DNV publishes guidelines for proper deployment of floating PV

Rebranded, Norway-based consultancy DNV has published a guide to help renewable energy developers in the construction of floating solar power plants.

The Recommended Practice guide, on top of describing the most common requirements for building a floating PV array, provides a series of technical guidelines for electrical safety, anchoring and mooring issues, operation and maintenance, and specific plant design that can withstand site-specific environmental conditions. “It aims to be valid and applicable in all major markets and geographic regions, for all defined applications within scope, from component level to system level, covering the entire life cycle,” its authors specified.

“It will take the industry around five years to reach full standardization,” said DNV consultant Michele Tagliapietra, adding that standards set by the IEC, ISO and DVN will be defined within two to four years, depending on component.

Launching the first global recommended practice document for floating solar, the company underlined that the technology requires significant attention on some parts of the system in the medium term. At the same time, a focus on durability and degradation will be needed in the long term.

“At the moment, in the medium term, the main cause of failure is [the] anchoring and mooring part of the system. This is not a surprise because these are new challenges for PV developers,” explained Tagliapietra.

The guide is a collaborative, joint industry project (JIP) involving 24 industry participants.

According to the paper, floating arrays can significantly increase the efficiency of PV technology. The total increase in energy yield will be positively influenced by stronger irradiation (around 2% more) and the cooling effect, although it can be negatively influenced by mismatch losses.

“When it comes to offshore PV, 5-10% higher yield is a broad but realistic range,” said Tagliapietra. “It depends on how you install the system. If you have systems detached from the water, you won’t have direct cooling from the water, you’ll, rather, have convective cooling, while if you have structures that are already installed in contact with the water, in that case you can have a higher efficiency boost because of a direct cooling effect,” said Tagliapietra.

In terms of safety and sustainability, the experts explained that the evaluation must be done case by case, depending on the floating structure and location.

“There are ongoing studies on how floating solar can be combined with marine life. It really depends on the layout and the conditions of the specific site,” Tagliapietra stated, adding there are cases of floating PV combined with aquaculture.

DNV said that installed capacity for floating solar power was just 10 MW at the end of 2015 but has accelerated considerably since then, reaching 2 GW at the end of last year. The first projects trace back to 2006.

“It is estimated that the total global potential capacity for deploying floating solar power on man made, inland waters alone could be as high as 4 TW [source: the World Bank] with an expected pipeline of more than 10 GW by 2025,” the company said.

Similar, Netherlands-focused guidelines for floating PV had been published by the Netherlands-based Foundation for Applied Water Research in February 2019.