Green Mountain Energy vs TXU Energy: Pure-Play Green or Every Plan Under One Roof

At a Glance

Factor	Green Mountain Energy	TXU Energy
Parent Company	NRG Energy (NYSE: NRG)	Vistra Corp (NYSE: VST)
Years in Texas	29 (since 1997)	24 as REP (since 2002)
Green Energy	100% renewable, every plan	Optional (GreenUp add-on)
Plan Variety	Fixed-rate only	Free nights, seasonal, EV, solar
Prepaid Available	No	No
Price vs Budget	40-75% premium	15-25% premium

Bottom Line: Green Mountain is the pure-play green company—every plan is 100% renewable, no exceptions, and it has been that way since 1997. TXU is the plan-variety incumbent with a huge menu, 24/7 support, and green as an option you add if you want it. You’re choosing between guaranteed green and everything-else-under-one-roof.

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The Green Question

This is the split that defines the whole comparison.

Green Mountain: Every plan is 100% renewable, Green-e certified. There is no non-green option to accidentally pick. The company launched in 1997 as the original 100%-renewable retailer in Texas, and 29 years later that is still the entire business. If verified green energy is the reason you’re shopping, this is the shortest path to it—you can’t get it wrong.

TXU: Green is a feature, not the foundation. TXU sells GreenUp, a 100% renewable-energy-credit add-on you can attach to any plan, plus dedicated products like Free Nights & Solar Days. The default plan is not green. You have to choose it. That works fine if you know to look—but it’s an extra step, and the renewable content rides on RECs bolted onto a conventional plan rather than a company built around them.

If “100% green, verified, no thinking required” is the goal, Green Mountain wins outright. If you want green but treat it as one box to check among many, TXU can match the outcome.

Plan Variety

Here the roles flip.

TXU runs the widest plan lineup in Texas. Free nights. Seasonal passes. Solar buyback. EV charging plans. GreenUp on top of any of them. Free Nights & Solar Days for households that shift usage to overnight or generate their own power. If your home has a specific rhythm—night-shift schedule, rooftop solar, an EV in the garage—TXU probably has a plan shaped for it.

Green Mountain offers fixed-rate renewable plans and Renewable Rewards solar buyback. That’s the menu. No prepaid, no free-nights, no time-of-use, no specialty structures. The trade-off is deliberate: one product, done one way, all green. If you want to match a plan to an unusual usage pattern, Green Mountain simply doesn’t have the shelf space.

Neither offers prepaid, so credit-challenged shoppers should look elsewhere in the market. Both run a conditional deposit—Green Mountain returns it after 12 months of on-time payments; TXU waives it for customers 55+, with a personal guarantee, and similar conditions.

The Price Premium

Be clear-eyed here: neither of these is the cheap option.

Green Mountain rates run roughly 17.5-21.7 cents/kWh against budget providers at 12-13 cents—a 40-75% premium. You are paying for verified 100% renewable energy and a 29-year track record. For some households that premium is the point. For others it’s a dealbreaker.

TXU runs 15-25% over budget providers. Higher than a discount retailer, lower than Green Mountain, and you’re paying for plan variety, 24/7 support, and brand safety rather than guaranteed green.

If price is your only lever, both lose to budget providers on ComparePower. Between these two, TXU is the lower premium.

Support and Stability

Both carry serious corporate backing. Green Mountain sits under NRG Energy (NYSE: NRG). TXU sits under Vistra Corp (NYSE: VST), with retail roots tracing back to 1882. Neither is a fly-by-night reseller, and both offer responsive customer support.

TXU’s edge is scale and access: 24/7 phone support and one of the largest service operations in the state. Green Mountain’s support is solid, but if round-the-clock phone access ranks high for you, TXU has the deeper bench.

The Verdict

Choose Green Mountain if:

• 100% renewable, Green-e certified energy on every plan is non-negotiable
• A 29-year green track record carries real weight for you
• You have solar and want Renewable Rewards buyback
• You’d rather never wonder whether your plan is green

Choose TXU if:

• You want plan variety—free nights, seasonal passes, EV, solar buyback
• 24/7 phone support and big-brand stability matter
• You want the lower premium of the two (15-25% vs 40-75%)
• Green as an optional GreenUp add-on is enough for you

The honest read: both cost more than budget providers, so neither is the pick if price is all that matters. Green Mountain is the choice when verified green energy is the whole reason you’re shopping—every plan, no exceptions, since 1997. TXU is the choice when you want options, always-on support, and the freedom to add green when you feel like it. Pick the one whose default matches what you actually care about.