CENECO initially serviced Silay City; on May 16, 1976, it took over the electric system of the Municipality of Murcia. On June 1978, with the help of the national government, CENECO purchased and took over the A. S. Diaz Electric service (ASDES) which served Bacolod City and Talisay. The following year, on June 1979, CENECO took over the Bago Electric System and Ma-ao Electric System in Bago City.