The global economy has a nearly insatiable appetite for power. Not the political kind, but the energy that drives modern life by fueling the flow of goods, people, and data

For decades, the economy relied on fossil fuels to supply it with the energy needed to keep moving. However, it has slowly pivoted to more sustainable sources like renewable energy in recent years. Given the rapid decline in costs and growing climate-change concerns, that transition appears poised to accelerate -- so I'm shifting more of my portfolio toward sustainable energy sources by building a basket of renewable-energy stocks.

This week I added to that mini-portfolio by purchasing more shares of renewable-energy yieldcos Atlantica Sustainable Infrastructure (AY -0.23%), Clearway Energy (CWEN -0.38%) (CWEN.A -0.29%), and NextEra Energy Partners (NEP -3.22%). Here's why I'm pouring more capital into the sector, and this particular trio of sustainable-energy stocks.

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Even in the best-case scenario for fossil fuels, renewable energy is the winner

Until recently, most energy-market forecasters expected the economy to continue consuming more oil each year, for at least the next couple of decades. However, that long-standing view is losing followers. One of the most chilling losses recently came from global oil industry leader BP (BP -0.85%), which plans to basically abandon the sector in the decades ahead, as it realigns its strategy with its outlook for the energy market.

In that company's view, even in a business-as-usual approach where the economy gradually transitions to renewable energy, we've already hit peak oil demand. BP estimates that fossil fuel's share of the energy market will decline from about 85% to less than 70% over the next three decades, ceding its market share to renewables. This view has BP planning to reduce its spending on fossil fuels and shift those investments into low-carbon energy sources. As a result, it sees its oil-equivalent production declining by 40% by 2030, while its renewable-energy generation grows 20-fold during that period.

Making green by going green

Atlantica, Clearway Energy, and NextEra Energy Partners all have one thing in common. These companies focus on acquiring, developing, and owning renewable-energy-generating assets that sell their electrical output to end users like utilities and large corporations, under fixed-rate power purchase agreements. That business model enables them to produce relatively steady cash flow and to pay attractive dividends that yield more than 4%.

Those above-average yields are only part of the attraction. All three companies have ample power to grow their cash flow and payouts in the coming years. Given the power of a growing dividend, all three have the potential to generate market-beating total returns in the coming decades.

For example, NextEra Energy Partners currently expects to grow its already above-average dividend by 12% to 15% annually through 2024. Powering that plan is its relationship with renewables-focused utility NextEra Energy (NEE -0.16%). That company is already the largest producer of wind and solar energy globally. On top of that, its backlog of development projects is bigger than the current operating portfolios of all but two other companies, so NextEra has a vast portfolio of projects that it can drop down to its affiliate to help power its dividend growth plan. Add its 4% yield to its growth potential, and this renewable-energy stock could generate double-digit total annual returns.

Similarly, Clearway Energy has relationships with strategic partners (private equity giant Global Infrastructure Partners and renewable project developer Clearway Energy Group) to help power its dividend-growth plan. In its case, the company expects to grow its payout by 5% to 8% per year (including delivering a high-end increase in 2021) as it invests in new renewable-energy projects. It already has several deals lined up, giving it a clear line of sight on future cash flow and dividend growth. Combine that upside with its nearly 5%-yielding payout, and it could also generate total annual returns in the double digits.

Finally, Atlantica also has a major strategic partner in utility Algonquin Power & Utilities, which provides it with a steady stream of investment opportunities. In addition, Atlantica has the flexibility to make third-party acquisitions, invest in organic expansion projects, and pursue other partnerships. That quartet of growth drivers should provide it with plenty of opportunities to expand cash flow and continue increasing its dividend. Again, given its already high yield (currently above 6%), Atlantica has big-time total return potential as it grows its portfolio, cash flow, and payouts.

High-powered total return potential

The global shift toward renewable energy is starting to accelerate, and companies focused on the sector should have plenty of growth opportunities. Those should enable them to expand their portfolios, cash flow, and dividends at above-average rates, which could power market-smashing total returns. I want more of that renewable upside in my portfolio, which is why I recently bought additional shares of Atlantica, Clearway Energy, and NextEra Energy Partners.