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Variable Frame: Why it matters, and when to use it ​

Variable frame length lets you change the modelling time step used by a scenario. By default, most projects run at half-hourly, but some systems change quickly enough that you may want to run at 5 minutes, 2 minutes, or anything in between.

This tutorial focuses on the benefits of variable frame lengths and a simple workflow for proving whether it is worth using.

When variable frame is useful ​

Variable frame is most valuable when you are trying to understand behaviour that happens “inside” a half-hour, for example:

  • Short spikes in demand or generation.
  • Dispatch and control actions that trigger on thresholds (operational criteria).
  • Start/stop behaviour, ramping, and minimum run-times (common in engines and turbines).
  • Maintenance events where you care about the exact time a shutdown starts, ends, and what it interrupts.

If your scenario is mostly long, smooth trends (monthly reporting, annual energy totals, broad financial comparisons), a longer frame is usually enough.

Build a baseline scenario at 30 minutes ​

Create (or copy) a scenario and keep the default Frame Length at 30 minutes.

Run the scenario and use:

  • Reports for the high-level totals.
  • Headroom (if relevant) to understand import/export constraints and curtailment risk.
  • Detail View to find the periods that look “interesting” (shutdowns, clipping, unmet demand, unusual cycling).

The goal here is to identify where higher resolution would add insight.

Identify a “problem period” in Detail View ​

Open Detail View and select a short date range that contains the behaviour you want to study (a couple of days is usually enough).

Examples of what to look for:

  • A recurring dip where demand is not met.
  • Battery behaviour that looks too “blocky” or delayed.
  • A generator that appears to start and stop too aggressively.
  • Heat supply that doesn’t line up with heat demand when you expect it to.

Detail View is where variable frame pays off most, because the plots are rendered at the model time step.

Create a high-resolution copy of the scenario ​

Copy the scenario so you can compare outputs cleanly.

In the copied scenario, change the Frame Length to something shorter (for example 10 minutes, 5 minutes, or 2 minutes). Then re-run.

What you are doing here is not “making the model better” by default—you are checking whether the extra resolution changes conclusions.

Compare the benefits you get from the shorter frame ​

1) More granular control of operational criteria ​

Operational criteria are evaluated on the modelling frame. A shorter frame means:

  • Thresholds can be crossed and reacted to sooner.
  • Competing criteria are resolved more frequently.
  • Fast changes (especially around setpoints) are captured instead of being averaged into a single half-hour outcome.

If you are using criteria to dispatch batteries, engines, heat sources, or exports, this is often the biggest practical benefit.

2) Loads and short events behave more realistically ​

If demand or generation has short spikes, a 30-minute frame can hide them by averaging. A shorter frame lets the model “see” the spike, which can change:

  • Peak import/export requirements.
  • Curtailment.
  • Unmet demand events.
  • Apparent battery power limits and cycling patterns.

3) Maintenance timing becomes clearer ​

Maintenance and downtime interact with operation on the frame boundary. Shorter frames make it easier to see:

  • Exactly when an installation is unavailable.
  • What demand or export opportunity it interrupts.
  • Whether maintenance causes a cascade effect (e.g. battery covers the gap, or unmet demand appears).

4) Detail View becomes genuinely “high-resolution” ​

Detail View is a diagnostic tool. With a shorter frame length, the plots become more readable for fast behaviour:

  • Starts/stops are clearer.
  • Charging/discharging looks less “stepped”.
  • You can pinpoint the moment an operational rule triggers.

If you are using Detail View to explain performance to stakeholders, variable frame can make the story much easier to defend.

Understand what happens to mismatched data ​

Most users won’t have raw data available at 2–5 minute intervals. That is fine: when your input data is at a different time step to the model, it is step-wise interpolated onto the model timeline (values are held until the next data point).

Practical implication:

  • Variable frame improves the simulation resolution, but it does not magically create higher-frequency measurement data.
  • You get the most benefit when either (a) your inputs are already high frequency, or (b) the dynamics you care about come from operational logic, constraints, and equipment behaviour rather than the raw dataset itself.

Quick decision guide ​

Use a shorter frame when you are:

  • Tuning operational criteria.
  • Investigating cycling, dispatch, or fast constraints.
  • Using Detail View to debug performance.
  • Modelling systems where ramping/min runtimes matter.

Stick to 30 minutes when you are:

  • Comparing broad annual totals across many sensitivities.
  • Focused on monthly/yearly reporting rather than short-term dynamics.
  • Not seeing any “timing” issues in Detail View.

Suggested workflow for best results ​

  1. Run at 30 minutes to find the issue.
  2. Use Detail View to isolate a representative period.
  3. Copy scenario → run at 5–2 minutes.
  4. Confirm whether conclusions change (not just the shape of graphs).
  5. Keep the shortest frame that gives you the insight you need.