Severn Subsea Technologies, part of the Severn Glocon Group, has developed an integrated telemetry and control system for wave power company Seatricity’s Oceanus 2 wave device, now moored at the Cornish Wave Hub.
The SST system will enable researchers to correlate wave movement with power generated, and thus optimise power generating conditions offshore.
Briefly, Seatricity wave energy generation is based on a float tethered to the seabed via a pump. Wave action pumps water at high pressure back to either the shore or a local hub, where a turbine converts the energy to electricity. The Oceanus 2 development device will use a control valve to simulate the turbine load.
Severn Subsea Technologies (SST) has designed and manufactured the valve gear, control, power and communications systems mounted on the buoy and at a shore-based locations at the St Ives Coast Watch Facility, and SST’s Redruth headquarters. Mechanically, the telemetry and control system comprises an electrically actuated control valve that can be modulated to vary the pumped water pressure as the wave height changes.
Power for valve actuation, data acquisition and communications is provided by an array of PV solar cells and sealed lead acid batteries, allowing 24 hour telemetry, mounted on the top surface of Oceanus 2. Communication with the shore is via a UHF radio modem link. SST has also equipped the Oceanus 2 with a WiFi interface allowing some system parameters to be changed from a boat close to the buoy.
Control will be carried out using a pair of programmable logic controllers (PLCs) located on the Oceanus 2 and ashore.
“The Oceanus 2 telemetry and control systems is the type of project in which we excel,” says SST managing director, Brian Green . “Our remit is to research new technology areas that draw on our engineering team’s ability to provide fresh thinking and innovative solutions in valve engineering and renewable technologies.”