Availability of a Wave Energy Converter (WEC) is of paramount importance if it is to become a commercially successful technology. This paper presents a statistical Monte Carlo methodology to assess the availability of WECs which is driven both by the reliability of components and the time to repair a failure which is dependent on external factors such as weather windows and other restrictions on marine operations.


The push towards the requirement for new and renewable energy sources in recent years has lead to a rapid increase in the number of commercial wave energy device developers. Aquamarine Power Ltd. (Aquamarine) was founded in 2005 to develop Oyster®, a device designed to interact with the dominant surge forces found in the nearshore wave environment. Oyster is a unique design of Wave Energy Converter (WEC) due to its nearshore location, the use of a bottom-hinged flap that completely penetrates the water column, and an onshore hydroelectric power takeoff (PTO). The oscillating motion of the flap is used to pressurise water and pump it to shore via a hydraulic piston and pipeline system. The pressurised water is then converted into electrical power through the use of a Pelton wheel system to turn an electrical generator. The water is then recycled through the system via a low pressure return pipeline. The Oyster 1 315kW proof-of-concept prototype was successfully installed at EMEC on Orkney in 2009. To date it has operated for over 6000 hours. This paper focuses on Oyster 2, the next generation device and a pre-commercial demonstrator with 3 flaps pumping to a single onshore hydroelectric power plant, rated at 2.4MW. The availability of any generator is key when calculating the economics (in particular, cost of power) of the device as the development progresses from demonstration to a commercial product.

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