British wholesale gas prices firmed on Wednesday morning on expectations of lower supply and rising demand, despite an oversupplied system.

The October contract was up 1.40 pence at 31.95 p/therm, an intraday high, by 0830 GMT.

The day-ahead and within day contracts were yet to trade.

Day-ahead prices should rise, however, said analysts at Refinitiv, as some Norwegian flows would be re-routed to the Continent following the end of maintenance at processing plant Karstoe.

This would see Langeled pipeline flows to the UK drop from current levels of 42 mcm/day.

Gas-for-power demand will drop 9 mcm to 59 mcm on Thursday, however, limiting price upside, they added.

Peak wind generation is forecast at 7 gigawatts (GW) on Wednesday and 8.7 GW on Thursday, out of total metered capacity of around 18 GW, Elexon data shows.

Lower wind output typically increases demand from gas-to-power plants.

Overall demand in Britain is set to average 113 million cubic metres (mcm)/day next week, up from current levels of 84 mcm/day, with temperatures dropping 2.3 degrees to average 11.3 degrees Celsius over the same period, according to Refinitiv data.

The gas system was over-supplied by 18.1 mcm, with demand at 180.7 mcm and supply at 201.7 mcm/day, National Grid data shows.

The October gas price at the Dutch TTF hub was up by 0.28 euro at 11.88 euros per megawatt hour.

Longer-dates contracts were receiving support from firmer carbon prices, said analysts at Energi Danmark in a morning report.

"We could very well see the market follow the carbon market in the coming time," they added.

The benchmark Dec-20 EU carbon contract eased 0.38 euro to 27.47 euros a tonne, but had gained 1.45 euros on Tuesday amid an afternoon surge.