Nov 2, 2021

Why do we need valves for geothermal energy?

Andreas Pischke
Andreas Pischke
Industry Manager, Power

The need for renewable energy sources is rising at a rapid pace. Geothermal is a clean and renewable source of energy, as it is continuously produced inside the earth. Reliable, high-performance valves play a significant role in producing renewable energy from geothermal sources.

Geothermal energy

Clean power from deep inside the earth

Geothermal energy is the heat that comes from inside the earth. This heat is then transferred to the upper layers of the earth's crust, enabling the geothermal energy to be used. Geothermal power plants use heat to produce electricity by heating reservoirs of water. One of three types of systems are then applied: Flash steam, dry steam, or binary cycle, the latter of which uses brine as a heat source. The steam (or, in the case of brine, a fluid with a low boiling point heated by the brine) rotates a turbine that drives a generator, which produces electricity.

The US leads the world in the amount of geothermal electricity generation, followed by Indonesia, Philippines, and Turkey. Did you know that Neles has been involved in several geothermal power plant projects around the world? We have worked with customers from Turkey to Kenya, Mexico, USA, Iceland, Indonesia, and several European countries.

Efficiency increase and silica scaling

The temperature range of brine and steam varies from 100°C to 370°C, enriched with more or less content of silica, lime and other minerals and sulfur. The technology for geothermal power generation has been improved over the past decades, making it also possible to use brine at 100°C and lower to generate electricity efficiently. The valves used play an important role, as they have to provide a minimum of pressure loss. Additionally, the valves must deal with the impurities mentioned above. Steam that can be as hot as 370°C has its own challenges on the valves and thus the entire system. The wrong choice of valves or inadequate maintenance could result in unnecessary energy losses and inefficient operation or in damages – especially to the separator and turbine blades.

The wrong choice of valves or inadequate maintenance could result in unnecessary energy losses and inefficient operation or in damages – especially to the separator and turbine blades.

The valves in a geothermal power plant are subject to rough process conditions, such as high-pressure, flashing, and silica scaling – and they must meet all safety requirements and efficient flow control. The variable pressures and temperatures can be very demanding on valve performance. One key challenge in these applications is silica scaling. The build-up of deposits in the valve leads to leakage. This amplifies the scaling and eventually results in complete failure of the valve.

Another challenge for the geothermal business can be project duration: the traditional deployment of geothermal power plants can take years, from project start to power online. These projects require large investments to complete. And in these kinds of huge projects, reliable and experienced partners are often welcome.

Safe, reliable, and energy-efficient geothermal power

With reliable, high-quality valves, geothermal power plants can produce renewable energy efficiently and safely at a low cost and with a low environmental impact. The availability of the geothermal plant is crucial, so durable valves requiring minimal maintenance are preferred. Our proven valve solutions are an ideal fit for the geothermal industry where the natural variation of fluid conditions can be very demanding. Neles has the industry’s widest product scope with an extensive pressure rating for the wellhead phase in the process. Customers can rely on us, as we have notable experience in sizing and selecting the right valves for their geothermal service. In addition, if maintenance or expert help is needed, we also support our clients with comprehensive life-cycle services. You can read about one successful customer case below.

An example of a successful partnership: Neles Resident engineer services

Did you know we can provide a dedicated expert – a single point of contact – for innovative and tailored services at your site? For example, a geothermal power production facility in Turkey contacted us to provide immediate service support to help solve their valve problems and to minimize production losses. We assigned a dedicated local service technician to the factory. With multiple visits per month, the geothermal facility reduced production losses and was able to define and prevent potential problems. Read more about our Resident engineer service

Which valves are the most suitable for geothermal plants?

Neles™ and Jamesbury™ valve solutions enable the efficient and reliable running of geothermal power plants. For example, the heavy-duty Neles Finetrol™ eccentric rotary plug valve is the perfect solution for separator level control (LCV) and the wellhead at the drill hole exit. Even with heavy scaling, the interaction between the still plug and the seat ensures that the valve continues to operate. On the turbine side, especially for binary cycle (ORC), our high-performance, soft-seated Jamesbury Wafer-Sphere™ and Neles metal-seated butterfly valves are used by many customers. These are just some examples of our efficient and reliable valve solutions for geothermal energy. For more detailed information, you can contact our experts at any time.

Highly qualified range of control valves and proven industry experience secure sustainability and fulfill safety and environmental requirements in geothermal plant processes.

So, as you can see, valves play an important role also in the geothermal business. We are proud to say that Neles’ highly qualified range of control valves and proven industry experience secure sustainability and fulfill safety and environmental requirements in geothermal plant processes. The resource potential of the continuously forming power beneath our feet is endless. Let’s just hope the technology for accessing the deep geothermal resource advances quickly so that it can become a major player in the clean energy future.

More about valves for geothermal energy