Start with the exit fee, then keep going
An exit fee decides whether you are free to move, but it says nothing about what you pay once you stay. Read it first, confirm the number, then move on to the parts of the bill that repeat every month.
Exit fees across the suppliers in our comparison run €0, so the whole field sits at the no-cost end. Endesa charges €0 to leave, Octopus Energy charges €0 and 100Green charges £0. No penalty means a bad price is a price you can correct next month rather than a bill you are stuck with, which changes how much risk each other number deserves.
The rankings of energy tariffs without exit fees narrow the field on that basis alone. Use them as a shortlist, then compare what follows.
Unit rate: the price per unit you actually pay
The unit rate is the cost of each unit of energy, and it dominates the bill of any household that uses a normal amount of power. The spread in our data is €0.11 to €0.45, so the cheapest and dearest unit rates sit far apart and the choice is worth real money.
Worked example: Endesa's unit rate is €0.12 and Octopus Energy's is €0.17. Neither figure is better in the abstract. Rates are tied to a market, a plan and a moment in time, so read each alongside the supplier's own page in the Endesa review and the Octopus Energy review.
A time-of-use or variable plan shifts part of the cost into cheaper or dearer hours. If your household can run the dishwasher, the washing machine or the car charger overnight, a plan shaped around usage can beat a flat rate at the same supplier. If your usage never moves, a flat rate is easier to predict.
Standing charge: the fixed cost that hurts light users
The standing charge is the part of the bill that arrives whether you use energy or not. Across our data it runs €0.09 to €144, a much wider spread than unit rates, which makes it the easiest saving to miss.
Endesa's standing charge is €2.85 against a unit rate of €0.12. Octopus Energy's standing charge is €6 with a unit rate of €0.17. A higher standing charge paired with a lower unit rate suits a household that uses a lot; a lower standing charge paired with a higher unit rate suits a household that uses very little or is away often.
Do the arithmetic before you commit. Multiply the unit rate by your expected usage, add the standing charge, and compare that annual figure across suppliers rather than reading either number alone. This is the single most useful step in the whole comparison.
Contract length and the type of tariff
No exit fee removes the penalty for a bad decision, but it does not remove the need to commit. Endesa offers fixed terms of 12, 36 and 60, Octopus Energy offers 12 and 100Green offers 12. A longer term often buys a better rate, so match the length to how settled your household is. Renting, moving or expecting a change of usage argues for the shortest term on offer.
Tariff type matters as much as length. Endesa lists fixed, time of use and ev, and Octopus Energy lists fixed, variable and green. A fixed plan gives you a known unit rate for the whole term, a variable plan follows the market, an electric vehicle rate rewards home charging and a time-of-use plan rewards shifting demand.
If the environmental claim is part of your decision, Octopus Energy reports 100% renewable supply based on certificates. Check how that is described on the plan you are considering, because certificates and physical generation are different things.
Check the market before the price
Prices are only comparable within a single market. Endesa is headquartered in ES and serves ES and PT, covering Spain, Canarias and Baleares. Octopus Energy is headquartered in IT and serves IT. 100Green is headquartered in GB.
The currencies differ too. 100Green's exit fee is quoted in pounds while Endesa and Octopus Energy quote in euros, so a straight number comparison across the two groups tells you nothing. Start with the supplier that actually serves your address, then compare within that group.
The contracting entity is worth noting before you sign, particularly for a single market operation. Endesa contracts as ENDESA ENERGIA S.A.U., Octopus Energy as Octopus Energy Italia Srl and 100Green as Green Energy (UK) Limited. Both Endesa and Octopus Energy also supply gas, not just electricity.
Export rates matter if you generate your own
If you have solar panels or plan to, the export rate is the money you get back for the energy you push into the grid. 100Green's export rate is £0.12 and Endesa's is €0.06. A high unit rate and a low export rate can be a poor trade for a generator, so read both numbers before choosing a plan.
The 100Green review sets out how its tariffs handle home generation. A supplier that pays poorly for exported power can erase the benefit of a cheap unit rate during daylight hours.
Support, apps and electric vehicle extras
Reliability shows up in how you get help when a bill looks wrong. Endesa offers support through email, chat and phone and Octopus Energy through email, phone and chat. Both include a phone line, a help centre and a written channel, which matters more than the count when you need an answer about a specific reading.
Scale and longevity are reasonable proxies for staying power. Endesa reports 12,700,000 customers and was founded in 1944, while 100Green was founded in 2001. A long-standing supplier is not automatically dependable, but it has more history behind the claim.
Electric vehicle owners have extra lines to check. Endesa lists a charger at €1,099 with power from 7.4 to 22, a warranty of 3 years, installation included and a tethered unit, managed through Tarifa Recarga en Casa and a mobile app. Bundle the charger with the tariff if you charge at home, and check the power range suits your supply and your car.
A short checklist before you sign
Run through these in order: confirm the exit fee, note the contract term, compare the unit rate against your real usage, add the standing charge to reach an annual figure, check that the supplier serves your address and your currency, and only then look at extras such as export rates, apps and chargers.
With no exit fee, being wrong is cheap to fix, which means the main risk is picking a plan that fits your usage badly. Spend your effort on the annual total and the term length.
Start with the energy tariffs without exit fees ranking, read the Endesa review and the Octopus Energy review for the detail behind these numbers, then decide with the total in front of you.