Methodology

Scope

OpenKWh compares residential electricity offers on Enedis and gas offers on GRDF in mainland France.

Local distribution areas outside Enedis or GRDF are handled separately when a reliable source allows them to be modeled.

Price calculation

Recurring annual cost combines subscription and consumption from the entered profile.

VAT-inclusive prices include taxes and network costs when those are already included in supplier grids.

Temporary promotions are separated from recurring annual cost so first-year savings are not confused with durable pricing.

For peak/off-peak offers, OpenKWh uses the entered peak and off-peak consumption to compute a total comparable with the Base profile.

Public references

When the profile allows it, electricity is compared with regulated Tarif Bleu and gas with the CRE gas reference price.

Peak/off-peak offers are compared with a normalized peak/off-peak profile built from the consumption entered by the user.

Ranking and filters

Relevance ranking combines price, stability, data quality, green guarantees, and contractual simplicity through a versioned, inspectable formula.

The default score weights recurring annual price at 45%, first-year cost at 10%, price stability at 20%, price-data status at 10%, green or biomethane guarantees at 5%, and contractual simplicity at 10%.

Recurring price remains the main scoring factor. Caps and penalties limit misleading rankings when an offer is materially more expensive, incomplete, ambiguous, quote-only, dominated by a comparable offer, or dependent on a temporary promotion.

Strict price sorts remain available and are not modified by qualitative criteria.

Green criteria can be included in or neutralized from the score to distinguish uses where they matter from uses where only price matters.

Score components, penalties, caps, and sources remain inspectable to explain why an offer appears at a given position.

Green guarantees and biomethane

Guarantees of origin, French origin, labels or sourcing methods, and biomethane percentages are modeled separately when source-backed.

ADEME VertVolt labels are distinguished by level, engaged or very engaged, and can carry provenance data by region, technology, percentage, and source.

OpenKWh separates contractual guarantees, paid add-ons, marketing claims, and the energy physically consumed on the grid.

When a supplier publishes energy provenance outside ADEME, it can be modeled as supplier-sourced data without being conflated with an audited public label.

A paid option is not included in the base price: it is calculated as a separate configuration, with its annual cost and the guarantees it unlocks.

When the source does not structure an option’s percentage, origin, or exact guarantee level, the option remains visible but does not satisfy filters that require those criteria.

For electricity-and-gas baskets, the green signal is weighted by the entered annual electricity and gas kWh consumption so minor and primary consumption do not carry the same weight.

Data quality

Each offer retains its sources, tariff-grid periods, price-evolution rules, CRE certainty level, and any conditions required for calculation.

Incomplete, ambiguous, or quote-only offers are identified separately so they are not mixed with fully computable offers.

The period during which an offer is open to subscription is separated from the tariff-grid period and from any fixed-price guarantee duration.

Comparisons

Public-reference deltas compare annual VAT-inclusive cost including subscription, not only the kWh price displayed by a supplier.

Similar-offer comparisons are computed inside the filtered group and are not an official market statistic.

Comparable-guarantee comparisons are shown only when they match the contractual guarantees of the inspected offer.

An offer without a green-electricity or biomethane guarantee is not presented as cheaper than a green or biomethane cohort when it does not share those contractual guarantees.

Local gas-zone resolution

For gas offers, supplier tariff zones are resolved locally from postal code, commune, and available source-backed mappings.

Supplier mappings are stored separately from tariff grids so they can be updated, audited, and linked to their own sources.