So Energy Review UK 2026: 100% Renewable Tariffs, ESB Ownership & Service Record

Last reviewed: 17 May 2026 | Chandraketu Tripathi, finance editor

Suppliers · So Energy

So Energy is a UK retail energy supplier positioned around a 100 percent renewable-electricity claim and a customer-service-led proposition. Founded as an independent challenger in the early 2010s, the business was acquired by ESB (Electricity Supply Board), the Republic of Ireland's state-owned utility group, in 2021. So Energy Trading Limited holds the Ofgem domestic gas and electricity supply licence and the brand serves an estimated 300,000 to 400,000 UK customer accounts as of early 2026, placing it among the smaller challenger suppliers rather than the post-Big-Six majors. This review covers the tariff range visible to customers in 2026, the supplier's track record on Citizens Advice star ratings and Ofgem complaints data, how the switching process behaves in practice, the company's approach to the Ofgem default tariff cap and standing charges, the renewable-electricity claim in detail, and the ownership and regulatory structure. Live unit prices are described structurally rather than quoted: the Ofgem default tariff cap is recalculated every three months and any specific pence-per-kWh figure printed in editorial would be out of date within weeks.

Tariffs available on the So Energy in 2026

So Energy operates a small, easily readable named tariff range rather than a long catalogue. The current product families visible on the supplier's published tariff schedule in 2026 are:

So Bright. A fixed-term product, historically offered in 12-month and occasionally 18-month versions. Fixed-term pricing is set at the point of contract and unit rates and standing charges are locked for the duration of the fixed period. Customers on a fixed-term tariff are not directly exposed to the quarterly recalculation of the Ofgem default tariff cap during the term, but at the end of the term they roll onto the supplier's variable rate unless they take action.

So Smart. A smart-meter and electric-vehicle bundle. The product offers a cheaper off-peak unit rate, typically across a defined overnight window, and a higher peak rate during the day. Eligibility requires a SMETS2 smart meter operating in half-hourly settlement mode and is positioned for customers with an EV or qualifying flexible-load device. So Smart is one of the products the brand uses to differentiate against larger suppliers' EV bundles.

So Flex. The variable-rate default tariff. Unit rates and standing charges on So Flex track the Ofgem default tariff cap and are recalculated for each quarterly cap period. Customers who do nothing at the end of a fixed-term So Bright contract drop onto So Flex. The product is dual-fuel capable and available on credit meters, with unit rates differing by Ofgem regional distribution zone.

This review does not quote specific unit prices. The customer-specific tariff information label that So Energy is required to issue under the Retail Energy Code is the authoritative current figure for any individual customer's quoted unit rate and standing charge.

Customer service track record

Three independent datasets are useful for assessing a UK supplier's customer service performance, and all three publish on a quarterly cycle.

Ofgem complaints per 100,000 customers. Ofgem publishes a quarterly bulletin showing the number of complaints received by each licensed supplier, normalised per 100,000 customer accounts. So Energy, as a smaller supplier, can show more volatility quarter to quarter because a smaller absolute customer base means individual complaint clusters move the per-100,000 figure more visibly. The current quarterly figure should be checked directly in the most recent Ofgem complaints data publication at ofgem.gov.uk.

Citizens Advice quarterly star rating. Citizens Advice publishes a supplier comparison table each quarter, scoring suppliers across five weighted service dimensions including complaints handling, ease of contact, accuracy of bills, customer guarantees and customer service ratings. So Energy has sat at the higher end of the table for several recent quarters, a position typically achieved by smaller customer-service-led challengers. Readers should consult the latest Citizens Advice supplier table at citizensadvice.org.uk for the current published star score.

Energy Ombudsman case volume. Where a complaint cannot be resolved by the supplier within eight weeks, or where the supplier issues a deadlock letter sooner, the case can escalate to the Energy Ombudsman, the redress scheme approved by Ofgem under section 47A of the Electricity Act 1989. The Ombudsman publishes aggregate annual statistics by supplier. So Energy's case volume reflects the smaller customer base, and the absolute number of cases is lower than at the post-Big-Six majors.

The customer-service-led positioning of So Energy is reflected in a relatively higher Citizens Advice score versus the supplier average over several recent quarters. Readers should still consult the latest published figures rather than rely on positioning that may have changed.

Switching process specifics

UK domestic energy switches in 2026 operate under the Faster Switching programme delivered through the Retail Energy Code Company, with a target switch completion of five working days from the date the gaining supplier confirms the request. A 14-day cooling-off window runs in parallel, during which the customer can cancel the switch under the Consumer Contracts Regulations 2013.

For So Energy as the gaining supplier, the practical timeline is: switch request submitted, gaining-supplier confirmation issued by So Energy within one to two working days, the 14-day cooling-off window runs in parallel, and the supply takeover takes effect on the date confirmed in the welcome pack. The losing supplier is required to issue a final bill within six weeks of supply takeover under Ofgem Standard Licence Condition 31E.

