There are a number of key features of the Neptune design that make it distinct from most of its competitors.
1. Commercial scale
Achieving commercial viability requires a high energy output per installation. At 2.4MW, Neptune is one of the most powerful tidal stream devices under development, generating electricity on both the flood and ebb tides.
2. Optimum energy capture
The horizontal axis tidal turbine design is similar to a wind turbine and gives predicted efficiencies of up to 45%. This is achieved through both variable speed operation and pitch control. Close integration of electrical and mechanical systems ensures fault tolerant design and UK grid code compliance.
3. High levels of reliability
The device uses commercial off-the-shelf, proven components, many used in the established wind industry. The design is simple and robust, aimed at achieving high levels of reliability through low component count, and use of duty/standby components at critical points.
4. Economies of scale
Neptune’s mechanical and electrical systems have been designed from the outset for large scale array deployments. For example, the electrical system is similar to some of the latest developments in off-shore wind turbine designs. This allows for a rapid transition from commercial demonstrator to commercial farms without major re-engineering. Also, the ‘steel can’ design of the Neptune nacelles enables the use of different power train components, to match any site specific requirements without major re-design.
5. Efficient installation and maintenance requirements
Once the initial device has been installed using a jack-up/heavy lift vessel, both minor and major maintenance schedules require relatively small work boats.
