Tariff Configuration

This guide covers setting up tariffs and pricing in OpenZEV.

Column headings sort tariffs within their categories. Price uses the lowest listed CHF rate for a multi-band tariff; unavailable prices stay last. Unit sorts by kWh, month or year. Applies stays a plain heading because it can describe several schedules. Import previews retain your ticks and billing choices when you change their order.

What is a Tariff?

A tariff is a pricing rule that defines how to charge participants for energy.

Each tariff has:

• a Category — Energy, Grid Fees, Levies or Metering Tariff (groups the lines on the invoice)
• a Billing mode — per kWh (By energy), a Percentage of energy tariffs, or a fixed fee (monthly, yearly, per metering point, or shared across the community)
• for per-kWh tariffs, an Energy type — which energy it prices:
  • Local — energy supplied within the community (solar)
  • Grid — energy imported from the external grid
  • Feed-in — credit for production fed back

The list is grouped by what applies when, with one row per tariff. The first group, with no heading of its own, shows each tariff's version in force today; Upcoming shows tariffs that have nothing in force yet but a version that starts later (for example next year's grid tariff, once imported); Ended tariffs is folded away and shows tariffs that have ended altogether — open it to look at or edit one that ended by mistake. When a tariff in force has a later version, its row says so under the validity — From 01.01.2027: 0.315 per kWh (+6.8 %) when the same bands get new prices (the change in brackets, one figure per band, in the order of the prices), Prices and schedule change from 01.01.2027 when the bands themselves change — and clicking that line opens the later version. Ended tariffs opens by itself when you follow a link to the past version of a tariff that has ended. The headings carry no counts.

Each category is a rate card, set like the tariff overview PDF, with one row per tariff:

• Tariff — the name, with a small icon for its energy type (a plug for grid, a solar panel for local, an arrow for feed-in; hover it for the name), and the first line of its note
• Applies — when each band applies (for example High (HT) Mon–Fri, 07:00–21:00, one line per band), the percentage and the grid price used as its base (with “incomplete base average” when dynamic coverage is partial), or a fee’s allocation basis
• Price (CHF) and Unit — the displayed version’s rate, per kWh, per month or per year
• Valid — the version's validity: since when it applies (since 01.07.2026), until when (until …), from when it will (starts 01.01.2027, with the year in bold, and the month too when it starts this year), or when it ended

An unnamed band shows its time window once. A high, low or time band with no time window (both times left empty) is the band for all other hours: it prices every hour the other bands of its months and weekdays do not cover, so "HT Mon–Fri 07:00–21:00, NT the rest" needs only the HT window. Only one band per season and weekday can do this. Hours that no band covers, and no such band catches, use the first band in the matching season (or the tariff's first band if no season matches). The detail pane and the band form say which hours are affected and what they are billed at — for example No band covers 00:00–07:00, 21:00–24:00; 07:00–21:00 · Sat–Sun. Those hours are billed as High (HT) 07:00–21:00 at 0.295 CHF/kWh — and warn when more than one band matches the same hour (the first match applies). While you fill in a band, the form shows whether the version's bands together cover every hour of the year. A version of a few weeks is only checked against the days it can contain.

A red badge next to the name means warnings: a gap between versions, a failed price fetch, or Hours without a band — some hours of the year have no band of their own and are billed at the fallback band (see below). Rows under Ended tariffs are grey but readable. Click a row to open the tariff's detail pane beside the list, where Edit and the other actions are; from Upcoming it opens on the upcoming version. On a narrow screen (a phone, or a small window) the pane takes the whole area and the list is hidden until you close it with X or the browser's Back button.

The list waits for the selected community to load. If loading fails, use Retry; a failed community refresh keeps the loaded scope and your open draft available.

Creating a Tariff

Managers create tariffs in Tariffs.

Switching community or losing write access closes the open tariff pane, its form and any import dialog or delete confirmation. Save your draft before switching.

The forms for creating and changing tariffs open in the detail pane, in the place you were just looking at the tariff, and the list stays beside them. If you leave with unsaved input — X, Cancel, Escape, the browser's Back button, picking another tariff or version, or reloading the page — OpenZEV asks whether to discard it; choosing Keep editing leaves your input and the selection as they were.

1. Click New Tariff

2. Enter details:

   • Name — Tariff identifier, printed on invoice lines (e.g., "Local solar")
   • Category, Billing mode and — for per-kWh tariffs — Energy type (see above)
   • Notes (optional)

3. Set Validity Period:

   • Valid From — Start date
   • Valid To — End date (leave blank for ongoing)

   Tip: Leave Valid To blank. When the price later changes, use New version rather than editing or creating a second tariff — see Tariff Versions.

4. Configure pricing: the fixed amount for a fee, the initial percentage for a percentage tariff (the tariff starts with one flat band at that percentage — you can split it into time-of-use bands afterwards, see Percentage of Energy Tariff), or — for a per-kWh tariff — a dynamic price source if it has one

5. For a per-kWh tariff without a dynamic source, add its Bands right in the form: Add band, enter price, times, weekdays and months, then Keep band. You can edit or remove a band before saving, and the form warns about hours without a band while you build the list (see Tariff Periods)

   

6. Click Create Tariff; the tariff and all its bands are created together, or — if the server rejects a band — not at all. The rejected band is marked in the list with the reason; fix it and save again. The new tariff opens in the pane

   A per-kWh tariff created without a band prices nothing until you add one later as a Tariff Period; a percentage tariff starts with its one flat band and takes more later

Importing Tariffs from Your Grid Operator

Swiss grid operators publish their tariffs in machine-readable form every year (Art. 7b StromVV). Rather than transcribing next year's prices by hand, point OpenZEV at that file and it will show you exactly what it would create.

