Scottish and Southern Energy (SSE) has ruled out raising electricity and gas prices over the next 18 months.
However, the firm said it cannot make any promises to cut the cost of its tariffs in the same period.
Chairman of the group Lord Smith of Kelvin said: "2008/09 was a tough year, dominated in the first half by very high wholesale prices for electricity and gas.
"Throughout, SSE managed its business in its usual no-frills way."
The firm recorded a profit of £1.25 billion during the last financial year a two per cent increase on figures for the 12 months prior to that which marks the tenth successive year that SSE has made money and increased dividend payments.
SSE supplies consumers and businesses with electricity and gas through its subsidiaries Southern Electric, SWALEC, Scottish Hydro Electric and Atlantic.
Meanwhile, the day after Scottish first minister Alex Salmond opened Europe's largest onshore windfarm, SSE unveiled plans for a large-scale windfarm in the Shetland Islands.
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