The government’s decision to turn to gas to address the issue presented an opportunity for Wärtsilä to demonstrate the benefits of its flexible power generation solution. Aceh Special District in northern Sumatra is one area that needs to strengthen its electricity system to ensure reliable electricity supply to consumers. Grid stability has to be improved and more capacity is required to serve a demand peak that occurs once a day for about five hours. When state utility PLN decided to build the new Arun gas fired plant to address its needs, it could have opted for open cycle gas turbines to do the job. However, after a careful lifecycle analysis, it decided to build a plant based on combustion engines supplied by Wärtsilä. With an output of 184 MW, generated by 19 Wärtsilä 20V34SG engines running on liquefied natural gas (LNG), when it begins operation it will be the country’s largest gas fired combustion engine plant. One major advantage of this solution compared to a gas turbine plant is the high degree of flexibility it offers. To provide grid stabilisation, the power plant has to be capable of fast start up. Arun will be able to reach full load in around 10-15 minutes. Further, because engines can be switched on or off according to load requirements, the remaining engines can run at full power and therefore the plant can maintain maximum efficiency over a much wider load range. By comparison, a gas turbine due to its much larger size would have to operate at part load and thus be much less efficient.

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