Turning the tide: harnessing tidal energy

Nova’s tidal turbines have powered homes and businesses across the Scottish Archipelago for over five years; we study their evolution and the company’s hopes of replicating the model in other parts of the world.

Tidal power is an abundant renewable source on a planet that is 70% water-covered and yet largely untapped.

Now, about 522 MW per year are generated worldwide by tidal energy.

Again in UK only, a potential of 10 GW could be generated annually by tidal energy. This would be enough to supply 15 million homes and offset 70 million tonnes of CO2 emissions. In addition, tidal power could have a market potential of about 100 GW.

The tides are much easier to predict than the amount of sun or wind available for other renewable sources. Tidal turbines are also turned with more force than their wind equivalent, because water has a higher density than air.

However, despite the construction of the world’s first tidal power station as early as 1966, the power source did not take off to the same extent as solar and wind power.

Tidal’s role in the climate solution

But all that could be about to change, as governments seek new ways to cut carbon emissions. Scottish company Nova Innovation is one of the leading companies in tidal energy.

John Meagher, Director of Business Development at Nova Innovation, says: “More and more people now recognize that tidal power is part of the solution to the climate emergency. Governments around the world are pledging to dramatically reduce carbon emissions and move away from dependence on fossil fuels, while at the same time, global demand for energy continues to rise.

“Solar and wind are essential for our future, but they alone are not enough to close the gap to meet our net zero carbon goals.

“The development of tidal power is similar to the evolution of the wind industry. All successful wind developers started at the kilowatt level before going up to scale. We see a similar trend for tidal power. This approach speeds up learning and product innovation.

Nova Innovation was only founded in 2010. But the company has made rapid progress with its tidal turbine technology. In 2018, the company joined forces to combine its tidal turbines with Tesla’s energy storage capacities. The result was the world’s first grid-connected tidal power station, delivering constant and variable power whenever needed. And Nova has proven itself in the Shetlands.

Proving technology

Petrol and diesel vehicles account for almost 20% of UK CO2 emissions. To meet carbon reduction targets, the Scottish Government has passed legislation to prevent the sale of new petrol and diesel cars by 2032. More energy from renewable sources is vital if electric cars are to replace properly diesel and gasoline vehicles on the roads.

To meet this demand, Nova Innovation built the world’s first charging station for electric vehicles (EV) entirely powered by tidal energy. The charging point is on the Shetland Island of Yell and was funded by a grant from Transport Scotland.

Meagher says the location and environmental conditions of the Shetlands provided an ideal location to prove the technology: “The UK has one of the largest tidal resources in the world. The Shetlands have a fantastic tidal resource and Nova selected it because of the good site conditions and the obvious opportunity to replace diesel production.

The EV charging station is the latest of Nova’s tidal power projects in the Shetlands, with the company’s turbines providing electricity to homes and businesses for more than half a decade. In 2014, Nova developed a 30 kW turbine prototype.

Then, two years later, in Shetlands, the company built the world’s first offshore tidal network, which involved three 100 kW turbines. They work like a wind turbine, only underwater and powered by the natural flow of water.

“The ingenuity behind the design is smart simplicity. Reliability is improved when components susceptible to failure are removed. Nova’s new M100-D direct-drive tidal turbine reduced costs by 30%, ”explains Meagher.

The predictability of tidal power

Meagher explains how the predictability of tidal power gives it an advantage over other renewable sources. Instead of building a dam or large intrusive structure, Nova’s turbines can sit individually or in groups on the ground in deep or shallow water, large rivers, and estuaries.

“What makes tidal energy compelling is its predictable nature. Wind and solar power have taken us at an incredible rate when it comes to approaching net zero goals, but they are not entirely predictable. Tidal power can add much-needed predictability to the grid by using a purely renewable resource.

“Another popular aspect of tidal power is that our underwater turbines are hidden and there is no visual impact on the landscape. There are no dams, no barriers and there is no impact on navigation – ships and vessels can navigate over our tidal fields without any problem, ”adds Meagher.

One of the concerns about tidal energy is its potential impact on marine life. Still, Meagher says this is an area his company is watching closely, with no issues detected so far.

“Marine life is free to roam around the wind turbine and extensive environmental monitoring of our tidal field in Shetlands has not detected any adverse effects on the marine environment. ”

Scaling

After proving the technology in Shetland, Nova is now in a position to develop and internationalize its business. Later in the year, the company is due to deliver the tidal network from Nova Scotia to Canada, consisting of 15 turbines capable of generating a combined power of 1.5 MW.

Homes and businesses will receive clean, reliable electricity from Nova Scotia Power, Canada’s utility. And there are other international projects that Nova is carrying out all over the world.

“We have projects in Scotland, UK, France and North America. We also have plans for projects in Indonesia across Asia. By 2030, we will be installing turbines all over the world, ”adds Meagher.

Another common caveat with tidal power is the costs involved. Establishing a new source of energy does not come cheap. Still, Meagher suggests that the costs associated with the tide are already falling thanks to Nova’s innovations, with further cost reductions expected as the technology becomes more widely adopted. Meagher also suggests that tidal power is on track to be more cost effective than nuclear and fossil fuels by 2030.

“The development of any form of new energy technology is expensive. When coal, oil, gas, nuclear, solar and wind took off, they all received financial support from governments to enable them to be marketed. Over time, costs have come down as the technologies mature, ”adds Meagher.

“Tidal power is a new technology, but the costs are coming down. It is already priced competitively with diesel production, offering significant benefits to isolated and island communities that often depend on imported diesel for their electricity.


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