13 February 2020 113118
Engineering

Gas Power Plant (PLTG)

Gas Power Plant (PLTG)
PLTG is a type of generator that uses "hot air" to turn a turbine. This hot air is generated by heating the air using the gas in the combustion chamber. The hot air is then flowed to the turbine. PLTG scheme is shown in Figure 1.



Natural gas power plants tend to have more environmentally friendly emissions than coal-fired power plants. The process of generating electricity using natural gas is quite different from the mechanism in the steam power plant (PLTU). The natural gas combustion process is not used to carry out the heating process like the PLTU but is used directly to turn the turbine. Before going through the combustion process, the air is compressed using a compressor. Then the compressed air is flowed into the combustion chamber to then react with the gas. In this process, the pressure contained in the air and the chemical energy contained in the gas are converted into kinetic energy which is then used to turn the turbine. The advantages and disadvantages of PLTG are summarized in Table 1.
Figure 1. Schematic of a gas turbine
 

Advantages
 
More efficient
 
Simple construction and smaller required area 
Electrical capacity is more varied
More environmentally friendly than PLTU
The speed in response to increased power is higher
Disadvantages
 
Usually to only meet peak power
 
Sound pollution
 
High operational cost
 
 
 
Table 1. Advantages and Disadvantages of PLTG
The gas that comes out of the gas turbine still has a high enough temperature. Thus, the hot gas can still be used. One of the uses of hot gas is to heat the working fluid used in the PLTU, through a device called Heat Recovery Steam Generator (HRSG). The combination of gas turbines and steam turbines in electricity generation is known as PLTGU (Gas and Steam Power Plants). PLTGU has higher efficiency compared to PLTU and PLTG, considering that there is less energy that is not utilized. T
 
Advantages
 
More efficient compared to PLTG
 
Lower operational cost compared to PLTG
 
Earlier starting time
 
More simple maintenance procedure
Disadvantages
 
Needs at least two kinds of fuel 
Shorter lifetime
 
 




The advantages and disadvantages of PLTGU are shown in Table 2. 
 

Author

Maesha Gusti Rianta ST., M.Sc

Email: maesha@indonesiare.co.id