A momentary fault on Boiler 3 of the Marsa power station produced a black cloud of smoke over Marsa this afternoon.
Enemalta said the fault developed in the combustion air controller which resulted in a shortage of air to Boiler 3 at about 6.30 p.m.
Remedial action was taken immediately and the boiler returned to normal after a few minutes.
The power supply was not affected. Enemalta apologised for any inconvenience caused.