Charging Revenue, Retail. Charging revenue, retail, for the three months ended September 30, 2024 increased $13.3 million, or 100%, to $26.7 million compared to $13.4 million for the three months ended September 30, 2023. Period-over-period growth was primarily due to an overall increase in throughput driven primarily by increased charging volume from a greater number of customers and more throughput per customer and, to a lesser extent, price increases.
Charging Revenue, Commercial. Charging revenue, commercial, for the three months ended September 30, 2024 increased $4.6 million, or 113%, to $8.6 million compared to $4.0 million for the three months ended September 30, 2023. Period-over-period growth was primarily due to higher charging volumes by the Company’s public fleet customers and, to a lesser extent, price increases.
Charging Revenue, OEM. Charging revenue, OEM, for the three months ended September 30, 2024 increased $2.8 million, or 191%, to $4.3 million compared to $1.5 million for the three months ended September 30, 2023. Period-over-period growth was primarily due to an increase in active OEM customers and increased throughput per customer.
Regulatory Credit Sales. Regulatory credit sales for the three months ended September 30, 2024 increased $0.4 million, or 21%, to $2.2 million compared to $1.8 million for the three months ended September 30, 2023 due to the impact of increased throughput, partially offset by decreased market prices.
Network Revenue, OEM. Network revenue, OEM, for the three months ended September 30, 2024 increased $0.2 million, or 15%, to $1.3 million compared to $1.1 million for the three months ended September 30, 2023. The period-over-period increase was due to increased marketing activities and membership fees from OEM customers, partially offset by decreased breakage.
eXtend Revenue. eXtend revenue for the three months ended September 30, 2024 increased $11.4 million, or 109%, to $21.9 million compared to $10.5 million for the three months ended September 30, 2023. The increase was primarily due to an increase in construction projects in process or completed, partially offset by decreased equipment sales, compared to the same prior-year period.
Ancillary Revenue. Ancillary revenue for the three months ended September 30, 2024 decreased $0.3 million, or 9%, to $2.6 million compared to $2.8 million for the three months ended September 30, 2023. The decrease was primarily due to decreased engineering and construction services.
Cost of Sales
Charging Network. Charging network cost of sales for the three months ended September 30, 2024 increased $13.3 million, or 86%, to $28.9 million compared to $15.6 million for the three months ended September 30, 2023. The increase in charging network cost was primarily due to a $9.0 million increase in usage-related energy costs resulting from increased throughput and a $4.3 million increase in non-energy charging costs.
Other. Other cost of sales for the three months ended September 30, 2024 increased $10.4 million, or 101%, to $20.8 million compared to $10.3 million for the three months ended September 30, 2023. The increase in other cost of sales was primarily due to an increase in costs related to eXtend, partially offset by a decrease of $0.4 million in costs related to ancillary revenue.
Depreciation, Net of Capital-Build Amortization. Depreciation, net of capital-build amortization, for the three months ended September 30, 2024 increased $2.9 million, or 34%, to $11.5 million compared to $8.6 million for the three months ended September 30, 2023 due to the growth of EVgo’s charging network.
Gross Profit and Gross Margin
Gross profit for the three months ended September 30, 2024 increased to $6.4 million compared to $0.6 million for the three months ended September 30, 2023 primarily due to increased gross profit from charging revenues and eXtend revenue, partially offset by increased depreciation, net of capital-build amortization. Gross margin for the three months ended September 30, 2024 was 9.4% compared to 1.7% for the three months ended September 30, 2023 primarily due to