Tesla (NASDAQ:TSLA) was up against some significant headwinds last year. Not only did the automaker face tough year-ago comparisons when soaring Model 3 deliveries led to 50% growth in vehicle deliveries, but it had to pause manufacturing in the spring of 2020 as it dealt with lockdowns related to COVID-19. Yet the electric-car maker still managed to grow vehicle deliveries 36% for the year.

Though Tesla's 2020 performance was impressive, it might look modest in comparison to the automaker's 2021 sales. The current consensus estimate for Tesla's vehicle deliveries this year is 850,000 units, up from about 500,000 in 2020. Indeed, one of the most recent analyst forecasts calls for 929,000 deliveries this year, which would mark growth of more than 85% year over year. 

Tesla's Models S, X, 3, and Y lined up on a road with mountains in the background.

Models S, X, 3, and Y. Image source: Tesla.https://ts.la/TeslaPressKit

Why deliveries should skyrocket

It's not too surprising to see analysts so bullish on Tesla's deliveries in 2021. The automaker has been making remarkable progress on expanding its production capacity. Going into 2020, Tesla had installed tooling at its factories for annualized production capacity of 640,000 units. By the end of the year, Tesla's installed annualized production capacity had reached 1.05 million vehicles.

Yet even these figures don't fully capture Tesla's manufacturing momentum. The company also had two production lines under construction at the end of the year -- a Model Y production line at its new factory in Berlin, Germany, and another one at its new factory in Texas. Tesla said in its fourth-quarter update that it expects to begin vehicle production at these new factories this year.

What to watch

Fortunately, Tesla investors will soon get better insight into whether analysts' optimistic outlook for the automaker's deliveries is realistic. The company will release its first-quarter financial results on April 26. Tesla's updates usually provide insight into recent delivery trends, demand, and more.

We already know Tesla kicked off the year with strong first-quarter deliveries, as it announced its quarterly deliveries ahead of its earnings report. Tesla delivered approximately 185,000 vehicles, up 109% year over year. However, other information in the earnings report should still be helpful to investors when assessing the company's growth potential. First and foremost, investors should look for any commentary from management on demand for its vehicles. Obviously, Tesla needs more than strong growth in production; it needs similarly high levels of demand, too.

In addition, investors can look to see if Tesla provides an updated view for its deliveries this year. So far, the automaker has only said that it expects total 2021 deliveries to increase more than 50% compared to 2020 deliveries.

Tesla will report its first-quarter results after market close on Monday, April 26.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.