Belconnen Depot, Canberra: Proving a Fleet Fits Before Committing to Grid Upgrades

The Problem

Canberra's transit authority set out to electrify the Belconnen depot's 85-bus fleet and needed a hard answer to a simple-sounding question: on the coldest winter morning, with every bus back at the depot and needing to charge, does the electrical service hold?

Winter matters here in a way summer never does. Cold weather cuts battery range, adds heating load, and compresses the usable charging window, all at once, on exactly the days when transit service can least afford a shortfall. A depot sized on a mild-day estimate is a depot that fails on the one day it actually gets tested.

How the Depot Digital Twin Was Used

Step 1: Build the fleet against real hardware. All 85 buses were modeled with their actual battery capacity and a fleet of 300 kW DC fast chargers (the exact charging infrastructure spec the depot planned to install) rather than a generic placeholder.

Step 2: Run the worst-plausible winter day, not an average one. The simulation doesn't ask "what does a typical night look like"; it asks "what does the worst night look like, with every vehicle present and full cold-weather derating applied." That's the day a depot actually has to survive.

Step 3: Read the answer straight off the spare-capacity ledger:


Service capacity (nameplate)	3,000 kW
Modeled charging peak (worst day)	2,100 kW
Spare after charging	900 kW

Step 4: Watch the peak build on the interactive load-profile timeline. The 24-hour chart shows managed charging ramping up as buses return through the evening and tapering as they depart the next morning, with a scrub bar that lets a planner step through the night minute by minute and see exactly how much headroom remains at any point.

Belconnen Depot 24-hour load profile: managed charging peaks at 2,100 kW through the evening

Step 5: Confirm every node in the electrical chain holds. The per-node view checks the service entry and downstream circuit against the modeled peak side by side: both comfortably under their rated capacity, with margin to spare.

Step 6: Open the storage business case for the next question. With headroom already confirmed, the Storage module is where Belconnen's planners go next: modeling whether an on-site battery could bank even more margin against future fleet growth, priced against a directional demand-charge rate. A "what if we grow" lever sitting one click away from "are we safe today."

The Result

The Depot Digital Twin modeled Belconnen's managed winter peak at 2,100 kW against a 3,000 kW service, a comfortable 900 kW of spare capacity, confirmed node-by-node across the depot's full electrical chain. The peak lands consistent with the published academic benchmark for this exact depot (Hendriks & Sturmberg, 2024, npj Sustainable Mobility and Transport), which models the same fleet's worst-case morning in the 3 MW range before any load management is applied, validating that Belconnen's charge-management strategy is doing real, measurable work to keep the depot inside its service envelope.

Why It Matters

"900 kW of spare capacity on the coldest morning of the year is the number that lets a transit authority sign off on an 85-bus conversion with confidence, not hope."

For a public transit authority answering to a city council and a ratepayer base, that's not just a planning number; it's the evidence that turns an electrification proposal into an approved capital project.