Fundamentally, the concept of millionaire-maker renewable energy stocks makes plenty of sense. At the moment, the energy paradigm focuses on the anachronistic non-renewable variety. However, political and environmental pressures dictate that we move away from hydrocarbons. Therefore, if you have the patience, long-term renewable energy investments could potentially deliver life-changing returns.

The latter point should be emphasized again. Unlike other millionaire ideas, these top renewable energy stocks to buy will require at least a few years to truly hit their stride. Don’t get me wrong: the underlying analyst support for these enterprises implies that you could be profitable within a 12-month timeframe. Nevertheless, the central theme here is about holding on for the long haul.

Even better, experts in the field suggest that the long approach could really pay off. From data compiled by Statista, the market value of the global renewable energy industry could hit over $2 trillion by 2030. Now I’m excited about these high-potential renewable energy stocks to buy!

Clearway Energy (CWEN)

Headquartered in Princeton, New Jersey, Clearway Energy (NYSE:CWEN) is one of the largest developers and operators of clean energy. According to its public profile, Clearway features over 5.7 gigawatts (GW) of wind, solar, and energy storage in operation. Though one of the most popular millionaire-maker renewable energy stocks, CWEN has struggled this year. Since the January opener, shares dipped 7%.

Nevertheless, the red ink also presents a contrarian opportunity for top renewable energy stocks to buy. Financially, while Clearway presents a mixed bag, it has enough positives to make it intriguing for speculators. Specifically, its three-year EBITDA growth rate (on a per-share basis) clocks in at 38.4%, beating out 83.28% of entities in the independent power producer sector.

Also, its trailing-year net margin comes in at 46%, outpacing 90.49% of rivals. Nevertheless, the market prices CWEN at a trailing multiple of just under 6. As a discount to earnings, Clearway ranks better than 83.4% of the competition. Finally, analysts peg shares as a moderate buy. Their average price target lands at $34, implying over 14% upside potential, presenting a solid candidacy for long-term renewable energy investments.

Array Technologies (ARRY)

Hailing from New Mexico, Array Technologies (NASDAQ:ARRY) is a leading global technology company providing tracker solutions and services for utility-scale solar energy projects. Per its corporate profile, Array represents one of the world’s largest manufacturers of ground-mounted systems. A technologically advanced enterprise, ARRY carries the potential to be one of the millionaire-maker renewable energy stocks. Since the start of the year, shares popped up over 13%.

Financially, as with other ambitious high-potential renewable energy stocks, ARRY carries a mixed bag financially. Most noticeably, its balance sheet could use some work. Also, its profitability metrics aren’t exactly lighting up the field.

On the flip side, though, Array’s three-year revenue growth on a per-share basis clocks in at 26.5%. This stat outpaces 80.9% of its semiconductor-focused peers. Despite this outperformance, ARRY trades at 1.92 times trailing sales. As a discount to revenue, Array ranks better than 63.41% of sector rivals.

Lastly, analysts peg ARRY as a moderate buy. Their average price target hits $26.45, implying nearly 23% upside potential. Overall, it could make for one of the promising buy-and-hold renewable energy stocks.

Bloom Energy (BE)

Based in San Jose, California, Bloom Energy (NYSE:BE) manufactures and markets solid-oxide fuel cells that produce electricity on-site. According to its public profile, the company’s main product – the Bloom Energy Server – delivers highly reliable and resilient, always-on electric power that is clean, cost-effective, and ideal for microgrid applications. A relevant idea for millionaire-maker renewable energy stocks, BE also struggled in the market, losing 14% since the Jan. opener.

Still, it’s possible that the red ink could offer daring speculators an opportunity to pick up top renewable energy stocks to buy at a discount. However, Bloom is a high-risk, high-reward trade. Per investment resource Gurufocus, one of the main concerns is that BE could rank among the possible value traps. In addition, the company suffers from poor fiscal stability, negative margins, and also below-zero growth.

So, what’s the good news? Despite the financial print warning investors away, analysts seem to like BE. Across 12 experts, seven of them rate it a buy while the others believe it’s a hold. Overall, the assessment stands as a moderate buy with an average price target of $24.25. If shares get there, we’re talking about upside potential of 47%.

On the date of publication, Josh Enomoto did not have (either directly or indirectly) any positions in the securities mentioned in this article. The opinions expressed in this article are those of the writer, subject to the InvestorPlace.com Publishing Guidelines.