AEMC Solar Curtailment Reform 2026: Installer Guide

What Curtailment Is and Why Your Clients Do Not Know About It

Curtailment occurs when your client's solar system is generating electricity but the local distribution network cannot accept more export. The inverter detects grid voltage rising above its permitted operating range and reduces or stops export. The sun is shining. The panels are producing. The electricity goes nowhere. The client earns nothing for that generation.

This happens most commonly in dense solar suburbs between 10am and 2pm on clear days, precisely when most solar systems are at peak output. The problem is systemic in areas where solar penetration reached 60 to 90 percent of homes in a short window. Distribution network service providers built their feeder infrastructure for load patterns that assumed most electricity flowed from the grid to homes. In high solar density areas, the reverse flow on sunny days exceeds the feeder's capacity to manage.

Most clients do not know this is happening to them. Their monitoring app shows the system is generating. What it does not clearly show is the gap between what the system could export and what it is actually exporting. Unless the client is actively comparing total AC generation against grid export, the curtailment is invisible. The feed-in credit on their electricity bill comes in lower than expected, and they attribute it to weather or seasonal variation rather than active network restriction.

For you as the installer who put that system on their roof, this creates both a risk and an opportunity. The risk: if the client eventually discovers their system has been curtailed for months without being told, they will hold you responsible. The opportunity: you can be the professional who identified the problem, explained it, and provided options before the client discovered it themselves.

What the AEMC Is Proposing

The AEMC's April 23 draft rule has two main components. First, distribution network service providers would be required to publish long-term distribution network plans every five years, covering a 20-year horizon and forecasting where network constraints and curtailment risk are highest. Second, annual updates between the five-year cycles would keep the data current as solar penetration continues to grow.

As PV Tech's April 27 coverage of the draft notes, the proposal requires DNSPs to publish data on existing network constraints, including the potential for rooftop solar exports to be curtailed, before making investment decisions. This is the AEMC explicitly acknowledging that clients and installers currently make installation decisions without knowing whether the system will be able to export its full generation potential.

For installers, this matters in two ways. In the near term, the June 4 submission period is a direct opportunity to shape the final rule. In the medium term, the rule if passed creates an information environment where you will be able to tell clients before installation whether their postcode carries curtailment risk and what the constraint profile looks like for the next decade.

How to Check Whether Your Installed Systems Are Being Curtailed

Before the rule takes effect and network data is published, the most reliable way to identify curtailment is through inverter monitoring data you already have access to. The diagnostic approach:

Step one: find total AC generation

Most modern inverters (Fronius, SMA, Sungrow, Huawei) report total AC generation and grid export separately in their monitoring apps or portals. The difference between total AC generation and the sum of self-consumption plus grid export represents potential curtailment.

Step two: look for persistent midday gaps

Curtailment typically appears as a consistent suppression of output during peak solar hours on clear days. If a system that should generate at 85 to 90 percent of rated capacity on a clear summer midday is consistently showing 50 to 60 percent, that gap warrants investigation.

Step three: check inverter event logs

Most inverters record voltage rise events in their event history. High frequency of voltage rise events during midday peak generation hours, particularly in high solar density postcodes, is a reliable indicator of curtailment rather than system fault.

What to Do for Clients Currently Being Curtailed

The most practical immediate solution is adding battery storage, which captures generated energy that would otherwise be curtailed and stores it for self-consumption in the evening. This does not resolve the network constraint, but it converts curtailed generation from wasted electricity into stored value that reduces the client's evening grid imports.

Adjusting the inverter's voltage rise settings within the permissible range can reduce curtailment frequency. Most inverters allow adjustment within the DNSP's approved tolerance band. This requires review of the specific DNSP's technical guidelines before implementation, as exceeding permissible settings creates a compliance risk.

For severe curtailment caused by a network constraint the DNSP is obligated to manage, lodging a formal complaint through the DNSP's network connection process can prompt scheduling of a feeder upgrade. Timelines vary significantly, typically measured in months to years rather than weeks.

Action before June 4: Pull the monitoring data for your five most recently installed systems in high solar density suburbs. If total AC generation consistently exceeds self-consumption plus grid export by more than 10 to 15 percent during peak solar hours, the gap is likely curtailment. Contact those clients proactively. Being the installer who identifies a problem before the client notices builds the trust that generates referrals.

How to Submit to the AEMC Consultation

The AEMC is actively seeking input from installers with field experience that is not captured in utility datasets. A submission does not need to be a formal engineering document. A single page describing your observations, the postcodes where you have identified curtailment, and specific requests about how you would like constraint data published is a legitimate and valuable contribution.

Key asks worth including in a submission: curtailment data published at postcode or substation level so installers can identify risk areas before quoting; notification to installers when a postcode reaches a solar saturation threshold; and disclosure requirements at point of sale for clients in constrained areas.

If you prefer to contribute through your industry body rather than submitting directly, contact the Clean Energy Council before June 4. They are compiling installer input for their formal submission, and field observations carry significant weight with regulators when specific and documented.

