Noel Grima (“From Marsa to Delimara and beyond,” TMIS 2 January) was indeed fortunate to be given a guided tour of Marsa and Delimara power stations. However, he was not spared a fair amount of spin, and not from turbines either.

Take the Interconnector (IC): as Grima himself realised, neither the Delimara extension nor the IC will be on stream by the end of 2011, when the 4000hrs (8760hrs = 1 year) left to most Marsa equipment may run out. I say “may” because with a mild winter and a reasonable summer, demand may remain low enough for Marsa not to be called upon for long periods of time.

But to come back to the IC, this is not a magic device. Its contract will contain a minimum use factor, meaning that it will never be idle. But there is a difference between the maximum power it can carry and its ability for fast response. The latter depends on the (major) source of that power.

To turn to turbines, “open” and “closed” cycle turbines are the same type of animal. The closed type use their hot exhaust (600C) to raise steam to drive a steam turbine, so that one is, in effect, getting a ‘fuel-free’ turbine with every pair of closed cycle turbines. That is how the gain in overall efficiency is obtained. Had Grima asked why, with such an efficiency gain, the Delimara combined cycle contributes only about 12 per cent of generation, the answer would have been ‘pure BWSC’: the turbines have to burn costly gasoil (diesel) and not cheap HFO.

Incidentally, HFO is not a misnomer, as Minister Fenech and Enemalta would have us believe. For a start, 0.7 per cent sulphur HFO is an EU imposition; not so long ago, in fact until well after EU entry, we were burning three per cent sulphur HFO, and then came down to one per cent sulphur under EU pressure. That apart, the “mere” 0.7 per cent of sulphur has NOT excused us from having to de-sulphurise the Delimara extension chimney gasses: an expensive elaborate process that will produce 30t of hazardous waste per day and 1t of toxic sludge from the misnamed HFO, which the piston engines cannot burn. But do not be perturbed, gentle reader. Ing. Peter Grima, with no previous experience of these systems, is “fully confident” that this “world prototype” chimney gas purification and dust collection system will work – so confident, in fact, as to confirm his belief on oath before the Auditor General.

Of course not one word was said to Noel Grima about using gasoil (diesel) instead of HFO to fuel the BWSC piston engines. For diesel, no de-sulphuriser is needed and no sludge is left over. Nor, to date, has there been any credible statement on the cost of a Delimara unit if diesel is used for the extension. The statements about cheap Sicilian electricity are a two-edged sword. The prices mentioned are well below domestic electricity prices in Sicily. But if they are correct, they provide another strong argument for using diesel in the extension. Such low-priced units from Sicily would ensure that the use of diesel would not create any ripple on overall unit price, let alone Minister Fenech’s 30 per cent “tsunami”.

Edward Mallia,

ATTARD