UK Energy Market Consolidation: E.ON-Ovo Merger Creates 'Big Three' Supplier Dominance

The UK's energy market is set for a significant consolidation as E.ON's takeover of rival Ovo Energy is poised to receive regulatory approval. Once completed, the deal will result in E.ON, Octopus Energy, and British Gas collectively supplying power to 74% of British homes, according to analysis by energy consultancy Cornwall Insight.

This merger dramatically reshapes the landscape from the 50-plus suppliers active before the 2021 energy crisis. As of this year, only 17 energy firms remain. "The big six have become the big three, and there have been questions raised over how this will impact household choice and the health of the market," said Tom Goswell, energy supply lead at Cornwall Insight.

Following the transaction, E.ON will become the UK's second-largest domestic energy supplier, commanding a 25% share of household electricity and gas accounts. Octopus Energy currently leads with 26%, followed by British Gas at 23%. The five largest suppliers—Octopus, British Gas, E.ON, EDF, and Scottish Power—will jointly control 90% of the domestic market once the E.ON-Ovo deal is finalized.

Market Dynamics and Consumer Concerns

The energy crisis, exacerbated by Russia's invasion of Ukraine, led to the collapse of numerous smaller suppliers unable to cope with soaring wholesale gas prices. Many of their customers were then transferred to larger companies through rescue arrangements.

Goswell explained that high wholesale prices since 2020 forced many smaller suppliers out, while the price cap limited customer switching. "The concern with fewer suppliers is that the pressure to compete eases off, taking with it some of the incentive to keep prices low and offer something different." This could potentially lead to higher long-term prices, despite the possibility of short-term attractive offers from the merged E.ON-Ovo entity.

However, Goswell also pointed out the benefits of fewer, larger firms. "Larger suppliers do bring with them a degree of stability, and after around 30 firms dropped out of the market, leaving customers wondering who would be sending their next bill, stability is not something to dismiss lightly." These larger entities also possess the scale to invest in specialized tariffs, such as those designed for electric vehicles or off-peak electricity usage, which smaller companies often find challenging to offer.

"The big suppliers have the resources to give people real choice, and the test over the next few years will be whether households who shop around find a genuine range of deals waiting for them rather than three versions of the same thing," Goswell added. No specific details regarding potential future price changes by E.ON or Ovo have been publicly released.

Customer Information During Transition

While the exact completion date for the E.ON-Ovo merger is not yet confirmed but expected later this year, customers of both firms are advised that no immediate action is required. E.ON and Ovo will continue to operate as separate entities for the time being.

Customers should not expect any immediate changes to their services, payment arrangements, including direct debits, or contact methods. The deal is structured to ensure no interruption to energy supply, and existing credit balances will remain protected. Tariffs will stay the same, and all existing fixed deals will be honored until their agreed terms expire. Customers eligible for the Warm Home Discount will continue to receive it, and the option to switch to a different provider remains available.

E.ON and Ovo have stated they will provide advance notification to customers if any changes to billing are anticipated.

Current Energy Price Landscape

Households not on fixed tariffs are currently facing the highest energy charges in three years. From October 1, the Ofgem price cap increased by 4%, following a 13% rise in July, reflecting global market price increases influenced by geopolitical events.

The typical annual bill, based on average gas and electricity usage paid by direct debit, stands at £1,723. This cap is calculated per unit of energy, meaning higher consumption results in higher overall costs.

Further increases are anticipated in January, with a typical annual bill forecast to rise by £276. Cornwall Insight predicts approximately a 16% quarterly increase in the domestic energy price cap in January 2027 due to sustained high wholesale energy prices. This would bring the annual bill for typical usage to £1,999, the highest level since March 2023.

Wholesale energy costs are the primary driver of Ofgem's domestic price cap, which is reviewed quarterly and incorporates network costs, environmental initiatives, and social levies.