OCE has taken a different approach: initially experimenting with various designs, the Company then discovered technologies which could make light, immensely strong turbine arrays and which could be adapted and applied to the rotating blades (rotors) of marine turbines to generate electricity. The company developed a multi-structural platform (SEACATS) which is smaller in the design than the competition and consists of nested honeycombed caissons forming independent arrays generating 1-2MW in power output each.
Since water is over 800 times as dense as air, the stresses on turbine blades are magnified compared with wind turbines. OCE’s technology uses an axial turbine with a rotor 3 meters in diameter, in a 5 meter caisson aperture. The one-meter blades are supported both on the inside and outside perimeters. As a result, the turbine is better able to withstand the stresses than a hub-mounted propeller blade of several meters in length. Furthermore, the shroud shelters the blades from non-layered and indirect flows.
Each individual caisson is a self-contained unit within a multi-caisson array and each array is independent from other arrays in a generating marine energy system. This allows for a maximum distribution of power and a minimum distribution of risk in case of failure. It also ensures that maximum output of any given time will be available and not susceptible to a total system crash as is the case when a single turbine is generating 2 MW.
OCE’s SEACATS technology will therefore work in the part of the cycle of tidal or ocean current flows in which the water flows more slowly at different depths, thereby increasing electrical generation of the tidal and ocean cycle in which the rotors are operating. The SEACATS array can also be suspended in any depth of water from the seabed to the surface to maximize power from flows. This is a competitive and patented OCE advantage over any other tidal or ocean current technology being able to operate on the seabed or suspended 100m below the water surface. The turbine systems will also be deployable in locations with slower ocean currents that are closer to population centres, helping reduce grid accessibility and bottleneck problems. Since ocean current energy is 24/7 in nature, OCE’s systems can generate continuously available electricity can be part of the “base load” and therefore more valuable.
A key component of the OCE technology is a patented ‘tidal bridge’ concept to retrofit existing bridges with SEACATS tidal energy systems. The technology allows for an independent tidal energy plant to be retrofitted beneath an existing structure (bridge or causeway) without compromising its the structural integrity. The tidal plant uses the bridge only to use as a cost effective means of transmitting energy to a nearby substation.