You may be familiar with the four main types of floating wind systems: semi-submersible (WindFloat), spar (Hywind), barge type (IDEOL), and TLP (TetraSpar). Excipio Energy, Texas-based offshore renewable energy company, recently developed a new Articulated Spar Leg (ASL) platform type: the Excibuoy.
Excipio’s floating offshore renewable energy system is unlike any other being considered and uses four spar-type legs, each attached by an articulated joint to a common deck — which in turn supports the wind turbine. The spar legs can be folded under the platform for construction and towing in shallow water. The legs are then lowered once out at sea and at the wind site.
In addition, the Excibuoy can be built in-port and requires no offshore heavy-lift vessels. The wind turbine may also be installed and pre-commissioned prior to sail out (and is moored conventionally). With the platform’s legs folded it will have the same draft as a semi-submersible design and be stable enough to tow.
According to the founders of Excipio, wave and current energy conversion technologies are mature but suffered from the high costs of the supporting structures, installation, O&M, and grid connections. It is also their view that floating wind turbines will become the dominant system in the near future. Knowing that the incremental cost of adding systems to a floating solution was low, Excipio studied the effect of combining the various types of offshore renewable energy technology into a single platform — the result being an improved LCOE.
In this process, Excipio created a system flexible enough to keep up with the latest technology, and sufficiently modular for the development of a robust supply chain.
According to Excipio, its team spent three years researching wind, wave, tidal, ocean flow, and OTEC energy technologies. The Excipio technology database contains more than 300 ORE technology companies, 1000 offshore renewable suppliers and service companies, and 1500 ORE technology patents. From this database, systems that were technologically mature and complement one another, were selected.
These research findings, combined with their extensive offshore experience, led Excipio to develop a system that uses common components, yet is not dependent upon any one supplier or technology.
This design strategy allows for a wide variation in the size and capabilities of each platform by adding or excluding component systems.
Excipio Energy’s Excibuoy is a modular design that can support any or all of the following technologies depending on the locally available resources:
- Wind turbines, up to the largest sizes being considered (12.5 MW as of this writing)
- Oscillating water column wave energy devices, located in the spar shaped legs
- Induced flow energy devices – located in base of the spar legs
- Point absorber wave energy devices mounted below the deck
- Surface current capture, also mounted to the underside of the deck
- Small, robust, direct drive wind turbines –to provide power during high wind conditions
- Up to a 10-MW OTEC system per platform.
Excipio have identified at least three potential suppliers for each component of the system and have agreements or expressions of interest with 12 companies to work with Excipio to supply components and/or help develop the Excibuoy.
Excipio Energy is currently pursuing funding to support the tank testing and computer modeling required to confirm the integrated power output.