Smart meter handover behaviour depends on the meter generation. SMETS1 meters installed under earlier supplier contracts can drop into dumb mode temporarily after a switch, taking manual reads until the meter is migrated onto the central Data Communications Company network. SMETS2 meters communicate via the DCC from installation and the switch is invisible to the meter. So Energy operates within the same DCC migration framework that all licensed suppliers follow.

Final billing on switch-out from So Energy is required within six weeks under Ofgem rules. Smaller suppliers can occasionally process final bills faster than the statutory deadline because the lower volume per quarter means less queue depth, but the regulatory floor is the same six-week window across the industry.

Price cap protection and standing charge approach

The Ofgem default tariff cap, introduced under the Domestic Gas and Electricity (Tariff Cap) Act 2018, sets a maximum unit rate and standing charge that licensed suppliers may charge customers on a default or standard variable tariff. The cap is recalculated each quarter using a wholesale-cost methodology Ofgem publishes openly. Customers on a fixed-term tariff are not protected by the cap and pay the contracted unit rate and standing charge for the duration of the fixed term.

So Energy's So Flex variable tariff is priced within the cap for the relevant Ofgem regional distribution zone. Standing charges differ by region, reflecting the different network distribution costs Ofgem allows for each of the 14 distribution zones. The supplier's published tariff information label, which Ofgem requires to be issued to each customer, sets out the customer-specific unit rate and standing charge in pence per kWh and pence per day.

Smaller renewable-focused suppliers have historically had less ability than the largest suppliers to hedge wholesale gas and power costs at scale, which means fixed-term product pricing can be less aggressive than the unhedged-cost benefit available to the very largest suppliers. This is a structural feature of smaller suppliers in any given quarter and is reflected in fixed-term pricing across the smaller end of the supplier market. The customer-specific tariff information label remains the authoritative figure at the point of quote.

Standing charges in the Ofgem default tariff cap have risen materially since 2022, reflecting the cost of supplier-of-last-resort exercises and the recovery of network and policy costs. So Energy, like all suppliers operating on the cap, applies the standing charge per day regardless of consumption. Ofgem has consulted publicly on alternative standing-charge structures, including a zero-standing-charge tariff option, but no industry-wide change to the standing-charge structure has been finalised at the time of writing.

Green credentials

So Energy markets 100 percent renewable electricity to UK domestic customers as a central part of its positioning. The mechanism behind that claim, as for most UK retail suppliers making the same claim, is the purchase of Renewable Energy Guarantees of Origin (REGO) certificates equivalent to the customer's annual consumption. REGOs are issued by Ofgem to renewable generators and traded separately from the underlying electricity. A REGO-backed claim does not mean the supplier procures matching physical generation in real time; it means certificates equal to annual consumption have been acquired and retired.

So Energy has historically been one of the smaller suppliers to make the renewable claim a foundational marketing position rather than an optional product tier. The wider ESB parent group operates substantial renewable generation in the Republic of Ireland, including wind and solar assets, plus thermal and pumped-storage generation. The retail claim made to UK customers is, however, a REGO-backed retail claim and the annual Fuel Mix Disclosure published under the Electricity (Fuel Mix Disclosure) Regulations 2005 is the authoritative document for the precise percentage breakdown by source.

So Energy has historically operated customer-fund-renewable schemes including tree-planting commitments per customer signed up. The current scheme structure and any associated third-party verification (such as Carbon Trust or Woodland Trust partnership) should be checked on the supplier's sustainability page for the current quarter. So Energy does not currently hold B Corp certification at the UK retail entity level; readers interested in B Corp status across UK renewable suppliers should compare published B Corp certification records directly at bcorporation.net.

Ownership, regulation and structure

The UK retail supply licence is held by So Energy Trading Limited, registered at Companies House. The licence sits within Ofgem's published register of licensed domestic gas and electricity suppliers and can be searched at ofgem.gov.uk. The supplier operates under the standard Ofgem Domestic Gas and Electricity Supply Licence conditions, including the Standards of Conduct, the Retail Energy Code, the Smart Metering Installation Code of Practice, and the Priority Services Register requirements for vulnerable customers.

The ultimate parent is ESB (Electricity Supply Board), the state-owned Republic of Ireland utility group, following the 2021 acquisition. ESB publishes consolidated group financial statements and is one of the largest utility groups in the Republic of Ireland. The UK retail entity's accounts are filed at Companies House and are publicly accessible under So Energy Trading Limited.

The UK head office is in London. Field engineering for smart-meter installation operates through accredited contractor networks under the Smart Metering Installation Code of Practice; smaller suppliers typically use third-party install partners rather than maintaining a large in-house field force. Gas-emergency response is delivered by the National Gas Emergency Service (0800 111 999) for all gas customers across the UK, regardless of supplier.

