GRIDRA

Tool

EV Charging Capacity Planner

Check whether a building's grid connection can support a planned EV charging installation — with and without dynamic load management.

Einfach erklärt

Ein Rechner, der eine Frage beantwortet: Wenn ich so viele EV-Ladepunkte installiere, reicht dann mein Netzanschluss aus? Er vergleicht die mögliche Gesamtleistung deiner Ladepunkte mit dem, was von deinem Anschluss nach dem normalen Verbrauch noch übrig bleibt — einmal angenommen, alle laden gleichzeitig, und einmal mit intelligenter Software, die die verfügbare Leistung automatisch aufteilt, damit nichts überlastet wird.

Scenarios

Saved on this device only — not synced anywhere yet.

Site & installation

01 / input

Sets typical starting values below — edit anything to match your actual site.


kVA

Contracted / metered connection rating. Converted to kW at cos φ = 0.95 (adjustable below).

kW

Non-EV peak demand already on the connection. Use a measured 15-minute maximum or a conservative design demand — not an average consumption figure, which can hide real peaks.


count

Dynamic load management

Actively caps total EV draw to available headroom


Advanced assumptions

ratio
kW / point

Lowest power a controlled point needs to be practically useful — depends on EVSE minimum current, phase setup and vehicle onboard chargers. Default ~1.4 kW assumes single-phase, ~6 A (IEC 61851).

Fits — with load management

Unmanaged, this installation would exceed the connection by 20.7 kW. Dynamic load management keeps every charging point powered within the existing 238 kW connection.

Indicative estimate. The simultaneity curve below is calibrated to residential, 11 kW domestic charging behavior. This site profile likely has a different real coincidence pattern — treat results as a rough guide, not a site-specific model.

Load vs. capacity

02 / readout
0 kW266 kW
CAPACITY
Baseline load EV charging load

Connection capacity

237.5 kW

Available headroom

117.5 kW

Projected EV load

117.5 kW

Total projected load

237.5 kW

Capacity utilization

100%

Active points

50 of 50

Power per active point

2.4 kW

All 50 charging points stay active at the same time — none need to queue — but since there isn't enough headroom to give everyone the full 11.0 kW rating at once, the system shares it fairly: roughly 2.4 kW per point rather than each one's full rating. The real split depends on EVSE minimum current, phase configuration, and vehicle onboard chargers.

Simultaneity factor

03 / model

Not every charger draws full rated power at once. g(n) is the share of combined rated power actually seen on the connection as the number of charging points n grows — the curve this planner uses for the unmanaged estimate above.

0.000.250.500.751.001102030405060

How the numbers are built: connection capacity (kVA) is converted to kW using the power factor set above (cos φ = 0.95). The unmanaged EV load applies the coincidence-factor curve cf(n) = 115.98%/n0.442 + 4.55%, the published Table IV fit for the 24 kWh / 11 kW domestic base scenario in “Coincidence Factors for Domestic EV Charging From Driving and Plug-In Behavior”, IEEE Transactions on Transportation Electrification, 2022 (DTU) — used exactly as reported, not re-fit. That formula itself exceeds 100% for a single EV, which is physically impossible since a coincidence factor is bounded at 1.0 by definition; we clamp to 100% there, and the paper itself flags this small-n regime as behaving differently from the ~50-unit scale the study is built around. The curve was measured for domestic/home charging at 11 kW specifically — applying it to other charger ratings or non-residential profiles (flagged above when selected) is a simplification; a production tool would want separate fitted curves per context and power level, ideally from GRIDRA's own metered data. The managed scenario models an active load-management system that caps total simultaneous EV draw to the available headroom, treating each active point as needing at least the minimum controlled charging power set above to be practically useful — the real value depends on EVSE hardware, phase configuration and vehicle onboard chargers. This is in the spirit of the kind of controllable-load setup required under Germany's §14a EnWG for many new charging installations, though site-level dynamic load management and DSO-level control under §14a are related but distinct control layers — this tool models the former only.