The Pico plant has been operational intermittently (but predominantly remotely) over the past year with only a couple of serious technical issues occurring. The first was caused by lightening which damaged the data communications link with the plant and control centre and the other was due to short circuits in the generator due to a carbon dust build up (new modifications appear to have resolved this issue now). As such in the past 12 months the highest production total was achieved in Pico’s history and 31MWhrs were put into the local grid. This surpasses the old record which was achieved in 2010 by almost 30%.
Because the machine has stabilised and operational issues have minimised, more time has been available for research activates. In particular a relief valve control strategy has been developed and implemented to increase power production in higher energy sea states by optimising the short term chamber pressure variance. The control strategy also acts to reduce the frequency and severity of turbine stall (which is associated with machine fatigue and noise emissions). The theoretical results of this control system have been validated with field test data. In addition to this some new power take-off control strategies have been devised and applied to the power electronics controller and are currently under investigation both numerically and with field tests. The objectives of these power take-off control strategies are to improve the plant performance and also to test the results projected by some early theoretical studies (by using the same control strategy). Finally a new relief valve aperture adjustment system is currently being fabricated. This system will be a passive valve (which is to be used in conjunction with the existing actively controlled relief valve) with the objective of partially correcting chamber pressure asymmetry which results from wave shoaling and defects in the plants structure.
Work continues to improve the machine performance, reduce maintenance intervals and minimise machine downtime.