Tesla says this is how its North American network for quick-charge stations will look by the end of next year. Tesla offers free charging at these stations for Model S owners. Tesla

South Korean automaker Hyundai is hoping to see more U.S. investment in hydrogen fuel infrastructure, but one of its top executives may have gone too far in suggesting electric carmaker Tesla took taxpayer money to help build its quick-charge network.

Michael O'Brien, Hyundai Motor Co. (KRX:005380) vice president for U.S. product planning, told Green Car Reports a lot of the money invested in Tesla’s Supercharger network came from government “grants and loans.”

Green Car senior editor John Voelker reached out to Diarmuid O'Connell, Tesla Motors Inc. (NASDAQ:TSLA) vice president for business development, for a response.

"I am furious at any allegation that any public money was spent on the Supercharger network," he told Voelker. "Those sites have been paid for entirely by Tesla Motors -- which continues to spend money on expanding the network."

The Hyundai executive was referring to a Department of Energy program from which Tesla received a $465 million government loan in 2010 during an important phase in Tesla’s business development. At the time, Tesla was still a largely unknown private manufacturer of a two-seat electric “geek’s plaything” roadster. It would be six months before the company listed stock on the NASDAQ and two more years before the rollout of the critically acclaimed Model S luxury sedan.

The government loan was a much needed injection of capital at the time, but it’s a stretch to suggest the money helped with the current ongoing development of Tesla’s Supercharger network, which in June reportedly delivered a record one gigawatt of electricity to U.S. Model S owners.

Tesla will soon announce the date of its second quarter earnings release, expected early next month. Analysts polled by Thomson Reuters expect the Palo Alto car company to squeeze out $3.4 million in profit on $810.6 million in revenue. Adjusted earnings per share are expected to be down 11 cents due to heavy global investment, a large part of which is building out the company’s quick-charge network in the United States, Europe and China.

Like Toyota Motor Corp. (NYSE:TMC) and Honda Motor Co. Ltd. (NYSE:HMC), Hyundai says hydrogen fuel cell technology has potential for wider adoption. Hyundai recently began offering a hydrogen fuel cell version of its Tucson SUV under a lease program in Southern California, which has enough hydrogen fueling outlets to support consumer use.

O'Brien’s controversial remark was related to the need for more investment in hydrogen fueling infrastructure for the technology to become mainstream. The investment, however, must come from somewhere besides the automakers, be it public or private.

Tesla CEO Elon Musk has criticized efforts to use the technology for mass produced automobiles.