The Balticconnector pipeline that transports natural gas from Finland to Estonia has been shut down after a leak was suspected in the early hours of Sunday morning.

A sharp drop in pressure in the pipeline triggered initial warnings of a possible puncture. Hourly data from Estonia’s transmission system operator, Elering, analysed by Reuters, showed a sudden drop in pressure at 23:00 GMT from 34.5 bar to around 12 bar. A further decline to just 6 bar occurred approximately one hour later, suggesting that gas had escaped into the surrounding ocean.

Finnish state-owned gas system operator Gasgrid said in a statement that repairing the pipeline, which extends 77km between the two countries, could take months if the suspected leak is confirmed.

"If it appears that the unusual pressure drop observed in the morning of Oct. 8 ... is due to a leak [that] caused damage to the pipe, repair work may take at least several months depending on nature of the damage," Gasgrid added.

An Investigation to determine the state of damage to the pipeline is ongoing, but Finland’s gas system remains “stable”, while the supply of gas is secure through the Inkoo LNG (liquid natural gas) floating terminal “for the time being”, the operator said.

The Balticconnector has an annual capacity of 2.6 billion cubic metres and can transport gas in either direction, depending on where demand is greatest. At the time of the incident, it was transporting approximately 30 gigawatt-hours of gas per day.

Both Elering and Gasgrid said that consumers in Estonia and Finland are receiving gas from other sources.

In an updated statement, Gasgrid said is has now assessed the extent of the gas leak and will “report the results after they are confirmed to the environmental authorities in accordance with the Environmental Protection Act”.