1. Natural Gas Combustion:
- Natural gas is mixed with air and then ignited in a combustion turbine.
- The combustion process generates hot gases that expand and cause the turbine blades to spin.
2. Gas Expansion:
- The high-temperature gases from the combustion turbine are directed to a heat recovery steam generator (HRSG).
- As the hot gases pass through the HRSG, they heat the water in the boiler tubes.
3. Steam Generation:
- The heat from the hot gases converts the water in the boiler tubes into high-pressure steam.
4. Steam Turbine:
- The high-pressure steam is then directed to a steam turbine.
- The steam expands and causes the turbine blades to spin.
5. Electricity Generation:
- The spinning of the turbine blades in both the gas and steam turbines rotates the generators connected to them.
- This rotational motion in the generators produces alternating current (AC) electricity.
6. Cooling:
- After passing through the turbines, the steam is condensed back into water in a condenser.
- The condensed water is then pumped back to the HRSG to repeat the cycle.
7. Transformers:
- The AC electricity produced by the generators is usually at a low voltage.
- Transformers increase the voltage of the electricity to enable efficient transmission over long distances through power lines.
This combined cycle process allows for increased efficiency in electricity generation by utilizing both the energy released from burning natural gas and the heat generated by the exhaust gases to drive the steam turbine. Natural gas power plants are widely used due to their efficiency, availability, and lower emissions compared to traditional coal-fired power plants.
