Geothermal energy is a capital-intensive renewable source that typically requires several years to achieve a return on investment. Therefore, factors such as design efficiency and operational hours during the average working life of a geothermal power plant (which ranges from 20 to 30 years) are crucial variables that can impact investment profitability. Regardless of the geographical location and technology utilized, certain factors ensure the long-term and effective operation of the geothermal plant, thereby increasing revenues. One of these factors is related to operations and maintenance.

Geothermal System Maintenance tasks

The Operation & Maintenance of the power plant covers the management of the turbine, lube & seal oil console, generator, cooling system, heat exchangers, pumps, electrical and control panels, and all the safety and control equipment of the plant (such as valves and instrumentation).

Effective geothermal maintenance of all facilities is crucial to ensure a high availability factor for the power plant and steady steam/brine production from the geothermal wells. Best practices for binary geothermal power plant maintenance include several activities that ensure smooth and efficient operation of geothermal power plants.

Geothermal maintenance checklist

In this paragraph we will delve into the key tasks and best practices outlined in the geothermal maintenance checklist, providing valuable insights into maintaining a reliable and sustainable geothermal energy system.

1) Strategic planning of maintenance activities

Daily, weekly and monthly checks must be carefully planned based on the actual system conditions to minimize the risk of unforeseen outages. Key operational maintenance checks to be performed by the power plant owner include:

  • Visual inspections of rotating equipment, such as turbines, to identify any anomalies
  • Check oil levels and the cleanliness of turbogenerator lube/seal oil skids and gearboxes
  • Verify bearing oil levels, seal oil pressure on feed pump skids, as well as the cleanliness of suction filters
  • Monitor the trend of working fluid levels
  • Verify the functionality of instruments and valves
  • Monitor and record the chemical composition of the heat source fluid.

In addition to the operation maintenance activities executed by the power plant operators, scheduled maintenance plans are conducted by the power plant equipment supplier under an after-sales maintenance contract. These activities are typically carried out bi-annually and involve checks, inspections, and analysis of the following equipment:

  • Turbine
  • Condenser
  • PLC control panel
  • ORC actuated Valves
  • Heat source actuated valves
  • Generator
  • Feed pump motor system and seal system
  • Exchangers
  • Turbogenerators oil console
  • Cooling circuit
  • Fluid transfer system

2) Careful selection of operation personnel

Skilled operators play a crucial role in maintaining the efficiency and reliability of the geothermal power plant, allowing for timely interventions and minimizing downtime. Their expertise contributes to the overall optimal performance of the system anticipating potential process, mechanical, or electrical issues during daily plant operation.

3) Quick remote support for power plant process assistance from the power plant supplier

Exergy’s After Sales Service offers a superior level of service and reliability.  With a skilled service team experienced in all aspects of power plant equipment operation and maintenance, we provide rapid and dependable in-house assistance for any issue related to our ORC plants.

The strength of Exergy’s service relies on the integration of the after-sales team with the engineering departments to provide immediate assistance for optimization guidance, remote control of operations during critical phases, and suggestions for smoother and optimized power production based on resource conditions.

Discover all the services included in the after-sales assistance!

4) Spare part stock

Maintaining a stock of spare parts in the customers’ warehouse is essential for promptly restoring full functionality in the event of an outage.

5) Dedicated site service staff

Exergy prides itself on its dedicated site service staff, always prepared to intervene on-site whenever necessary. By efficiently organizing site teams, Exergy minimizes downtime to maximize productivity and ensure uninterrupted operations for its clients.

How often should a Geothermal System be serviced?

Checks, inspections and some maintenance activities should be carried out by the operator daily, weekly and monthly depending on the equipment. While the overall power plant system maintenance offered under an after-sales contract by the supplier is generally programmed twice a year with estimated downtime of total 3 days per years.

What is the life expectancy of a Geothermal System?

The average life expectancy of a geothermal power plant is very long,  usually between 20 to 30 years. However, depending on the technology installed, the resource condition and the location, this can increase to 50 years or more.


Accurate and prompt geothermal power plant system maintenance, carried out by experienced and skilled staff, is crucial for the long and efficient operation of the plant. Exergy’s after-sales maintenance program offers the advantages of no unpredicted stoppage, continuous operation and long plant life, ensuring maximum electricity production levels for the customer and an average availability rate of 99% for its geothermal power plants.

Find out more about Exergy’s after-sales service package here.

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