Constellation vs Green Mountain Energy
Quick Verdict
Green Mountain Energy has 29 years in Texas. Constellation has 15. That's not nothing—Green Mountain Energy survived every grid crisis since 1997.
Experience matters for stability. Price matters for your wallet. Check both on ComparePower.
14-Year Experience Gap
Green Mountain Energy: 29 years in Texas. Constellation: 15 years. Companies don't survive 29 Texas summers by accident.
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 Corporation (NASDAQ: CEG). 15 years in Texas—they've survived enough grid crises to prove they won't fold mid-contract. Based in Baltimore, Maryland.
Green Mountain Energy: Owned by NRG Energy (NYSE: NRG). 29 years in Texas—that track record matters when you're signing a multi-year contract. Based in Houston, Texas.
What They Actually Sell
Constellation offers fixed-rate, green. They sell "green" plans (mostly accounting—same electrons, but they buy renewable credits).
Green Mountain Energy offers fixed-rate, variable-rate, green, solar-buyback. 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 down to "The Verdict" for the quick answer. For actual rates, check ComparePower. Takes 2 minutes.
See how they compare on price
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Category Breakdown
29 years vs 15—14+ 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 Corporation (NASDAQ: CEG) | NRG Energy (NYSE: NRG) |
| Years in Texas | 15+ | 29+ |
| Headquarters | Baltimore, Maryland | Houston, Texas |
| Fixed-Rate Plans | ||
| Variable Plans | ||
| Prepaid Options | ||
| Green Energy | ||
| Free Nights/Weekends | ||
| Deposit Required | Conditional | Conditional |
| Credit Check |
Trust & Complaint Data ▼
Trust & Reputation
External ratings comparison
Trust Score is a weighted average: Google (40%), BBB (35%), Trustpilot (25%)
Complaint Comparison
PUCT Data • Jul-Dec 2025
Constellation
Green Mountain Energy
Constellation and Green Mountain Energy have similar complaint rates
The Verdict
- You want a Fortune 500-backed provider with real generating assets behind the name
- Clean energy matters--and you want it from a company that actually owns power plants
- You prefer simple fixed-rate plans without free-nights gimmicks or tiered pricing games
- You value bill credit plans that reward higher usage (1,000+ kWh households)
- You want a company that's survived 29 Texas summers (Constellation has 15)
- You want more green plan variety (check if they have actual renewable generation backing)
- You need month-to-month—Constellation locks you in for 12 months minimum
Done researching? See actual rates.
Constellation or Green Mountain Energy — find out which one is cheaper at your address.
Frequently Asked Questions
Q: When should I choose Constellation over Green Mountain Energy? ▼
You want a Fortune 500-backed provider with real generating assets behind the name. Clean energy matters--and you want it from a company that actually owns power plants. You prefer simple fixed-rate plans without free-nights gimmicks or tiered pricing games. You value bill credit plans that reward higher usage (1,000+ kWh households).
Q: When should I choose Green Mountain Energy over Constellation? ▼
You want a company that's survived 29 Texas summers (Constellation has 15). You want more green plan variety (check if they have actual renewable generation backing). You need month-to-month—Constellation locks you in for 12 months minimum.
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: 29 years. Constellation: 15 years. That 14-year gap matters—Green Mountain Energy survived the 2011 freeze, the 2021 disaster, and every summer in between. Track records like that don't happen by accident.
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, green. Green Mountain Energy: fixed-rate, variable-rate, green, solar-buyback. Green Mountain Energy has more options (4 plan types vs 2). More options = more ways to optimize, but also more ways to pick wrong. If you just want simple fixed-rate power, ignore the complexity. If you have specific needs (EV charging at night, pool pump, work-from-home AC), the right specialty plan can save you $50/month.
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 you want a fortune 500-backed provider with real generating assets behind the name. Green Mountain Energy wins if green energy is a real priority, not just a checkbox. For everyone else? Whoever's cheaper for your usage right now. Check ComparePower—it takes 2 minutes.
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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