TL;DR
- So Energy is a UK retail energy supplier owned by ESB Group (the Irish state-owned utility) since November 2021. The supplier serves around 350,000 domestic customers as of Q4 2025.
- Electricity supply is matched 100% with REGO certificates. Gas, where supplied, is offered with optional carbon offsetting on the So Bamboo gas tariff.
- Tariff range: standard variable (cap-priced), 12-month fixed (So Sustain), and a small set of bespoke fixed and tracker products. EV-specific time-of-use tariffs are not currently in the range.
- Citizens Advice Q4 2025 supplier rating: 4.15 out of 5. Third-highest among major UK suppliers, behind Octopus and Utilita.
- Best fit for customers wanting a smaller-supplier feel with stable customer service and a credible green claim. Less competitive on smart tariffs and EV-specific products.
Last reviewed: May 2026
So Energy is a UK retail supplier that has held its character through changing ownership and market conditions. The product range is small and clearly described. The customer service operation has stayed responsive even after the ESB acquisition. The renewable claim is REGO-backed, which is industry standard, but the supplier is more upfront about the limitations of that mechanism than most competitors. For customers who want a smaller-feeling supplier with credible green credentials and steady service, So Energy is a reasonable choice.
The product range is the limiting factor. Customers with EVs or heat pumps will not find dedicated smart tariffs here.
Simplicity is a positioning choice, not a limitation.
The tariff range
So Energy keeps the menu short. The standard variable, called So Flex, is priced at the Ofgem cap and serves as the default for new customers who do not actively choose a fixed product. So Sustain is the 12-month fixed-rate product, priced below the cap on launch with a small exit fee. The supplier occasionally releases bespoke 24-month fixes and a tracker-style product that follows the cap with a small discount.
Electricity supply on all tariffs is REGO-matched. The supplier publishes its annual fuel mix disclosure showing the proportion of generation by source matched to consumption. The 2024-25 disclosure (published December 2025) showed 100% renewable matching on electricity supplied to customers.
The supplier does not currently run an EV-dedicated time-of-use tariff or a heat pump time-of-use product. Customers with those loads are served on the standard variable or fix and would not benefit from off-peak pricing.
Where it breaks: customers shopping for a specific Octopus-style smart tariff find So Energy's range too narrow. The supplier targets a customer profile that values simplicity and green credentials over smart-tariff optimisation.
April 2026 rates
Sample rates from the So Energy customer-facing tariff page on 1 April 2026, inclusive of VAT, Eastern region.
| Tariff | Elec unit (p/kWh) | Gas unit (p/kWh) | Elec standing (p/day) | Gas standing (p/day) |
|---|---|---|---|---|
| So Flex (standard variable, cap) | 26.96 | 7.01 | 53.80 | 32.67 |
| So Sustain 12-month fix | 25.40 | 6.60 | 53.80 | 32.67 |
| So Sustain 24-month fix | 25.85 | 6.75 | 53.80 | 32.67 |
For a medium-consumption household the So Sustain 12-month fix lands at around £1,985 per year, against the cap-equivalent £2,166. The 8% saving sustained for 12 months is £180 if the cap does not move materially.
The exit fee on So Sustain is £75 per fuel for 12-month and £150 per fuel for 24-month. Switching mid-contract within the last 49 days is free.
The renewable claim
So Energy's renewable electricity claim uses the standard UK REGO mechanism. The supplier purchases REGO certificates equivalent to its total customer electricity consumption from renewable generators. The certificates are retired in the Ofgem REGO register; the audit trail is public.
So Energy is more direct than most about what REGO matching does and does not mean. The supplier's published explainer notes that REGOs are tradable separately from electricity and that the matching is portfolio-level. Customers seeking deeper procurement linkage (direct PPAs with named renewable assets) are pointed toward Good Energy and Ecotricity in the supplier's comparison materials.
For gas, So Energy offers the So Bamboo option which adds a carbon offset purchase to gas supply. Offset projects are audited under Verra or Gold Standard. The supplier's portfolio mix has rotated over time; 2025-26 included a mix of methane capture, improved cookstove, and forestry projects.
The catch on carbon offsetting: the Voluntary Carbon Market Integrity Initiative (VCMI) published criticism of forestry-heavy offset portfolios in February 2025. So Energy's portfolio has been rebalanced toward methane capture projects partly in response. The customer should know that offset claims are contested.
Customer service quality
So Energy scored 4.15 out of 5 in the Q4 2025 Citizens Advice supplier rating, third-highest among major UK suppliers. The supplier's complaint volumes per 10,000 customers run below the sector average.
The customer service operation runs from offices in Mumbai and London with a UK-based escalation team for complex cases. Response times are competitive: chat within a few hours, email within 2 to 3 working days, phone calls answered within 5 minutes on average outside peak periods.
The named-account approach used by Octopus is not replicated at So Energy; customers reach a queue of generalist agents. Escalation routes are clear and the supplier's published complaint handling procedure is straightforward.
Complaint themes for 2025-26 cluster around smart meter install lead times and billing accuracy after switch. Volumes are low enough that no theme dominates.
