The gravitational forces of the sun and moon consistently raise and lower the tides of our oceans. Researchers are finding out that harnessing this energy to power homes in coastal communities may not be a question of if but more of when. In trials a single tidal stream turbine generated over 130MWh of electricity in seven days, around 7% of the requirement of the Orkney Islands, where it is based. Post 2025 some 180MW of tidal energy is planned for in the UK alone.
Ride the tide
The well-understood forces of our solar system provide tidal turbines with a unique advantage over other sustainable energy sources. They are able to produce green energy on a consistent basis. Researchers can even calculate, from historical knowledge of tides, how much energy potential a coastal region has.
As green energy prospectors look to the ocean, tidal energy has become a viable option. Undersea turbines are putting the ocean’s relentless movement of tides to use. These underwater turbines are 85 to 90 percent efficient at converting kinetic energy into electricity. Burning fossil fuels like coal is on average 32 to 42 percent efficient. Floating tidal turbines, the latest advancement aided by marine industry technology, allow the turbines to be a significantly more portable and more easily maintained solution.
Run a tidal ship
On the surface of the water it appears to be just another vessel, but the experimental craft deploys turbines below the water that appear and work similarly to wind turbines. Part of the reason the technology shows promise because the turbines are on retractable legs. The vessel can be transported from location to location and is considered relatively easy to maintain, lowering operation and maintenance costs. It sits in the tide using anchors and stabilizers to collect energy from coastal waters. Workers can access the electrical parts by simply boarding the ship while the turbines can be repaired and maintained in dry dock if necessary.
Orbital Marine Power Ltd. and SKF are collaborating to reduce the cost of generating tidal energy by mounting wind turbines to a nacelle – effectively creating wind turbines under the water. SKF pitch-control modules aid in regulating the angle of the ship to provide constant power production.
Harnessing the tides
Floating tidal turbines are the latest development used to produce energy. Tidal barrages and tidal fences are also promising technologies. Tidal barrages are installed in coastal dams while tidal fences generate energy using large turnstiles under water. With the help of the marine industry a future of tide turbine farms under the water and away from site could be much closer. All forms of tidal power are in development stages off the coast of Scotland where the rising and falling of the ocean is already a dependable part of the power grid and looks to deliver electricity to even more homes.