Enormous amounts of methane hydrate are stored deep beneath the ocean floor – a substance similar to ice composed of methane and water. These natural deposits contain more energy than all known fossil fuels combined. However, exploiting these resources requires highly precise measurement technology, especially in extreme depths.
Methane hydrate, also known as "combustible ice," forms under high pressure and low temperatures, as found in the deep sea or permafrost areas. It is a crystalline substance with methane molecules embedded in a lattice of water molecules. Estimates suggest that approximately 3,000 gigatons of carbon are stored in methane hydrates worldwide – more than in all known coal, oil, and gas reserves combined.
The SUGAR Project: Exploration and Use of Methane Hydrate
Led by the Kiel Leibniz Institute for Marine Sciences (IFM-GEOMAR), the SUGAR project (Submarine Gashydrate Deposits: Exploration, Extraction, and Transportation) was launched. The goal is to develop technologies to extract methane from hydrates while safely storing carbon dioxide (CO₂) in the seabed. A subproject focuses on seismic surveying of hydrate deposits using deeply towed hydroacoustic streamers.
Challenges in Deep-Sea Measurement Technology
Accurate pressure measurement is essential for precisely locating measurement nodes at depths of up to 4,000 meters. The requirements for the sensors are therefore high:
Corrosion resistance: Suitable for use in saline seawater
High accuracy: Total error band (TEB) better than 0.1 bar
Fine resolution: Better than 0.01 bar
Extended measurement range: 0 to 400 bar, corresponding to 0 to 4,000 meters of water depth
Temperature resistance: -2 to 40 °C
Electrical insulation strength: Over 600 V against seawater
Energy efficiency: Low power consumption at 5V and 3.3V supply voltage
Communication interfaces: I2C and Modbus up to 100 kbit/s
Due to these requirements, piezoresistive pressure sensors with titanium housings supplied by STS Sensor Technologie Sirnach AG were chosen. Titanium offers excellent corrosion resistance and mechanical stability under extreme conditions.
The development of methane hydrate as a future energy source requires innovative technologies and precise measurement techniques. Projects like SUGAR demonstrate how interdisciplinary collaboration between research institutions and industry partners like STS Sensor Technologie Sirnach AG contributes to the development of such technologies. With robust and precise pressure sensors, the safe and efficient use of these vast energy reserves becomes possible.