Elon Musk, Tesla CEO, called fellow billionaire Bill Gates "clueless" in reply to a question posted on Twitter over the weekend.

Someone with the handle Richard Reina asked Elon Musk his opinion on Gates' declaration referring to electric trucks. And Musk replied that "he has no clue," thus continuing the bickering between the two billionaire geniuses.

Gates, Microsoft co-founder, had cast doubts on the viability of electric trucks, according to a report on CNN.

In his blog post in August, Gates had explained that he was doubtful about the potential of electric vehicles as long-haul vehicles because they would need big and heavy batteries.

Gates, who is also a philanthropist, wrote that even with the big breakthrough in battery technology, electric vehicles might not be a practical solution for vehicles like 18-wheelers, passenger jets, and cargo ships.

He added that electricity works in covering short distances, but electricity will not be a solution for heavy and long-haul vehicles.

Gates said the problem with using electricity as a viable option is that batteries are big and heavy, and more batteries will be needed to power a vehicle that is carrying more weight. He noted that batteries would add to the weight, according to an article on GeekWire.

Elon Musk's Tesla had revealed the Cybertruck, its new electric pickup, last year, as well as the Tri Motor All-Wheel-Drive, the more expensive version of the truck. Tesla said the production for the Cybertruck would start in 2021 and 2022 for the Tri Motor AWD.

Gates added in his blog post that biofuels would be more of a viable solution for commercial vehicles. The philanthropist then credited legacy automakers GM and Ford, and new car makers Rivian and Bolinger for producing all-electric pickup trucks. Tesla, however, was not included.

This was not the first time that the two billionaires have butted heads. Earlier this year, Elon Musk said that a conversation with Gates is underwhelming. This after Gates had said that he bought an electric Porsche Taycan instead of a Tesla. 

Gates also did not appreciate the comments of Musk regarding the COVID-19 pandemic. The Microsoft CEO had called them outrageous, according to a report on Business Insider

Gates made the comments when he guested on CNBC's Squawk Box. He had said that Musk should stick to his area of expertise instead of spreading falsehood regarding the COVID-19.

Aside from spreading falsehood about the pandemic, Musk had also expressed doubt on the severity of COVID-19 in the U.S., even while cases were starting to rise.

He said on social media that the figures are messed up by a lot of COVID-19 false positives.

He added that tests with only five percent false positive rate would add up to the million fake COVID-19 cases, even when there is actually none.

Gates then said that Musk is great at making electric cars and rockets, but he is not involved in making vaccines. 

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