The case for using gas oil in Delimara

Minister Tonio Fenech’s recent announcement that he intends to ask the European Commission for an extension of life for the Marsa power station (MPS) had been expected for some time. Taken in isolation it provided no great novelty though it did supply some low-calibre political ammunition to the minister’s adversaries.

However, there was some interesting detail in the ministerial statement. One aspect that came across strongly is the apparent belief by the minister that the public has a very short memory. So we were told that the Enemalta decision to use low (0.7 per cent) sulphur heavy fuel oil (HFO) should soften the heart of the EC and readily get us a MPS extension. But the EC has just told us that our power station emissions for 2009 – some two years after we had told the world we were switching to low-sulphur HFO – were above EU limits. We are reminded Enemalta is seeking an EU loan for boiler modifications at Delimara designed to cut dust and sulphur dioxide emissions in line with EU limits.

For the first time in very many months, it has been made clear that the Delimara Power Station Extension (DPSE) will not substitute all of the MPS potential power. MPS stands at 240MW while DPSE will come up to 144MW. Yet that statement by itself does not provide us with a very clear picture, not least because the minister confuses electrical power (MegaWatt) with electrical energy (MegaWatt-hour).

The crucial point is not only the power at your disposal but also the length of time the generators operate. Taking a GigaWatt-hr (GWh) to equal 1000MWh, a good value for the present annual electrical energy production would be 2300GWh, of which Marsa can be taken to contribute 45 per cent or 1035GWh. Now if DPSE (144MW) is working continuously for a year, it would produce 1244GWh, more than the present production of Marsa. We could dispense with the Sicily connection. Of course, all engines have downtime for maintenance and repair. So let us assume that DPSE will operate for a total of eight months in a year. That would give us 829GWh; the shortfall after Marsa closure (206GWh) will have to come from the Sicily cable.

Now let us look at costs: if the average cost of 1GWh is €A, the total cost of generation is €2300A. When DPSE is fully operational using HFO and Marsa is still open to provide the shortfall, the average cost will come down for the simple reason that DPSE will be much more efficient (47 per cent) than Marsa (23 per cent), meaning that DPSE will use about half the amount of fuel compared to MPS to generate the same number of units. In fact the average cost of a unit will drop to €0.8A.

But what if DPSE uses gas oil (diesel) rather than HFO? According to Enemalta figures, the average price of a gas oil unit is 24 per cent greater than that of a HFO unit, taking into account HFO-gas oil price difference, maintenance costs and different flue gas cleaning costs. When this is taken into account, the average cost of a DPSE (gas oil) unit remains at 0.6 of the current HFO unit and this because of the great gain in efficiency of DPSE. The overall average cost of a unit comes to €0.86A, significantly less than the present cost.

There is a further point to be made for when the Sicily cable is in place. A recent ministerial statement said that we would be getting electricity from Sicily at a much cheaper rate than we can produce it here.

So when the remaining high-cost Marsa units are replaced by lower-cost Sicily units, the average unit cost will come down further. Surely this clinches the case for giving up HFO for DPSE (and please remember that the DPSE piston engines have to be started and stopped on gas oil not HFO), with its expensive desulphurisation and its daily 30t of hazardous waste and 1t of HFO sludge, and run the engines on gas oil.

If the minister can rebut the above, it is high time he does it; if he cannot, let him “forever hold his peace” and switch DPSE to gas oil forthwith.