It's never too late to start investing. Whether you're just out of school and looking to make your first trades or close to retirement and hoping to beat the market's returns, 2021 looks like a great time to start your investing journey. But where?

Well, first you'll need a brokerage account. Once you have one, you'll need to buy your first stocks. We asked three of our Motley Fool contributors what stocks they'd recommend right now for first-time investors. They came back with Brookfield Renewable Partners (NYSE:BEP)Clean Energy Fuels (NASDAQ:CLNE), and Union Pacific (NYSE:UNP). Here's why they think these are good picks for beginning investors.

A smiling young man and woman hold fans of $100 bills.

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Put some pep in your portfolio with a clean-energy powerhouse

Scott Levine (Brookfield Renewable Partners): So you've decided that 2021 is the year when you're going to start investing in stocks? Congratulations. You're on the path to greater financial independence. As you embark on your investing journey, you'll likely want to gain some exposure to the renewable energy industry. From environmental, social, and governance (ESG)-conscious companies to nations trying to meet their Paris Agreement goals, renewable energy solutions are gaining a rapidly increasing presence on the energy landscape.

But where do you begin? The number of renewable energy-related stocks may seem overwhelming. Fortunately, Brookfield Renewable Partners makes it easy. Providing exposure to various niches of the renewable energy industry, the company's portfolio includes solar, wind, hydroelectric, and energy-storage assets. In addition, with a presence on four continents, the company's portfolio totals more than 19,000 megawatts (MW) of installed capacity, making it one of the largest publicly traded renewable energy investment options for investors. And there's plenty of growth that the company sees in its future. It has a development pipeline of projects totaling 18,000 MW.

It's not only the all-in-one approach to renewable energy that makes Brookfield Renewable Partners a compelling option. The company is on sound financial footing as it has an investment-grade balance sheet rated BBB+ with a stable outlook by S&P Global Ratings, and it has about $3.4 billion in available liquidity. Moreover, the company remains keenly focused on increasing shareholder value as management has targeted a long-term goal of delivering 12% to 15% returns to unit holders. While past performance is no guarantee of what the future holds (an important lesson for novice investors to grasp), it's worth noting that Brookfield Renewable Partners, since its inception, has delivered an annualized total return of 18%.

As fellow fool, Matt Frankel, points out, great stocks for beginners are ones that are "either leaders in their respective fields or very close to it." Brookfield Renewable Partners clearly fits the bill. This, plus the fact that it's committed to increasing shareholder value while maintaining its financial health, makes it a great stock for beginners to build their portfolios around.

Plenty of growth in the tank

John Bromels (Clean Energy Fuels): I agree with Scott that clean energy is a great place to invest right now. However, while share price shouldn't be a consideration for investors, beginners -- even those with limited capital or a brokerage that doesn't offer fractional shares -- shouldn't put their entire nest egg into a single share of stock. Biogas specialist Clean Energy Fuels' stock, though, is currently trading for less than $10 per share, allowing beginners to diversify their portfolios.

Together with current CEO Andrew Littlefair, energy bigwig T. Boone Pickens, in 1997, founded Pickens Fuel Corp. (the predecessor company of Clean Energy Fuels, incorporated in 2001) in hopes of promoting natural gas fuel as a cheaper and cleaner alternative to traditional diesel fuel. Unfortunately, persistently low oil prices during much of the 2010s, along with the rise of battery-powered vehicles, and solar and wind energy technology, conspired against Clean Energy's natural gas-based solutions. The company's shares are trading for less than half of what they were ten years ago:

CLNE Chart

CLNE data by YCharts.

Clean Energy was down but not out. And its second act is being powered by a different kind of clean fuel: biogas. In 2020, top Big Oil companies including ChevronBP, and Total have announced various kinds of partnerships with Clean Energy Fuels to develop and market clean biogas fuel. That's given the stock a roughly 150% boost in 2020, but the biogas revolution is only just beginning.

I expect that Clean Energy Fuels shares will continue their sharp rise in the new year and will power even beginner investors to some juicy returns. 

Better than money in the bank

Lee Samaha (Union Pacific): The railroad offers novice investors some valuable education into investing for the long term. First, its market position is very safe. Railroads own their infrastructure, giving them significant business moats. In addition, Union Pacific and another major railroad, BNSF, dominate the West Coast. Simply put, it's highly likely that Union Pacific will still be around when you end your investing life.

Second, all the major railroads are on a drive to improve operating margins by adopting precision scheduled railroading (PSR) management techniques. Simply put, it's a set of principles designed to run the same carload volumes by using fewer assets. You can read about the details in the article, but for now, it's enough to know that companies can improve earnings even with relatively low revenue growth.

Third, railroad revenue is tied to the industrial economy, so it does tend to move up and down with how the economy is performing at large. In a nutshell, buying Union Pacific stock is kind of a bet on the long-term prospects for the U.S. economy.

Finally, if you are starting your investing life, you are probably doing it because it offers better returns than, say, keeping the money in the bank. In this context, Union Pacific's nearly 2% dividend yield will come in handy. Throw in the security of its market position and the possibility for dividend growth via earnings growth, and you have a recipe for a good stock to with which to start your investing life.

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.