Constellation UK business energy supplier profile
Constellation UK is the UK-facing brand for Constellation’s energy business. The public site positions the group as a large US energy supplier with a UK presence, but the site content available here does not expose public business contact details or published non-domestic deemed/out-of-contract rate tables.
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Snapshot, in plain English
Is Constellation UK right for your business?
Licensed for 11 years with accounts currently filed. Sizing detail not yet independently researched, but the Companies House profile shows an established, active licensee suitable for single-site SME and mid-market multi-site contracts. Run standard counterparty due diligence before a 3-year commitment above £250k spend.
Risk band reasoning: Active, 11 years trading, accounts current.
| Your business | Fit | Why |
|---|---|---|
| Single site SME | Fit | Often competitive on single-site fixed rates. |
| Multi-site SME | Fit | Most mid-market suppliers handle multi-site billing. |
| I&C £250k to £1m spend | Possible | Check counterparty viability over a 3-year term. |
| I&C above £1m spend | Not suited | Below the scale threshold for I&C tenders. |
Quick facts
| Trading name | Constellation UK |
|---|---|
| Licence holder | CONSTELLATION GENERATION LTD. Parent: Constellation Generation Limited (Company No. 09198137); UK site also references Constellation Energy Corporation (Nasdaq: CEG) |
| Supplies | Electricity |
| Website | www-stage.constellationenergy.co.uk |
| Business phone | +44 20 3319 1808 |
| Email / contact | support@constellationenergy.co.ukContact page |
| Rate status | Quote required |
Company data
Live data on the licence-holding companies behind Constellation UK, compiled by Purely Energy's independent research team and refreshed monthly.
Constellation UK out-of-contract and deemed rates
Not publicly published / quote required
If you are on deemed, default, rollover, variable, or Out-of-contract rates, ask for a written renewal quote and compare it against live market prices before agreeing a new contract.
Where your p/kWh actually goes
Indicative split for a UK I&C electricity bill in 2026, sourced from Cornwall Insight's non-commodity cost research. Your meter, region and contract type shift the exact mix, but the four components are always present.
- Wholesale energy, 38%Gas or power bought on the wholesale market. The figure most coverage focuses on.
- Non-commodity costs, 53%Network charges (DUoS, TNUoS), policy levies (RO, FiT, CfD, Capacity Market), CCL and balancing costs.
- Supplier margin, 6%What the supplier earns. Always priced into the unit rate.
- Broker margin, 3%What we earn for tendering and managing the contract. Shown separately on every Purely Energy quote.
Who Constellation UK may suit
Likely a fit for larger business and public-sector energy procurement, especially organisations seeking tailored electricity supply arrangements rather than standard published tariffs. No public evidence of SME price-book style business pricing was found.
Trading name and licence-holder notes
The licence-holder appears to trade publicly as Constellation UK rather than under the exact legal entity name Constellation Generation Limited. Ofgem lists Constellation Generation Limited under electricity supply (domestic & non-dom) and gas shipper licensing, while the UK homepage references Constellation Energy Corporation as the wider group.
Switching from Constellation UK to a fixed business contract
UK businesses can switch electricity supply away from Constellation UK once their fixed contract ends, or after resolving any open objection or termination-window issue. The process is the same for every supplier on the non-domestic market, but a few checks done in the right order make the transfer materially faster.
- 1. Find your contract end date. It's on your last renewal letter or the most recent bill from Constellation UK. Most non-domestic contracts have a 1 to 6 month termination window before that date, outside of which you may auto-roll onto a new fixed term.
- 2. Get your MPAN ready. The 21-digit MPAN (electricity) and 6 to 10-digit MPRN (gas) uniquely identify each meter and are needed for any competing quote. Both appear on your bill.
- 3. Compare against the live market. Constellation UK doesn't publish standard out-of-contract rates, so request a written renewal quote first and benchmark it against live market prices before agreeing anything. Purely Energy can run your meters against the wider UK panel and come back with the cheapest fixed offers.
- 4. Settle the final bill and clear any objections. Constellation UK will issue a final bill within 6 weeks of supply transferring. If a balance is outstanding, they can object to the switch under industry rules, so clear it before the transfer date to avoid a hold.
- 5. Sign the new contract. Once the new supplier has your MPAN/MPRN and signed contract, the transfer typically completes within 4 to 8 weeks. There is no break in supply, you simply receive your first bill from the new supplier.
Need help with any of these steps? Our team handles the paperwork end-to-end as part of every quote.
Need help comparing Constellation UK?
Purely Energy can check your current rates, compare renewal options across electricity suppliers, and review whether switching could reduce your business energy costs.
FAQs
Who supplies energy under the Constellation UK brand?+
The Ofgem non-domestic licence is held by CONSTELLATION GENERATION LTD., ultimately part of Constellation Generation Limited (Company No. 09198137); UK site also references Constellation Energy Corporation (Nasdaq: CEG). The trading name on your bill or contract may differ from the licence holder, which is normal and reflects how UK energy is regulated.
What is the Constellation UK business contact number?+
Constellation UK can be reached on +44 20 3319 1808 or by email at support@constellationenergy.co.uk. The official contact page is https://www.constellationenergy.co.uk/contact-us.
Does Constellation UK publish out-of-contract rates?+
Constellation UK does not appear to publish a standard deemed or out-of-contract rate online. Business customers should request a written renewal quote in advance of their contract end date and compare it against live market prices.
Can I switch away from Constellation UK?+
In most cases, businesses can switch electricity supply away from Constellation UK at the end of a fixed-term contract or after resolving any objections, debt, termination-window, or meter-data issues. The safest route is to check your contract terms, final bill position, and renewal dates before starting a transfer.
How long does it take to switch from Constellation UK?+
Once a new supplier has the meter point details (MPAN/MPRN) and a signed contract, a non-domestic switch typically completes within 4 to 8 weeks. Supply does not break: the new supplier takes over billing on the transfer date.
Is Constellation UK a UK-licensed supplier?+
Yes. Constellation UK is on the Ofgem non-domestic licensee register for electricity. Ofgem maintains the official register at ofgem.gov.uk.
What are out-of-contract business energy rates?+
Out-of-contract rates are the prices a business pays when no fixed-term contract is in place with its supplier. They can be materially higher than negotiated contract rates, so businesses should check their contract end date and renewal window before they expire.
Other UK electricity suppliers
Compare Constellation UK against these other UK non-domestic electricity licensees on the same directory.
- arto.energyARTO.ENERGY LTD.
- BarbicanPowerBARBICAN POWER LTD.
- Bryt EnergyBRYT ENERGY LTD.
- Champion EnergyFARRINGDON ENERGY LTD.
- Clear Business (Sinq Power trading as Clear Business)SINQ POWER LTD.
- Clear Business; electricity supplier brand referenced as Sinq Power LimitedVERASTAR LTD.
Or browse the full UK business energy supplier directory.
Sources
Public data this profile is built from. Always verify rate and contract details on the supplier's own website before relying on them.