Electrical Energy from Stretching Yarn

by Emil Morhardt

Well, yarn, sort of. This yarn is made by twisting carbon nanotubes until they become so twisted that the coil up into a helical spring-like configuration. You can do the same thing with cotton yarn or string. When the South Korean researchers (Kim et al., 2017) put the coil into an electrolyte then stretched it what they got was electrical current. Not a lot, but these are small laboratory-scale experiments and what the researchers had in mind was generating small amounts of energy to power sensors, for example, sewn into a shirt or gloves that are stretched and released under normal activities, but that wouldn’t work very well if the subject had to be immersed in an electrolyte. Or would it? They tried immersing the device, which they call a twistron, into the Gyeonpo Sea off South Korea where the temperature was 13ºC (a chilly 55ºF) and the sodium chloride content was 0.31 M, a nice electrolyte solution. But instead of sewing the yarn into a diver’s wetsuit, they attached it between a floating balloon and a sinker on the seabed to see if they could harvest ocean wave energy. Yes! They got it to light up a green LED whenever a wave came by. Continue reading

Tidal and Wind Energy Companies Share a Power Grid to Provide Reliable, Renewable Energy

by Mary-Catherine Riley

Atlantis Resources partnered with Lockend Wind Energy to spearhead the world’s largest grid connection of any commercial tidal project (https://eandt.theiet.org/content/articles/2016/11/meygen-tidal-power-project-poised-to-feed-scottish-highland-electricity-grid/). This initiative is thought to be the first combination of electricity to power an existing grid. Currently, MeyGen is in the first phase of construction, installing 86 turbines to generate 86 megawatts (MW). However, the project has room for growth. Atlantis hopes to expand the facility’s capability to power 175,000 homes using 269 turbines producing almost 400 MW (3,4). The glaring downside is the cost. Funds for the first stage of the MeyGen project are £51million ($82m) (http://www.meygen.com/the-project/meygen-news/). Moreover, while the power of strong currents in the Pentland Firth in northern Scotland makes it an ideal location for tidal generation, the area’s harsh storm and wave conditions could destroy the turbines. Lastly, the grid connection is limited until further expansion occurs in future years due to limited grid capacity. Continue reading

Tidal and Wave Power Full of Promise in Scotland

by Erin Larsen

In the northeast-most corner of Scotland sits the future site of the world’s largest array of tidal turbines, undersea windmills turned by the waters. As the race to develop alternatives to fossil fuels continues to accelerate, ocean energy is a clean-tech holy grail. Now, with Scotland’s estimated $1.5 billion MeyGen turbine project under way, the promise of tidal energy has never been closer.

Once all the undersea cables are laid, substations are built, and 269 turbines are put in place, MeyGen will have a production capacity of 400 megawatts of power – enough to power 175,000 homes. The project is being overseen by Atlantis Resources. Continue reading

Marine Energy Device Mooring and Foundation Designs

by Cassandra Burgess

The deployment of marine renewable energy (MRE) devices requires new approaches to offshore mooring and foundations. Mooring and foundations are essential components of MRE device structures, enabling a device to remain in one spot while responding to the movement of tides or waves. Foundations and moorings often account for up to 10% of the total cost of building and maintaining an MRE device; designing a foundation of mooring that can be built at minimal cost requires analyzing the site characteristics, the direction and magnitude of forces on the device, and responses of different technologies to these forces, and the ease of installing and decommissioning the device. These steps present a novel challenge for MRE devices, because such devices have different requirements than traditional offshore technologies. One of the main challenges in applying traditional technologies to this problem is that MRE devices often need to be able to move. This is because the response of the device itself to tides and waves, which is necessary for energy production, is generally linked to the response of the foundation or mooring system. Thus these systems are required to endure loads both horizontally and vertically and to move with the device in some cases. This differs from more common offshore technologies, such as drilling platforms, where movement is not desired. Because of this novel challenge, Karimirad, Koushan, Weller, Hardwick, and Johanning suggest in their 2014 paper that new guidelines need to be developed to aid in the design of MRE device structures. Continue reading

Fishing Boat Transformed to Harness Energy from Ocean’s Waves

by Niti Nagar

It might be possible to harness the movement associated with the ocean’s natural waves using docked fishing vessels. Researchers are demonstrating this simple idea is feasible using a demonstration vessel currently docked offshore in Western Norway.

Transforming a vessel into a wave power plant requires installing four large chambers, in the vessel’s bow, each equipped with an air-powered turbine. As the waves strike the vessel, the water levels in the chambers rise leading to an increase in air pressure, which consequently drives the four turbines. The chambers respond to different wave heights, allowing greater wave heights to contribute more air pressure. Each turbine is capable of produced 50kW. Using mathematical models and simulations, the researchers expect the plant to produce 320,000 kW per year. Continue reading