'Motion of the ocean' | Fred Olsen enters offshore solar with 'radically simple' Bolette

Norway’s Fred Olsen is entering the fast-emerging offshore solar sector with a “radically simple” system it claims can withstand tough challenges facing PV at sea while keeping costs down and delivering significant sustainability benefits.

Bolette deploys solar modules within a pre-tensioned rope mesh, distributing the wind and wave loads encountered by the system through the mesh itself and its mooring system.

According to Fred Olsen 1848 CEO Sofie Olsen Jebsen, the system can deal with the often-demanding environmental forces PV system face offshore, compared to the more benign conditions on lakes and reservoirs for inland floating solar systems, where it might also be suitable for use.

“It’s trying to solve the issues we’ve seen in floating solar – that when you have large wind and wave loads the floating systems will have problems.

“As well as managing these issues we’ve been trying to keep the costs down – which is why it’s so radically simple and consists of a very few basic elements, which makes it quite unique we believe.”

Jebsen added: “It is designed in a very cost-efficient manner to follow the motion of the ocean, even in near- and offshore conditions.”

Bolette in its full-scale version will be deployed in standardised 3MW, 200 x 200 metre ‘islands’ of modules that Jebsen said are scalable all the way to gigawatt level.

That will, the Norwegian group believes, allow it to be deployed at sufficient scale and low enough cost to help meet surging energy demand in coastal population areas where options onshore are limited.

“The key to unlock floating solar is to place it outside high demand centres where you have high need for electricity but you don’t have any space on land. That could be in nearshore marine environments.”

Jebsen said while Fred Olsen 1848 isn’t yet releasing precise figures, “on cost, the numbers look very promising”.

Fred Olsen 1848 developed Bolette in-house with an eye on simplicity of sourcing as well design, using readily available, recyclable components that can be procured locally.

One of the key challenges facing the emerging floating solar sector is operations and maintenance, including specific issues such as bird fouling, which the Fred Olsen team has address with a custom-designed O&M solution for cleaning and maintenance of each 7,000-panel island – including use of a purpose-designed catamaran that can move efficiently over arrays.

Jebsen said: “We need to think holistically within floating solar to both create a system that survives the environmental loads and is cost-efficient.

“There are few others that are able to solve the challenge of operating in nearshore marine environments, while still being cost-efficient,” she claimed.