The advantages and challenges of DC collection grids for offshore floating PV

Abstract

Offshore floating photovoltaics, tidal turbines and wave converters face similar challenges in terms of grid integration: electrical power must be transferred over long distances through a reliable and efficient grid connection. Whereas AC power collection systems are considered the industry standard for large-scale photovoltaics and (offshore) wind systems, a DC power collection grid may be more suitable for offshore floating photovoltaics. This work provides a qualitative discussion on the advantages and challenges tied to the grid integration of offshore floating PV systems through DC collection grids. The proposed advantages include reduced transmission and power conversion losses, improved power density, reliability, power quality, efficient integration with energy storage and high-voltage DC links, and flexibility in power flow control. Whereas many of these advantages apply onshore as well, this work argues that reduced transmission losses, improved power density and reliability benefits are more significant offshore. To unlock this potential however, challenges such as high capital costs, adequate protection, dynamic grid stability and lack of standards must be addressed.