The new Delimara power station extension hit a snag after some exhaust cleaning filters were damaged during test runs, The Times has learnt.
The dust filter bags were meant to last two years but were damaged after some months of operation.
Enemalta Corporation confirmed 30 filter bags had been damaged but said the problem was not significant. “The fault occurred in 1.4 per cent of the dust filter bags, that is, in 30 bags out of the 2,200 bags installed,” a spokesman said.
The filter bags are used to remove hazardous sulphur oxide (SOX) fumes created when sulphur in heavy fuel oil is burnt. The filtering equipment is crucial for the power plant to remain within EU emission targets.
Sources said the very long and narrow filter bags were damaged when they hit each other and the metallic structure that houses them, after exhaust gases flowing through the equipment caused turbulence.
The exhaust passes through the filtering equipment before entering the chimney where it is released to the atmosphere.
However, the Enemalta spokesman insisted the air filtering equipment was not damaged and it was “still performing within contract specifications”.
Dust emissions from the plant, she added, were still within “the BAT (best available technology) limits for this type of plant”. The Delimara power station extension is a prototype because it combines air filtering equipment with diesel engines run on heavy fuel oil.
Enemalta said the cause of the damage was still under investigation by the manufacturer of the equipment and the power station’s main contractor, BWSC.
“Given the investigation is in the early stages and information is still being gathered, any comment to the actual cause of the failures would be premature,” the spokesman said.
Appropriate remedial measures will be taken only after the cause of failure was “properly determined”, she added.
According to sources, if the problem persists Enemalta may have to change the power station fuel to the cleaner but more expensive gasoil that produced much less SOX when burnt.
However, Enemalta insisted the impact of the damaged filter bags on emissions was minimal and there was no reason to use gasoil.
Last February, Finance Minister Tonio Fenech told Parliament that testing at the power station extension had started and no problems were encountered.
Last month, the planning authority recommended a nine-month extension to the environmental permit of the power station to allow independent consultants enough time to collect air quality data.
The environment permit was issued earlier this year. It gave Enemalta the right to use the highly contested and polluting heavy fuel oil for a nine-month trial period that ends in September.
The recommendation to change the conditions of the permit will mean the plant will continue using heavy fuel oil until June next year.
At the end of the monitoring period, the planning authority will decide whether the extension should continue to use heavy fuel oil or shift to gasoil.
No decision has yet been taken on the permit extension.
When asked whether the request for a nine-month extension was related to the problems encountered with the air filtering system, the Enemalta spokesman said the request was not made by the company.
“This was a request by the independent consultant appointed by the monitoring committee comprised of a representative of the local councils and Enemalta and chaired by the planning authority,” she said.