Freezing weather and record demand for U.K. natural gas has forced grid operator National Grid PLC (NGG) to issue a Gas Balancing Alert to the market via email Thursday, the second such alert this week.

Freezing weather and record demand for U.K. natural gas has forced grid operator National Grid PLC (NGG) to issue a Gas Balancing Alert to the market via email Thursday, the second such alert this week.

Gas Balancing Alerts are triggered when gas demand threatens to outstrip supply. It warns major users of gas they may have to cut consumption because of the cold weather and companies on interruptible gas contracts risk further reduction or cessation of their supply.

"This is a major concern," said British Glass director general David Workman. "So far I've no feedback on disruptions but the longer the cold snap goes on, the more worrying the situation becomes for the [glass] industry. Even in mild winters we've worried about interruptions because of the lack of gas storage provision."

"A substantial number of industrial consumers have had their gas supplies interrupted to maintain supplies to domestic consumers," an employee at a food processing business in the Midlands region of the U.K., who didn't want to be named told, Dow Jones Newswires this week.

However, it remains unclear how many businesses may have been impacted by Thursday's alert. Companies sign contracts for interruptible supply in exchange for lower energy costs.

"As a result of this latest alert, demand has subsequently fallen, which indicates major end users have potentially turned down production or turned to coal," said Nick Campbell, an analyst at Inenco.

Prior to this week, National Grid has only once resorted to using the alert, in 2006, following a prolonged shutdown at the
U.K. 's primary storage site after a fire.

National Grid's forecast for Thursday's demand has fallen from near record highs, but supply remains under considerable pressure following an outage earlier in the day at a Norwegian gas field.

Norwegian gas supply to the
U.K. through the pipelines dropped significantly as a result of a shutdown in the Troll A gas field. Consequently, forecast supply dropped from around 474 million cubic meters to 443 million cubic meters.

Late Thursday traders said prices for prompt within-day
U.K. natural gas had softened following the alert after trades heard at 54 pence a therm earlier in the day , around 20% higher than deals done at close of trading Wednesday.

"Two gas supply alerts in one week shows just how precarious the
U.K. 's energy position has become," said opposition energy and climate change spokesman Greg Clark.

"Business users are first in line to take the hit, paying higher prices than they would if we had more gas in storage, and now being warned they face cut-offs. This is the last thing our economy needs right now--forced cuts to gas supplies adding to the woes of the recession."

The
UK 's pressing need for gas has been further exacerbated by freezing temperatures in continental Europe , which means supply from Norway 's Langeled pipeline and through the Interconnector pipeline that links the U.K. with Belgium has been limited, traders said.