Question 1

What is a combined cycle gas turbine (CCGT)?

Accepted Answer

A power plant that generates twice from the same fuel. A gas turbine burns natural gas to spin a generator, then its 500–600 °C exhaust passes through a heat recovery steam generator (HRSG) to raise steam, which drives a second turbine. That recovered second cycle is why combined cycle reaches 60–64% net electrical efficiency where a simple-cycle turbine manages 35–42%.

Question 2

How efficient is CCGT power generation?

Accepted Answer

H-class combined cycle plants exceed 64% net electrical efficiency — the highest of any thermal power cycle in commercial operation. If the remaining heat is captured and sold rather than rejected, a combined heat and power configuration lifts total fuel efficiency above 90%, because energy that would otherwise go up the stack becomes district heating, absorption cooling or industrial process steam.

Question 3

Why do data centres build their own gas generation instead of using the grid?

Accepted Answer

Because new transmission interconnection for large loads now takes five to seven years across much of North America, while AI capacity is needed now. Behind-the-meter generation is built on the customer side of the meter, so it sidesteps the interconnection queue entirely — a campus can energize in 18–24 months and lock fuel costs rather than riding volatile grid rates.

Question 4

How long does it take to build an on-site CCGT plant?

Accepted Answer

Typically three to four years from order to commercial operation for a full combined-cycle plant, including permitting, long-lead turbine procurement and construction. Where speed matters more than efficiency, reciprocating engine gensets and aeroderivative simple-cycle turbines deliver in 9–24 months instead, at 35–50% efficiency rather than 60–64%.

Question 5

What capacity range does on-site CCGT cover?

Accepted Answer

Roughly 50 to 500+ MW, scalable to the facility's actual load. Below about 20 MW the economics usually favour reciprocating engines, linear generators or solid oxide fuel cells, which hold their efficiency at smaller scale and permit more easily in urban settings where air quality and noise are the binding constraints.

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