1.1 General This part of IEC62600 provides the essential design requirements to ensure the engineering integrity of wave, tidal and other water current energy converters, referred to as marine energy converters (MECs), for a specified design life. Its purpose is to provide an appropriate level of protection against damage from all hazards that may lead to failure of the primary structure, defined as the collective system comprising the structural elements, foundation, mooring and anchors, piles, and device buoyancy designed to resist global loads. This document includes requirements for subsystems of MECs such as control and protection mechanisms, internal electrical systems, mechanical systems and mooring systems as they pertain to the structural viability of the device under site-specific external environmental conditions. This document applies to wave, tidal and other water current converters and to structures that are either floating or fixed to the seafloor or shore. This document applies to structures that are unmanned during operational periods. This document addresses site-specific conditions, safety factors for critical structures and structural interfaces, external load cases (including extreme load magnitude, duration, and frequency), failure probability and failure consequences for critical structures and structural interfaces (overall risk assessment), and failsafe design practices (demonstration of adequate redundancy). The effect of subsystem failure on the primary structure is also addressed. This document does not address the effects of MECs on the physical or biological environment (unless noted by exception). This document is used in conjunction with the appropriate IEC and ISO standards, as well as regional regulations that have jurisdiction over the installation site. 1.2 Applications This document is applicable to MEC systems designed to operate from ocean, tidal and river current energy sources, but not systems associated with hydroelectric impoundments or barrages. This document is also applicable to wave energy converters. It is not applicable to ocean thermal energy conversion (OTEC) systems or salinity gradient systems. Although important to the overall objectives of the IEC62600 series, this document does not address all aspects of the engineering process that are taken into account during the full system design of MEC systems. Specifically, this document does not address energy production, performance efficiency, environmental impacts, electric generation and transmission, ergonomics, or power quality. This document, to the extent possible, adapts the principles of existing applicable standards already in use throughout the marine industry (structure, moorings, anchors, corrosion protection, etc.) and by reference, defers to the appropriate international documents. This document adheres to a Load Resistance Factor Design (LRFD) approach and the principles of limit state design as described in ISO2394 . MECs designed to convert hydrokinetic energy from significant hydrodynamic forces into other forms of usable energy, such as electrical, hydraulic, or pneumatic may be different from other types of marine structures. Many MECs are designed to operate in resonance or conditions close to resonance. Furthermore, MECs are hybrids between machines and marine structures. The control forces imposed by the power takeoff (PTO) and possible forces from faults in the operation of the PTO distinguish MECs from other marine structures. The goal of this document is to adequately address relevant design considerations for MECs that have progressed to an advanced prototype design stage or beyond. This refers to technology concepts that have been proven either through analysis, open water test data, scale model testing in tanks or dry land test facilities, and that are ready for commercialization. It is anticipated that this document will be used in certification schemes for design conformity.