Malta’s LNG power plant combines flexibility with low emissions

In March 2013, the winning candidates in a national election pledged to improve environmental conditions and reduce electricity prices. They created the EGM consortium to reach these goals. EGM identified natural gas as the best solution for the country’s energy needs. Natural gas has dramatically lower emissions than heavy fuel oil and significantly lower CO2 emissions per unit of energy produced, compared to other fossil fuels. Plus, it generates less noise and less smell, and delivers greater efficiency. 

The project developers opted for liquefied natural gas (LNG) as the fuel source and a double-hulled purpose-built tanker as a floating storage unit (FSU), to be moored in the water adjoining Delimara. 

With these guidelines, Siemens Energy developed the unique configuration of the new Delimara 4 power plant based on three key components:

• The FSU tanker docked just offshore where the LNG is stored at -162 degrees Celsius. It is transferred by pipe to
• an onshore regasification plant where the LNG is reconverted to natural gas. The regasification compound operating capacity is sufficient to handle both the new Delimara 4 facility and eight turbines from the existing Delimara 3 plant on the same site. The latter used to run on heavy fuel oil but all have been converted to gas, as well. 
• Finally, the combined cycle power plant (CCPP) consisting of three Siemens Energy SGT-800 gas turbines, three boilers, and one Siemens Energy SST-900 steam turbine, equipped with the SPPA-T3000 control system, has a totaling capacity of 215 megawatts. 

“Distributed generation ensures a reliable power supply. The SGT-800 is the best in its category in this power range, and being equipped with the modern dry low emission technology it meets emissions standards for a wide range of operation modes,” notes Franz Haslinger, Siemens Energy's General Project Manager for the Malta project.

In addition to providing a customized technology solution, Siemens Energy – through its Financial Services division – helped structure the overall financing concept and, ultimately, became one of three investors in the project. The capital support from Siemens Energy underscores its confidence in the project’s long-term success and positions the company as a key partner.

The great advantage of a CCPP is its flexibility. The gas turbines can run alone without the boilers or steam turbine in a so-called open cycle. In combined cycle mode the gas turbines, boilers, and steam turbine run simultaneously. In this case, the steam generated by one or more of the gas turbines and boilers is used to drive the steam turbine, so the latter runs without an additional source of fuel. “The three-to-one ratio of gas to steam turbines increases the efficiency of the plant significantly,” Dörfler points out. While a combined cycle plant is nothing new in Europe, it is new for Malta. 

The novelty of a combined cycle plant was not the only challenge. Lay-down room on the building site was also an issue, since construction was restricted to the existing Delimara plant boundaries. Markus Bratok, Siemens Energy Site Manager at Delimara, recalls that sometimes only half the desired number of square meters was available. “Our space was very narrow. To cope, we practiced just-in-time inventory because we had no room for storage.” 

Time pressures were another challenge. Siemens Energy Commissioning Manager Alexander Krewenka recalls: “EGM wanted the gas turbines to enter commercial operation as soon as possible to produce electricity for the hot high season here in summer.”

In March 2016, IJ Global Awards honored the Delimara plant as the best European Power Plant Project of the Year. On August 10, 2017, it was handed over to EGM and virtually all – 99 percent – of testing had been completed to “very satisfactory results,” reports Dörfler.

One happy result: The efficiency of the gas turbines was higher than expected. 

Another measure of success: Particulate matter in the air was reduced by 90 percent with the gas turbines. Overall, the plant is 50 percent below EU emission standards. Reduced electricity costs of 20 percent have already been passed on to domestic and commercial/industrial sectors in Malta.

These results have been noticed abroad, and Malta’s CCPP has received many visitors to the project from other islands in Europe and worldwide – from Corsica to New Caledonia. You might call them pilgrims to the shrine of Max, Maximilian, Anna and Vilhelmina.

July 12, 2018

Claudia Flisi is a journalist based in Milan.

Picture credits: Darrin Zammit Lupi