If you use SP Services, you will be paid at the standard electricity tariff rate minus grid charges (~25% of the cost of electricity) which would be around S$0.21/kWh in Q2 2022, where retail electricity tariff is S$0.2794/kWh. If you are with an Open Electricity Market (OEM) retailer, the price that you will be able to sell the excess energy generated by your solar panel system at will be based on the Wholesale Uniform Singapore Energy Price (USEP). USEP rates are determined half-hourly and fluctuate widely but across 2021 has averaged S$0.1963/kWh.