A business bill may charge for more than energy
If your business bill includes a demand charge, a solar assessment should first separate reducing energy purchases from reducing the maximum power drawn from the grid. These items use different data, so a percentage reduction in energy should not automatically be applied to peak-demand charges. This article explains how to prepare an assessment for accounts that have this charge. It does not mean every customer category pays the same charges, and it is not a bill calculation for a particular business.
Check the tariff before interpreting a peak
PEA's January 2023 tariff document lists demand charges in baht per kilowatt separately from energy charges and uses average demand over 15-minute intervals in relevant provisions. Check the actual account's tariff category, supply voltage and conditions with the electricity provider. Do not automatically substitute an instantaneous maximum displayed in an app for the value used in billing. A current assessment must reconfirm the rates and rules applicable to the relevant billing period. This article does not quote current unit prices or the Ft charge.
Solar can reduce one interval while the maximum occurs elsewhere
Consider a hypothetical business without batteries. At noon, average building demand is 80 kW and solar supplies 30 kW to the load, leaving 50 kW drawn from the grid. During another interval relevant to the demand assessment, the building draws 75 kW when solar is not generating. If both intervals fall under the same measurement conditions, the noon value of 50 is still not the period's maximum. This example explains why all relevant intervals matter; it is not a formula for the actual charge or savings.
Match the timing on both sides
Useful records include bills identifying the tariff, time-stamped power-demand data at the grid connection, and solar reports covering matching intervals. If only monthly kWh totals are available, record the limitation: they do not show when the peak occurred. Note known operating times of major equipment, holidays and unusual business events. Distinguish metered values from estimates, and ask the report provider what averaging interval each column uses so that incompatible data are not compared.
Test scenarios before judging the investment
Ask the assessor to show at least a case where solar generation coincides with peak demand and a case where the peak still occurs during low generation, identifying the changed assumptions. Any proposal to reschedule equipment or add hardware needs a separate review of production effects, safety and costs. Do not stop or switch industrial equipment yourself based on a chart in pursuit of a lower bill. Energy savings may still be useful even when demand charges do not fall as much, but each component should be shown transparently.
Give the design team questions grounded in real data
When discussing a solar system with Kintury Energy, prepare bills, available peak-demand data and the business operating schedule. Ask whether the proposal separates benefits from energy and demand charges, which periods it uses and what further measurements are needed. If only bills are available, start by confirming the items and how to obtain data from the electricity provider. Do not assume more panels always reduce peak charges proportionally. The aim is a proposal whose assumptions and limits can be explained.
