The Big 6 energy providers are the UK’s largest energy suppliers that dominate the market. As of 2026, they are British Gas, Octopus Energy, E.ON Next, OVO Energy, EDF Energy, and Scottish Power. Together, these companies supply over 87% of UK households with gas and electricity, though the composition has changed significantly from the original Big 6 energy that dominated the market in the early 2000s.
If you’re looking to switch energy providers or simply want to understand the UK energy market better, this comprehensive guide will walk you through everything you need to know about these major players, how they’ve evolved, and what this means for you as a consumer.
Have big 6 energy providers changed?
The UK energy market has undergone dramatic transformation since its liberalisation in the late 1990s. The term “Big 6” originally referred to British Gas, EDF Energy, E.ON, npower, ScottishPower, and SSE, which collectively controlled nearly 99% of the domestic energy market by 2008.
However, significant market restructuring has occurred since then:
- In 2019, SSE sold its retail business to OVO Energy
- In 2021, npower’s customer base was absorbed by E.ON Next
- By 2023, Octopus Energy had grown dramatically through acquisitions, including taking over Shell Energy’s UK customers
- In 2025, Octopus Energy surpassed British Gas to become the UK’s largest energy supplier with 23.7% market share
This evolution reflects both regulatory changes aimed at increasing competition and the impact of the 2021-2022 energy crisis, which led to the collapse of many smaller suppliers.
| Original Big 6 (2008) | Current Big 6 (2026) |
|---|---|
| British Gas | Octopus Energy |
| EDF Energy | British Gas |
| E.ON | E.ON Next |
| npower | OVO Energy |
| ScottishPower | EDF Energy |
| SSE | ScottishPower |
The question of have big 6 energy providers shifted in structure becomes clear when you look at the mergers and acquisitions since 2019.
Who Are the Current Big 6 Energy Providers?
Let’s take a closer look at each of the current Big 6 Energy providers and what makes them distinctive in today’s market:
1. Octopus Energy 
Founded in 2015, Octopus Energy has risen meteorically to become the UK’s largest energy supplier with approximately 24% of both the electricity and gas markets. Their success stems from:
- Their proprietary Kraken technology platform that enables efficient customer management
- 100% renewable electricity tariffs
- Innovative pricing models like Agile Octopus (with 30-minute pricing tied to wholesale costs)
- Strong focus on EV-friendly tariffs and smart home integration
- Strategic acquisitions, including Bulb Energy’s 1.7 million customers
Octopus aims to achieve net-zero operations by 2030 and has expanded its customer base significantly by absorbing customers from failed suppliers during the energy crisis.
Octopus Energy reveals its global vision for smart energy tech. Read more here.
2. British Gas
The UK’s oldest energy supplier, British Gas (part of Centrica) remains a market giant with 20% of the electricity market and 27.2% of the gas market. Key features include:
- Extensive history dating back to 1812
- The British Gas Energy Trust, which has written off up to £2,000 in energy debt for over 21,000 customers since 2021
- Commitment to reduce greenhouse gas emissions by 40% by 2034
- Net-zero operations target by 2045
- Range of tariffs including fixed, variable and EV options
Despite losing its top position to Octopus, British Gas maintains strong brand recognition and customer loyalty.
3. E.ON Next
E.ON Next, the customer-facing brand of German multinational E.ON, holds 16% of the electricity market and 13.4% of the gas market. Distinctive aspects include:
- Absorption of npower’s customer base in 2021
- Strong focus on renewable energy tariffs
- Next Gust tariff sourcing energy from Yorkshire wind farms
- Climate-neutrality target for its operations by 2040
- Use of Octopus Energy’s Kraken platform under license to improve customer service
E.ON has invested over £3.5 billion in UK renewables since 2009, highlighting its commitment to green energy.
4. OVO Energy
Founded in 2009, OVO Energy grew substantially by acquiring SSE’s retail business in 2020. It now holds 12.6% of the electricity market and 10.6% of the gas market. Key features include:
- Plan Zero commitment to reach net-zero by 2035
- Power Move plan that rewards customers for using energy at greener, cheaper times
- Tree-planting initiatives (aiming for one million trees annually)
- Range of tariffs including variable, fixed, EV, and greener options
- Smart home integration with thermostats and energy management tools
OVO’s acquisition of SSE marked a symbolic end to the original Big 6 era.