So Energy does not currently operate a regulated credit business in the UK retail brand and is not authorised by the Financial Conduct Authority in that capacity. Standard supplier credit arrangements (the supply of energy on account, where the customer pays in arrears) operate under Ofgem licence conditions rather than under FCA regulation. Payment plans for arrears, where offered, fall under Ofgem's vulnerability and ability-to-pay rules.

Frequently asked questions

Who owns So Energy?

So Energy Trading Limited is the UK retail energy supply entity. The ultimate parent is ESB (Electricity Supply Board), the state-owned Republic of Ireland utility group, following the 2021 acquisition. ESB operates substantial generation and network assets in the Republic of Ireland. The UK retail head office is in London. The Ofgem supply licence is held in the UK subsidiary's name and the company is registered at Companies House.

What tariffs does So Energy offer in 2026?

The named tariff range includes So Bright (a fixed-term product, historically offered in 12 and 18 month versions), So Smart (a smart-meter and electric-vehicle bundle with cheaper off-peak unit rates) and So Flex (the variable rate that tracks the Ofgem default tariff cap). Specific live unit prices are not quoted in this article because the cap is recalculated quarterly; the customer-specific tariff information label issued at the point of switching is the authoritative current figure.

How is So Energy rated by Citizens Advice and Ofgem?

Citizens Advice publishes a quarterly star rating across five weighted service dimensions. So Energy has sat at the higher end of the supplier comparison table for several recent quarters, a position typically achieved by smaller customer-service-led challengers. Ofgem also publishes complaints per 100,000 customers each quarter, and smaller suppliers can show more volatility because a smaller customer base means individual complaint clusters move the per-100,000 figure more visibly. Readers should check the most recent published figures at citizensadvice.org.uk and ofgem.gov.uk.

Is So Energy genuinely 100 percent renewable?

So Energy markets 100 percent renewable electricity to UK domestic customers and the mechanism is the purchase of Renewable Energy Guarantees of Origin (REGO) certificates equivalent to annual customer consumption. A REGO-backed claim does not mean the supplier procures matching physical generation in real time; it means certificates equal to annual consumption have been acquired and retired. The annual Fuel Mix Disclosure issued under the Electricity (Fuel Mix Disclosure) Regulations 2005 sets out the precise percentage breakdown by source and is the authoritative document for assessing the renewable claim.

How long does a switch to or from So Energy take in 2026?

UK domestic energy switches operate under the Faster Switching programme with a target of five working days from the gaining supplier's confirmation, plus a 14-day cooling-off window. The losing supplier is required to issue a final bill within six weeks of supply takeover under Ofgem Standard Licence Condition 31E. Smart meter handover behaviour depends on whether the meter is SMETS1 (which can temporarily drop into dumb mode pending DCC migration) or SMETS2 (where the switch is invisible to the meter).

What happens to my supply if So Energy were ever to fail as a supplier?

All UK domestic energy customers are protected by Ofgem's Supplier of Last Resort process under Standard Licence Condition 8. If a licensed supplier exits the market, Ofgem appoints another licensed supplier to take over the failed supplier's customer accounts, and supply is not interrupted. Credit balances are protected through industry funding arrangements. So Energy is a licensed supplier operating under standard Ofgem conditions, so its customers are within the same Supplier of Last Resort protection as any other UK domestic energy customer.

How we verified this article

The Ofgem licence position for So Energy Trading Limited was verified against Ofgem's published supplier licence register and Companies House at find-and-update.company-information.service.gov.uk. The customer-base figure of an estimated 300,000 to 400,000 accounts reflects the most recent publicly available disclosures from the supplier and parent group at the time of writing.

Citizens Advice quarterly star rating positioning and Ofgem complaints per 100,000 customers data are described in directional terms only. Readers should consult the most recent Citizens Advice supplier table at citizensadvice.org.uk and the most recent Ofgem quarterly complaints publication at ofgem.gov.uk for current published figures before drawing conclusions.

Tariff names and tariff structure descriptions are drawn from So Energy's published tariff schedule and customer-facing product pages. No specific live unit prices or standing charges are quoted in this article because the Ofgem default tariff cap is recalculated quarterly and any number quoted would be out of date within weeks. Readers should check the customer-specific tariff information label issued at the point of switching for current numbers.

Kaeltripton.com is an independent editorial publisher and is not paid by So Energy or any other supplier referenced in this article. No commission is taken on switches and no preferential placement is offered to suppliers in editorial content.

Sources

• Ofgem - Domestic supplier complaints data quarterly publication
• Citizens Advice - Compare energy suppliers customer service ratings
• Ofgem - Energy supplier licence register
• Energy Ombudsman - About the redress scheme
• So Energy - Tariffs and customer information
• Companies House - So Energy Trading Limited record
• GOV.UK - Electricity Fuel Mix Disclosure Regulations 2005