100Green is the new name for Green Energy UK (GEUK), the independent energy supplier which has been supplying green energy to residential and business customers for over 20 years. 100Green is still the only energy company in the UK to supply 100% green gas and renewable electricity to its customers.
"A catalyst for the change of name was also to avoid confusion in some quarters on what the GEUK acronym stood for, and the need to update and improve our website for our customers. Supplying 100% green energy to our customers, along with first-class customer service - is what our business is all about. The 100Green name focuses on our unique offer to customers, concisely summing up what we do: supplying 100% green and renewable energy - green and simple."
Doug Stewart, Founder and Chief Executive, 100Green
| Company detail | 100Green |
|---|---|
| Previously known as | Green Energy UK (GEUK) |
| Founded | 2001 |
| Founder | Doug Stewart, Founder and Chief Executive |
| Head office | Ware, Hertfordshire |
| Ownership | Independent, with free shares offered to customers |
| Customers | Residential and business |
| Fuel mix | 100% renewable electricity and 100% green gas |
| Tariffs | Sparkling, EKO and Tide |
| Exit fees | None |
| Customer services | 01920 486 156, 8am to 8pm weekdays, 9am to 1pm weekends |
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If you have a customer services query or want to make a complaint, there are a number of ways in which you can contact them:
| Contact method | Details |
|---|---|
| Phone | 01920 486 156 8am to 8pm weekdays 9am to 1pm weekends (excluding public holidays) |
| hello@100green.com | |
| Post | 100Green Black Swan House 23 Baldock Street Ware Herts SG12 9DH |
| BSL SignVideo | Using SignVideo, 100Green offers a free service for BSL customers. |
| Complaints route | Details |
|---|---|
| Phone | 0808 175 4975 |
| complaints@100green.com | |
| Post | The Directors 100Green Black Swan House 23 Baldock Street Ware, Herts SG12 9DH |
Below is a list of their available energy tariffs:
For comparison purposes, energy prices shown above are based on average usage figures only. Prices may vary depending on the region you live in and your own gas and electricity usage. To see the best energy deals for where you are, run a gas and electric comparison today.
100Green offers a range of 100% green and renewable energy tariffs with no exit fees, providing flexibility and eco-friendly options.
| Tariff | What it offers |
|---|---|
| Sparkling | A simple, 100% renewable energy option available as variable or fixed, with no extra fees. |
| EKO | A premium fixed-term green tariff, independently eco-labelled, that supports local wildlife. |
| Tide | A time-of-use green tariff, promoting efficient energy use with variable rates depending on when you use energy. |
All tariffs are powered by renewable sources like wind, solar, hydro, biomass and anaerobic digestion. Plus, 100Green is the UK's only supplier of 100% green gas.
100Green was founded in 2001 by Doug Stewart and remains an independent UK energy supplier.
Based in Ware, Hertfordshire, 100Green is the first and only private UK company to offer free shares to its customers, who can then make recommendations to help improve and grow the business. All customer shareholders are free to attend 100Green's AGM and question board members.
If you want to switch to a company that offers 100% renewable energy, then 100Green is well worth considering. Founded in 2001, it was the first UK energy supplier to offer a choice of green-only tariffs and is still the only UK provider to offer 100% green gas.
100Green deals are sometimes more expensive than others on the market, usually because renewable energy production is more expensive than non-sustainable resources. A wind farm, for example, physically takes up more space than a traditional power plant but produces less electricity overall.
But 100Green's drive to make renewable energy the rule rather than the exception means they set rates that are competitive not only within the green market, but also the entire utilities industry.
See how 100Green compares with other suppliers for your home.
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100Green's fuel mix is made up entirely of 100% renewable energy.
All its green electricity is generated within the UK using a range of renewable energy sources, including biomass, photovoltaic solar, small-scale hydro, wind, anaerobic digestion and energy from waste. It also uses combined heat and power (CHP), which is typically generated from one of the following:
100Green also invests in renewable technologies and avoids both brown energy and nuclear generation.
| Supplier | Coal | Gas | Nuclear | Renewable | Other | CO2 (g/kWh) | Nuclear Waste (g/kWh) |
|---|
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Last updated: 29 September 2026. Tariff availability and pricing change frequently, so always confirm current rates through a comparison using your own postcode and consumption.
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