100Green Review Summary
Last updated: 5th September 2025
At a Glance Summary
100Green is a small, independent UK energy supplier with impeccable green credentials, offering 100% renewable electricity and 100% green gas.
It stands out for its exceptional customer service, earning the top spot in the Citizens Advice ratings and a “Recommended Provider” status from Which? for 2025. However, this commitment to green energy and service comes at a premium price, as the supplier is exempt from the Ofgem price cap.
While not the cheapest option, 100Green is an excellent choice for environmentally conscious consumers who prioritise top-tier service and are willing to pay more for genuine green energy.
Who is 100Green?
Founded in 2001 and originally known as Green Energy UK, 100Green is a small, Hertfordshire-based supplier with a singular focus: to provide the UK’s greenest energy.
Unlike many suppliers who offer ‘green’ tariffs by simply offsetting emissions, 100Green matches 100% of the electricity its customers use with renewable generation and, uniquely, provides 100% green biogas.
While it is a premium-priced supplier, its service levels are consistently rated among the best in the country.
What tariffs does 100Green offer?
100Green offers a straightforward range of fixed and variable tariffs, all of which come with no early exit fees, giving customers flexibility. Their tariffs include:
- Fixed Tariffs: These lock in your unit rates for a set period, protecting you from wholesale price increases. An example is the Eko Energy 2026 tariff, which not only provides green energy but also meets strict sustainability criteria and contributes to a global Climate Fund.
- Variable Tariffs: Their standard variable tariff, Sparkling SVT, tracks the wholesale market, meaning your prices can go up or down.
- Electric Vehicle (EV) Tariff: 100Green offers a smart EV tariff that provides cheaper off-peak electricity, making it ideal for charging your vehicle overnight.
- Economy 7: An Economy 7 option is available for customers with compatible meters, offering cheaper electricity during a seven-hour night-time window.
How do 100Green compare on price?
100Green is positioned as a premium green supplier and is generally more expensive than the market average. It has an exemption from the Ofgem price cap, allowing it to charge more to cover the higher costs of sourcing 100% green gas.
The table below shows an estimated cost for an average UK household.
Estimates are for a typical dual fuel customer with average consumption, paying by Direct Debit. Based on prices from September 2025. Actual costs will vary depending on your usage, location, and the date you sign up.
| Tariff Name | Tariff Type | Monthly Cost | Annual Cost | Early Exit Fee |
| Sparkling Guarantee – Mar 2026 | Variable | £171 | £2,058 | £0 |
| Sparkling SVT | Variable | £172 | £2,062 | £0 |
| Eko Energy 2026 | Fixed | £186 | £2,229 | £0 |
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What do other 100Green reviews say?
100Green receives exceptionally strong reviews for its customer service from official consumer bodies, though its Trustpilot score is slightly lower.
Trustpilot: As of September 2025, 100Green has a score of 4.1 out of 5 stars on Trustpilot from over 1,200 reviews. Positive reviews frequently praise the friendly and efficient UK-based customer service team. Some negative reviews mention issues with billing estimates, highlighting the importance of submitting regular meter readings.
Citizens Advice (Jan – Mar 2025): In the latest quarterly survey from Citizens Advice, 100Green was ranked #1 out of 16 suppliers, with an overall score of 3.9 out of 5 stars. It scored highly for its low number of complaints and ease of contact.
Which? (2025): The 2025 Which? energy survey named 100Green a Which? Recommended Provider. It achieved a total score of 70% and a customer score of 76%, earning praise for its customer service and complaint handling.
How green is 100Green’s energy?
100Green has arguably the strongest green credentials of any supplier in the UK. According to its official fuel mix disclosure, its energy comes from:
- 100% Renewable Electricity: Generated from sources like solar, wind, and hydro.
- 100% Green Gas: All of its gas is biogas generated through anaerobic digestion from agricultural waste. This makes it one of the very few suppliers not reliant on natural gas and carbon offsetting for its ‘green’ gas tariff.
This commitment to supplying genuinely green gas, rather than just offsetting fossil fuel gas, sets it apart from almost all other UK suppliers.
What is 100Green’s customer service like?
Customer service is where 100Green truly excels, consistently outperforming its rivals.
Complaints: 100Green receives very few complaints, a key factor in its top ranking with both Citizens Advice and Which?.
Contact & Wait Times: According to the latest Citizens Advice data, the average call centre wait time is just 17 seconds, significantly better than the industry average. Email response times are also strong, with 92.4% of emails responded to within 2 working days.
Opening Hours: The UK-based team is available by phone from 8 am to 8 pm, Monday to Friday and 9am to 1 pm on weekends.
What is 100Green’s website/app like?
The 100Green website is informative but can be slightly difficult to navigate. However, it provides key functions like submitting meter readings, viewing usage, and managing your account.
The supplier now has a mobile app available for both Apple and Android devices, allowing customers to manage their accounts on the go.
- Apple App Store: The app scores a respectable 4.2 out of 5 stars from over 130 ratings.
- Google Play Store: The Android version scores lower, with a rating of 2.9 out of 5 stars from over 80 reviews.
Users generally find the app useful for submitting meter readings and checking their balance, but some Android users report functionality issues.