Running an import

1. Go to Tariffs and click Import from grid operator.
2. Paste the Tariff document URL — usually a .json file linked from your operator's tariff page. If you stored it under Settings → Grid Connection → Tariff document URL, it is filled in for you.
3. Click Read document. Nothing is saved at this point. You get a table of everything the document offers, with a Status for each row.
4. Tick what you want. Select standard tariffs ticks only what the operator itself flags as its standard product — a document can carry 35 rows when your community needs four, so nothing is pre-ticked wholesale. If the document covers more than one year — operators often publish next year's prices beside this year's — pick a year in the year filter to see only the tariffs valid in it. Changing the year resets the ticks to that year's standard tariffs.
5. Click Import N tariffs.

Leave Remember this address for next year's tariffs ticked and the URL is stored on the ZEV, so next year's refresh is one click.

One published tariff can become two

A published tariff often carries both a monthly base price (Grundpreis) and a per-kWh energy price (Arbeitspreis). An OpenZEV tariff is billed one way or the other, never both, so such an entry is imported as two tariffs:

Netznutzung Basis (Grundpreis)     CHF 7.00/month
Netznutzung Basis (Arbeitspreis)   CHF 0.284/kWh

Those suffixes are your operator's own words, and they appear on invoice lines, so a participant comparing an invoice against the published tariff sheet sees matching vocabulary.

Choosing how a fee is billed

The document says a base price is CHF per month. It cannot say who pays it — that depends on how your community relates to its operator. So each fee row has a Billed as picker, and the choice is yours:

Billed as	When it is right
Shared monthly fee (default)	The usual ZEV: the operator bills the community once for its connection, and the fee is split across participants
Monthly fee	A vZEV whose participants each hold their own contract with the operator
Per metering point, monthly	A charge levied per meter — a metering fee is the typical case

Getting this wrong bills the same connection several times over, so the picker never guesses on your behalf beyond the default.

What the statuses mean

Status	Meaning	Imported?
New	Nothing like it in this community yet	Yes
New version	You already have this tariff; the document carries a later price. See Tariff Versions	Yes
Already imported	A version already starts on that date — you have imported this document before	No
Name conflict	A tariff of that name exists but means something else (a different category or energy type), which cannot be reconciled automatically	No
Not supported	The entry cannot be represented — the row says why	No

Only New and New version rows can be ticked.

Importing next year's document

Re-importing is the normal yearly workflow, and it is safe to run twice:

• Rows you have already imported come back as Already imported and are left alone. Nothing is rewritten.
• A newer price arrives as New version. Your existing version is closed the day before the new one starts, so the two never overlap and no period is billed twice.
• If you renamed a tariff after importing it, the new version still lands in it. OpenZEV records which published price each tariff came from, so it recognises your renamed tariff as the same one; the row says Will be added to "your name", and it keeps the name you gave it.
• The way you chose to bill a fee is remembered. Next year's document proposes the default again, but the import matches what you already decided rather than refusing the row.

What is not imported

These are reported in the preview rather than skipped silently — a row that cannot be imported always says why:

• Power / demand charges (CHF/kW) — OpenZEV does not bill demand, and no demand data is metered.
• Reactive-power charges (CHF/kVarh).
• Storage grid-usage refunds.
• A dynamic tariff with no fetchable URL, or a component with no billable energy value in CHF/kWh. V2 metering components are supported when they publish an energy price.
• Prices in a unit that cannot be billed — an energy price not in CHF/kWh, or a base price not in CHF/month — and negative prices.

Where a published price is more precise than OpenZEV stores, it is rounded and the row tells you so.

Dynamic tariffs

Some operators no longer publish a fixed price at all — they publish a URL that serves a new price every quarter-hour. Importing one of these creates a tariff linked to that price source instead of to fixed bands; OpenZEV fetches it on a schedule and bills each reading at whatever the series says for that moment, negative prices included.

• The import preview marks a dynamic row with a Dynamic badge and shows the URL it will fetch from, instead of a list of prices — there is nothing to list yet.
• The document never names which product the source should use (an operator like Groupe E publishes several, at materially different prices). Enter the correct product name in the preview before importing. Leaving the visible product field blank explicitly confirms the endpoint default. V2 product names returned by discovery are retained with the source.
• On the Tariffs page, a dynamic tariff reads Dynamic, average and the dates the average covers (the most recent 30 days) under Applies, beside its average price. These dates are not the tariff's validity, which the Valid column shows. If the source's last scheduled fetch failed, a red Price fetch failed badge appears next to the name, with the failure shown as a tooltip.
• You can also link a plain energy tariff to an existing dynamic source by hand, from the tariff's edit form — useful once a source has already been created by an earlier import.

Managers can choose an existing shared source or create a new source from the energy-tariff form. Viewers can inspect linked sources and price history. Click a dynamic tariff to see its source name, fetch status and last successful fetch. Source details unfolds the endpoint, protocol, product, stored coverage and usage. Usage counts cover the whole platform.

