It’s a busy and exciting week for Quoceant this week. As part of our Novel Wave Energy Convertor technology project for Wave Energy Scotland we’re testing our Ectacti-Hull technology in the FloWave wave tank, throwing many different waves at the model and measuring how it behaves.
Wave Energy Converters must be both robustly survivable and produce sufficient average yield to deliver attractive economic performance. Many different Wave Energy Converter (WEC) concepts, forms, and engineering solutions have been proposed but the compromise between these two drivers, performance and survivability, remains a major barrier to improved cost of energy. To break this fundamental conflict between performance and survivability, Quoceant is developing a novel concept to introduce the ability to substantially change the machine hull volume on command; in the same way that sailing ships reef their sails to deliver both speed and survive storms, selectable hull volume change would allow a WEC to grow substantially to absorb much more power during most of the year, while reverting to a smaller, robustly survivable form in storm conditions.
Quoceant has researched a number of ways of delivering such a system. The most promising solution identified uses inflatable volumes to cost effectively provide a gross increase in volume around a rigid load bearing core. The Ectacti-hull technology (derived from the word ectactic, meaning to dilate) being developed is intended to provide the economics of an otherwise un-survivable machine with the survivability of an otherwise uneconomic machine and is applicable to a wide variety of WEC designs.
We’ve been working on, analysing, and refining this concept over the last year, completing multiple 2D and 3D Finite Element Analysis studies on different embodiments of the technology, undertaking preliminary engineering, design and costing work, and building scale models to functionally test the system. Seeing the behaviour of the system in real waves is an important piece of the technology development program as well though, hence the current tests in FloWave. As a result of our background, experience and knowledge from the development of the Pelamis WEC, we’re using a line-absorber type WEC to test the technology, but the concept is applicable to many other WEC types as well.
The aim of the testing program is to confirm the benefits of the Ectacti-Hull technology on both performance and survivability. We’re testing two different forms of the same model, the ‘inflated’ and ‘deflated’ configurations. The inflated configuration would be used to absorb maximum power in the majority of sea conditions. However, in larger storm conditions, where survivability becomes the main driver, the deflated configuration would be used. Demonstrating the differences in response between the two states will be a key outcome of the testing program.
Ultimately, Quoceant is aiming to quantify the expected strong reduction in Levelized Cost of Energy, taking into account integrated capital cost, impact on annual average yield, operational costs and availability. If viability is proven through this project, it would represent a transformational step reduction in not only the opening cost of energy of many WEC designs, but also the long term floor cost of energy.
