources at moderate temperatures (up to 150-180 °C).
  • They can be used for electricity generation with low-temperature resources (close to 90-100 °C), which would not be feasible with flash steam.
  • They reduce the problems associated with scaling fluids: carbonate scale can be prevented by installing downwell pumps, while silica scale is minimized avoiding concentration of geothermal fluid caused by flashing.
  • They may be the best technical and economical choice, despite the generally higher unit cost of the installed capacity, thanks to the higher power output and to the reduction of the on-site construction time.

Our Experience

After the construction of the first plants in Italy and Africa in the early Nineties, Turboden completed a 1,000 kWel plant in Austria. We have also recently built a 1,500 kWel plant in Soultz-sous-Forets (France). This plant, using the Hot Dry Rock technology, allows to produce electricity exploiting the heat stored in the rocks located at 5,000 meters beneath the earth. The water, injected under pressure, reaches deep impermeable rocks fractured by the drilling where it is heated at 180°. This is the first EGS (Engineered Geothermal System) plant in Europe. You can find a detailed list of our geothermal units in the References section.

Is it suitable for you?

Geothermal ORC enables the exploitation of low and medium temperature (90°C to 200°C) geothermal reservoirs. Since geothermal sources are regular and continuous, the output is completely predictable. Indicatively a power output of at least 500 kWel should be reached to have a cost effective plant. Target clients include the owners of licences for the exploiting of geothermal reservoirs.

A significant market potential exists in the EU, where large incentives are offered (e.g. Germany) and in specific global regions, like the so-called Ring of Fire around the Pacific Ocean (Chile, Peru , Ecuador, Colombia, Central America, Mexico, California and Alaska, Russia, Japan, Philippines, New Guinea and New Zealand).

As a rule of thumb, Turboden suggests a minimum electric size of 500 kW to implement a cost effective plant. Please contact our Sales Department for a specific offer.

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