US retail energy supplier

Green Mountain Energy US

Founded in 1997 in Vermont and now headquartered in Austin, Texas, Green Mountain Energy is the longest-running 100% renewable retail-electricity supplier in the United States. Every kilowatt-hour sold is matched with Green-e certified renewable energy from US wind, solar and hydro. Owned by NRG Energy (NYSE: NRG) since 2010.

See Green Mountain plans Call 1-866-785-4668

Founded 1997 ~700,000 Austin, TX 6 states served

Founded

1997

Years in the US market

Customers

~700,000

Households served

About

Who is Green Mountain Energy?

Registered as Green Mountain Energy Company, Green Mountain Energy uses this legal name for state public-utility-commission filings and customer contracts. The trading name on bills is the shorter, more recognisable form.

The company is headquartered in Austin, TX, where it runs senior management, customer operations and regulatory liaison with state commissions.

Green Mountain Energy was established in 1997. A longer track record means more years operating under state-commission rules and a wider history of customer feedback, billing and regulatory interactions.

Green Mountain Energy is part of the NRG Energy group, which provides shared governance, financial backing and a broader pool of expertise in wholesale-market trading, hedging and regulatory work.

Service area

Where Green Mountain Energy operates

Electricity

6 states

Service availability varies by zip code within each state. Eligibility depends on your local utility's deregulation status — check on Green Mountain Energy's website with your zip code before enrolling.

Plan structure

What plan types does Green Mountain Energy offer?

Pollution Free e-Plus (Texas)

Flagship 100% renewable fixed-rate plan in Texas. Matched with wind and solar RECs. Available in 12, 24 or 36-month terms.

Pollution Free e-Plus Solar

Texas plan blending grid power with a higher share of solar RECs. Aimed at customers who specifically want to support solar build-out.

Northeast 100% Renewable Fixed

Fixed-rate 100% renewable plans in NY, NJ, PA, MA, IL — Green-e certified. 12 or 24-month terms.

SolarSPARC

Pay a small monthly add-on; Green Mountain donates the proceeds to community-solar projects in low-income neighbourhoods. Available on most plans.

Renewable content: Every plan Green Mountain sells is 100% renewable — matched with Green-e certified RECs from US wind, solar and small-hydro generators. Texas plans typically use a 90% wind / 10% solar mix; Northeast plans use a wind-heavy mix.

See current Green Mountain plans & rates

Timeline

Green Mountain Energy — key moments

1997

Green Mountain Energy founded in South Burlington, Vermont — the first US retail-energy company to sell exclusively renewable electricity.
2002

Enters the newly deregulated Texas market as a retail electric provider. Moves headquarters to Austin.
2010

NRG Energy acquires Green Mountain Energy for $350 million, keeping the brand and 100% renewable mandate intact.
2017

Green Mountain claims customers have collectively avoided more than 70 billion pounds of CO2 emissions since 1997.
2024

Crosses 700,000 active customer accounts across 6 states.

Contact

Reach Green Mountain Energy customer service

Green Mountain Energy's customer service handles enrollment questions, billing, switching and complaints. Have your account number from a recent bill ready to speed up the call.

Have your Green Mountain account number from a recent bill ready to speed up the call.
For service outages or downed wires, call your local utility — not Green Mountain. The retail supplier never handles the physical grid.
24/7 chat support available for Texas customers via the website.
Spanish-language service available at the same number.

Customer service

1-866-785-4668

Mon-Fri 7 a.m. - 8 p.m., Sat 8 a.m. - 5 p.m. CT

Green Mountain Energy online account

Frequently asked

Green Mountain Energy — answers to common questions

Green Mountain Energy is regulated by the public utility commission in each state where it operates. Reliability is best judged against your own usage profile: read recent reviews, confirm the customer-service hours match when you actually need to call, and compare the unit rate against the utility's price-to-compare for your zip code.

Plans can typically be enrolled directly on Green Mountain Energy's website or by calling 1-866-785-4668. Before signing up, always compare the unit rate (¢/kWh for electricity, $/therm for gas) against your utility's price-to-compare for your zip code.

You can switch your retail supplier at any time, though early termination fees (typically $50-$200) may apply if you are on a fixed-rate plan and within the contract term. Check your enrollment letter or Terms of Service for the exact figure. Switching back to your default utility supply is always free.