100Green Energy Review: The UK's Only 100% Green Gas and Electricity Supplier

In the journey towards a net-zero future, UK consumers are increasingly seeking energy suppliers that align with their environmental values. While many providers offer "green" tariffs, 100Green (previously known as Green Energy UK) has carved out a unique position in the market. They are currently the only UK supplier guaranteeing both 100% renewable electricity and 100% green gas.

This comprehensive guide explores what makes 100Green different, from its energy sources and tariffs to its customer service and pricing structure, helping you decide if it's the right choice for your home.

1. What Truly Sets 100Green Apart?

In a marketplace where "green" can sometimes be a confusing label, 100Green's proposition is refreshingly straightforward. Their core commitment is to provide energy that is as sustainable as currently possible, a promise that extends beyond just electricity.

100% Green Gas: A UK First

The most significant differentiator for 100Green is its gas supply. While other suppliers may offer carbon-offset gas tariffs, 100Green directly supplies biomethane, or 'green gas'. This isn't a fossil fuel with its emissions balanced elsewhere; it's a completely different product.

The gas is produced through a process called anaerobic digestion. This involves breaking down organic matter—such as agricultural waste, food waste, and crops grown specifically for energy—in an oxygen-free environment. This process releases biogas, which is then purified to become biomethane and fed directly into the national gas grid. By choosing 100Green, customers ensure that for every unit of gas they use, an equivalent unit of green gas has been produced and supplied to the network.

100% Renewable Electricity

Alongside its unique gas offering, 100Green supplies 100% renewable electricity. This energy is generated exclusively from UK-based natural sources, including:

• Wind Power: Harnessing the power of the UK's ample wind resources.
• Solar Power: Capturing energy from the sun via photovoltaic panels.
• Hydropower: Utilising the flow of water to generate power.
• Organic Generation: Creating energy from biomass and other organic materials.

Crucially, 100Green's fuel mix does not include nuclear power. While low-carbon, nuclear energy is not considered renewable due to its reliance on finite resources like uranium and the long-term environmental challenges of waste storage.

2. Understanding 100Green's Tariff Options

To cater to different customer needs, 100Green provides a range of straightforward tariffs. A standout feature across all their plans is the absence of exit fees, giving customers complete flexibility to switch away if their circumstances change without financial penalty.

• Fixed Tariffs: For those who value price certainty, fixed tariffs lock in your unit rates and standing charges for the duration of the contract. This protects you from market volatility. 100Green also offers a 'premium' green tariff, which invests in additional sustainability projects, such as protecting wildlife habitats near generation sites and funding renewable initiatives in developing nations.
• Standard Variable Tariff (SVT): This tariff has no fixed end date, and the price you pay for energy can fluctuate in line with wholesale market costs. The supplier is obligated to provide 30 days' notice of any price changes.
• Time-of-Use Tariffs: Specifically designed for households with high overnight energy consumption, such as electric vehicle (EV) owners. This tariff, which requires a smart meter, offers a significantly cheaper rate for electricity during a seven-hour off-peak window, typically between midnight and 7 am. This makes it much more economical to charge your car or run appliances like washing machines and dishwashers overnight.

3. The Price Cap Exemption: What Does It Mean?

You may notice that 100Green is exempt from the Ofgem energy price cap. This special status is granted to a small number of suppliers who can demonstrate that their business model genuinely supports and invests in renewable energy generation.

The exemption means their Standard Variable Tariff can be priced higher than the cap set by the regulator. However, this is a reflection of the real-world cost of producing 100% green gas and electricity without relying on carbon offsetting. Customers on this tariff have made an active choice to opt-in, prioritising the highest level of environmental sustainability over the lowest possible price.

4. Customer Service and User Experience

100Green has built a reputation for strong customer service, a fact underscored by its win as Best Small Supplier in the 2025 Uswitch Energy Awards. Unusually in an age of chatbots and online-only support, the company actively encourages customers to get in touch via telephone for a more personal service.

To support modern account management, 100Green also offers:

• A Mobile App: Available for both iOS and Android, the app allows customers to manage their accounts, submit meter readings, and view their energy usage.
• Smart Meters: They provide and install smart meters for free, which is a prerequisite for their innovative Time-of-Use tariff.

With a TrustPilot score of 4.0 from over 1,200 reviews, feedback generally praises the company's green credentials and helpful support team.

5. Additional Products and Services

Beyond supplying energy, 100Green is engaged in creating a more flexible and sustainable energy system.

• High Tide Scheme: This is their version of the Demand Flexibility Scheme. Customers are rewarded with account credit for reducing their electricity consumption during specified peak hours, helping to balance the grid and reduce reliance on fossil fuel power stations.
• Energy Export: For homeowners with solar panels, 100Green will purchase any surplus electricity you generate and export to the grid, providing you with credit on your account.

6. Is 100Green the Right Supplier for You?

Choosing an energy supplier is a personal decision based on budget, priorities, and values. 100Green is an excellent fit for:

• The Environmentally Conscious Consumer: If your primary goal is to minimise your household's carbon footprint with the greenest fuel available, 100Green is arguably the best choice in the UK.
• Electric Vehicle Owners: The Time-of-Use tariff offers substantial savings for those who can shift their charging to off-peak hours.
• Customers Seeking Transparency: Their straightforward promise of 100% green gas and electricity, without complex offsetting schemes, offers clarity.

However, it may be less suitable for those whose primary concern is finding the absolute cheapest tariff on the market, as their price cap exemption reflects the premium cost of their genuinely green energy.

7. How to Switch to 100Green

Switching is a simple process. Using an energy comparison website, you can enter your postcode and usage details to see if 100Green is available in your area and how its prices compare to other deals. The switch itself is handled entirely by the suppliers and typically takes just a few weeks with no interruption to your power supply.