Green credentials

Norway already has strong green credentials, with 98% of its electricity coming from renewable energy sources, primarily hydropower. Elaine Maslin looks at initiatives to harness the power of the ocean and to help reduce offshore wind costs.

Sites where NeoTurbine has potential.  Images from NeoTurbine.

Bulgarian-born Norwegian Nikolay Hroulev hopes to add to the mix with a scalable tidal energy convertor.

The Oslo-based engineer has a varied career on which to draw, having worked in South Africa, Canada, Sweden and Norway, in the mining, food and structural steel industries – always as a design engineer. He’s designed industrial conveyors, dehumidifiers, and special weighing machines. For the last 10 years, he has worked in Norway’s subsea industry.

It’s an environment in which he has pursued an idea he had while at university studying automotive engineering: a turbine-type engine powered by water. Now, those ideas are being put into action. In 2002, he came up with the NeoTurbine concept, working on it in his spare time.

In 2014, he presented the concept to Connect Norge and Innovation Norway. Last year, Hroulev formerly set up NeoTurbine and, with the help of some funding from Innovation Norway and backing from Global Maritime Group, Hroulev was able to build a 75cm-diameter scale prototype, and put it through testing at the Stadt Towing Tank laboratory in Måløy, western Norway. The tests were successful, Hroulev says, with 25% efficiency achieved, and now NeoTurbine is working with Sogn Industri, which is preparing a tidal test site west of Norway, at which a full scale, 2m diameter NeoTurbine could be tested, to be followed by 5m and 10m diameter versions.

he NeoTurbine concept.

“The challenges with tidal and ocean current are extreme conditions, high water velocity, environmental impact on marine life, corrosion, installation, and accessibility,” Hroulev says. “Our solution is a vertical axis turbine, which is the most efficient and environmentally neutral turbine technology. It has low manufacturing and running costs and can be used in deep and shallow water. It is durable, efficient and scalable.”

The idea is based on a Darrieus type turbine, a type of vertical axis turbine which curved aerofoil blades. This will be mounted inside a structure, which makes sure the water continues through the bi-directional turbine, instead of just being dissipated by the blades, unless it’s mounted underneath a floating structure, in which case it would be open.

The blades, mounted vertically as two sets of four blades in each system, will generate power through a gear box to a permanent magnet generator, even in very slow water speed, Hroulev says. “NeoTurbine can perform in very lower water current, up to 2m/sec,” he says. The system will generate power from as low as 0.1m/sec, compared to others which do not start until 2-4m/sec, and up to 15m/sec, which is above any current found naturally, he says.

Hroulev says full scale turbines will be 2m (40kw rating), 5m, and 10m (1 MW) in diameter, with the different sizes being used according to the site or application.

“The good thing with my turbines is that they can be installed next to each other and on top of each other, like Lego bricks,” he says, using concrete gravity-based foundations. “So, you can create a kind of tidal fence across a fjord, for example. You cannot do this with others.” In such a scenario, fewer generators per turbine would be required as they could be connected, he says. If mounted beneath a floating, anchored facility, the generator would be onboard the floating structure.

So far a number of companies have been supporting him, including Global Maritime Group, Nordikraft, Havkraft and HydroWave, as well as organizations including Connect Norge, Innovation Norway, and GCE Subsea.

He’s also been working with universities, including the Norwegian University of Life Sciences, and the University of Bergen, which have produced market analysis and engineering comparison studies.

The next step is securing funding for a prototype to be tested at sea. He needs about US$240,000, which he would be able to get matched by government funding.