"The problem is that batteries are big and heavy," Gates wrote in a blog post in late August. "Even with big breakthroughs in battery technology, electric vehicles will probably never be a practical solution for things like 18-wheelers, cargo ships, and passenger jets. Electricity works when you need to cover short distances, but we need a different solution for heavy, long-haul vehicles."
Gates pointed to biofuels--rather than battery power--as a possible solution for commercial vehicles.
Musk has reportedly directed Tesla to ramp up production of the Semi, a commercial vehicle with a range of up to 500 miles, for its upcoming debut, Reuters reported in June. As of 2019, companies including Pepsi, FedEx, Walmart, UPS and Sysco had placed orders for Tesla Semis.
In his blog post, Gates also left Tesla out of a list of companies that have made breakthroughs in electric vehicle technology, even though Tesla has furiously promoted its yet-to-debut Cybertruck.
"[I]ncreased competition in the market means there are more choices available to customers than ever before, from compact sedans to sleek sports cars," Gates wrote. "You’ll even be able to buy an all-electric pick-up truck soon thanks to legacy companies like GM and Ford and new carmakers like Rivian and Bollinger."
The two billionaires do not always see eye to eye. Musk has repeatedly claimed that the coronavirus panic is overblown, while Gates has warned about the possibility of a world-changing pandemic for several years.
FOX Business' inquiry to Tesla was not immediately returned.
FOX Business' Jonathan Garber contributed to this report.