Enemalta is currently accepting expressions of interest for a e21.6 million project (75 to 80 per cent of which will be funded by the EU) that is expected to reduce dust (particulate matter) emitted from two boilers at the Delimara power plant by 80 per cent, and the two other main pollutants by 30 per cent.

Enemalta chief executive officer Karl V. A. Camilleri and chief technical officer Peter Grima told this newspaper that the project was planned after Dutch consultants Kema carried out a study on the boilers at the power plant.

Ing. Grima explained that the project is aimed at preparing the boilers for the more stringent emission limits that the EU is set to impose by way of a revision of the Large Combustion Plant Directive in 2016.

The revised directive will play an important role in the European community’s efforts to combat acidification, eutrophication (stimulates excessive plant and algae growth, reducing dissolved oxygen in the water when dead plant material decomposes), and ground-level ozone as part of the overall strategy to reduce air pollution.

This will be done by controlling emissions of sulphur dioxide (SO2) and oxides of nitrogen (NOX), and particulate matter from large combustion plants – those whose rated thermal input is equal to or greater than 50 megawatts.

Meanwhile, Enemalta has tried finding the optimum means of reducing emissions, particularly by using better quality fuel (low sulphur oil as opposed to heavy fuel oil).

While dust and SO2 emissions are below EU limits, he said that NOX do sometimes exceed the limit.

The boiler modifications required to reduce dust emissions will take about four to six weeks. During that period, the first phase of the technical modifications to reduce other emissions will also be carried out, along with a major overhaul of the combustion plants.

The second phase would form part of another project that would take about six months to complete.

Enemalta’s chief executive officer said that before the project is undertaken, other sources of energy need to be in place (such as the planned interconnectors that will link Malta’s electricity grid to Europe’s) as it would be difficult to shut down a boiler for a whole six months without having hitches in the system.

Asked about the black smoke recently released from one of the chimneys of the Delimara power plant, the Enemalta chief technical officer admitted that black smoke indicates that there is a problem – there is usually not enough air for proper combustion.

Ing. Grima said the black smoke lasted about two to three minutes due to a minor fault, but he said it was the first time this happened in about three or four years.

He pointed out that Enemalta had invested heavily in continuous emission monitors for each of the power plant’s two chimneys, as well as in smoke density monitors on the boilers.

He said the fact that the Delimara power plant’s main chimney is 150 metres high (it was designed in 1988-9) is an advantage.

If it were designed today, with modern technology and with cleaner fuel in mind, the main chimney would have been much lower.

The fact that it is so high takes emissions up higher, mitigating, to a certain extent, the effect of air pollution on the ground below.

As for the Marsa power plant, the EU’s Large Combustion Plant Directive had established that it has 20,000 hours of operational life left, effective from 1 January 2008.

This means that if the plant operates on a 24/7 basis, the plant would have to be decommissioned by April 2012 at the latest.

The Marsa power plant releases carbon dioxide emissions at an efficiency generation factor of 23 per cent, so the sooner it is decommissioned, the better.

The existing plant has aged considerably. Over the years, a number of turbines have been refurbished, but some of the older steam turbines at Marsa Power Station date back to the 1960s.

Planned timeline

Pollutant Effects Particulate matter (PM) Chronic exposure to PM contributes to the risk of developing cardiovascular and respiratory diseases, as well as lung cancer. The mortality in cities with high levels of pollution exceeds that observed in relatively cleaner cities by 15 to 20 per cent. Even in the EU, average life expectancy is 8.6 months lower due to exposure to coarse dust particles (PM2.5) produced by human activities. Sulphur dioxide (SO2) SO2 can affect the respiratory system and the functions of the lungs, and causes irritation of the eyes. Inflammation of the respiratory tract causes coughing, mucus secretion, aggravation of asthma and chronic bronchitis and makes people more prone to infections of the respiratory tract. Hospital admissions for cardiac disease and mortality increase on days with higher SO2 levels. When SO2 combines with water, it forms sulphuric acid, the main component of acid rain, which is a cause of deforestation. Oxides of nitrogen (NOX) NOx consist of a mixture of nitric oxide (NO) and nitrogen dioxide (NO2). NOx are critical components of photochemical smog – nitrogen dioxide produces the yellowish-brown colour of the smog.

While NO does not significantly affect human health, elevated levels of NO2 cause damage to the mechanisms that protect the human respiratory tract and can increase a person’s susceptibility to, and the severity of, respiratory infections and asthma. Long-term exposure to high levels of nitrogen dioxide can cause chronic lung disease. It may also affect sensory perception, for example, by reducing a person’s sense of smell.

Particulate matter (PM): Chronic exposure to PM contributes to the risk of developing cardiovascular and respiratory diseases, as well as of lung cancer. The mortality in cities with high levels of pollution exceeds that observed in relatively cleaner cities by 15 to 20 per cent. Even in the EU, average life expectancy is 8.6 months lower due to exposure to coarse dust particles (PM2.5) produced by human activities.

Sulphur dioxide (SO2): SO2 can affect the respiratory system and the functions of the lungs, and causes irritation of the eyes. Inflammation of the respiratory tract causes coughing, mucus secretion, aggravation of asthma and chronic bronchitis and makes people more prone to infections of the respiratory tract. Hospital admissions for cardiac disease and mortality increase on days with higher SO2 levels. When SO2 combines with water, it forms sulphuric acid, the main component of acid rain, which is a cause of deforestation.

Oxides of nitrogen (NOX): NOx consist of a mixture of nitric oxide (NO) and nitrogen dioxide (NO2). NOx are critical components of photochemical smog - nitrogen dioxide produces the yellowish-brown colour of the smog.While NO does not significantly affect human health, elevated levels of NO2 cause damage to the mechanisms that protect the human respiratory tract and can increase a person's susceptibility to, and the severity of, respiratory infections and asthma. Long-term exposure to high levels of nitrogen dioxide can cause chronic lung disease. It may also affect sensory perception, for example, by reducing a person's sense of smell.

Planned timeline

September 2009: call for expressions of interest for Delimara boiler modification project closes

Autumn 2010: modifications on first boiler begin

Winter/spring 2011: modifications on second boiler begin

2011: Delimara power station extension in service

Beginning of 2012: first interconnector that will link Malta’s electricity grid to Europe’s in place

2013: second interconnector in place