Tesla shares could reach $50 in 3 years-analyst

* Tesla shares rise more than 7 percent

* Tesla's costs lower than most luxury automakers

* Model S on track for mid-2012 customer delivery

DETROIT, Jan 24 (Reuters) - Shares of electric carmaker Tesla Motors Inc (TSLA.O) could double to $50 over the next three years, a JPMorgan analyst wrote on Monday, and the stock rose more than 7 percent.

"We continue to believe the majority of the investment community (and the majority of the automotive industry) is substantially underrating Tesla's potential," analyst Himanshu Patel wrote in a research note.

Patel said Tesla shares could reach $40 to $50 in the next three years as the company could eventually become a premium automaker with a full line of vehicles and with a lower cost structure than its rivals.

He noted that Tesla's operating margins could be on par with German luxury carmakers of as much as 9 percent.

Tesla is planning to launch its Model S sedan in mid-2012. Assuming no delays, the company is on track to start full commercial production by the second quarter of 2012, suggesting it will meet its deadline, Patel said.

After the Model S, Tesla's next focus will be a crossover known internally as "Model X," which will be built on the same platform as the Model S.

While other automakers such as Ford Motor Co (F.N) are paring back their various vehicle platforms to cut expenses, Tesla does not have such legacy costs. Instead, the automaker is developing its models on a single platform.

This suggests that future variants on the Model S platform "may be considerably more profitable than what is typical" for most automakers, Patel wrote in the note.

But a delay in Model S manufacturing would be a risk to JPMorgan's "overweight" rating on Tesla shares. Other risks include rival offerings from established luxury automakers such as Volkswagen's Audi (VOWG_p.DE), which will launch an electric sports car in 2012.

Tesla shares rose 7.1 percent to $24.67 in afternoon Nasdaq trading. (Reporting by Deepa Seetharaman; Editing by Lisa Von Ahn)