More than 9,000 lights will be switched off
The switch-off has begun of more than two-thirds of a council's street lights in an attempt to cut energy costs.
Powys council is plunging 9,380 of its 14,000 lamps into darkness.
The decision was made after it was realised the council's £500,000 lighting bill was set to rise by £175,000.
The first phase is affecting a number of areas in the south of the county including parts of Llandrindod Wells and Rhayader.
Two out of three lights in non-sensitive areas are being switched off as the council attempts to manage its power budget following increases in energy costs.
But locations covered by CCTV, pedestrian crossings and trunk roads, will not be affected by the move.
Councillor Gwilym Evans, who is responsible for street lights, said: "The (council's governing) board decided that the only way to keep within budget with the scale of increases was to switch off the majority of lights in some areas.
"That work has now started."
The project could also cut the council's carbon footprint by up to 1,100 tonnes a year and reduce night sky pollution.
Officials had planned to shutdown 5,000 lights this year, and 6,400 in 2009.
However, following a re-think they decided to increase the tally because they faced an overspend on energy costs of £43,000.