The Pelamis P2 hydraulic PTO system comprised three main parts: primary transmission, secondary transmission, and the energy storage that lay between them. This report details the assumptions, costs and some of the various options for the three system parts. The majority of the costs used in the analysis are the actual costs for the P2-002 machine procured in 2010, however some costs associated with the earlier P2-001 machine have been used where required. 

Appropriate cost metrics are derived for each of the major components and their associated parts, and are presented throughout the document. For the primary PTO components, cost per unit weight or volume is likely the most relevant metric for each of the different types of technology described.

For the secondary PTO system, the cost per kW of electrical rated power is provided where possible or additional metrics such as cost per generator have been defined. In each section the scalability of the particular system in question has been discussed. Due to the modular nature of the energy storage and secondary systems, they lend themselves well to scaling up.

The cost breakdown includes hydraulic cylinders, manifolds and piping, control and instrumentation. Sample costs for a secondary PTO system of different electrical ratings ranging from 205kW to 1MW are also given.

This report gives more context and description to the PTO costs in the High Level Cost Metrics report.