The waste deal between Norfolk and Suffolk has been extended to 2020.
The agreement, which was signed until 2016 last year, allows Norfolk County Council to send its waste to a Suffolk facility where it is treated to generate electricity.
It processes around 210,000 tonnes of residual waste that Norfolk generates each year.
Matthew Hicks, Suffolk County Council’s Cabinet Member for Environment and Public Protection said: “This is an extension of current arrangements which benefit both local authorities, saving each county in the region of £1 million between 2014 and 2016.
“The extension of this agreement will not increase the volume of waste moved into Suffolk and the number of trucks transporting waste from Norfolk will not change. There are currently eight movements each day, moving around 40,000 tonnes of residual waste from Norfolk.”