Below the source, the pane charts the fetched prices of the last 30 days of the tariff's validity without opening anything. If the source has no price for time that has already passed, a yellow notice says so as dates (for example No prices for 03.10.2026 – 05.10.2026), the chart shades those stretches red and breaks the line there, and Exact missing intervals lists the timestamps. Invoice generation stops for a period that needs a missing price, so fetch the prices again or wait for them to fill in. Dates in the future are not reported, as prices may not be published yet. Change the date range above the chart to look further back; Fetched interval prices opens the statistics and the interval table, twelve rows at a time, with previous and next buttons under it. Administrators can follow Manage source in platform admin to its operational row; managers create and reuse sources in the tariff form.

Reading a dynamic tariff's price

An operator's fetched price changes every quarter-hour, so the Tariffs page shows a representative average instead of a rate: Avg CHF 0.123/kWh, with a tooltip explaining the reference window. It is weighted by interval duration over the trailing 30 days within the tariff's validity — not a fixed rate, and the contract and tariff overview say so in a footnote.

The BFE reference market price (below) publishes one price per quarter, and only weeks after that quarter has ended, so its trailing 30 days would always be empty. For that kind of source the window ends at the last fully published day instead of at today; the reference dates beside the figure say which period it covers.

For a percentage tariff, the base uses grid tariffs and prices at today, clamped to the displayed version's validity. A historical percentage version therefore uses its historical base, not the latest average of an ongoing grid tariff.

• Partial means the window has gaps; the average covers only what was fetched.
• Price unavailable (or base price unavailable on a percentage tariff) means nothing was fetched for the window. No substitute number is shown, and a percentage tariff built on it has no base either — printing a partial sum would understate the rate.

Feed-in at the BFE reference market price

Many operators pay feed-in remuneration as the greater of a minimum price they guarantee or the federal reference market price for the period. Since 1 January 2026 that is also the statutory default when nothing else is agreed (Art. 15 EnG/EnV, reference price per Art. 15 EnFV).

Set this up in two parts:

1. Add the reference price as a source. In the dynamic source dialog, choose the kind BFE reference market price instead of an operator endpoint. Pick the series your installation reports on — quarterly or monthly — and the technology (photovoltaics for a normal rooftop ZEV). There is no URL to enter and nothing to discover: OpenZEV downloads the federal publication and stores its whole history, back to Q3 2023, the moment you save.
2. Link a feed-in tariff to it and enter the minimum. On a feed-in tariff with that source selected, the form shows Minimum price (CHF/kWh). Leave it empty if your operator pays the reference price flat.

Every exported kWh is then credited at whichever is higher for that moment. The Tariffs page shows the reference average with min. CHF 0.080/kWh beside it, and the tariff overview PDF prints the rate together with the guaranteed minimum.

• A quarter can only be billed once BFE has published it — roughly ten working days after the quarter ends. Until then the period counts as unpriced: readiness names the days and invoice generation refuses, rather than falling back to the minimum and under-crediting a producer whose reference price later turns out to be higher.
• The minimum is part of a tariff version. Renegotiating it means creating a new version from the date it changes, exactly like any other price.
• The figures are federal open data (Opendata BY). Reusing them outside OpenZEV — a newsletter, your own report — requires naming the source, the Swiss Federal Office of Energy (BFE).

Operating a price source (administrators)

Sources live under Platform → Overview → Dynamic prices and are shared across communities: two ZEVs on the same operator product fetch once, together.

• Status is Healthy, Failed (with the user-safe error), Not fetched, or Disabled. A source with an unresolved older window shows Retry from <date> — the earliest range a refresh still needs to fill.
• Disable a dead endpoint with the Enable scheduled fetches toggle instead of deleting it: stored prices stay as billing evidence, the schedule skips it, and the tariff keeps billing from history.
• Refreshes run every 4 hours over yesterday → two days ahead (operators republish during the day; day-ahead prices arrive in the afternoon). A new enabled source additionally fetches up to 400 days of history once, right after import. Disabled sources do not start automatic fetches; an explicit administrator fetch is still available. Re-enabling an old source fetches at most 14 days on a scheduled run; use backfill for older missing history.
• 404 is a failure by default. If the operator documents that this URL uses 404 for an empty publication, an administrator can enable empty_on_not_found on the source in Django admin. This opt-in treats every 404 as empty, including a removed product; verify the URL when gaps persist. Rechecking capabilities preserves this setting. 410 always fails.

Recovering a refused price series

• BilledPriceChanged: an operator changed a price or interval already retained for an invoice. The original remains stored. Check the operator's publication and affected invoices before correcting or cancelling invoices; retries cannot reconcile conflicting billing evidence. On a BFE reference price source this also stops newly published quarters from arriving, because every fetch re-reads the whole federal history and the conflict fails the run as a whole. Resolve the revised quarter — cancel or correct the affected invoice, then clear the source's prices — rather than waiting for the next scheduled refresh.
• PriceIntervalConflict: a replacement is overlapping or incomplete. Backfill the complete unbilled range. A complete replacement can change interval resolution atomically while preserving billed historical intervals. A partial replacement that changes a price is refused without clipping either boundary. A same-priced response clipped at a fetch boundary safely extends only the uncovered portion and keeps the existing stored boundary. If the endpoint no longer serves the complete interval, keep the old series and create a replacement source/version for future pricing.
• PriceSeriesConflict: the run reports one or more such refusals. Independent valid intervals may have been stored, but the source remains failed. Examine the price history and first reported conflict, then retry manually once the cause is resolved. Deterministic schema/product errors also need configuration or upstream correction; Celery does not retry them as outages.
• Clear fetched prices is available only when no non-cancelled invoice retains the source. Drafts count too. Editing or deleting a tariff cannot release its invoice's stored provenance. Clearing waits for any invoice generation transaction using the source before rechecking protection.

