Charging Revenue, Retail. Charging revenue, retail, for the six months ended June 30, 2024 increased $25.0 million, or 159%, to $40.7 million compared to $15.7 million for the six months ended June 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.
Charging Revenue, Commercial. Charging revenue, commercial, for the six months ended June 30, 2024 increased $8.8 million, or 213%, to $12.9 million compared to $4.1 million for the six months ended June 30, 2023. Period-over-period growth was primarily due to higher charging volumes by the Company’s public fleet customers.
Charging Revenue, OEM. Charging revenue, OEM, for the six months ended June 30, 2024 increased $4.8 million, or 314%, to $6.4 million compared to $1.5 million for the six months ended June 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 six months ended June 30, 2024 increased $1.0 million, or 34%, to $3.8 million compared to $2.8 million for the six months ended June 30, 2023 due to the impact of increased throughput, partially offset by decreased market prices.
Network Revenue, OEM. Network revenue, OEM, for the six months ended June 30, 2024 increased $1.6 million, or 47%, to $5.1 million compared to $3.4 million for the six months ended June 30, 2023. The period-over-period increase was primarily due to increased marketing activities and membership fees from OEM customers.
eXtend Revenue. eXtend revenue for the six months ended June 30, 2024 increased $3.2 million, or 7%, to $46.8 million compared to $43.6 million for the six months ended June 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 six months ended June 30, 2024 increased $1.5 million, or 33%, to $6.2 million compared to $4.6 million for the six months ended June 30, 2023. The increase was primarily due to increased revenue from engineering and construction, equipment sales, and licensing, partially offset by decreased revenue from advertising.
Cost of Sales
Charging Network. Charging network cost of sales for the six months ended June 30, 2024 increased $21.5 million, or 98%, to $43.5 million compared to $22.0 million for the six months ended June 30, 2023. The increase in charging network cost was primarily due to a $15.0 million increase in usage-related energy costs resulting from increased throughput and a $6.5 million increase in fixed charging costs.
Other. Other cost of sales for the six months ended June 30, 2024 increased $8.9 million, or 26%, to $43.5 million compared to $34.7 million for the six months ended June 30, 2023. The increase in other cost of sales was primarily due to an increase of $7.3 million in costs to support eXtend revenue and an increase of $1.2 million in costs to support ancillary revenue.
Depreciation, Net of Capital-Build Amortization. Depreciation, net of capital-build amortization, for the six months ended June 30, 2024 increased $7.9 million, or 58%, to $21.5 million compared to $13.6 million for the six months ended June 30, 2023 due to the growth of EVgo’s charging network.
Gross Profit and Gross Margin
Gross profit for the six months ended June 30, 2024 increased to $13.2 million compared to $5.6 million for the six months ended June 30, 2023 primarily due to increased gross profit from charging revenues, partially offset by increased depreciation, net of capital-build amortization. Gross margin for the six months ended June 30, 2024 was 10.9% compared to 7.3% for the six months ended June 30, 2023 primarily due to higher margins on charging revenue resulting from improved leveraging of charging station costs, partially offset by lower margins from eXtend revenues resulting in a mix