AAA puts the national diesel average at a record $6.06 per gallon, up about 63% from $3.71 a year ago.

Tesla Inc. (TSLA  ) could add roughly $80 billion in value from its Semi business, Morgan Stanley says, as U.S. diesel prices hit a record $6.06 per gallon. Analyst Andrew Percoco says the bigger prize may eventually come from autonomy, with Tesla potentially charging fleets as much as $18,000 a month per truck for self-driving software.

Morgan Stanley Sees $17 Billion Software Business

Percoco put diesel front and center in his Friday note: "$6 Diesel...Enter Tesla Semi."

Morgan Stanley estimates Tesla could have 82,000 Semis on the road by 2040, generating roughly $17 billion in software revenue and $7.5 billion in earnings before interest and taxes.

Tesla could charge $12,000 to $18,000 per month for autonomous software on each truck, or about $0.85 to $1 per mile.

That opportunity adds $20 per share to Morgan Stanley's Tesla bull case, equivalent to roughly $80 billion in market value. Percoco raised his bull-case target to $840, while keeping an Equal-Weight rating and $400 base-case target.

Tesla is trading at $366 at time of writing.

$6 Diesel Changes the Math

Morgan Stanley estimates autonomous trucks could cut fleet costs by roughly 20%, largely through lower labor, fuel and insurance expenses.