Generating power from wind, waves and sun

Stavanger’s Rosenberg yard built ships until the oil age came to Norway in the 1970s, when it became a technology company involved in engineering, procurement, construction and installation (EPCI) contracts for the petroleum sector.

The Worley group, which now owns the company under the name Rosenberg Worley, sees big opportunities to contribute to the industry being built up around renewable energy.

Laid off – got new idea
Flex2power was conceived in 2016 by one of Rosenberg’s experienced engineers, who had been laid off because of the downturn in activity after oil prices slumped. His idea was to develop a flexible foundation for a wind turbine which weighed and cost less while retaining strength and stability.

Originally intended to work together with natural forces, this approach was later complemented by harnessing both wave and solar energy on one and the same foundation – thereby further strengthening its competitiveness.

The solution was protected by three patents and placed in a separate company, Flexible Floating Systems AS. Rosenberg Worley has entered into an exclusive agreement with this venture for using the technology.

Energy from three sources
Central to the concept is a semi-submersible floater which serves as a base for the wind turbine. It comprises a structure placed on a concrete base frame attached to the seabed by a standard mooring system.

Four flexible steel cubes with pontoons floating on the sea are positioned around the floater. The motion of these units converts the energy in the waves into electricity via a hydraulic system which drives a generator.

Promoted globally, the concept has attracted substantial market interest – primarily because of its lower cost and smaller footprint in the sea. It has been adopted as a cluster project for Energy Transition Norway (ETN), and is thereby supported by all the Norwegian energy companies because they sit on ETN’s technical committee which determines the projects to be supported.

More efficient and less use of space
The big benefits of the Flex2power concept are lower cost for renewable energy production and a big reduction in the amount of sea area used because power is generated from waves and sun as well as wind. This is unique, in that no other solution produces energy to the same degree from several renewable sources on the same foundation.

Compared with a pure offshore wind development, twice the amount of energy can be produced for virtually the same costs for floater, mooring, transformer station and cable to land. Calculations indicate that Flex2power only requires a sixth of the sea area needed by pure offshore wind facility.

Big market potential seen
The global market for floating offshore wind power is expected to expand substantially in coming years. Flex2power has the potential to take a substantial slice of this market. If the pilot plant currently being planned demonstrates its cost effectiveness, robustness and space savings, the way is open to a very good commercial future.