Definition
An Open Cycle Gas Turbine (OCGT), also called a simple-cycle or peaker turbine, is the most basic form of gas-fired generation: a single gas turbine that exhausts its hot gases straight to atmosphere without recovering any waste heat. That simplicity costs efficiency, with typical figures of 33-43% at full load, but it buys speed. An OCGT can be brought online and taken offline in minutes, which is why grids worldwide rely on them for peaking duty.
The efficiency trade-off
Because an OCGT throws away the exhaust heat that a combined-cycle plant would reuse, it burns more fuel per kilowatt-hour and carries a higher heat rate. Efficiency also falls further at partial load, so OCGTs are happiest running near their rated output for short bursts rather than throttled down for hours.
Where OCGTs fit mining
For a sovereign miner, an OCGT's appeal is flexibility rather than fuel economy. Operators monetizing flared or intermittently available gas may favour a fast-starting turbine that can follow gas supply, and miners can act as a flexible load that absorbs whatever the turbine produces. For sustained, fuel-cost-sensitive hashing, however, a reciprocating engine genset or a combined-cycle plant usually delivers cheaper energy.
The decision hinges on run-hours and gas price. If the plant will hash around the clock, efficiency wins; if it must start and stop with an intermittent fuel stream, the OCGT's quick response and lower capital cost can justify the fuel penalty. Weigh it against the unit's turndown ratio and its baseload-versus-peaking role.
In Simple Terms
An Open Cycle Gas Turbine (OCGT), also called a simple-cycle or peaker turbine, is the most basic form of gas-fired generation: a single gas turbine…