Power Supply and Communication Platform for Offshore Based Systems

Autonomous applications 2

Instrumentation located offshore, whether it's for monitoring, measurements, surveillance, communication or other purposes, and whether it's located on the seabed, in the water column or at surface, requires power and often a floating platform.

Presentation material can be downloaded here.

 

kiloWatt at Sea - Offshore Based Instrumentation Platforms

Operation of autonomoly operated instrumentation offshore is a rapidly growing market. Active and passive sonar buoys operated by the Navy, environmental monitoring instruments operated by researchers and weather forcasters, cellular communcations masts operated by telecom companies, sumbsea oil well monitoring instruments operated by oil and gas companies are only examples of such applications.

Traditionally, reliable generation and availability of multi kW power has been very limited, and instrumentation engineers have been constrained to energy capacity of onboard battery packs. In addition to limited power, they also require frequent recovery for charging.

The Fred. Olsen Autonomous Sea Power wave energy conversion technology offers on site power generation in the multi kW range with high reliability, low visiblity and minimal maintenance requirements. Autonomously operated and with onboard energy storage, it can provide continuous power supply even in calm sea, while also providing a communication platform.

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Wave generated power is advantagous over solar, wind and other renewable sources because they are

  • Compact and small
  • Located close at surface with low visibility or below surface with no visibility
  • Low heat signature
  • Robust and can handle rough conditions
  • Low maintenance requirement
  • Reliability and uptime

The components involved in a deep water configuration of a power supply solutiona power producing unit at the top:

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A reactive body of encased seawater that the winch can work against:

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And the seabed assembly with moorings (and attributs for power and communication for seabased instrumentation).

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The complete assembly could be stored in a compact state and towed or transported onboard a vessel, for self installation.

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For shallow water configuration (<200m), the power unit can be towed with it's moorings winched up, lowering it by itself once on site. This makes for a very cost effective installation and recovery.

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Sumberged Configuration

The Fred. Olsen Power Take-Off Unit requires a force to be inflicted on it for it's winch line tension algorithm to function. This force could be in the form of a floating structure. However, this force may as well be provided by a submerged enclosed air volume like illustrated below.

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Fred. Olsen has done extensive simulation work on buoancy control for vertical positioning, and power absorbation. Based on this, we believe an adaptation of our current surface based PTO to a submerged version for completely underwater power production and export, is possible. 10m to 20m would be a suitable range in terms of available pressure difference for power production, buoancy control, stealthiness, communication and accessibility.

Below is an exceprt from a simulation model developed in house. This scenario produced an average power output of 0.3kW.

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A system like this could be sized to fit within the boundaries of a torpedo tube and as such be forward deployed by a submarine.

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