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Aerial view of rows of photovoltaic modules at a large solar farm

Stage 7 of 13 / Calculation

Dispatch the system hour by hour

Run a rule-based hourly dispatch and read self-consumption, self-sufficiency, curtailment and unserved energy.

  • Practitioner
  • 13 stages
  • 14 min
  • Solar PV and electrical storage
Development preview Solar PV and Battery: Full Engineering Workbench
Development preview. The calculations on this journey run on existing EngiMetric engines, but the journey text and scope have not completed independent engineering review. The route is excluded from search while it remains a preview.
Professional review required.The engines are implemented and unit-tested in this repository, but the journey copy, defaults and boundary still require review by a licensed engineer before publication. The route remains a noindex preview. Current verification state: Needs engineering review.

After this stage you can

Learning objectives
  • Explain the dispatch order and why it changes self-consumption.
  • Read the hourly balance and identify surplus, deficit and outage hours.
  • Distinguish unserved energy from curtailment.

The engineering

Dispatch is where the components meet. PV serves load first, surplus charges the battery, then exports or curtails. A deficit comes from the battery down to its reserve, then from the grid, and only then becomes unserved energy. The order matters, and the workbench states it.

The model enforces an energy balance every hour. If PV plus discharge plus import plus unserved does not equal load plus charge plus export plus curtail, the run is wrong and the report says so. That invariant is tested rather than assumed.

Three strategies are available: self-consumption, backup-priority and time-of-use. Grid charging is an explicit choice, not a hidden default. The schedule of outages is a user-defined stress case, not a probabilistic reliability model.

EngiMetric / solar workbench

Your project, computed stage by stage

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Preview screen. Inputs are saved in this browser only. Resource presets and tariffs are illustrative. Failed checks stay visible; a clean summary is not a stamped design.

Inputs and outputs

What this stage owns

You own

  • Hourly PV and load series
  • Battery usable energy, power, reserve and efficiencies
  • Grid availability schedule and import/export limits
  • Strategy, cheap/expensive hours and grid-charge permission

You produce

  • Annual import, export, charge, discharge, curtailment and unserved energy
  • Self-consumption and self-sufficiency percentages
  • SOC range, equivalent cycles and an energy-balance pass/fail

Your deliverable for this stage

Capstone evidence

A dispatch summary with the balance check, self-consumption/sufficiency and a SOC trace.

Stage assumptions, limits and sources

Provenance

Assumptions

  • One-hour intervals with no intra-hour dynamics.
  • The dispatch policy has no foresight of tomorrow's weather or tariff.
  • Battery efficiency is constant and applied one way on charge and discharge.

Constraints

  • No minimum up/down time, ramp limit, frequency response or grid-code constraint.
  • No dynamic export control or curtailment instruction from a network operator.

Limitations

  • Unserved energy is an energy shortfall, not a statement of which loads were lost.
  • No thermal management or auxiliary consumption.
  • Outages are scheduled, not sampled from a reliability model.

Review status

  • Needs engineering review
  • Professional review is required before publication or use as a design basis.

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Stage kind: Calculation / Journey: solar-bess-screening / Stage: dispatch