Stories

The harbour in Mo i Rana in Northern Norway is ice-free during winter, thanks to two pipes that blow air through tiny holes and create bubbles in the water.

The licence only called for an ice-free lane, so that ships could enter, but now the entire Rana fjord is ice-free.

It is early morning a winter day in 2013, and Rana industrial harbour is already teeming with activity. Large containers are transported away. Loading and unloading is constant. There is a cold wind blowing. Old Man Winter has a firm grip. Behind the vessels, the harbour is ice-free, and the sea is a dark blue.

What the residents here fear the most, is that the so-called "Rana Ice" will take hold. In the past, when the fjord, the community's only link to the outside world, would freeze, Rana was isolated for months at the time.

Bubbles in the sea

In 1968, a bubble facility solved the problem. Quite simply.

The significance of this can hardly be understated. In the beginning, the foundry Norsk Jernverk AS, coke and ammonia producer Norsk Koksverk AS and the mining company Rana Gruber AS dominated – companies that export their goods. Now, the Mo Industrial Park is the largest of its kind in Norway, and an industrial hub in Mo i Rana with its own industrial terminal and harbour. The harbour here is now Norway's most modern and the country's sixth largest, measured in cargo tonnage.

When the Norwegian Energy and Water Resources Directorate (NVE), and now, Statkraft, developed the Rana Power Plant, one of the licence conditions was to maintain an open lane in the ice during winters, so that ships could enter and exit the fjord without fear of any ice.

The power plant is located 10 minutes from the town centre. This is also where power plant manger Marianne Fineide has her of fice. She is the boss of another important industry that harvests the natural resources in the area – hydropower. One kilometre inside the mountain is a gargantuan hall, where four large Francis turbines operate at capacity.

"This is a large power plant. We produce 500 MW and our task is to run when prices are high," says Fineide, greeting two colleagues who perform maintenance at the plant.

"We also make sure the plant is spick and span, to avoid unnecessary disruptions to our operations. We've just finished a major overhaul in the mountain hall. The flooring has been replaced, and the walls have been painted in light colours. Here at the Rana Power Plant, the sky is always blue," she says, pointing to the ceiling. The cafeteria has retained its 1960s style, and the dusk on the wall lends a certain tropical and holiday feel for the three guys who are having their coffee break.

The Mo i Rana city is all about the bubbles!

Per Anders Nygaard

More freshwater, more ice

The power plant's intake is from Lake Storakersvatnet. After passing through the turbine, the water enters the Rana River and finds its way down to the harbour.

"We're adding more freshwater to the fjord during winter than normal, and freshwater freezes more easily than saltwater," says Fineide. "So there's an added risk of ice with the power plant. The facility starts at minus five centigrade, but we'll soon introduce more parameters that will ensure optimum start-up. These include measuring the salt content of the fjord."

Upgraded and efficient

The compressor building, housing three 960 kW compressors, was recently upgraded at a cost of NOK 19 million. From here, warm air is pushed through two pipes that are solidly-anchored at a depth of 15 metres, suspended between two jetties. The pipes have been perforated with holes from 2 to 4 mm, and were replaced and upgraded in 2007. When the bubbles leave the nozzles, they expand as they rise to the surface, carrying with them warmer saltwater from lower layers. This mixes the freshwater in with the lower layers. This affects the entire harbour, and an icefree harbour is now a given in Rana.

"The upgrade gave us an energy-efficient facility, so that no oil exits together with the air," says Fineide. "The licence only called for an icefree channel, so that ships could enter, but now the entire Rana fjord is ice-free. The facility's efficiency surpassed everyone's expectations."

Excellent cooperation

Another person who is very pleased with the harbour being ice-free, is, naturally, Mo i Rana's harbourmaster, Per Anders Nygaard.

"It's very important for businesses in Mo," he says.

Nygaard manages one of Norway's largest industrial harbours, and has an excellent relationship with Statkraft.

"We have about 1200 ships calling each year, and last year was one for the record books," he says, adding that 4.1 tonnes of cargo passed through –the highest volume ever in Mo i Rana.

No wonder then that the harbourmaster offers freshly made rum cake, coffee and a very happy smile. He still remembers the 1951-1952 winter, when the entire fjord froze over.

The bubble facility was the first of its kind in Norway. It was tested at MARINTEK's sea basin in Trondheim, before being installed in 1968. It was placed at the very end of the fjord and where the Rana River enters the sea.

"The effect was tremendous," Nygaard says.

Text: Anne-Lise Aakervik
Photo: Erik Thallaug
The article is also published in Statkraft's magazine People & Power no. 1/2013