LGC definition

Written and checked by the Energy Merchants desk · Reviewed 2 October 2026

A Large-scale Generation Certificate (LGC) is created by an accredited renewable power station for each megawatt-hour of eligible electricity it generates above its baseline. It is part of the large-scale side of the Renewable Energy Target (RET), and the Clean Energy Regulator (CER) administers the register.

Liable entities, mainly electricity retailers, buy LGCs and surrender them to meet their annual obligation. That demand sets the price.

LGC and STC side by side

In practice

The definition becomes useful when a commercial customer asks which route is better for a roof of 150 kW. Up to 100 kW, and from 1 October 2026 up to 1 MW (see mid-scale solar STCs), the STC route gives upfront certificates and fast money. Above 1 MW, or for older systems above 100 kW, LGCs are created as the system generates, which means revenue arrives over time and depends on metering and reporting. Because LGCs are valued at a fraction of STCs per megawatt-hour, the financial picture is different, and the larger system may need a financier or an offtake arrangement.

Installers who primarily do homes will seldom touch an LGC, but the term appears in commercial quotes and power purchase agreements.

Common confusion

LGCs are not “bigger STCs”. They are generated on a different basis and have separate demand. Nor are LGCs a GreenPower product, though some consumers buy and retire them voluntarily to claim renewable electricity use.

Meanwhile, see LGC meaning for the plain-language version, the certificate trading glossary for neighbouring terms, and pricing for current STC rates.