As Eskom applied for more than 20% increase in the tariff 2022 more businesses are looking at supplying their own power especially during the peak times as well as standard working hours.
A cost-saving can be achieved by using BESS (Battery energy storage system) and discharging it during peak hours (typically between 6 am and 10 am as well as 6 pm and 10 pm).
1) first peak tariff energy is provided by stored energy during the night with an additional PV in the first hours of the day, where PV on a good day provides up to 70% of the consumption and 30% comes from BESS.
2) Standard times 10 am-6 pm - the demand in the commercial and industrial space is higher and if the installed PV capacity is 30% more than the average load, the operation can be supplied completely by very low-cost Solar PV power and recharge the battery system with the excess PV instead of throttling or selling to the grid at a low rate.
3) Second peak tariff is in the evening hours when the battery is fully charged and covers the complete load until 10 p.m.
Depending on the State of Charge the battery can be topped up from the Grid at night when the off-peak tariff is available at a lower cost.
In the winter when the season changes to High Demand (typically the three winter months) the difference between off-peak and peak time becomes significantly higher.
In this case, the battery is charged fully at night and supplies most of the energy during the first peak tariff energy slot in the morning.