Constellation vs Green Mountain Energy
Quick Verdict
Same wires. Same grid. Same electrons flowing to your house. The only real difference? Who sends you the bill and what they charge.
Since there's no major differentiator, this comes down to price. Check ComparePower for current rates.
Complaint Comparison
PUCT Data • Jul-Dec 2025
Constellation
Green Mountain Energy
Constellation and Green Mountain Energy have similar complaint rates
Trust & Reputation
External ratings comparison
Trust Score is a weighted average: Google (40%), BBB (35%), Trustpilot (25%)
The Verdict
- Carbon-free energy matters--and you want it from a company that generates it
- Your business has sustainability commitments that require real clean energy sourcing
- You want simple fixed-rate plans without promotional games
- Nuclear power doesn't bother you (it's carbon-free, just not 'renewable')
- You need month-to-month—Constellation locks you in for 12 months minimum
- You'll pay 15-25% more for authentic renewable energy--and feel good about it
- Environmental track record matters, not just a 'green' label
- You want your electricity company to support wind/solar infrastructure
Category Breakdown
27 years vs 22—5+ more grid crises survived
Both sell green plans—check who has actual renewable generation backing
Rates change constantly. Check ComparePower with your actual usage.
Side-by-Side Comparison
| Feature | Constellation | Green Mountain Energy |
|---|---|---|
| Parent Company | Constellation Energy (NASDAQ: CEG) | NRG Energy (NYSE: NRG) |
| Years in Texas | 22+ | 27+ |
| Headquarters | Baltimore, Maryland (Texas operations in Houston) | Austin, Texas |
| Fixed-Rate Plans | ||
| Variable Plans | ||
| Prepaid Options | ||
| Green Energy | ||
| Free Nights/Weekends | ||
| Deposit Required | Conditional | Conditional |
| Credit Check |
What Actually Differs
Constellation and Green Mountain Energy deliver the exact same electricity through the exact same wires. The electrons don't care whose logo is on your bill. What differs: the price, the service when something goes wrong, and the fine print in contracts.
Who's Behind These Companies
Constellation: Owned by Constellation Energy (NASDAQ: CEG). 22 years in Texas—they've survived enough grid crises to prove they won't fold mid-contract. Based in Baltimore, Maryland (Texas operations in Houston).
Green Mountain Energy: Owned by NRG Energy (NYSE: NRG). 27 years in Texas—that track record matters when you're signing a multi-year contract. Based in Austin, Texas.
What They Actually Sell
Constellation offers fixed-rate, variable-rate, green. They sell "green" plans (mostly accounting—same electrons, but they buy renewable credits).
Green Mountain Energy offers fixed-rate, variable-rate, green. They sell "green" plans (mostly accounting—same electrons, but they buy renewable credits).
The Money Part
Constellation: Deposit depends on credit—expect $200-400 if your score is below 600.
Green Mountain Energy: Deposit depends on credit—expect $200-400 if your score is below 600.
The Honest Answer
Both are legitimate. Neither is a scam. The electricity is identical. What matters is: (1) who's cheaper for your actual usage, (2) whether you need to skip a credit check, and (3) if you care about green marketing. Scroll up to the "Choose if..." sections—they'll tell you which one fits your situation. For actual rates, check ComparePower. Takes 2 minutes.
Company Snapshots
Constellation
- Parent Company
- Constellation Energy (NASDAQ: CEG)
- Years in Texas
- 22+
- Headquarters
- Baltimore, Maryland (Texas operations in Houston)
- Deposit Required
- conditional
Green Mountain Energy
- Parent Company
- NRG Energy (NYSE: NRG)
- Years in Texas
- 27+
- Headquarters
- Austin, Texas
- Deposit Required
- conditional
More Head-to-Head Matchups
See who wins when Constellation and Green Mountain Energy face other competitors.
Featured In Best-Of Lists
See where Constellation and Green Mountain Energy are featured in our category guides.
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"I like that it searched multiple companies for me. So I don't have to search one by one. Saves time."
— Lacy L., Texas
See Current Rates
Compare current plans from both companies.
Frequently Asked Questions
Q: When should I choose Constellation over Green Mountain Energy? ▼
Carbon-free energy matters--and you want it from a company that generates it. Your business has sustainability commitments that require real clean energy sourcing. You want simple fixed-rate plans without promotional games. Nuclear power doesn't bother you (it's carbon-free, just not 'renewable').
Q: When should I choose Green Mountain Energy over Constellation? ▼
You need month-to-month—Constellation locks you in for 12 months minimum. You'll pay 15-25% more for authentic renewable energy--and feel good about it. Environmental track record matters, not just a 'green' label. You want your electricity company to support wind/solar infrastructure.
Q: What is the main difference between Constellation and Green Mountain Energy? ▼
Green Mountain Energy leads in track record. Both companies deliver the same electricity through the same grid—the real differences are in pricing, service quality, and available plan types.
Q: Is Constellation or Green Mountain Energy cheaper? ▼
Anyone who answers this without knowing your zip code and usage is lying. The "advertised rate" is calculated at exactly 1,000 kWh—use 800 or 1,200 and the math changes completely. Both companies exploit this. Check ComparePower with your actual usage. Takes 2 minutes, and you'll see real numbers instead of marketing.
Q: Which company has been in Texas longer, Constellation or Green Mountain Energy? ▼
Green Mountain Energy: 27 years. Constellation: 22 years. Similar track records. Both have survived enough Texas summers to prove they won't fold mid-contract.
Q: Which is better for green energy, Constellation or Green Mountain Energy? ▼
Both sell "green" plans. But "green" in Texas electricity means they buy renewable energy credits—it's accounting, not physics. Your electrons come from the same grid as everyone else. Want to know which has renewable generation backing versus just buying paper credits? Gexa has NextEra (the largest renewable generator in the US) behind them. Most others just buy credits. That's the difference.
Q: What types of plans do Constellation and Green Mountain Energy offer? ▼
Constellation: fixed-rate, variable-rate, green. Green Mountain Energy: fixed-rate, variable-rate, green. Similar variety. Both have enough options for most situations.
Q: Which is better overall, Constellation or Green Mountain Energy? ▼
Same grid. Same wires. Same electrons. The electricity is literally identical—the only differences are price, service, and plan options. Constellation wins if carbon-free energy matters--and you want it from a company that generates it. Green Mountain Energy wins if you'll pay 15-25% more for authentic renewable energy--and feel good about it. For everyone else? Whoever's cheaper for your usage right now. Check ComparePower—it takes 2 minutes.