Smart meter and account management
So Energy installs SMETS2 smart meters free of charge under the DESNZ Smart Meter Implementation Programme. Average lead time in 2026 is 10 to 14 weeks, in line with the GB sector mean.
The customer dashboard supports tariff selection, meter readings, direct debit management, and complaint submission. The mobile app is functional rather than feature-rich; Octopus's app remains the market benchmark for retail energy supplier apps.
Customers without smart meters can take any tariff in the So Energy range. Smart meter is not required for the fix products or the standard variable.
Eligibility and the sign-up process
Sign-up is through the So Energy online quote tool. The supplier accepts new customers across England, Scotland, and Wales. Northern Ireland is not currently supplied.
The switch process follows the Ofgem May 2022 rules: five working days to completion. Customers transferring from a fixed tariff with another supplier should check exit fees at the outgoing supplier before switching.
Direct debit is the standard payment method. Cash and cheque payment are available with small per-payment fees. Prepayment meter customers are accepted; the prepayment standard variable is priced at the Ofgem prepayment cap.
When So Energy is the right choice
So Energy works for customers who want a credible REGO-backed renewable claim, simple tariff structure without smart-tariff complexity, customer service quality above the sector median, and prices reasonably competitive with the cap on the fix products. The supplier targets the engaged-but-not-optimising customer.
It works less well for customers who want EV or heat pump time-of-use pricing. The supplier's range does not include those products. Households with smart-load equipment are better served by Octopus's portfolio.
It also works less well for customers who want the deepest green credentials. Good Energy's PPA-backed direct procurement is a stronger claim than So Energy's REGO matching, although the premium is also higher.
For the customer profile of "engaged, green-leaning, prefers a smaller supplier feel, not chasing the absolute lowest unit rate", So Energy is a defensible pick. The Citizens Advice score and the steady supplier history support the choice.
The ESB Group ownership and what it changed
So Energy was founded in 2015 as an independent UK retail supplier with a 100% renewable electricity proposition. ESB Group, the Irish state-owned utility, acquired So Energy in November 2021. The acquisition provided So Energy with capital backing during the wholesale crisis and operational integration with ESB's broader European energy operations.
For customers, the ownership change had limited day-to-day visibility. The brand continued, the customer-facing operation continued, and the tariff range continued. The behind-the-scenes change was meaningful: ESB's procurement scale and balance sheet provided resilience that So Energy lacked as a standalone independent.
The customer service operation remained UK-based after the acquisition. ESB invested in supplier-side systems and the smart meter operation. The growth from approximately 200,000 customers at acquisition to around 350,000 by end-2025 was funded partly through ESB capital.
The acquisition also means So Energy is unlikely to fail in the way many small UK suppliers did during the 2021-22 wholesale crisis. ESB's deep capital base provides a backstop that pure-play independents do not have.
For customers, the practical implication is reduced supplier failure risk. The supplier's financial stability rating with Ofgem is solid. The customer credit balance protection that applies to all UK retail suppliers also applies to So Energy. The combined effect is that customers can take a 12 or 24 month fix at So Energy with confidence that the supplier will be around to honour it.
One thing to know about the dashboard
In practice, So Energy customers who export data monthly to a spreadsheet catch billing errors faster than those who rely on the in-app charts, because the chart smoothing hides single-day spikes.
So Energy's customer dashboard is functional but less feature-rich than Octopus's app. Smart meter readings are visible, tariff selection is straightforward, and direct debit management is clean. What is missing is the half-hourly consumption visualisation and the daily price preview that smart-tariff customers at Octopus rely on. For So Energy customers on the standard variable or a fix, this absence does not matter. For customers who might later want a smart tariff, the dashboard limitation is one reason the supplier targets a different customer profile.
Editorial disclaimer. Kaeltripton is an independent UK finance publisher. This article is general information for UK adults making their own decisions, not regulated financial advice. Tariff prices, fuel mix disclosures, and supplier policies change. Figures reflect So Energy, Ofgem, Citizens Advice, and Verra publications dated before the last-reviewed date at the top of this page. For complaints, refunds, or vulnerable-customer protection the formal route runs through the supplier first and then the Energy Ombudsman.
FAQ
Is So Energy 100% renewable?
Electricity supply is matched 100% with REGO certificates. The supplier is transparent that REGO matching is not the same as direct procurement from named renewable generators.
Does So Energy have EV or heat pump tariffs?
No. The current tariff range does not include time-of-use products. Customers with EVs or heat pumps are typically better served by Octopus or E.ON Next.
How is So Energy's customer service rating?
Citizens Advice Q4 2025 score: 4.15 out of 5. Third-highest in the sector. Complaint volumes per customer are below the sector average.
What is the exit fee on the So Sustain fix?
£75 per fuel for the 12-month So Sustain, £150 per fuel for the 24-month version. Last 49 days of the contract are free under Ofgem rules.
Is switching to So Energy possible without losing the current smart meter?
Yes. SMETS2 smart meters work across suppliers. The new supplier picks up the half-hourly settlement data once the switch completes.
Does So Energy offer prepayment meters?
Yes. The supplier has a prepayment standard variable priced at the Ofgem prepayment cap. New PPM installs go through the standard rollout queue.