Republishing the same prices at another interval resolution is harmless: the original stored rows remain as evidence. Cancelled invoices release price protection but still retain the source itself; disable an obsolete source instead of deleting invoice provenance. Evidence covers applicable tariff windows conservatively, including tariffs that produced no invoice line. Sources shared by several ZEVs serialize invoice generation and maintenance; a long invoice transaction can delay a fetch or clear operation.

If migration 0014 refuses existing intervals

1. Keep the previous release running with invoice generation and price-fetch jobs paused. Take a database backup before correcting any stored prices.
2. Use the row/source IDs in the error to inspect the affected source. For example, in python manage.py shell, read DynamicPricePoint.objects.filter(source_id=source_id).order_by("valid_from").values("pk", "valid_from", "valid_to", "price_chf_per_kwh") after importing the model from tariffs.dynamic.models and setting source_id to the reported UUID. For invalid-range errors that only name row IDs, first inspect those rows to find their source.
3. Compare the overlapping or inverted intervals with the original operator publication and retained invoices. Do not bulk-delete or clip billed history to make the migration pass. If the correct historical inputs cannot be established, retain the backup and resolve the invoice evidence with the operator before proceeding. There is no safe generic repair.
4. For verified unbilled data, have the administrator apply the reviewed correction while writers remain paused. Record the original rows and the correction. Retry python manage.py migrate; the preflight checks again before adding constraints. Resume jobs only after migration succeeds.

Migration 0015 can similarly refuse an exact-URL source that incorrectly claims range-query support. Its error names the source UUID and URL. Verify that the endpoint must be fetched verbatim, set supports_range=False for that source, and retry the migration; do not change the source URL or tariff identity.

Version 2 sources need an explicit operator product name, even when the endpoint has no published prices yet. An old blank v2 source must be disabled and replaced with a named source. Missing product metadata in a v2 response is a provider/schema error, distinct from the provider returning a different product.

Transfers preserve invoice totals and source provenance, but do not include the original price points. Keep a database backup when retaining the fetched billing inputs is required; an operator may no longer publish that history.

Tip: Import prices exactly as published — they are net of VAT. If your community pays VAT it cannot reclaim, set the VAT treatment in ZEV settings rather than adjusting tariff prices by hand; a re-import would undo that.

Outbound URL checks

Tariff downloads must resolve to public addresses. The check cannot rule out DNS rebinding, so also restrict outbound traffic at the network level (see the VSE import spec).

Energy Tariff Types

Local Energy Tariff

Charges for energy consumed from the ZEV's own production.

Pricing options:

• Flat rate — Single price per kWh (e.g., CHF 0.12/kWh)
• Time-of-use (HT/NT) — Different rates by time-of-day
  • HT (high tariff) — Peak hours (e.g., 06:00–22:00)
  • NT (night tariff) — Off-peak (e.g., 22:00–06:00)

Example:

Local Energy Tariff "Summer Local"
├─ HT (06:00–22:00): CHF 0.10/kWh
├─ NT (22:00–06:00): CHF 0.05/kWh

Grid Energy Tariff

Charges for energy consumed from the external grid (not covered by local production).

Usually higher than local tariff to reflect grid cost.

Example:

Grid Tariff "Grid 2026"
├─ HT: CHF 0.28/kWh (includes distribution)
├─ NT: CHF 0.18/kWh

Feed-In Tariff

Credits for participant production fed back to community/grid.

Often lower than local tariff (encourages consumption of own production).

Example:

Feed-in Tariff "Solar Credit"
├─ Flat: CHF 0.08/kWh

Percentage of Energy Tariff

A percentage tariff derives its price from other active tariffs rather than specifying a fixed CHF/kWh rate.

Instead of setting a price, you set a percentage (0–100%). During billing, OpenZEV looks up the sum of all active grid energy tariff rates at each timestamp and multiplies by the percentage to calculate the effective per-kWh price.

If the community folds VAT into its prices (VAT treatment inclusive), the percentage is taken of the grid price with VAT — what a participant would otherwise pay — so 65% of a CHF 0.2000/kWh net grid price bills CHF 0.1405/kWh, not CHF 0.1300/kWh. The local line itself gets no VAT added, and the invoice line shows the base with VAT (for example "65% von CHF 0.2162/kWh").

Configuration:

• Billing Mode — Select Percentage of energy tariffs
• Energy Type — Local Energy, Grid Energy, or Feed-in (determines which energy stream the tariff applies to)
• Initial percentage — The percentage value to start with (e.g., 50%), only asked when creating the tariff

Saving creates the tariff with one flat percentage band. Like a per-kWh tariff, a percentage tariff can be split into several time-of-use bands — open its entry and use Add Period to add a High/Low or named band, this time entering a percentage instead of a CHF/kWh price. A local-energy surcharge that is cheaper at midday and dearer in the morning and evening, for example, can be modelled as three bands (00:00–10:00 at 90%, 10:00–16:00 at 60%, 16:00–00:00 at 90%) instead of a single flat percentage — see Tariff Periods for how bands, weekdays and months combine; everything there applies to a percentage tariff's bands exactly as it does to a per-kWh tariff's.

