Advanced Composite Cold Water Pipe

Following our request for OTEC updates, Lockheed Martin provided us with a conference paper entitled “Selection and validation of a minimum-cost cold water pipe material, configuration, and fabrication method for ocean thermal energy conversion (OTEC) systems”.

The paper is an overview of the work done by Lockheed Martin on an advanced fiber composite cold water pipe (CWP) for a 100 MW offshore OTEC facility. For this scale of commercial plant, the CWP is not only 1000m (3300 ft.) in length, but also on the order of 10m (33 ft.) in diameter.

First assembled OTEC 4m CWP core
First assembled OTEC 4m CWP core

The deployment and operation of such a large component in harsh offshore conditions poses a significant challenge; according to many it is the #1 challenge of OTEC development.To satisfy the structural requirements of a pipe in these conditions Lockheed Martin, led by Dr. Alan Miller, studied the cold water pipe architecture, materials and fabrication process. They came up with an innovative approach of building a hollow-core cold water pipe directly down from the floating OTEC platform and ending up with what is essentially a one-piece pipe structurally. This approach, according to Lockheed Martin, maximizes durability and reliability during operation, eliminates major deployment risks, and enables affordable fabrication of very large diameter (>4m) pipes.

The successfully-validated molding region for the 4m ID initial CWP
The successfully-validated molding region for the 4m ID initial CWP

The initial work validated the most critical elements of the fabrication process at the 4m diameter scale needed for Lockheed Martin’s future OTEC Pilot Plant.  It was supported by the US Dept. of Energy as part of their Advanced Water Power Program,

which is advancing the technology for renewable energy from the oceans. The OTEC foundation will follow LM’s steps in developing the planned 10MW OTEC Pilot Plant. Further information: