Vistra vs. Constellation vs. Talen Energy: Which Nuclear-Heavy Stock Is the Better AI-Power Bet?

Advanced chips from Nvidia and others deliver impressive computing power but also consume massive amounts of electricity. As a result, hyperscalers are searching high and low for reliable power as these data centers come online.

The energy demand boom is coming as nuclear energy makes a major comeback. U.S. policymakers have set a goal of quadrupling the country's nuclear capacity by 2050, creating a potentially significant tailwind for the nuclear sector.

Vistra (NYSE: VST), Constellation Energy (NASDAQ: CEG), and Talen Energy (NASDAQ: TLN) are three companies positioned to benefit from growing power demand. But which stock offers investors the most compelling opportunity today? Let's compare the three companies and find out.

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Constellation Energy is a clear leader in nuclear power capacity

Everyone is seeking reliable, clean energy to meet growing electricity demand. For AI data centers, nuclear power is an ideal solution. That's because nuclear delivers reliable 24/7 baseload energy, which is needed to meet the continuous compute demand of training and inference for these AI models.

In total power capacity, Constellation is the clear leader with 55 gigawatts (GW) of generation capacity. Of this, roughly 22 GW comes from nuclear power, giving Constellation the largest nuclear fleet in the U.S. Constellation has secured major deals with hyperscalers in recent years, including 20-year power purchase agreements with both Microsoft and Meta Platforms.

Constellation's nuclear fleet achieved a 93% capacity factor in the second quarter. Running at this high a capacity factor maximizes megawatt-hours and gives Constellation operational leverage, as variable costs remain relatively low. The capacity factor reflects its reliability, which helps Constellation command a premium on contracted PPA rates.

Vistra is carving out its place in the data center market

Vistra is the second-largest energy producer of the bunch, with 44 GW of total power generation capacity. Of that capacity, roughly 6.6 GW comes from nuclear energy in the ERCOT (Texas) and PJM interconnection regions.

In September 2025, Vistra signed a 20-year PPA with Amazon Web Services for nuclear power from Camanche Park in Texas. And in January 2026, the company signed a 20-year PPA with Meta Platforms for 2,609 MW from its nuclear plants in the PJM region. Vistra's capacity factor is a solid 92.9% in ERCOT and 91% in PJM but still trails Constellation's impressive figure.

In another major agreement, Vistra, KKR, Nvidia, and Kuwait Investment Authority announced the launch of Helix Digital Infrastructure in June. Helix will facilitate the development of AI data centers and is backed by $10 billion in investments. As part of this partnership, Vistra becomes Helix's preferred power provider.

Talen Energy is anchored to Amazon

Talen Energy is a smaller player that owns and operates roughly 15.7 GW of power generation capacity across PJM, Ohio, Indiana, and Montana. The company also has 2.2 GW of nuclear power capacity through a 90% interest in the Susquehanna Nuclear Power Plant in Pennsylvania. This is a small portion of Talen's power capacity, but it makes up most of its clean energy output.

Talen is anchored to one massive hyperscaler partner: Amazon. In March 2024, Talen sold its 960-MW Cumulus data center campus (land and infrastructure directly adjacent to its Susquehanna nuclear plant) to AWS for $650 million in cash. In June 2025, AWS signed a PPA with Talen through 2042 to deliver up to 1,920 MW of nuclear power, with incremental ramp-up.

Which energy stock is a better buy today?

If you're considering investing in the AI data story, these three stocks offer compelling options. If you're more aggressive, Talen Energy is a high-risk, high-reward small-cap stock anchored by its co-location agreement with Amazon Web Services. Risk remains high because its clean baseload energy strategy relies on a single nuclear plant, Susquehanna in Pennsylvania.

Constellation and Vistra remain aggressive energy plays relative to traditional utilities, but both should benefit from growing demand for clean power. If I had to choose between the two, I'd give the nod to Constellation Energy because of its massive nuclear fleet and long-duration power purchase agreements that provide cash-flow visibility for years to come.

Courtney Carlsen has positions in Constellation Energy, Meta Platforms, Microsoft, Nvidia, and Vistra. The Motley Fool has positions in and recommends Amazon, Constellation Energy, KKR, Meta Platforms, Microsoft, Nvidia, Talen Energy, and Vistra. The Motley Fool has a disclosure policy.