Example:

Percentage Tariff "Local Energy 50%"
├─ Energy type: Local Energy
├─ Band: Flat, 50%
├─ Effective price: 50% of grid energy rate
│   (if Grid HT = CHF 0.28/kWh → Local = CHF 0.14/kWh)
│   (if Grid NT = CHF 0.18/kWh → Local = CHF 0.09/kWh)

Example with time-of-use bands:

Percentage Tariff "Local Solar Surcharge"
├─ Energy type: Local Energy
├─ Band "Morning": 00:00–10:00, 90%
├─ Band "Midday":  10:00–16:00, 60%
├─ Band "Evening": 16:00–00:00, 90%

Cover the whole day. The bands should together cover all 24 hours. Give every band a time window, or leave both times empty on one band to make it the band for all other hours ("the rest of the day"). Without such a band, an hour no band covers is billed at the tariff's first band instead, which is usually not what you meant.

This is useful when you want to set local energy prices as a fraction of the grid energy rate, so that price changes to the grid tariff are automatically reflected.

Fixed Fee Tariff

Flat monthly or yearly charges (not energy-dependent).

Charge types:

• Monthly fee — CHF X per month, charged to each participant
• Yearly fee — CHF X per year, charged to each participant (paid monthly as CHF X/12)
• Per-metering-point fee — CHF Y per active meter per month. A community metering point is charged once and split across the community by allocation weight, instead of being charged to its holder.
• Per-metering-point yearly fee — CHF Y per active meter per year, billed in monthly instalments (CHF Y/12). Split the same way as the monthly variant.
• Shared monthly fee — CHF X per month for the whole community, divided between the participants
• Shared yearly fee — CHF X per year for the whole community, divided and paid monthly

Example:

Fixed Fees 2026
├─ Community admin fee: CHF 50/month     (each participant pays 50)
├─ Meter maintenance:   CHF 5 per meter/month
├─ Caretaker contract:  CHF 90/month shared  (3 participants → 30 each)

Shared Fees

Use a shared fee for a cost the community carries jointly — a caretaker contract, an insurance premium, the ZEV's own administration — rather than one attributable to a participant's consumption or meters.

The price you enter means something different here. For every other fixed fee, the amount is what one participant pays. For a shared fee it is what the whole community pays. Entering CHF 20 intending "per person" will bill the community CHF 20 in total, not CHF 20 each.

How a shared fee is split

• The amount is divided between the participants active in each billed month.
• The division is recalculated every month, so somebody joining in February does not change what January cost.
• Each participant is charged only for the months they were actually a member.

Split key. When you pick one of the two shared billing modes, a Split key selector appears with two options:

Split key	Divides the amount by
Equally between participants (default)	Headcount — everybody pays the same share
By allocation weight	Each participant's allocation weight

Equally is the original behaviour and stays the default, so existing shared fees are untouched. Choose By allocation weight when the community has agreed that a joint cost should follow the same key as common-area energy — for example, billing the caretaker contract by floor area rather than per head.

With every participant left at the default weight of 1, both keys produce exactly the same amounts.

Switching the key changes what people pay. The selector only appears for the two shared modes, and the change is recorded in the audit log along with the rest of the tariff edit. Regenerate draft invoices to apply it.

The split key applies only to the two shared fee modes. Per-metering-point fees on a community metering point always divide by allocation weight — there is nothing to configure, because the cost belongs to a shared meter rather than to the community as a whole.

For a worked example of how a shared fee splits as members join and leave, and how rounding works, see How Energy Allocation and Billing Works.

A note on the issuer: the issuer is counted like anyone else, provided they have a participant record in the ZEV. An issuer that is not a participant (a property management company, say) is not counted and not charged.

Credits: enter a negative amount to distribute a community-wide rebate across the participants. It appears on invoices as a credit line.

Tariff Periods

Tariff periods hold a per-kWh tariff's prices. There are no default periods: a new per-kWh tariff has none until you add one. A percentage tariff uses the same periods and the same Add Period form, entering a percentage instead of a CHF/kWh price — everything below about period types, time windows, weekdays and months applies to it unchanged. Each period has a type:

Period type	Use for
Flat	One price around the clock
High (HT) / Low (NT)	The usual two-rate tariff, e.g. HT 06:00–22:00 and NT for the rest
Time band	Any further price — a weekend rate, a winter price — named with its own Band name

To add one:

1. Click the tariff to open its detail pane
2. Click Add Period under the version's bands
3. Enter:
   • Period type (see above) and, for a time band, a Band name
   • Time from / Time to — HH:MM (24-hour format), in Swiss time (CET/CEST): 06:00 means 06:00 on the clock in Switzerland in winter and summer alike, whatever format the readings were imported in
   • Weekdays and Months the period applies to (all selected means every day / all year)
   • CHF/kWh (per-kWh tariff), or Percentage (percentage tariff)
4. Click Save Tariff Period

Crossing midnight: If the end time is not after the start time, the period wraps past midnight: 22:00–06:00 covers the night, and an end time of 00:00 means the end of the day (16:00–00:00 is the evening). The weekdays you select refer to the day of each hour itself, so a Monday–Friday 22:00–06:00 period covers Friday night up to midnight and the early hours of Monday to Friday, but not Saturday morning.