5. EDF Energy
The UK subsidiary of French energy giant Électricité de France, EDF Energy supplies 10.5% of the electricity market and 8.7% of the gas market. Notable aspects include:
- Britain’s largest generator of zero-carbon electricity
- Operation of nuclear plants including Hinkley Point C
- Expanding offshore wind portfolio
- Net-zero target by 2050
- Specialised tariffs for homes with heat pumps or solar installations
EDF occasionally runs challenges for customers to shift electricity usage away from peak times, offering rewards like free hours of electricity.
6. Scottish Power
Owned by Spanish energy firm Iberdrola since 2007, Scottish Power holds 8.2% of the electricity market and 7.2% of the gas market. Key features include:
- 100% of electricity generated from its own wind farms
- Divestment from fossil fuels in 2018
- £10 billion planned investment in UK green infrastructure by 2030
- Net-zero greenhouse gas emissions target by 2039
- Specialized tariffs for heat pumps and solar panels
A common consumer question is have big 6 energy providers improved their renewable commitments or are smaller green suppliers still leading the way?
What Technological Innovations Are Driving the New Big 6?
The current Big 6 are investing heavily in technology to differentiate themselves and enhance customer engagement. Key innovations include:
Smart Home Integration and IoT Devices
Companies like Octopus Energy and OVO Energy are leading with smart home technology integration:
- Smart thermostats that optimise heating based on usage patterns
- Energy usage dashboards providing real-time consumption data
- Smart EV chargers that automatically charge during off-peak hours
These tools help customers visualise and manage their usage, optimise consumption patterns, and ultimately save money.
AI-Powered Customer Service
Artificial intelligence is revolutionising customer service in the energy sector:
- Octopus Energy’s proprietary Kraken platform automates customer queries, billing, and switching
- E.ON Next also uses Kraken under license, offering similar efficiencies
- 24/7 self-service options through apps and online portals
When people ask have big 6 energy providers adapted to new technology, the rise of smart home integration offers a clear answer.
Dynamic Pricing and Time-of-Use Tariffs
Innovative tariff structures are changing how consumers use energy:
- Agile Octopus tracks wholesale prices and reflects them in 30-minute time slots
- Octopus Go offers discounted overnight electricity for EV charging
- OVO’s Power Move rewards customers for shifting usage to off-peak times
These tariffs encourage customers to use energy when it’s cheapest and greenest, benefiting both consumers and the grid. See more here
How Did the 2021-2022 Energy Crisis Reshape the Market?
The energy crisis of 2021-2022 was a watershed moment for the UK energy market, with skyrocketing wholesale prices leading to the collapse of over 30 smaller suppliers. This crisis taught several important lessons and reshaped consumer trust:
Key Lessons from the Supplier Collapse
- Unsustainable business models are risky: Many smaller suppliers operated with thin margins and inadequate hedging strategies
- Regulatory oversight needed strengthening: Ofgem’s “light-touch” licensing allowed underprepared companies to enter the market
- Customer disruption came at a high cost: The total cost of failed supplier bailouts reached approximately £2.7 billion, ultimately paid through higher bills for all consumers
Another angle is whether have big 6 energy providers benefited from the crisis by absorbing customers from failed challengers.
Impact on Consumer Trust
The crisis significantly affected how consumers view energy suppliers:
- Trust in smaller challenger brands declined sharply
- Established providers like the Big 6 gained perceived stability
- Consumers became more cautious about switching to unknown brands
- Price is no longer the only consideration – stability and service now matter more
This shift in consumer sentiment has contributed to the reconsolidating of the market around the current Big 6.
Should You Choose a Big 6 Energy Supplier?
