Turndown Ratio

Turndown ratio describes how wide an operating range a power source can cover, defined as the ratio of its maximum stable output to its minimum stable output. A unit that can run cleanly from 100% down to 20% of capacity has a turndown ratio of 5:1. The higher the turndown, the more the equipment can be throttled back without losing efficiency, stability, or, in combustion equipment, a clean flame.

Why turndown matters for generation

For on-site mining power, turndown determines how well a generator or turbine can follow a changing load or a variable fuel supply. A high turndown ratio lets a plant idle down when fewer miners are running, or when gas flow drops, while staying within its safe and efficient envelope. Reciprocating engine gensets are notable here, with some able to run as low as roughly 10% of rated load, which makes them attractive for flexible and spinning-reserve applications.

Turndown and mining loads

Because ASIC fleets can be powered up and down in blocks, a generation source with poor turndown forces an operator into an all-or-nothing choice: run miners to soak up the minimum output, or shut the plant down entirely. Good turndown gives finer control and avoids wasting fuel or dumping power. Installing several smaller units instead of one large one effectively raises the whole plant's turndown by letting individual machines switch off.

Note that running near the bottom of the turndown range usually carries an efficiency penalty, so cross-check the unit's heat rate at part load and confirm its prime rating covers your steady hashing draw.