Multi-Tariff Configuration

Most ZEVs use multiple tariffs simultaneously:

Tariff	Purpose	Typical Price
Local Energy (HT)	Community supply, daytime	CHF 0.10/kWh
Local Energy (NT)	Community supply, night	CHF 0.05/kWh
Grid Energy (HT)	External grid, daytime	CHF 0.28/kWh
Grid Energy (NT)	External grid, night	CHF 0.18/kWh
Feed-in	Participant solar credits	CHF 0.08/kWh
Fixed Fee	Monthly admin cost, per participant	CHF 50/month
Shared Fee	Joint community cost, divided between participants	CHF 90/month total

During billing, OpenZEV automatically selects the right tariff for each timestamp and energy type.

Tariff Versions

Prices change — usually every year. Rather than creating a new tariff each time, add a version to the existing one.

All versions of a tariff share its name. That is what makes them versions: the name identifies the tariff, and the validity windows say which version applied when.

Local Energy                                    ← one tariff, three versions
├─ 2025-01-01 → 2025-12-31   0.10 CHF/kWh
├─ 2026-01-01 → 2026-12-31   0.11 CHF/kWh
└─ 2027-01-01 → (open)       0.12 CHF/kWh       ← active

Adding a New Version

1. Click the tariff to open its detail pane, then click Schedule price change
2. Enter the date the new prices take effect (defaults to today)
3. Adjust the prices (pre-filled from the current version); the form says what will apply from that date
4. Click Schedule price change

OpenZEV closes the previous version automatically on the day before, so the timeline stays continuous. You never set an end date by hand — the form names the closing date it will use as you pick the start date.

Why this matters: if a day falls between two versions, OpenZEV has no price for it. The energy still appears on the invoice but is charged at nothing — a whole month can be given away without any warning. Letting OpenZEV compute the end date removes the off-by-one that causes this. Any series that already has a gap is flagged on the tariff entry.

You can also insert a version between two existing ones; OpenZEV bounds it on both sides.

Comparing Versions

The Tariffs page shows one entry per tariff, using the version selected by the current list view rather than listing every version separately. Click it to open the detail pane beside the list with everything else.

At the top of the pane, Schedule price change, Rename and Duplicate act on the whole tariff. Under them, each version in force or scheduled has its own card, the one in force first:

• The card opens with its status — Current or Upcoming — and its validity window, so you can't mistake a future version for the current rate, and has its own Edit button. Below come the dynamic source if there is one, or the price bands with a pencil on each and Add Period under them. The notes appear on a card only when they differ from the ones the list row already shows.
• A scheduled version starts as a single line — its prices, what they change against the version before (for example −1.7 % / −2.2 %) and a red Hours without a band badge if it has uncovered hours. Click it to open the card and edit its bands. It is open from the start when you came to it from the list's From 01.01.2027: … line.
• Next to each band price, a scheduled card shows how that price moves against the version it replaces (−0.005 (−1.7 %)); a fixed fee shows its amount.

History is folded away under the cards, with the number of ended versions. Open it for the price chart and the list of past versions with their window and price; click one to show its card — marked Ended — underneath. A tariff without ended versions has no history. Switching versions in the pane does not change the version shown in the list.

To delete a version, open the ⋮ menu beside Edit on its card and choose Delete this version; to delete a band, click the trash icon beside its pencil. Both ask for confirmation first, and the confirmation repeats that existing invoices are not recalculated. Correcting a superseded version's end date is a normal follow-up to adding a new one, so Edit is on every card.

The pane stays open across a page reload or a shared link — the URL records which tariff and version you're looking at. X, Escape and the browser's Back button all return to the list.

Price History

Once a tariff has more than one version, its detail pane also charts how its price moved over time; open History to see the chart.

• The line is stepped, not sloped — a price holds for its whole window and then jumps. A sloped line would suggest it drifted between two Januaries.
• HT and NT are separate lines, so you can see the spread widen or narrow.
• Uncovered stretches are shaded red and the line breaks: nothing was billed there. This is the same problem the list's gap badge reports, shown on a timeline.
• For a percentage tariff the chart shows one line per band, each the effective price it worked out to, derived from the grid tariffs in force at each point — so it moves when those move, even in months this tariff itself did not change. A note under the title says so. A tariff with a single flat band still shows one line, exactly as before bands existed.

Price Progression

The price history above follows one tariff. To see what one kWh costs in total and how that moved over the years, click Price progression in the header of the Tariffs page. It adds up every per-kWh tariff that applies, the way an invoice would price a kWh, and is read-only for everyone who can open the tariffs.

• One energy type at a time. Choose grid, local or feed-in. Energy, grid fees, levies and metering tariffs of that type are summed; types are never mixed, and a feed-in credit is its own view.
• One line per band. The total depends on when the energy is used, so each distinct time of use (for example Mon–Fri 07:00–20:00 and all other hours) is its own stepped line. When a tariff changes its hours, the old line ends and a new one starts.
• Net and gross. The community's VAT setting decides what you can switch between. VAT-registered: Excl. VAT and Incl. VAT. Not registered, upstream VAT folded into prices: the published price and the billed price, where only the tariffs that carry VAT (grid energy, grid fees, levies, metering) are grossed. Not registered: one value, because prices are billed as entered. The VAT rate in force on each day is used, so a rate change shows as a step even when no tariff changed.
• The price on a day. Under the chart, the table breaks one line down on a chosen day into subtotals per category and the tariffs behind them. Click the chart, or pick the line, to change what it shows. A percentage tariff states its share and the grid price it was taken of.
• What is missing is marked. A stretch where a category has a gap in its own history (nothing in force between two versions), or where a tariff cannot be priced here, is shaded red and named under the chart, because the total there is understated. A category that simply starts later, or was discontinued, is not a gap.
• Dynamic tariffs are included as a monthly average. A dynamic tariff has a fetched price every 15 minutes or hour, not bands, so the progression uses the average of the fetched prices for each line, month by month; the day's table says so and how much of the month's hours were covered. A month with only some prices is marked and averaged over what was fetched; a month with none is marked and left out. A percentage tariff based on a dynamic grid price takes its share of that average. A price that is valid for a whole period, such as a quarterly reference market price, applies to every month of the period. A period that has not been published yet (the newest quarter is published weeks after it ends) shows as having no fetched prices.
• Fixed fees are separate. Monthly, yearly, per-metering-point and shared fees are not per kWh, so they are listed below with their own unit and never added to the price. A shared fee shows what the whole community pays, split by headcount or weight, not one participant's share.

The view is kept in the address, so you can share a link to it, and a date range limits both the chart and the fixed fees.

Renaming

Renaming is done for the whole tariff, not per version — the name is what holds the versions together, so renaming just one would split it into two unrelated tariffs. Rename sits at the top of the detail pane, and tells you how many versions it will affect.

Duplicating

Use Duplicate (also at the top of the detail pane) to create a different tariff starting from an existing one's numbers. It asks for a new name and leaves the original untouched. (Use Schedule price change instead when the prices of the same tariff have changed.)

Which Version Gets Billed

OpenZEV picks the version that was valid on each individual reading's timestamp — not the one valid at the end of the invoice period. So an invoice covering a price change is priced correctly on both sides of it: a January–March invoice uses the old price for January and the new one from February.

Tariff Validation

When saving a tariff, OpenZEV checks:

Check	Requirement
Valid From ≤ Valid To	Validity period must be in order
No overlapping windows for the same name	Two tariffs called the same thing can't both be valid on the same date — see below
Versions agree on identity	All versions of a name share one category, billing mode and energy type
Price format	Numeric, up to 5 decimals (e.g., 0.12345 CHF/kWh)
Mandatory fields	Name, type, validity period, prices

If validation fails, you'll see a clear error message. Fix and retry.

Several Tariffs at Once Is Normal

You can have as many tariffs applying simultaneously as you need, including in the same category, with the same billing mode and the same energy type. This is the usual shape of a Swiss tariff sheet:

Grid Fees
├─ Netznutzung Arbeit         0.09000 CHF/kWh
└─ Systemdienstleistung SDL   0.00750 CHF/kWh

Levies
├─ Netzzuschlag               0.02300 CHF/kWh
└─ Kantonale Abgabe           0.00500 CHF/kWh

All four apply at once, and each becomes its own line on the invoice, so participants see what they are paying for rather than one merged figure.

The only thing OpenZEV blocks is two tariffs with the same name whose validity windows overlap — because same name means same tariff, so an overlap means two prices claim the same day:

✗ Local Energy   2026-01-01 → (open)      ← old version, never closed
  Local Energy   2026-04-01 → (open)      ← new version
    Both apply. Every participant is billed twice.

✓ Local Energy   2026-01-01 → 2026-03-31  ← closed automatically
  Local Energy   2026-04-01 → (open)

Use Schedule price change and you never hit this: OpenZEV closes the old window for you. You only see this error when editing validity dates by hand. If two tariffs really are meant to apply together, give them different names — which you would want anyway, since the name is what appears on the invoice line.

Because a shared name makes two tariffs versions of each other, they must also agree on what the tariff is — same category, same billing mode, same energy type. OpenZEV rejects a version that disagrees and tells you which value the others use. If you meant a genuinely different tariff, give it a different name.

Copying Tariffs to Another Community

The tariff-only JSON export has been replaced by a whole-ZEV transfer. To move a tariff structure to another instance, export the ZEV with only the Tariffs section selected and import it there — the result is a new ZEV carrying just the pricing. See ZEV Export and Import.

Editing and Deactivating Tariffs

Updating a Tariff

Tariff errors use your selected language where supported. Invalid bands are identified by number, and failed saves preserve your entries. Errors on the Price progression page also use your selected language where supported.

Edit future tariffs freely:

1. Click the tariff to open its detail pane
2. Click Edit on the version's card
3. Change prices, periods, validity dates
4. Click Save

Changes apply to new invoices only. Past invoices keep original tariffs.

Edit works on one version: the form is titled Correct this version, with the tariff's name and the version's validity window under the title, and says again that existing invoices are not recalculated. The fields that identify the tariff — name, category, billing mode, energy type — are not in the form at all: they are shared by every version, so changing them on one alone would break the series. Use Rename for the name; for a different category, billing mode or energy type, create a separate tariff. The cursor starts in the first field, and Notes is a multi-line box.

Prices changed from a certain date? Use Schedule price change instead of editing. Editing rewrites what the current version has always charged; a new version records the change, keeps the old prices on the record, and lets invoices spanning the switch bill each part correctly. See Tariff Versions.

Deactivating a Tariff

Set Valid To to exclude from future invoices:

1. Click the tariff to open its detail pane
2. Click Edit on the version's card
3. Set Valid To to today or last usage date
4. Click Save

Important: Never delete a tariff—always set Valid To instead. This preserves invoice audit trail.

