Under the Sea

The natural gas that powers buses and brings light to your home may come from Norway’s Snøhvit field, which sets new standards for harvesting the riches of the deep.

Under the Sea
StatoilHydro Plant | Infographic by Don Foley StatoilHydro Plant | Infographic by Don Foley

Each December, the sun sets over northern Norway and doesn’t reemerge until late January. But this past winter, a fiery vista of reds and oranges pierced the darkness. It wasn’t the northern lights, at least not the natural ones. It was the flare-off from the Snøhvit gas field, the first major Arctic fossil-fuel facility outside of Alaska.


The Arctic holds up to 25% of the world’s untapped natural-gas and oil reserves — one reason Russia planted a flag by submarine last year on the North Pole seafloor, and Canada, Denmark, and the United States have tussled over territory. But even if you control the seas, how do you get the goods beneath them? StatoilHydro, the Norwegian energy giant, puzzled over that for years after finding Snøhvit (Norwegian for “snow white”) under the Barents Sea in the 1980s. Now technology has enabled it to build the world’s longest undersea pipeline and wells operated remotely from the island of Melkøya. The gas, destined mostly for the United States, began flowing a few months ago.

Snøhvit is just the beginning of the Arctic’s adventures in energy. Russian gas titan Gazprom has awarded StatoilHydro a 24% stake in its Shtokman field, also in the Barents. That field, which holds at least 15 times more gas than Snøhvit, is more than 200 miles farther from land. But going that distance is no longer a pipe dream.


Melkøya connects to the wells via a 90-mile umbilical line. The communication cables are fiber optic, which carry more data over longer distances than copper


The gas and some water shoot out of the wellheads at a pressure of around 260 bar — enough to drive it down the pipe to land. At high pressures and low temperatures (the water is around 39 degrees Fahrenheit), gas and water can form a gummy slush called “hydrates,” so antifreeze is constantly pumped into the wellhead.


Snøhvit’s first-of-its-kind safety system features multiple backups. If communication lines fail, signals can be sent to the wells through power cables. If those die, then a ship, always on standby, can hook a new line to the wells and provide an interim satellite linkup.


The high-tech Snøhvit facility on Melkøya requires only 400 people — significantly less manpower than a traditional offshore platform. Just four technicians are needed to remotely operate the gas wells.



Once on land, the gas goes to a slug catcher, which removes the water and antifreeze. The antifreeze is recycled and pumped back to the wellheads. The water, which will go back to sea, first runs into a tank filled with microbes that devour pollutants.


StatoilHydro boasts that Snøhvit is the world’s most environmentally friendly liquefied natural gas (LNG) plant. At other LNG plants, the CO2 extracted from the gas goes into the atmosphere. At Melkøya, 700,000 tons of CO2 is captured and injected into sandstone 90 miles out to sea — the first time this has ever been done from an onshore facility. But the environmental group Bellona cautions that millions of tons more are still released into the air.


After cleaning, the gas goes into a “cool box,” where it’s chilled to -261 degrees and liquefied. Snøhvit’s technology — and the availability of cold air and water to aid refrigeration — means that the cooling is 20% more energy-efficient than at any other plant.


The Arctic conditions and lack of infrastructure meant that the complex gas-cooling plant couldn’t be built on Melkøya. Instead, it was assembled on a barge at a Spanish shipyard, moved to Norway, maneuvered into a custom-built dock, and cemented into place.


The LNG goes into two 160-foot-high tanks before being loaded onto ships destined for either the United States or Spain. StatoilHydro expects the shipments to gross around $2.7 billion a year.