Story about Geothermal Power Plant

Hiii.

Today I’ll share a lil about Geothermal Power Plant in Indonesia. I choose one power plant : Patuha Unit 1. Location of Patuha Unit 1 is near Patuha Mountain, Ciwidey Village, Bandung District, West Java. This location about 40 km south from Bandung City, exact location in Sugih Mukti Village, Pasir Jambu District.

This power plant build in 2012 and start operation in 2014. The capacity ofthis power plant is 60 MW. Total geothermal potency in this area arround 400 MW with steam categorize as dry steam. The administrator of Patuha Unit 1 is Geo Dipa Energi. Power electricity produce by PLTP Patuha Unit 1 distribute to network system transmission electricity JAMALI (Java, Madura, Bali) PLN 150 kV.

Power generation Patuha unit 1 operate continue for 24 hr to meets the load of PLN JAMALI network. Total area for this power plant : 15 Ha, well : 8 Ha (10 wells production and 2 wells injection). This Area can be seen below :

Source for this picture : EVALUASI PEMANFAATAN ENERGI Di PT. Geo Dipa Energi (Persero) Unit Patuha Tahun 2021

System schematic for Patuha Unit 1 can be seen below :

The system categorize as single flash system with several component such as :

• Turbine for expansion process through convertion entalphy steam to mechanical energy to rotate shaft of generator, so that electricity can be generate.
• Condenser for condensation process through decrease pressure of steam and change the phase from vapor to saturated liquid.
• Pump for increase pressure of saturated liquid and deliver the liquid to well injection.
• and so on.

After gain several information of this geothermal power plant, I do analysis the performance of this geothermal using Cyclepad Software.

The appearance of this software is below :

In this software we can build the system and analyze it, but in order to analyze the system, we will need several data about the power plant. The data I get for this plant is basically from the source that I mention before. Here the data that I will be input to the cyclepad software :

Thermodynamic analysis of geothermal patuha unit 1 using cyclepad software. This analysis using some assumptions to adapt to the features on the cyclepad software. Here are some of the assumptions given in the thermodynamic analysis of geothermal patuha unit 1 :
- Turbines: adiabatic, isenthropic
- Condenser: isobaric
- Pump: adiabatic, isenthropic
- The boiler is assumed to be well: isobaric
- Quality out condenser : x = 0

From the assumption and data table, the system of geothermal patuha unit 1 is made on the cyclepad. The system can be seen at pictured below :

In addition to the schematics of the patuha unit 1 geothermal system, cyclepad software can also describe T-s diagram for the system. Diagram of T-s patuha unit 1 geothermal system can be seen as follows :

In the T-s diagram, the turbine input phase at the saturated vapor and output phases of turbine is in the mix phase between vapor and liquid. Then the mix phase will enters the condenser and turns into saturated liquid which will be injected back into well by the pump. From the cyclepad software, geothermal patuha data unit 1 for each state (S1,S2,S3 and S4) can be determine.

The properties obtained in each state correspond to the properties in the table thermodynamic properties patuha geothermal unit 1.

In addition to the data of each state on the cyclepad, the data of each component can also be obtained as follows :

● Turbine : Shaft power is 70 MW,
● Condensor : Heat rejected from steam is 209 MW
● Pump : Shaft power is 78.93 kW
● Boiler : Heat absorb from steam is 279 MW

The data cycle properties of the analyzed system are as follows:

Thermal efficiency for the geothermal patuha unit 1 is : 25.02% with a net energy is 69 Mw.
After cycle analysisi, we will do sensitivity analysis
In sensitivity analysis, we will plotted a graph between dependent variables is usually variables that want to be increased in performance, for example eta thermal with independent variable i.e. temp enters the turbine.

Based on the plot of the chart above, if temperature inlet increase, then
the efficiency is also increase. This is caused by delta enthalphy in turbines increased, so that the W turbines also increased. As the W turbine increases, the W is electric in the system also increases and results in greater efficiency.