This applies to Delete this version too. Deleting a version removes the prices that applied in its window, which leaves a gap: energy in those days is then billed at nothing. Reserve it for a version created by mistake — one you have not billed against.

Tariff Application During Billing

When OpenZEV generates an invoice:

1. For each timestamp in billing period:

   • Identify energy type (local vs. grid)
   • Find applicable tariff by validity date
   • Find applicable period (HT vs. NT) by timestamp
   • Multiply energy × price

2. Fixed fees:

   • Sum all applicable monthly fees by calendar month in period
   • Apply yearly fees as monthly installments (price ÷ 12)
   • Group by metering point type if per-point fees

3. Final invoice:

   • Sum all line items
   • Apply VAT if configured
   • Create PDF invoice

See also: How Energy Allocation Works for detailed billing logic.

Printing a Tariff Overview

Click Tariff overview (PDF) on the Tariffs page toolbar and choose Valid tariffs to download every tariff in force today, grouped by category (Energy, Grid Fees, Levies, Metering) — the same grouping and order as an invoice's line items.

• Each price band is listed and named on its own line, using the exact same wording as the participation contract (HT/NT, a seasonal band's month range, or a plain band's time window) — the two documents describe a tariff the same way.
• A percentage-of-energy tariff prints one row per band — a tariff with a single flat band prints one formula (e.g. 18.00 % × 29.50 Rp./kWh), and a tariff with several time-of-use bands prints one row per band, each named the same way a per-kWh band is. Each is computed from the same grid tariffs the participation contract uses. If the grid tariff it is based on has more than one price band, a footnote explains that the figure shown is the tariff's base rate, not what any single reading is actually billed at.
• A shared fee states how it is split (equally, or by weight) — the figure printed is what the whole community pays, not one participant's share.
• The document states the ZEV's VAT treatment. Under VAT inclusive, an explicit note says the prices shown are net and that VAT is added on the invoice — the number on this document is deliberately not the number a participant is billed.
• All versions, including superseded and future ones adds the tariff versions not in force today, shown greyed out with their full validity span instead of "from …".

There is no date picker (yet) — the overview always reflects today. Only the community's managers and viewers, and admins, can download it; there is nothing on this document a participant does not already see broken out on their own participation contract or invoice.

One-off Charges

A tariff describes a price that recurs. A cost that happens once — postage for the invoice run, a repair, a one-time fee — is not a tariff. Record it as a charge in the Charges section under the period's invoices (Billing → Invoices, pick the period) and OpenZEV puts it on the right invoices as its own line, under Other charges.

Because the charge lives apart from the invoice, it survives regeneration: regenerate a draft as often as you like and the line comes back.

Adding a charge

Choose Add charge and fill in:

Field	Meaning
Description	What appears on the invoice line, e.g. Postage, March invoice run
Total amount (CHF)	The whole cost, greater than zero
Date	Decides who pays (see below); limited to the period you are working in
Who pays	All participants, or Selected participants
Split	Equally or By weight (the participants' allocation weight); only shown when more than one person pays
VAT	Taxable or Pass-through (see below)

A live Who pays what table under the form shows each participant's share before you save. It uses the same calculation the invoice does.

The date decides

A charge is billed on the invoice whose period contains its date, and the people who pay are the members on that date. Somebody who joined after the date is not charged; somebody who left before it is not either. Both a single invoice and a batch run therefore agree on who pays what.

Rounding

Each share is rounded to the centime on its own, exactly as for shared fees. CHF 10.00 divided between three people bills CHF 3.33 each, CHF 9.99 in total. The form tells you when rounding leaves part of the amount unrecovered (or bills slightly more than the total). A share that rounds to zero is left off.

VAT

Treatment	Use it for	Effect on a VAT-registered community
Taxable (default)	Your own service or cost	Part of the VAT base: VAT is added on top
Pass-through	An expense you pay in the participant's name and pass on at cost	No VAT is added

Check with your tax adviser that a cost really qualifies as a pass-through before you use it. OpenZEV applies the choice you make; it does not judge it.

If the community is not VAT-registered, or folds VAT into its prices, the charge is billed as entered.

Changing and deleting

Edit or delete a charge from the row's actions menu. Draft invoices that already carry it keep the old line until you regenerate them — the Overview lists those drafts under the Charges step so you don't forget.

The period locks with the first approval

As soon as any invoice of the period is approved (or sent or paid; a cancelled one does not count), the period's charges are frozen: you cannot add, edit or delete any of them, and the Add charge button is replaced by a warning. This holds for the whole community, not only the people who pay the charge, so the period is always billed from one set of charges. To change something afterwards, correct the invoice (see Correcting a paid invoice), or record the cost in a later period.

Add every charge before you approve the first invoice of the period, then regenerate the drafts.

Charges are part of a ZEV export archive and of backups.

Tariff Tips

Use consistent naming: Helps operators find right tariff.

• ❌ Bad: Tariff1, FeeX, new_rate
• ✓ Good: Local Energy HT 2026-Q2, Grid Energy 2026, Fixed Fees Monthly

Plan ahead: Create seasonal tariffs before the season starts.

Test with draft invoices: Generate test invoices before finalizing.

Review after each quarter: Check if tariffs align with actual ZEV costs.

Next Steps

• Check data quality: Metering Analysis
• Understand allocation: How Energy Allocation Works
• Bill a one-off cost: One-off Charges
• Generate invoices: Invoice Management