Anyone who's followed the solar industry for the past dozen years can tell you that it's seen both massive global growth, and that winning stocks in the sector have been few and far between. One of the few long-term winners is Enphase Energy (ENPH -0.79%), with shares up 1,920% over the past decade. 

How good is that? It's turned a $1,000 investment into $20,000, almost nine times better than the S&P 500 over the same period.

That's fantastic if you've owned shares for a decade. But if you bought at the recent peak, you've seen your investment fall 61% in value. Whether you bought at that peak, have held for many years, or are thinking about buying Enphase stock, I have good news: There are very good reasons to buy shares now, and hold for years to come. Keep reading for a closer look at three reasons why it's a buy now. 

Reason 1. A cash-cow company that's broken the usual mold

Enphase's core business is making solar panel-level electronics, primarily micro-inverters that manage the power generated from solar panels, and supply it to homes, businesses, and the electric grid. Typically, these middle-player electronics companies are commodity players, fighting over price and earning thin margins. 

However, Enphase has broken that mold, and proven itself a value-ad partner for solar panel makers and solar installers, and turned that value into strong margins and cash flows. And over the past couple of years, it has rolled out energy storage systems, leveraging its existing distribution and installer partner relationships to steadily take market share from this growing part of the renewables market. 

And even with some softness in the North American market, Enphase has managed to continue growing cash flows; operating cash flow is up 63% while free cash flow is up 59% over the past year. 

ENPH Free Cash Flow Chart

ENPH Free Cash Flow data by YCharts

Reason 2. The valuation has gotten compelling

While cash flows have continued to grow, the company's stock price has gone the other direction. One reason is the initial pop from the Inflation Reduction Act has worn off. But quite frankly, there's a good argument that Enphase's run-up got way ahead of the company's prospects. 

For essentially all of 2022, Enphase stock traded for more than 80 times EV to EBIDTA, and was almost never less than 50 times operating cash flows. This is an extreme valuation that very few companies ever "grow" into. 

But Enphase's sell-off has put it squarely within a more reasonable valuation. At recent prices, shares now trade for 24 times EV to EBITDA, and less than 20 times operating cash flow. 

ENPH EV to EBITDA Chart

ENPH EV to EBITDA data by YCharts

To be clear, this isn't exactly cheap. But Enphase, while still likely to face ups-and-downs of the cyclical demand for solar, is still very much a growth business that will rarely sell for cheap. 

Reason 3. The future for solar and storage is incredibly bright for this market leader

In many ways, Enphase is a bit of a unicorn. As described above, it's proven a rarity as an electronics manufacturer that few end customers would recognize that's been able to command very good profit margins. When you combine that with the decline in the share price that's brought it down to a reasonable valuation, there's good reason to put it on your watchlist. 

But what moves Enphase from watchlist to time-to-buy for me is the long-term growth potential. The solar industry has matured significantly, but it's still very early in the growth story. Solar and other renewables still make up a small fraction of global energy production, but it steadily making up more of every year's capital investments. Combine that with a fast-growing energy storage business and the combined benefits of a single ecosystem that makes life easier for installers and customers, and Enphase is building a lead on its competitors. 

Put it all together, and investors looking to profit from the global push for renewables should definitely consider buying Enphase on this pullback.