Standards Development

Scope

This document sets out general guidelines and recommendations for the design and installation of floating photovoltaic (PV) power plants. A PV power plant is defined within this document as a grid-connected, floating system comprising multiple PV arrays and interconnected directly to a utility’s medium voltage or high voltage grid. Additional criteria are that PV power plants are restricted from access by non-qualified persons and are continuously monitored for safety and protection, either by on-site personnel or by active remote monitoring. Technical areas addressed are those that largely distinguish PV power plants from smaller, more conventional installations, including floating array configurations, cable routing methods, cable selection, overcurrent protection strategies, equipotential bonding over large geographical areas, and equipment considerations.

Safety and design requirements are referenced to the applicable requirements of IEC 62548 to address distinct differences relative to the design requirements for residential, commercial and other non-power plant applications.

In general, existing standards are referenced wherever possible for uniformity. Emphasis is placed on systems employing d.c. string-based systems using large scale central inverters or 3-phase string inverters, but relevant sections are also applicable to systems employing a.c. modules or d.c./d.c. converters. Medium voltage transformers, switchgear, collection systems, substations, utility interconnection, auxiliary loads, energy storage systems, and communication services are addressed, but discussion is mostly limited to recommended references to other standards and requirements.

Purpose

Floating photovoltaic (FPV) installations is a new but fast-growing segment in the PV industry, with huge upside potential. By mid-2022, more than 4 GWp have already been installed globally. The planned projects are increasing both in numbers and scale, with some of them moving even into GW-scale (e.g., in South Korea, Laos). Just to demonstrate the almost limitless deployment potential for FPV, a global assessment of all in-land water bodies (i.e., excluding near-shore and off-shore areas) showed that with only 10% cover of the water surfaces, the total potential installed capacity could be 23 TWp – which is 23 times the cumulative global installed PV capacity to-date. Those 23 TWp could generate ~25,000 Terwatt-hours per year – which is approximately the total current annual electricity consumption of the world. So, with just 10% surface cover of all reservoirs with Floating PV installations, the entire world could be powered today. 

Given this enormous potential and the fast pace of deployment, it is very critical to have quality and safety standards in place at an early stage. That’s also the reason why it is planned to publish a Technical Specification first, which later can be expanded into a full IEC standard. It is noted here that in the absence of such international standards, the FPV industry has already taken first steps in that direction by publishing a ‘Recommended Practice’ for Floating PV installations (by DNV), which has also been referenced in the Singapore TR100:2022. There are many issues that have been reported from the design, implementation, and operation of FPV plants. Those range from electrical installation (e.g., how to do earthing in an installation over water or carry out insulation resistance measurements), proper mooring & anchoring, suitable cable & connector selection, cable routing and management, location of inverters and transformers (e.g., over water or on land) to O&M issues such as cleaning of bird droppings. All those have been addressed in the Singapore TR100:2022, which is therefore a good starting point for the project work under this NWIP, which will be carried out in a team consisting of members of IEC TC82 WG3. The need for this TS was also highlighted by members of WG3 in the previous semi-annual meetings and therefore strong support from P-member countries is expected