Malaysia's Tenaga Nasional will buy 180MW of power from Singapore's PowerSeraya, a unit of Petroliam Nasional, until 15 June.
The decision was taken after Petroliam Nasional's gas production platform was shut down, which affected gas supply to the utility.
This is the first cross-border commercial sale of power between the two countries, and represents 1.5% of the total demand, the company told the Star.
PowerSeraya chief executive officer John Ng noted that the power being supplied to Tenaga is received from an oil-fired steam plant at a 3,800MW facility.
The electricity is being transmitted through two 230kV submarine cables linking Malaysia's national power grid with Singapore's transmission network at Senoko.