DUBAI (Reuters) - UK stocks of liquefied natural gas have swollen over the last week, data from National Grid shows, after three big Qatari deliveries helped replenish low heating fuel supplies during the coldest March in over half a century.
Britain's relatively small gas stocks fell to just 2,594 gigawatt hours (about 225 million cubic metres) on Saturday, according to the latest data from National Grid, as prolonged cold weather kept heating demand well above seasonal norms.
But three large deliveries from Qatar of super-cooled gas over the last week, with the latest unloading in Wales on Saturday, have swelled additional stocks of liquefied natural gas (LNG) held at import terminals to 6,219 GWh, or around 540 mcm, up from 358 mcm last Sunday.
Despite gas demand expected to be around 303 mcm on Sunday, about 20 percent above normal for the time of year, National Grid expects supplies coming from Norway, continental Europe and the UK's own North Sea gas fields to exceed demand.
Britain's Met office said on Thursday that March looked set to be the coldest since 1962, with a mean UK temperature of just 2.5 degrees Celsius between March 1 and March 26.
The prolonged cold weather has drained UK stocks held in traditional storage sites in gaseous form to around 5 percent of capacity on Saturday.
But with plentiful supplies coming in by pipeline, Britain's three large LNG import terminals only made small contributions to UK gas supply over the weekend, despite large deliveries to two of them over the last week.
The terminals - two in south Wales and one near London - each have several large storage tanks, some the size of London's Albert Hall, where they keep the gas super-chilled in its liquid state before warming it back into gaseous form when needed.
The three deliveries from Qatar, the world's largest LNG exporter, have swollen Britain's LNG stocks from around 30 percent full last Sunday to over 40 percent full ahead of the working week - a time when gas demand from industry rises.
Another LNG tanker is on course to deliver a cargo from Trinidad on Monday, according to ship tracking data on Reuters, which should boost UK gas stocks by about another 80 mcm.
According to Reuters analysis of AIS data transmitted by the world's fleet of LNG tankers on Sunday, there were no other ships indicating that they are heading to Britain.
There were three Qatari LNG tankers heading north through the Red Sea on Sunday, any of which might be destined for the UK. Qatari LNG tankers typically do not specify their final destinations until they have emerged from the Suez Canal.
(Editing by Catherine Evans)