Technology

Tidal force

 By Michelle Leslie

The Bay of Fundy is home to the highest tides in the world, holding the potential to unleash an enormous amount of energy. More water flows into this region than all the world’s freshwater rivers combined, over 100 billion tonnes of water. Harnessing the power of these tides to generate electricity could offset greenhouse gas emissions by one million tonnes per year, in Atlantic Canada alone. In the past, tidal energy has not been without its challenges but a new project is hoping to change that. Behind the doors at Canada’s leading research facility on tidal technology, The Fundy Ocean Research Center for Energy (FORCE), a world first was developed. It’s known as The Vectron or aquatic spacecraft and it is able to accurately measure water turbulence in real time, providing a scientific breakthrough. The detailed, continual stream of data allows tidal developers to build turbines that are able to withstand the power of water, which is 800 times denser than air. Ah, the Vectron could also provide benefits to the oil and gas industry…

The Bay of Fundy is home to the highest tides in the world. More water flows into this region than all the world’s freshwater rivers combined, over 160 billion tons of water per day. These enormous surges of water hold the potential to unleash tremendous amounts of energy. Harnessing the power of these tides to generate electricity could offset emissions while unlocking huge economic potential.

The challenge in harnessing tidal energy is that these massive flows of water test the limits of technology. But a new development could change that. Canada’s leading research facility on tidal energy, the Fundy Ocean Research Center for Energy (FORCE), has developed a new technology that could facilitate the harvesting of Fundy’s energy potential. “It’s like a lunar lander, although it’s arguably easier to design for space than the Minas Passage,” states Matthew Lumley, Communications Director for FORCE.

It’s known as the Vectron, or aquatic spacecraft, and it relies on something called acoustic Doppler profiles. Essentially, the Vectron sends a ping into the water. This ping bounces off sediment that is moving through the water column and sends it back to the receptor, telling you how fast and in what direction the water is moving. Using multiple Vectrons, the beams converge in a single point to get extremely high resolution data.

Vectron will be the world’s first instrument to accurately measure turbulence throughout the water column

The Minas Passage, near Parrsboro, Nova Scotia, where an in-stream tidal turbine is expected to be deployed later this year, is capable of seeing water levels rise at high tide to 14 meters or 45 feet. All that water moves at a high rate of speed, posing further challenges when designing a turbine. The Fundy coastline pinches in at the Minas Passage, and like pinching your thumb on a garden hose, when you close the opening the water pressure increases.

According to Lumley, “You are working in a highly energetic environment, like a class 4 hurricane. You may draw a circle around the site and say don’t go there, but it’s the very reason that drew the interest of the technology developers. If you double the water speed you have EIGHT times the power potential.” Harnessing that potential has been challenging. The strength of Fundy’s tidal currents quickly ripped apart the last tidal turbine in 2009 .

Since the initial test by OpenHydro, the Vectron scientific breakthrough means tidal developers now have access to a continuous stream of high resolution data on water turbulence. This data should allow developers to understand the aquatic environment. They can then design turbines that are able to withstand the power of water, which is almost 800 times denser than air.

The Bay of Fundy, as with other tidal locations, sees variations in the speed of water, and it’s those variations that could make Fundy a huge generator of clean power. Water flowing through the Minas passage can increase from 4 meters/second or 14km/hr to 5 meters per second or 18 km/hr, but the energy output increases almost tenfold thanks to water’s density.

Traditional tidal energy projects, like the Annapolis Royal Tidal Power plant in Nova Scotia, the only one in North America, is similar to a hydro dam in which a barrage or a lagoon captures water as it rises and falls during tidal cycles and then directs it into turbines. Like traditional hydroelectric dams, these tidal projects have been shown to have negative environmental impacts.

This new tidal technology is different. The in-stream tidal turbines are best described as fully mobile, submersible wind turbines. They measure 6 meters or 19 feet in diameter and sit directly on the seabed floor, without the use of drilling and they are out of the way of ships. As the tides ebb and flow, ocean currents move across the blades, turning them and creating energy.

The Hopewell Rocks Tidal Exploration Site is a fantastic place to experience the Bay of Fundy's world famous tides

While in-stream tidal energy is still in its infancy, the prospect of low impact, tidal energy is exciting to the team at WWF-Canada.

“WWF is trying to help reach a goal of 100% renewable by 2050, so in order to reach that we need renewable from different types but we want it to be habitat friendly,” says Sarah Saunders, an Oceans Specialist “Renewable in a way that doesn’t have a negative impact on the environment.”

In a recent report by WWF-Canada, it found that while further monitoring of large scale turbines was required, there were no negative environmental impacts of in-stream tidal turbines in Scotland and Northern Ireland. Scotland is charging towards a cleaner economy. By 2020, the country wants all of its electricity, and over ten percent of its heating supply, to be generated by renewable sources. Tidal energy in Scotland has the potential to be a major contributor. The power from Scotland’s tides could eventually supply the entire United Kingdom with one-third of its electricity generation needs.

In early March, Scotland took a huge leap forward in tidal power generation with the first turbine in the Shetland Tidal Array project to produce grid connected power.

In Canada, the successful development of tidal energy will take the country one step closer to achieving the environmental targets set forth by Prime Minister Trudeau. Besides helping meet those emissions targets, investing in tidal has the potential to create jobs. “We have offshore supply and service companies that have been working in oil and gas, and these skills directly translate into the tidal industry.” says Lumley.

Nova Scotia has high hopes for a greener, cleaner energy mix. The province has committed that 40 percent of electricity production will be renewable by 2020. The breakthrough in tidal technology generation will be put to the test later this year when Cape Sharp Tidal plans to deploy an underwater tidal turbine, moving one step closer to the dream of in-stream electricity generation.

 

SEE MORE: Wave after wave by Nicholas Newman

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about the author
Michelle Leslie
Alberta, Toronto and now Ottawa. Meteorologist, Journalist & Munk School Of Global Affairs Fellow.