In short: Large-scale Generation Certificates (LGCs) are the federal incentive for solar systems above 100 kW. Unlike the upfront STC discount on smaller systems, LGCs are earned annually: one certificate for every megawatt-hour the system actually generates, verified against meter data, until the scheme ends in 2030. Two things have changed the LGC conversation in 2026: certificate prices have fallen hard as large-scale supply outran the fixed federal target, and an announced STC expansion is set to replace LGCs entirely for new 100 kW–1 MW systems installed from 1 October 2026, subject to regulations being made.
What Is an LGC?
A Large-scale Generation Certificate represents one megawatt-hour of renewable electricity generated by an accredited power station under the federal Large-scale Renewable Energy Target (LRET). The LRET obliges electricity retailers to surrender a set number of certificates each year, which creates the demand side of a traded certificate market. Your solar system supplies the other side: generate a megawatt-hour, create a certificate, sell it.
The word “large-scale” is doing less work than it sounds. The threshold is 100 kW of capacity, so a solar system on a mid-sized warehouse roof sits in the same scheme as a grid-scale solar farm. At or below 100 kW a system claims Small-scale Technology Certificates (STCs) instead, which are deemed upfront rather than earned year by year. There is no partial claim across the two: the whole system falls under one scheme based on its size.
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Who Is Eligible, and What It Takes
To create LGCs, a system above 100 kW must be accredited as a power station with the Clean Energy Regulator. That brings obligations a small system never sees: an application before certificates can be created, revenue-grade metering of generation, and annual electricity generation returns. Certificates are created in the regulator’s registry against actual metered output, then sold either through a broker or agent, under a long-term offtake, or on the spot market.
This is the administrative trade at the heart of the 100 kW line. An STC system gets its incentive as a point-of-sale discount and never thinks about it again. An LGC system takes on registration and reporting in exchange for a revenue stream that arrives one year at a time. That overhead, more than the certificate maths, is why so many Australian commercial roofs carry a 99 kW system.
LGC vs STC at a Glance
| STCs | LGCs | |
|---|---|---|
| System size | Up to 100 kW (current rules) | Above 100 kW |
| When you are paid | Upfront, at point of sale | Annually, as generation is metered |
| Basis | Deemed (predicted) generation to 2030 | Actual metered generation, 1 LGC per MWh |
| Admin | Installer handles it | Power-station accreditation + annual returns |
| Price risk | Locked in on day one | Exposed to the certificate market every year |
| Scheme end | SRES ends 2030 | LRET ends 2030; no LGCs created after |
For the full three-scheme comparison including Victorian VEECs, see STC vs VEEC vs LGC. The short version for stacking: a 100–200 kW Victorian system can pair its LGCs with VEECs, and any state can pair LGCs on the solar with battery incentives on a co-located battery.
What an LGC Is Worth in 2026
Here is where most older guides will mislead you. LGC spot prices spent years in the $40s and $50s, and a lot of published content still quotes those numbers. The market has moved: the LRET target has been fixed at 33,000 GWh since 2020 while large-scale wind and solar kept building, so certificate supply now comfortably exceeds the demand retailers are obliged to meet. Spot prices slid through 2025 (around the low $30s in January) and by mid-2026 have traded in the single digits, with forward prices declining further toward the scheme’s 2030 end date.
That does not make LGCs worthless: on a 250 kW system generating around 350 MWh a year, they are still real revenue, and voluntary demand (corporates surrendering certificates for green claims) puts a floor under the market that the mandatory target no longer provides. But it does change how they should be quoted. An LGC stream priced at a flat $45 per certificate for ten years overstates the asset badly; priced off the current forward curve it is a modest, declining line item that ends in 2030. If a payback figure you have been shown leans heavily on LGC revenue, ask which price and which years sit behind it. The LGC calculator uses a live market default you can override to match your broker’s pricing.
The October 2026 Change: STCs to 1 MW
The second thing reshaping the LGC story: on 5 August 2026 the federal government announced that STC eligibility will expand from 100 kW up to 1 MW for solar installed from 1 October 2026, subject to regulations being made. Once in force, a new 300 kW system would take a whole-system upfront STC discount at a fixed five-year deeming instead of registering as a power station and collecting LGCs against a weakening price outlook. Given where LGC prices sit, that trade favours the upfront certificate for almost any new mid-scale project that can be installed after the start date.
Three caveats. The regulations were not registered at the time of writing, so the 100 kW limit is still the law today. Systems already accredited for LGCs keep their arrangements. And systems above 1 MW stay under the LRET and keep earning LGCs regardless. We covered the announcement in detail, including what is still unconfirmed, in the STC expansion guide.
How Amperage Models LGC Revenue
Because LGCs are annual, market-priced, and time-limited, modelling them as a flat number is the easiest way to flatter a payback figure. Amperage prices the stream the way the market does: the certificate count rides the system’s actual modelled generation (degrading a little each year as panels age), each year is valued against a per-year forward LGC price rather than a single flat rate, and the stream stops at the end of 2030 when the LRET ends. The same treatment runs through the sizing matrix, so when you compare a 99 kW scenario against a 150 kW scenario side by side, the LGC line reflects what those certificates are actually likely to fetch, not a 2023 price. For installs dated on or after 1 October 2026, the announced mid-scale STC regime is available as an explicit opt-in, quoted with a pending-regulation flag, with the LGC stream removed to match.
Every scheme, current price, and stacking rule lives on the solar incentives hub, which stays updated as the rules move.
The Short Version
LGCs pay commercial solar above 100 kW one certificate per metered megawatt-hour, every year until the LRET ends in 2030. They demand power-station accreditation and carry market price risk, and that market has fallen from the $40s to single digits as supply outran the fixed target. For new mid-scale projects, the announced 1 October 2026 STC expansion is likely to make upfront certificates the better path once the regulations are registered. Until then, quote LGCs off the forward curve, not off a blog post from three years ago.
LGC calculator — annual certificates and revenue for your system →
Solar incentives hub — every Australian scheme with live prices →