Operational Insights: Methodology

Operational Insights sits early in your workflow, bridging grid dynamics with the upcoming pipeline to enable rapid first-pass screening of sites, regions and assets without needing to connect separate datasets and tools.

Users can review historical signals, compare projects, lines and substations, and identify questions where deeper diligence or analysis is required. All in RenewMap’s responsive, easy-to-use platform.

These pages outline the methodology of the metrics provided by Operational Insights. This page gives a quick overview, while each metric has a full page with more detail.

Where the data comes from

All the operational data in Operational Insights is derived from data published by the Australian Energy Market Operator (AEMO) via NEMWEB.

Data sources & coverage sets out the update cycle and the time period, regions, units and equipment currently covered.

Project measures

Generation and Load

Generation (MW) is a unit’s average measured output, averaged over a half hour. Load (MW) is the same measurement from the other side of zero: how much the unit was drawing from the grid, which matters for batteries and pumped hydro that both charge and discharge.

Full derivation: Generation & Load

Curtailment

Curtailment Total (MW) is the gap between what a wind or solar generator could have produced and what it was actually dispatched to produce. It’s a measure of lost renewable generation that the market didn’t receive, because a network constraint was binding, or because the price was too low to be worth generating into.

Full derivation: Curtailment

Revenue and Missed Revenue

Revenue ($) values a unit’s output at the spot price that applied at the time, adjusted for transmission losses. It’s positive when the unit was generating and negative when it was consuming; and it can be negative while generating or positive while consuming, because NEM prices go below zero. Note this is Net Spot Revenue: it only includes revenue from the spot market, and subtracts spot costs for loads (e.g. battery charging).

Missed Revenue ($) is the same calculation applied to curtailed energy: what the output that never happened would have been worth. It’s the number that tells you whether curtailment actually cost anything.

Both figures are spot market outcomes only. They don’t include contracted revenue, FCAS, certificates or any cost of running the plant.

Full derivation: Revenue & Missed Revenue

Network measures

Line Flow

Flow is the measured power flowing through a piece of transmission equipment, taken from AEMO’s telemetry.

Full derivation: Line Flow

Ratings and Thermal Headroom

A conductor can only carry so much current before it sags and heats beyond its design limit, so every piece of equipment carries a rating: Normal for continuous operation and Emergency for short periods after a contingency. Ratings are dynamic: they move with ambient temperature and equipment configuration, which is why you’ll see them change through the day and across seasons.

Thermal Headroom is the simple arithmetic difference: rating minus flow. It’s the honest first answer to “how much room is left on this line”.

Full derivation: Ratings & Thermal Headroom

Constrained Headroom

Equipment is rarely limited by its own nameplate rating. It’s limited by what the market is allowed to dispatch, and AEMO enforces that through constraint equations that often bind well before any individual asset reaches its physical limit, because of a contingency somewhere else on the network, a parallel path that would overload if this one tripped, or a group of assets sharing one limit.

Constrained Headroom starts from Thermal Headroom and subtracts the reduction implied by the thermal constraints actually being enforced on that equipment.

Full derivation: Constrained Headroom

Marginal Value and Binding Hours

When a constraint binds, the NEM dispatch engine reports its Marginal Value: the shadow price, in dollars, of that limit. It’s the answer to “if this limit were relaxed by one megawatt, how much cheaper would this dispatch interval have been?” A large Marginal Value is the market’s own measure of how expensive a bottleneck is.

Is Binding records how much of the half hour at least one matched thermal constraint was actually binding, as a proportion from 0 to 1. Summed across periods it becomes Binding Hours: a simple way to rank the parts of the network that are constrained most often.

Full derivation: Marginal Value & Binding Hours

Common questions

Each metric page ends with its own questions. Some questions you might have:

Getting started

• Why does my project have no operational data at all?
• Why does Operational Insights data stop at the end of last month?
• Is this settlement data?
• Why does history start in January 2022?

Reading the numbers

• Why doesn’t this match the number I get from another source?
• Is a low output day the same as curtailment?
• Why is revenue negative?
• Why is Missed Revenue zero when curtailment was high?
• Why do both flow directions have values in the same half hour?
• Why is Thermal Headroom higher than Constrained Headroom?
• Why does my reconciliation come out half an interval off?

Gaps and blanks

• Why is Generation populated but Curtailment is blank?
• Why does that line have no operational data at all?
• Why is Marginal Value zero when the line looks full?
• What about projects in Western Australia?

Using it for a decision

• Can I treat Thermal Headroom as available capacity for a new project?
• Can I use Constrained Headroom to size a new connection?
• Does this include PPA revenue, FCAS or LGCs?
• How do I compare congestion between two lines?

If your question isn’t covered, please get in touch.