Sensors for tidal generation applications

Renewable, abundant, clean and resilient are just some of the adjectives used to describe why harnessing the ocean for energy has the potential to provide a reliable, sustainable and environmentally friendly source of power.

Tidal power plants are typically located in areas with large tidal ranges. Tidal barrage and tidal stream generators are the main two types of generator used to convert the kinetic energy of water as it rises and falls with the daily tidal cycles, although new and innovative wave energy converters are continuously under development. Tidal turbines operate in a similar way to wind turbines, with the obvious difference that they are designed to work underwater and spin as the tide flows, generating electricity.

How to select sensors for tidal generation technology

At the heart of tidal generation technology are the sensors that are critical for ensuring the generator operates safely, efficiently and reliably in the challenging subsea environment. Sensors used in saltwater applications need to be designed and constructed with special considerations in order to ensure stable and accurate operation. Key factors of the specification include:

1. Corrosion resistance
316 stainless steel is generally considered the gold standard for saltwater applications, however, there is growing interest in, and exploration of, titanium as it is for all intents and purposes corrosion-free in an ocean environment. The sensor’s housing, connectors and wiring should also be designed to resist corrosion and abrasion and properly protect the sensor.

2.Temperature range
Saltwater temperatures can vary widely depending on the location and time of year. To ensure accurate readings, sensors must be able to withstand a broad range of temperatures.

3. Water pressure
The performance and reliability of sensors can be significantly affected by water pressure, with high water pressure causing physical damage to submersible sensors and potentially causing the sensor housing or other components to crack or break. Sensors in our submersible range offer bar pressure ratings from 10 bar to 350 bar, with 10 bar representing a pressure of 10 times the atmospheric pressure at sea level, which is approximately 1 bar.

4. Waterproof ratings
Submersible sensors are designed to be fully waterproof, and are typically designed with a hermetically sealed housing that protects the internal components from water. An IP68 rating indicates the sensors can withstand continuous immersion in water at a depth of over 1 metre for a prolonged period of time.

5. Non-contacting technology
In tidal energy applications, non-contacting sensors offer several advantages over traditional contacting sensors. With no physical contact with either the element being measured or other parts, there is reduced wear and tear and the likelihood of the sensor failing is negligible. They are also highly accurate as they are not affected by factors such as vibration or friction.

By paying close attention to these considerations and specifying accordingly, taking into account elements such as the depth of the water, the temperature, the salinity and the presence of other environmental factors, it is possible to ensure reliable and accurate operation of the sensors that are an essential component of tidal energy generation.