# Gas turbines and combined cycle

Turbines burning gas directly, alone for peaking or with a steam turbine on the exhaust.

Source page: https://www.materialinsights.org/energy/e_gas_turbines/

Conversion and use · Conversion devices · No. 97

- Conversion and use
 Conversion and use · Conversion devices · Foundation · Energy

A jet engine paired with a steam turbine makes the best fossil power plant, and data centres have booked them to 2031.

Chart: Illustration: Gas turbines and combined cycle

##### Where it comes from

Chart: Map of where it comes from

A gas turbine compresses air, burns gas in it and expands the hot gas; a combined cycle uses the 650 C exhaust to raise steam for a second turbine.

##### Three things to know

1. Turbine blades work in gas at about 1,650 C, far above their melting point, kept alive by cooling and ceramic coatings.
2. Peakers run only 10 to 15% of hours, so each MWh costs USD 149 to 251, against USD 48 to 109 for combined cycle.
3. Jet engines have climbed from about 10% overall efficiency in the late 1940s to about 40% today.

##### The journey

1. 1 **Air in**Compressor squeezes air hard
2. 2 **Combustion**Gas burns at about 1,650 C
3. 3 **Gas turbine**Hot gas spins compressor and generator
4. 4 **Exhaust heat**About 650 C gas raises steam
5. 5 **Steam turbine**Adds about one third more power

##### Go deeper pick a tab to open it in full

## Other sections

- [Overview](https://www.materialinsights.org/energy/e_gas_turbines/overview/index.md)
- [Correlation](https://www.materialinsights.org/energy/e_gas_turbines/correlation/index.md)
- [Science and limits](https://www.materialinsights.org/energy/e_gas_turbines/science/index.md)
- [Value chain](https://www.materialinsights.org/energy/e_gas_turbines/valuechain/index.md)
- [Unit economics](https://www.materialinsights.org/energy/e_gas_turbines/economics/index.md)
- [Engineering methods](https://www.materialinsights.org/energy/e_gas_turbines/methods/index.md)
- [Equipment and suppliers](https://www.materialinsights.org/energy/e_gas_turbines/equipment/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_gas_turbines/links/index.md)