Mozambique is to increase power supplies to South Africa to help it cope with severe electricity shortages.
Most of Cahora Bassa's power already goes to South Africa
More than 75% of the power generated from Mozambique's huge Cahora Bassa Dam is already sold to South Africa.
A senior official from the company that runs the dam told the BBC that this will be increased next month thanks to a recent refurbishment of the facility.
The move follows news that electricity prices in South Africa are set to rise by more than 50% to ease the crisis.
The South African government said it backed the plans proposed by the state power company Eskom.
The rise would help to offset higher fuel costs and fund major new projects to ease pressure on supplies, it said.
A shortage of power caused a series of blackouts in January, forcing mines to suspend production for several days over safety concerns.
The crisis has been blamed on years of under-investment by the government and rising demand.
The BBC's Jose Tembe in Mozambique's capital, Maputo, says the deal follows negotiations between the two governments which are in their final stages.
Load shedding means regular power cuts in South Africa
Juliao Pondeca, from the Cahora Bassa Hydroelectric company, says that because of a more than $60m refurbishment of the dam, it can now supply additional energy.
At the moment much of Cahora Bassa's power-generating capacity of 2,075 megawatts is sold to its southern neighbour.
Our correspondent says Eskom has also agreed to help with the building a new dam on the Zambezi River - the Mphanda Nkuwa Dam - 60km downstream from Cahora Bassa.
Countries in the region import and export electricity from each other.
However, earlier this year South Africa was forced to cut its supply to its neighbours because of shortages at home.