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

Stage 8 of 13 / Decision

Decide the system architecture

Choose DC- or AC-coupled storage and a grid-tied, hybrid or off-grid boundary, and record why.

  • Practitioner
  • 13 stages
  • 10 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
  • Compare DC and AC coupling on losses, retrofit and backup.
  • Match the configuration to the site's reliability promise.
  • Record the chosen architecture and the rejected alternative.

The engineering

DC coupling shares the inverter between PV and battery; AC coupling gives the battery its own converter. The choice affects retrofit difficulty, conversion losses, backup behaviour and the ability to expand storage later. The workbench models the energy consequences of the configuration but does not auto-select an architecture.

A grid-tied system can export surplus; a hybrid system can also island critical loads; an off-grid system has no grid to absorb a deficit. Those are different reliability promises. The same PV and battery can look adequate in one boundary and fail in another.

Record the decision and its rejected alternative. A reviewer needs to see why the architecture was chosen, not only what was chosen. This stage is deliberately a decision, not another calculator.

EngiMetric / solar workbench

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Your deliverable for this stage

Capstone evidence

A one-paragraph architecture decision with the chosen configuration and the rejected alternative.

Stage assumptions, limits and sources

Provenance

Assumptions

  • The configuration drives the dispatch boundary and the economics context.
  • Coupling efficiency differences are represented through the stated round-trip efficiency.

Constraints

  • The workbench does not size converters for a specific coupling topology.
  • No automatic architecture optimisation is performed.

Limitations

  • No detailed converter efficiency map, standby loss or parallel-inverter design.
  • No utility interconnection or islanding protection study.

Review status

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

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Stage kind: Decision / Journey: solar-bess-screening / Stage: system-architecture