Many operators expect energy to be their main electricity cost. At high-power sites, the surprise is often the demand or fixed charge: a part of the bill based on the maximum power the site draws, or the contracted load, rather than the energy used.
How demand charges work
Commercial and high-tension electricity tariffs in India typically have two parts: an energy charge per kWh, and a fixed or demand charge based on contracted or maximum demand. Exact rules differ by state and connection type. If several high-power chargers run at full power at the same time, even briefly, the site may record a high maximum demand for the month, or need a higher contracted load.
Check your DISCOM's tariff order for how demand charges are calculated for your connection category. India's 2024 charging guidelines also set rules for EV charging tariffs, which your DISCOM applies.
What load management does
- Caps the site total: chargers share an agreed maximum, so the site never exceeds its contracted demand.
- Shares power intelligently: vehicles that can accept more power get it; nearly full vehicles get less.
- Uses building headroom: where chargers share a connection with a building, charging uses spare capacity in real time.
- Shaves peaks with storage: a battery can supply short bursts of power, so the grid connection sees a lower peak.
The effect on the business case
Without load management, a site may need a larger connection and pay higher fixed charges for capacity it uses only occasionally. With it, the same number of chargers can run on a smaller connection, while most drivers notice little difference in charging speed.
Getting it right
- Measure the existing building load before designing the charging site.
- Set the charging limit with a safety margin.
- Review the data after a few months and adjust limits as usage grows.
How PxT can help
PxT Energies designs load-managed sites and can add storage where it improves the economics. See also our guide to getting more chargers onto the same grid connection.