When deciding between a Big 6 or a smaller alternative, consider these factors:
Advantages of Big 6 Suppliers
- Financial stability – Less likely to go out of business during market volatility
- Extensive resources – Often offer more comprehensive customer service and support options
- Innovative tariffs – Many now offer specialised tariffs for EVs, heat pumps, and solar panels
- Warm Home Discount participation – All Big 6 energy providers participate in this scheme to help vulnerable customers
Advantages of Smaller Suppliers
- Potentially better customer service: According to Ofgem, 72% of smaller energy supplier customers were satisfied with service levels in 2023, compared to 62% for large suppliers
- Niche specialisation: Some focus exclusively on renewable energy or specific customer segments
- Competitive pricing: May offer deals on par with or cheaper than the Big 6
- Community focus: Some operate as cooperatives or have strong local connections
Alternative suppliers to consider in 2026 include:
- Utility Warehouse
- Utilita
- So Energy
- Good Energy
- Ecotricity
- Outfox the Market
- 100Green
Best energy suppliers for 2025 according to GOV.uk
How to Switch Energy Suppliers Effectively
Switching energy suppliers is easier than many people think. Here’s how to do it effectively:
Before You Switch
- Check your current tariff details and any exit fees
- Gather a recent energy bill with your usage information
- Consider what matters most to you: price, customer service, green credentials, or specific tariff features
The Switching Process
- Compare deals using a comparison service (like Switcheroo)
- Enter your postcode and current usage details
- Review available tariffs based on your priorities
- Select your preferred supplier and tariff
- Provide your details to complete the switch
Thanks to Ofgem’s switch guarantee, the process typically takes just 5-14 days, with no interruption to your supply. Your new supplier will handle all the arrangements with your old provider.
Common Switching Misconceptions
Many people hesitate to switch due to misconceptions:
- Myth: Your pipes and cables will need to be replaced
- Reality: You’ll receive the same energy through the same infrastructure
- Myth: Renters can’t switch suppliers
- Reality: If you pay the energy bills directly, you have the right to choose your supplier
- Myth: Switching is complicated and time-consuming
- Reality: The process is simple and handled mostly by your new supplier
Frequently Asked Questions About the Big 6 Energy Providers
Why has the composition of the Big 6 changed over time?
The Big 6 has evolved due to market consolidation, regulatory changes, and the rise of challenger brands. Key factors include Ofgem’s efforts to increase competition, mergers and acquisitions among suppliers, and the 2021-2022 energy crisis that led to many smaller suppliers failing. This created opportunities for companies like Octopus Energy to grow rapidly by acquiring customers from failed suppliers.
How do the Big 6 balance renewable commitments with affordability?
The Big 6 are navigating this challenge through several approaches: investing in renewable infrastructure to secure long-term price stability, participating in government-backed energy efficiency schemes, developing innovative tariffs that reward off-peak usage, and establishing support funds for vulnerable customers. For example, British Gas has allocated significant funds to help customers with energy debt, while Octopus focuses on technology to make renewable energy more affordable.
What happens if my energy supplier goes bust?
If your supplier fails, Ofgem’s Supplier of Last Resort (SoLR) mechanism ensures your energy supply continues without interruption. You’ll be automatically transferred to a new supplier chosen by Ofgem, typically one of the larger, more stable companies. Once the transfer is complete, you can shop around and switch to another supplier without exit fees if you prefer.
Are Big 6 Energy suppliers more expensive than smaller alternatives?
Not necessarily. While smaller suppliers sometimes offer competitive rates, the Big 6 have the scale to negotiate better wholesale prices and weather market volatility. Price differences vary by region, usage patterns, and specific tariffs. The best approach is to compare available deals based on your specific circumstances rather than assuming bigger means more expensive.
How can I tell if an energy supplier is financially stable?
While it’s difficult to predict with certainty, indicators of stability include: longevity in the market, size of customer base, parent company backing (especially international energy companies), transparent financial reporting, and whether they own generation assets or just supply energy. The Big 6 are generally considered the most stable due to their size and resources.
One of the top questions we hear is have big 6 energy providers changed enough to regain consumer trust after the energy crisis.
Conclusion: Making the Right Energy Choice for Your Needs
The UK energy market has evolved significantly, with the current Big Six Energy Providers, Octopus Energy, British Gas, E.ON Next, OVO Energy, EDF Energy, and Scottish Power, dominating the landscape in 2026. These companies have adapted to changing market conditions through technological innovation, strategic acquisitions, and a growing focus on renewable energy.
When choosing an energy supplier, consider what matters most to you: price, stability, customer service, green credentials, or specialised tariffs. The Big 6 suppliers offer the security of established brands with significant resources, while smaller suppliers may provide more personalised service or niche offerings.
Remember that switching is simpler than ever, with the entire process typically taking less than two weeks and requiring minimal effort on your part. By comparing options regularly, you can ensure you’re getting the best deal for your circumstances.
Ready to explore your energy options? Switcheroo makes it easy to compare suppliers and find the perfect fit for your household’s needs, potentially saving you hundreds of pounds each year while ensuring you get service that matches your priorities.
The debate over whether have big 6 energy providers offer the best value ultimately depends on what households prioritise: stability, green tariffs, or price.
