Dynamic electricity tariffs for company cars: account for home charging costs transparently

A dynamic household tariff can be combined with reimbursement of company car electricity. This requires a process that combines verified home charging energy with a permitted and documented price. You must therefore establish the reimbursement method first. The wholesale price at the start of charging or a simple average of displayed hourly prices is not automatically the correct value for payroll.

This article is intended for fleet management, HR and Finance in Germany. It covers the monthly process for fluctuating household electricity prices, as of 24 September 2026.

Separate electricity purchasing from employer reimbursement

With a dynamic tariff, the energy price changes with the market. The German Federal Network Agency explainsthat the unit rate follows wholesale market prices and can change several times a day. Such a contract requires an intelligent metering system.

However, this purchasing situation does not mean the employer has to recalculate every individual market price change. Reimbursement of company car electricity charged at home is subject to its own tax requirements. The internal policy should explicitly separate these two aspects: the household buys electricity; the company reimburses documented charging costs under the agreed method.

An optimisation system may be able to identify inexpensive charging periods. Whether it recognises the correct vehicle, produces complete reimbursement records or works with your charger are additional questions. Price optimisation alone does not make the month-end close auditable.

Also record who requests a late supplier document. Without an assigned responsibility, even a technically complete charging record can remain unprocessed. A short reminder specifying the billing month is more helpful than repeatedly asking in general terms for all electricity documents to be submitted.

Choose the method for the calendar year

Under the German Federal Ministry of Finance letter of 11 November 2025, paragraphs 28 to 30 , dynamic tariffs may use average monthly electricity costs per kWh, including a proportionate standing charge. The prescribed standard electricity rate is an alternative. The choice between actual costs and the standard rate must be applied consistently for the calendar year; a document created by the employee themselves is not accepted as evidence of the individual electricity price.

Finance therefore has two different possible approaches. With actual costs, a documented value is needed each month. With the standard electricity rate, the applicable price remains fixed for the calendar year; measured home charging energy is still required. The decision should be workable both technically and organisationally.

The general StromNow guide to reimbursement in 2026 explains the basic rules. For a dynamic tariff, also record which monthly document is authoritative, when it becomes available and how subsequent invoice corrections are handled.

Use the documented consumption price, not merely a market average

A simple arithmetic mean of hourly prices does not account for how much electricity was actually purchased in each hour. If the household charges and consumes electricity mainly in different time windows, its actual average may differ considerably.

A wholesale electricity price chart also does not automatically show the household's full costs. The specific supply contract may contain additional price components and a standing charge. Accounting therefore needs the supplier's traceable bill and a documented treatment of the relevant cost components.

Agree with your tax adviser how to derive the permitted monthly average from the available documents. Do not present an allocation rule you have devised yourself as a statutory formula in the company car policy. The process should remain understandable when an employee changes supplier or tariff product.

Organise the month-end close into two data streams

The first data stream contains home charging energy: vehicle, metering source, period and any individual sessions required. The second contains the price evidence: supplier, billing month, documented costs and the approved value derived from them. The two are combined only at the close.

Set a deadline by which both data streams should be available. If the supplier bills later, this delay must be planned for. An outdated monthly value should not silently be used as the final value for a new month.

A worked example shows the difference

Hypothetical example for one month: After checking the supplier's document and the defined cost scope, the usable average electricity price is €0.29 per kWh including VAT. Suitable metering records 240 kWh of home charging for the company car. This gives €69.60.

If a price app had displayed an unweighted market average of €0.08 per kWh for the same month, that value would not be interchangeable without further consideration. It may reflect a different cost scope and a different weighting over time. The example illustrates the difference between market information and the value actually needed for reimbursement; it is not a tariff offer.

If the standard electricity rate chosen for the calendar year is used, its applicable value would determine the calculation instead. Do not retrospectively select the higher or lower amount for each month. Corrections within a method must be distinguished from a change of method.

Check metering particularly carefully for time-dependent session billing

Some companies want to price individual charging intervals instead of using a monthly value. This creates additional technical requirements. According to the AGME technical guidance of 9 January 2026 , frequent tariff changes and quarter-hourly billing also require compliance with the relevant national metering requirements.

An existing timestamp or a breakdown in a table therefore does not prove the suitability of the metering chain. Check the intended billing arrangement with the technical provider and relevant specialist bodies before rolling it out as standard. The Finance Ministry's simplification and German metrology law answer different questions.

Keep exceptions limited and traceable

Typical exceptions include changing supplier mid-month, a corrected electricity bill or a failed data transfer. Keep the original version and the change in a traceable form. Document the affected period and whether any money has already been paid. This allows a difference to be explained objectively.

A workable process does not require every employee to purchase private electricity in the same way. The company does, however, need clear input data and an approval process that can be applied consistently. Limit individual exceptions to genuinely necessary cases and assess whether their administrative effort is appropriate for the fleet's size.

With the StromNow offering for home charging company cars , you can discuss the preparation of home charging energy data and reimbursement amounts. Bring an anonymised monthly bill and your desired reimbursement workflow to the consultation. This allows a specific assessment of how the dynamic tariff, metering data and payroll should work together.