What billing options are available?
100Green aims for simplicity in its billing. The standard payment method is monthly Direct Debit.
You can choose a fixed Direct Debit, where you pay the same amount each month and build up credit over the summer, or a variable Direct Debit, where your payment reflects your actual usage each month. To do this, you must submit monthly meter readings. Paperless billing is the default, but you can request paper bills if needed.
Does 100Green offer a recommend-a-friend referral scheme?
No, 100Green does not currently offer a refer-a-friend scheme or any other new customer joining incentives. Their focus is on providing high-quality service and genuinely green energy rather than on acquisition bonuses.
Who is 100Green good for?
- The Environmentally Conscious: If you want the greenest possible energy and are willing to pay for it, 100Green is the clear market leader.
- Those Prioritising Service: If you are tired of long call queues and poor service, their award-winning, UK-based team is a major draw.
- Customers Wanting Flexibility: With no exit fees on any tariff, you are free to leave at any time without penalty.
Who might 100Green not suit?
- Budget-Focused Customers: As a premium supplier that is exempt from the price cap, 100Green is one of the more expensive options on the market.
- Prepayment Meter Users: They do not offer tariffs for prepayment meters unless a customer is in debt and needs one for payment management.
- Tech-Heavy Users: While they have an app, it’s not as feature-rich as those from larger suppliers, and the Android version has mixed reviews.
Competitor Comparison: 100Green vs Ecotricity vs Good Energy
100Green’s main rivals are Ecotricity and Good Energy, two other pioneers of the green energy movement.
- Ecotricity: Also offers 100% renewable electricity and is moving towards green gas. It invests heavily in building new renewable generation, which it calls its “bills into mills” model. Its customer service is generally well-regarded but doesn’t quite reach the top-tier ratings of 100Green.
- Good Energy: Provides 100% renewable electricity and carbon-neutral gas, which is a mix of biogas and offset natural gas. Like 100Green, it receives strong customer service scores but doesn’t offer 100% green gas across the board.
The key differentiator for 100Green remains its unique commitment to providing 100% green biogas to all customers.
Our Verdict
100Green is a supplier that delivers exactly what it promises: exceptional green credentials and outstanding, UK-based customer service.
It is the undisputed choice for consumers who want to make the most sustainable energy choice possible.
This premium offering comes with a higher price tag, making it unsuitable for those on a tight budget.
However, if your priority is environmental impact and you value first-class service, 100Green is one of the best suppliers in the UK and is well worth the investment.
FAQS
Below are a few quick questions you may need answers to, along with our 100Green review:
Is 100Green a good energy supplier?
Yes, 100Green is considered an excellent supplier, particularly for customer service and green credentials. It was ranked #1 by Citizens Advice (Jan-Mar 2025) and is a Which? Recommended Provider for 2025.
Is 100Green expensive?
Yes, 100Green is typically more expensive than average. This is because it is exempt from the Ofgem price cap to cover the higher cost of supplying 100% renewable electricity and 100% green biogas.
What is 100Green’s fuel mix?
Their fuel mix is 100% renewable electricity from sources like solar, wind, and hydro, and 100% green gas (biogas) from anaerobic digestion.
Who owns 100Green?
100Green is an independent company, not part of a larger energy group. It was founded in 2001 by Doug Stewart.
Does 100Green have an app?
Yes, 100Green has a mobile app for both Apple and Android devices where you can manage your account and submit meter readings.
Is 100Green part of the Warm Home Discount scheme?
Yes, 100Green is a participant in the Warm Home Discount scheme, offering eligible customers a rebate on their winter electricity bills.
Does 100Green have smart meters?
Yes, 100Green is actively rolling out smart meters to its customers, which can help with accurate billing and energy management.
Are there any exit fees with 100Green?
No, one of 100Green’s key selling points is that none of its tariffs have early exit fees.
How to contact 100Green
Address: Black Swan House, 23 Baldock Street, Ware, Herts, SG12 9DH
You can contact Green Energy UK customer service by calling: 01920 486 156
You can email them at: hello@100green.com
Opening hours:
- 8am – 8pm weekdays
- 9am – 1pm weekends
- Closed on Bank holidays.
Switch to 100Green
The easiest way to switch to 100Green is through a comparison website. This will allow you to check if 100Green is one of the cheapest suppliers for you (tariffs vary based on your area) and will allow you to quickly and easily switch to them.
Our top rated supplier Octopus Energy is currently offering £50 credit to any new customer that uses our referral link. Click below to see why we rate them so highly and get your £50.
I was switched into Green Energy by SwitchD. I immediatey said no as I had just moved house and wanted to stay with the house’s existing supplier, SoEnergy.
I cancelled the DD for Green Energy that had been set up without my approval. Green Energy has failed to respond to email requests to cancel the Erroneous transfer. When phoning I am told I am 35th in the queue.
Switchd, who made the switch to Green Energy, have not been able to help in sorting this out. I have subsequently cancelled my subscription to SwitchD. . I am now in contact with OFGEM over the unauthorised switch and Green Energy s failure to respond to communications.
I would not recommend this supplier because I have found it impossible to communicate with them.