UK GAS-Day-ahead gains on expected rise in demand and reduced supply

(Clarifies Teesside gas plant maintenance to start on Friday June 3, not Tuesday June 1, in a bullet point and in 4th paragraph)

* Lower temperatures expected to boost household demand for gas

* Maintenance at St Fergus to start on June 1, at Teesside June 3

* Within-day gas down on balanced system, more wind output

May 31 (Reuters) - The British day-ahead gas price rose on Tuesday on expectations of higher demand due to a drop in temperatures and reduced domestic supply because of planned maintenance.

The day-ahead contract gained 0.98 pence to 33.15 pence a therm at 0950 GMT from the previous settlement.

Analysts at Thomson Reuters (Dusseldorf: TOC.DU - news) said lower temperatures were expected to drive up household demand for gas at a time when planned maintenance would also reduce domestic output.

Flows from the UK Continental Shelf will likely be reduced from Wednesday due to maintenance at St Fergus terminal, followed by maintenance at the Teesside gas processing plant on Friday, and after Norway's biggest gas field Troll was shut for annual maintenance on Saturday.

"Prompt contracts have firmed on expectations of higher demand over the remainder of this week, in addition to reduced Norwegian suppply," a UK-based trader said.

Supply from liquefied natural gas (LNG) terminals is at around 35 mcm/day but could rise later this week as the Zarga LNG tanker is expected to arrive on June 3, traders said.

Meanwhile, gas for immediate delivery fell by 0.30 pence to 32.50 pence per therm on a well-supplied system, while windy weather increased output from wind power turbines, thus reducing demand for gas in power generation.

Total (LSE: 524773.L - news) supply was seen at 186 million cubic metres (mcm) per day and demand at 185 mcm, leaving Britain's gas system broadly balanced, National Grid (LSE: NG.L - news) data showed.

Further along the curve, the gas contract for June delivery firmed by 0.52 pence to 32.20 pence/therm.

The Dutch day-ahead gas price at the TTF hub rose by 0.26 euro to 14.30 euros per megawatt hour.

In the European carbon market, front-year allowances eased by 0.08 euro to 6.04 euros a tonne. (Reporting by Nerijus Adomaitis in Oslo; editing by Nina Chestney)