Planning Your Business Around the Post-Reform Environment

The AEMC draft rule, if passed in something close to its current form, creates a more transparent market for rooftop solar over the next decade. Installers who understand both the technical and network dimensions of solar installations will have a structural advantage over those who focus only on equipment and installation cost.

In the near term, the practical application is straightforward: identify the high-curtailment areas in your service region, have an honest conversation with clients in those areas about feed-in expectations, and lead with battery storage as part of the initial system proposal where curtailment risk is material. This is not upselling for its own sake. It is providing a complete solution for a real problem that the network creates and that cannot be solved by a better inverter or more panels alone.

Frequently Asked Questions

Q1. How do I check whether my client's system is being curtailed?

Compare the inverter's total AC generation output against the grid export figure in the monitoring system. Most modern inverters report both separately. If total generation consistently exceeds the sum of self-consumption plus grid export by more than 10 to 15 percent during peak solar hours (typically 10am to 2pm), the gap likely represents curtailment. Also check the inverter event log for voltage rise events. These are the inverter's response to grid voltage rising above its permitted range due to high local solar output. High frequency of these events in dense solar suburbs during midday generation periods is a reliable indicator of curtailment rather than a system fault or communication error.

Q2. What is the difference between zero export and curtailment?

Zero export is a deliberate configuration applied at installation: the system is programmed not to export to the grid at all, typically in embedded networks or buildings where the connection agreement does not permit export. The client expects no feed-in income and the configuration is intentional. Curtailment is an involuntary restriction imposed by grid voltage conditions: the inverter is configured to export and attempting to export, but is being repeatedly suppressed by voltage rise caused by high local solar penetration. A client on zero export has no feed-in income to lose. A client experiencing curtailment is losing feed-in income they are entitled to under their connection agreement. Check the inverter's export settings before diagnosing curtailment to ensure you are not misidentifying a configured restriction as a network problem.

Q3. Which regions of Australia have the highest curtailment risk?

Curtailment risk is highest where solar penetration is dense relative to the network's absorption capacity. South Australia under SA Power Networks, South East Queensland under Energex, and parts of Western Australia under Western Power currently experience the highest frequency of curtailment events. Specific postcodes in outer-suburban growth corridors, where 70 to 90 percent of homes installed solar in a 2 to 3 year window, are most exposed. The feeder infrastructure was never designed for the reverse-flow volumes that result from mass adoption. Within these regions, single-stage residential developments where solar adoption coincided with a specific incentive period are most at risk. If you are installing in these areas, a conversation about curtailment risk before installation is a professional obligation.

Q4. Does curtailment affect panel or inverter warranties?

No. Curtailment does not void panel warranties, inverter warranties, or CEC accreditation compliance for the installation. The system is functioning as designed. The restriction is imposed by network conditions, not by any equipment failure or installation error. Clients often ask whether frequent voltage rise trips damage the inverter over time. Most modern grid-tied inverters are engineered to handle voltage rise events without degradation: the trip is a protective mechanism, not a component stress event. Check the inverter manufacturer's technical documentation for the specific model if the client raises this question. From a regulatory and compliance perspective, a system experiencing curtailment due to network conditions meets all installation compliance requirements.

Q5. How do I submit to the AEMC consultation before June 4?

Submissions are made directly through the AEMC consultation portal at aemc.gov.au. Search for the active distribution network planning rule change to find the correct submission form. A submission can be as short as a single page. You do not need a formal engineering document or legal representation. The most valuable installer submissions contain specific field observations: postcodes where you have identified curtailment in monitoring data, estimates of the percentage of systems in those areas that appear affected, and specific requests about how you would like constraint data published. The AEMC explicitly values practitioner evidence not available from utility datasets. If you prefer to contribute through your industry body, contact the Clean Energy Council directly before June 4 to include your observations in their formal submission.

Q6. Can a battery fully resolve curtailment income loss for a client?

A battery significantly reduces but does not fully eliminate the financial impact of curtailment. Here is why: curtailment typically occurs during peak solar generation hours, often 10am to 2pm. A battery that fills completely during this window will absorb the curtailed generation and store it for evening self-consumption, recovering the financial value of that energy. However, if curtailment is so severe that generation is restricted even after the battery is full, the remainder is still lost. For most residential systems in moderately curtailed areas, a well-sized battery (10 to 13 kWh) recovers the majority of curtailment-related income loss by converting wasted generation into self-consumption value. In extremely constrained areas, even a large battery cannot recover all of the lost generation, and the DNSP network upgrade is the only complete solution.

Sources

• AEMC , aemc.gov.au , Draft rule: modernising distribution network planning. April 23 2026. Submissions due June 4.
• PV Tech , pv-tech.org , AEMC proposes 20-year distribution planning to ease solar curtailment (April 27 2026)
• PV Magazine Australia , pv-magazine-australia.com , Energy commission targets lower curtailment, 28.3 GW, 4.3 million installs, June 4 deadline