The 100 MW plant has come online after testing was completed last week, said its operator, independent power producer Gigawatt Mozambique.
The plant, located near the South African border, is to run on gensets comprised of 13 Rolls Royce engines and ABB generators.
Total costs have been estimated at $235m since the project’s start in 2014.
The plant’s power will be purchased by state-owned utility Electricidade de Moçambique (EDM) under a long-term power purchase agreement, and is expected to supply around 12 per cent of the nation's total power demand.
The project’s second phase is planned at 250 MW and a combined-cycle plant is expected to come online within 36 months.
Significant gas discoveries since 2010 in Mozambique's Rovuma basin have prompted investor interest in a number of power projects.