The highways department at Northamptonshire Council Council saved nearly £2m last year by switching off half of the street lights across the county.
The council gave the figures in a Freedom of Information request submitted by the BBC.
The Conservative-run council said it would have spent more than £4.9m on lighting this year but instead it spent £3m.
The authority made the move to turn off half of its 66,000 lights as part of a plan to save £100m in four years.
The figure confirms the council's claims that it would save the money in electricity and maintenance costs.
David Farquhar, the council's assistant director for highways, said: "In energy savings alone, we have saved in excess of £850,000 in the first year, but this is offset by £250,000 which is the cost of spending four months to switch the lights off."