Letters | Sunday, 28 June 2009

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Blackout – Enemalta had reserve capacity

Reference is being made to Raphael Vassallo’s article published the 21 June (“Blackout predicted by Enemalta report in 2006”). The questions relating to this article were received at 14:17hrs on Saturday afternoon and therefore did not leave reasonable time to respond in time for publishing on the Sunday paper.
The Enemalta ‘Generation Plan’ is a report carried out by the Corporation in 2006, identifying potential weak spots in the existing system and mapping out the policy and plans to counteract these and to ensure that the Corporation is able to meet the national demand as efficiently as possible whilst respecting the environment and also whilst minimising costs. At the time the generation plan was completed, the load growth was significantly higher and the best available technology was different.
Today with the lower growth rate which has actually been recorded, the present reserve margin is still greater than 60MW at the anticipated peak load of circa 430MW and the Corporation has sufficient reserve capacity to meet the coming demand. In actual fact the generation capacity is 551MW, which at this time of year is derated (due to +30degC temperature) to about 510MW. At the time of the incident the load was 320MW and there was 30MW in reserve with 160MW of generating plant out of service. The out of service plant consisted of 90MW on planned overhauls and the rest on unplanned maintenance following faults, one of which occurred just days before. Two days after the incident, only 60MW remains out of service, and this is expected to be available for service by the end of June.
The development of flue gas abatement technology, since the generation plan was compiled, has opened other technological solutions to the Corporation. The implication that Enemalta did not have sufficient reserve capacity to cover for the tripping of the gas turbine on Tuesday 16th is clearly unfounded, at the time of the fault, there was one other gas turbine on standby, and following the fault, supply was restored to all areas, as was clearly indicated in the presentation to the media last Wednesday. Furthermore the fault on this gas turbine fault followed a previous fault, where a 70MW unit had to be taken out of service the previous weekend (without any disruption of supply) and a previous fault on another 30MW unit which was still under repair.
The fact that there may be interruption of supply as a result of a fault, does not indicate that the Corporation is unable to meet demand. It is an unfortunate fact of life that it is not possible for any electricity provider in the world to guarantee that there will be no interruptions of supply. This fact is independent on whether the provider of electricity is a monopoly or not, and it occurs everywhere in the world. Such interruptions to supply may originate from faults in the generating plant or in the distribution system, and whilst most affect a relatively small proportion of the connected customers, some will result in widespread or total system shutdowns.
The Corporation has embarked on a plan to upgrade its generation and distribution infrastructure, both to meet the anticipated future demand, improve efficiency and reduce environmental impact and to improve system reliability. The incident last Tuesday could still happen, even with new plant and infrastructure, but the effect and duration can be expected to be minimised. The Corporation is undertaking the following strategic investment initiatives:
a) The new generating plant will be comprised of eight heavy duty diesel engines, all of which will be capable of quick start – full load in less than 30 minutes compared to three to four hours for steam plan, these will complement the existing five quick start gas turbines giving a total quick start capability of over 300MWt.
b) A SCADA (supervisory control and data acquisition) system to monitor and control the distribution system is also to be installed, and this together with the quick start engines will enable rapid re-energisation of the whole network.
c) The planned interconnector to Sicily will comprise two 225MW links, giving a total capacity of 450MW, and capable of an overload capability of 810MW for 1 hour (180%).
The Corporation is keeping up its investment in all its areas of activity – both distribution and generation and retail with millions of Euros invested each year: distribution, retail (new distribution centres, feeders and substations and smart meters etc) and generation (140 MW) which are not covered by the present tariffs incurring significant losses each year despite the public crusade against it which is led by the media every time tariffs are revised upwards or when a legitimate decision like that of investing in new generating capacity is announced.
However whilst all of these investments together with the parallel investments in the distribution network, will improve reliability and reduce significantly the possibility of shutdowns such as that experienced last Tuesday and will provide the Corporation with the ability to restore power after major incidents like last Tuesdays total shutdown faster, it cannot totally remove the possibility of such incidents. As stated above, this is a state of affairs that all electricity providers throughout the world have to face, and Enemalta will continue to invest in its infrastructure and personnel in order to provide the Maltese public and economy with as reliable a service as possible.

Ing. Alexander J. Tranter
Chairman, Enemalta

Editorial note

Raphael Vassallo writes: The email was sent on Saturday at 2pm only because questions sent on Friday morning to Enemalta’s press officer Ian Vella had been ignored. Dr Tranter was aware of this situation as I explained it to him personally over the phone on Saturday.

Allow me to make two clarifications in response to your opinion page last Sunday (“Sorry, did you say ‘guarantee’?” Saviour Balzan, 21 June).
The Tuesday press conference held at Enemalta following the blackout was not a justification of what happened but an explanation of what happened based on what Enemalta engineers observed at the time.
Faults, breakdowns and blackouts, although rare, do occur. Nowhere in the world can this be eliminated completely. What Enemalta is doing and will continue to do, is to invest significantly in the appropriate energy infrastructure, not only to continue to reduce the incidence of such occurrences in the future but also t increase the country’s security of supply.
You also managed to make a number of inaccurate statements concerning my lack of an energy background. I graduated in mechanical engineering from the University of Malta in 1988 and my final year thesis was related specifically to alternative energy. I am also a former employee of Enemalta Corporation: I was a shift engineer in charge of boilers 5, 6, and 7 at the Marsa Power Station following my graduation, having been sponsored by the Corporation during the infamous student-worker period. And by the way, I am from Floriana, not Sliema.

Ing. Alex J. Tranter
Chairman, Enemalta Corporation

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