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Commercial Solar PV, Battery Storage & EV Fleet Sizer

Integrate onsite renewable generation and battery storage (BESS) to charge electric vehicle fleets without exceeding agreed network import or export capacities. This tool sizes the battery buffer, determines your statutory DNO connection pathway (G98 vs G99), and models ENA EREC G100 export limitation failsafe timing.

DNO Regulatory Gate: Systems with aggregate generation exceeding 16A per phase (3.68 kW 1-ph / 11.04 kW 3-ph) require formal G99 prior approval before commissioning. ENA G100 schemes must achieve failsafe curtailment within 5.0 seconds.

1. Solar PV & Grid ConnectionSupply Phase ConfigurationSolar PV Array Peak Capacity (kWp)Total installed DC nameplate capacity of the solar array.DNO Agreed Maximum Export Capacity (kW)Set to 0 kW for strict zero-export limitation sites.

2. Battery Storage System (BESS)Battery Usable Storage Capacity (kWh)Depth of discharge adjusted usable energy (typically 90% of nominal).Battery Inverter Continuous Rating (kW)Maximum continuous discharge power into the building AC switchboard.

3. EV Fleet Charging ProfileTotal Daily EV Fleet Energy Demand (kWh/day)Combined daily battery recharge requirement across all fleet vans/cars.Peak EV Simultaneous Charging Demand (kW)Unconstrained charging load (e.g. 6 × 7.4 kW = 44.4 kW).

System Sizing & Compliance

Statutory DNO Connection PathwayCALCULATING...

Total Peak Inverter Generation--

Full Output Phase Current--

ENA G100 Export Scheme Status--

Solar & Storage Synergy

EV Fleet Solar Self-Consumption--

Average Daily Solar Generation--

Peak Shaving Buffer Effect--

Residual Grid Fleet Import--

Evaluating regulatory classification...

ENA EREC G98, G99 & G100 Export Formulation

ENA EREC G98, ENA EREC G99 & ENA EREC G100 Issue 2

AM2 PORTFOLIO & DESIGN AUDIT FORMATTRANSPARENT FIRST-PRINCIPLES MATHS

Scenario: 400V 3-phase commercial supply, 50 kWp Solar PV, 30 kW / 60 kWh BESS battery, 15 kW agreed DNO export limit, EV fleet requiring 180 kWh/day with 44 kW unconstrained peak:

Total Inverter Capacity: Solar Inverter (50 kW) + BESS Inverter (30 kW) = 80 kW total connected generation capacity (approx 115 A per phase).
DNO Classification: Since 80 kW (115 A/ph) exceeds the 11.04 kW (16 A/ph) de-minimis threshold, ENA EREC G99 Standard Application (Form A2) applies. Prior written DNO consent is mandatory before energisation.
ENA G100 Compliance: Because generation (80 kW) exceeds the 15 kW export limit, a certified ENA G100 Export Limitation Scheme with CT monitoring and 5.0 s failsafe isolation must be specified.
Daily Energy Balance: At 3.2 peak sun hours (UK average), the 50 kWp array produces approx 160 kWh/day. Paired with the 60 kWh battery to buffer morning and evening charging peaks, 85%+ of EV charging energy is covered onsite by clean solar.

DNO Fast-Track Note (ENA EREC G99 Section 6.2): If the combined capacity of solar and battery storage is restricted so that simultaneous export can never exceed the export limitation threshold, certain DNOs offer streamlined assessment under Fast-Track Form A1-2.

Statutory Standards: ENA EREC G98 Issue 1 • ENA EREC G99 Issue 1 Amd 9 • ENA EREC G100 Issue 2 • BS 7671:2018+A3