UK GAS-Prices rise on trading frenzy while oil up and market undersupplied

July 11 (Reuters) - British wholesale gas prices rose in busy trde on Thursday, as some traders looked to boost their positions in a market that was undersupplied while oil was lifting the energy complex.

* The within-day contract rose by 3.98 pence to 35.75 pence per therm at 0840 GMT, a rise of more than 12%.

* Day-ahead gas prices were 2.05 pence higher at 35.70 pence per therm, while the August contract was up by 1.05 pence at 34.80 p/therm.

* "Τhere was way more trading activity in the morning than usual," said a British gas trader, adding traders that tried to increase short positions caused a hike in prices.

* "Οil is once again, as yesterday, pointing the whole energy market into a specific direction," he said, while the system's undersupply also gave prices a boost.

* Oil futures hit a six-week high on Thursday as oil rigs in the Gulf of Mexico were evacuated ahead of a storm, while an incident with a British tanker in the Middle East highlighted ongoing tensions in the region.

* Brent crude futures reversed early losses and were up 36 cents, or 0.5%, at $67.37 a barrel by 0643 GMT. Earlier in the session, they hit their highest since May 30 at $67.39, after ending Wednesday up 4.4%.

* Gas demand is forecast at 171.9 million cubic metres (mcm) and flows at 150.6 mcm/day on Thursday, leaving the system undersupplied by 21.3 mcm, National Grid data shows.

* Britain's total gas imports from Norway were expected to reach 71 million cubic metres (mcm) on Thursday, 5 mcm short of Monday's levels, as maintenance was cutting flows.

* Ongoing maintenance at Norway's giant Troll field lasting until July 19 was reducing flows by 9 mcm per day.

* An ongoing outage at the Nyhamna gas processing plant was also reducing flows by 9.2 mcm/day and is expected to last until Aug. 27.

* Peak wind generation is low on Thursday, forecast at 1.9 gigawatts (GW), but it is expected to grow to 4.9 GW on Friday, out of a total metered capacity of around 12 GW, Elexon data shows.

* Low wind output usually increases gas demand for electricity produced in gas-fired power stations.

* In the Dutch gas market, the day-ahead gas price at the TTF hub was 0.35 euros higher at 12.85 euros per megawatt hour.

* Benchmark Dec-19 EU carbon contracts were up 0.23 euros at 28.42 euros a tonne, extending gains from Wednesday, when they hit a new 11-year high. (Reporting by Lefteris Karagiannopoulos in Oslo Editing by Edmund Blair)