Combined Cycle Power Plant (CCPP), How Does It Work?

Recently, technology has kept developing, making more energy efficiency efforts emerge and be invented; one is the Combined Cycle Power Plant (CCPP). CCPP combines a Gas-Fired Power Plant and a Steam-Electric Power Plant.

To get to know more about Combined Cycle Power Plant, how it works, and its benefits, read the explanation below!

What Is a Combined Cycle Power Plant (CCPP)?

Combined Cycle Power Plant (CCPP) is a technology using steam and gas to produce electricity. This power plant is considered more environmentally friendly, has low carbon emissions, and is efficient.

CCPP is an advanced step in the power plant field in which it has two turbines rotating the generator: a steam turbine and a gas turbine.

Those two units work separately in physics but still depend on each other during the operational process. The gas turbine will be heated first to produce exhaust gas. The gas will operate the steam turbine boiler to produce steam. Once the steam is out, the steam turbine will start to work.

Despite working together, it does not mean that both turbines need separate fuel. A steam turbine can work using exhaust gas from the gas turbine. As a result, the energy needed is more efficient.

In the United States, CCPP is becoming common and widely developed. According to the data from the U.S. Energy Information Administration, there are two main factors in CCPP usage, namely generator efficiency and natural gas cost efficiency.

The introduction of more sophisticated turbine technology can increase the efficiency of natural gas power plants. Additionally, lower natural gas prices increase the capacity factor of CCPP because the electricity produced is cheaper than other power plants, such as coal-fired power plants.

In addition, research published on Springerplus declared that the gas turbine efficiency, which is around 28–33%, can be escalated to 60% by recovering some of the low-grade thermal energy from the exhaust gas for the steam turbine process.

How Combined Cycle Power Plant Works

As explained before, the Combined Cycle Power Plant uses two turbines to produce electricity, which are steam and gas turbines. In detail, CCPP uses thermodynamic cycles: Brayton cycle for gas turbine and Rankine cycle for steam turbine.

The gas turbine is operated at a high temperature, usually 2600 degrees Fahrenheit, to produce exhaust gas. The gas will be directed to the Heat Recovery Steam Generator (HRSG).

HRSG catches the heat to produce steam, generating the steam turbine, resulting in electricity. This process is considered more efficient for a power plant compared to a Gas-Fired Power Plant and a Steam-Electric Power Plant.

Combined Cycle Power Plant Components

To work properly, a Combined Cycle Power Plant (CCPP) needs some primary components, such as a gas turbine generator, HRSG, steam turbine generator, and control and electricity system. Below is the completed explanation:

1. Gas Turbine Generator

The gas turbine generator is the main part of CCPP, containing a combustion room, compressor, and turbine. The compressor condenses the air into high pressure. Then, the pressure is combined with the fuel in the combustion room.

The combination is lit to create hot gas, spreading through the turbine. The hot exhaust gas is brought to HRSG for the next use.

2. Heat Recovery Steam Generator (HRSG)

HRSG works to catch the heat from the exhaust gas to create steam. HRSG has three important components: superheater, evaporator, and economizer. The economizer will heat the feed water before entering the evaporator.

In the evaporator, the feed water is converted to steam which is heated by a superheater to a certain temperature and pressure.

3. Steam Turbine Generator

This generator receives high-temperature and pressure steam from the HRSG. The steam moves to the turbine and generates the propeller connected to a generator. This process will create additional electricity.

The steam that successfully moves the propeller will return to water and it will return to the HRSG as feed water. The cycle will return to the beginning until the CCPP operates properly.

4. Electricity and Control System

For a safer, more efficient, and more reliable operational process, CCPP needs an advanced electricity and control system. This system regulates the temperature, flow rate, and pressure. Aside from that, it will ensure that the electricity transmission to the end consumer or network runs safely.

The Advantages of Combined Cycle Power Plant

Combined Cycle Power Plant is an innovation in power generation that is more energy efficient and has several benefits, including:

1. Reducing Fuel Consumption

CCPP can reduce fuel consumption to produce electricity. CCPP leverages natural gas as an environmentally friendly fuel compared to crude oil and coal.

2. More Efficient

CCPP is considered more efficient because it combines gas and steam turbines compared to power plants that rely on gas or steam only. This power plant also has a higher flexibility because it can set the energy outcome based on the demand and has a faster development process.

3. Low Emission

CCPP also has low emissions compared to Steam-fired Power Plant because natural gas produces lower carbon emissions per electricity unit. In addition, if CCPP is equipped with a more advanced combustion and emissions control system, it can reduce pollutants like NOx.

Example of Combined Cycle Power Plant in Indonesia

Now, you already understand the definition of a Combined Cycle Power Plant, how it works, and its benefits. In Indonesia, several electricity supply companies use CCPP, one of them is Krakatau Chandra Energi.

Krakatau Chandra Energy is a subsidiary company of the Chandra Asri Group providing various energy infrastructures, such as electricity providers, electricity services, and new renewable energy.

For electricity provider service, Krakatau Chandra Energy uses a Combined Cycle Power Plant (CCPP) with a total capacity of 120 MW. The CCPP has two HRSG, two gas turbine generators, and one steam turbine generator.

Krakatau Chandra Energy’s CCPP uses natural gas and ensures that the electricity produced follows the industry standard.

This is the information about Combined Cycle Power Plant you can learn. CCPP can be a solution to a more efficient and eco-friendly energy solution compared to crude oil and coal. The emissions are lower, making it suitable for lower emissions energy solutions for industry.