Grid-fee discount for heat pumps: which module under § 14a EnWG really pays off

The short answer

Anyone who makes their heat pump or wallbox controllable by the grid operator pays lower grid fees under § 14a EnWG: either a fixed annual flat rate (Module 1) or just 40 per cent of the grid-fee energy price via a separate meter (Module 2). In the example network of Stadtwerke Flensburg, Module 1 saves a flat 124.68 euros net in 2026, while Module 2 pays off there from about 2,700 kWh of heat pump electricity a year.

For a detached house this is a lever worth a good hundred euros. For a central heat pump in an apartment building, the choice of module decides a sum that stands out in the business case. How efficiency in existing buildings depends on it is set out in the guide to heat pumps in apartment buildings.

What does § 14a EnWG govern, and whom does it affect?

§ 14a EnWG empowers the Bundesnetzagentur to require agreements on grid-oriented control “in return for grid-fee reductions”. The agency did so with determinations BK6-22/300 (control) and BK8-22/10-A (fees). Since 1 January 2024 they cover new installations with more than 4.2 kW of grid connection capacity: heat pumps including immersion heaters, private wallboxes, air-conditioning units and battery storage when charging. Public charging points are not included.

The trade-off is clearly defined. The grid operator may no longer refuse or delay connecting such installations by pointing to a possible local overload. In return it may dim them temporarily when an acute overload threatens. Normal household electricity is not affected.

How far may output be dimmed?

Nothing is switched off. According to the Bundesnetzagentur, a minimum output of 4.2 kW must always be available. For larger installations, such as large heat pumps or cascades totalling more than 11 kW, a scaling factor of 0.4 applies under direct control: a 30 kW cascade keeps at least 12 kW when controlled. With an energy management system a simultaneity factor is added, and self-generated PV power can be used first.

Dimming is only allowed while the risk persists. As long as a grid operator has no real-time data, it may control preventively on the basis of its grid planning, but then for no more than two hours a day and for at most 24 months per grid area.

Module 1, 2 or 3: what does each module deliver?

Module	How it works	Requirement	Flensburg example network 2026 (net)
Module 1	fixed annual flat rate per market location	controllability	€124.68 reduction per year
Module 2	grid-fee energy price cut to 40 %	separate meter, no load metering	3.06 instead of 7.66 ct/kWh, no grid-fee standing charge
Module 3	time-variable energy price, only combined with Module 1	smart metering system	2.70 / 7.66 / 9.19 ct/kWh (low, standard, peak load)

The Module 1 flat rate consists of a nationally uniform base of 67.23 euros net plus a stability bonus that depends on the local energy price. That is why it varies by grid area. At the outset the Bundesnetzagentur gave a range of 110 to 190 euros a year (as of 2023). Module 3 has applied since April 2025. In Flensburg the time windows only apply in the first and fourth quarters, with the cheap window from 2 to 5 a.m., and the time-variable price then covers the entire grid offtake of the market location. For heat pumps the Bundesnetzagentur names Module 2 as particularly suitable, for electric cars the combination of Modules 1 and 3. Anyone who chooses no module gets Module 1.

What does it save in practice? A worked example

Assumptions: Stadtwerke Flensburg grid area, 2026 price sheet, all amounts net and covering only the grid-fee component. Case A is a detached house with 4,000 kWh of heat pump electricity, case B a central heat pump in an apartment building with 30,000 kWh and no load metering.

	Case A: 4,000 kWh	Case B: 30,000 kWh
without § 14a (7.66 ct/kWh)	€306.40	€2,298.00
Module 1 (−€124.68)	€181.72	€2,173.32
Module 2 (3.06 ct/kWh)	€122.40	€918.00
Saving Module 2 versus none	€184.00	€1,380.00

Calculation: Module 2 saves 4.60 cents per kilowatt hour. It therefore overtakes the Module 1 flat rate from 124.68 / 0.046 ≈ 2,710 kWh. The cost of the second meter has to be deducted. For a conventional single-rate meter the Flensburg price sheet lists 10.50 euros a year; modern metering devices and smart metering systems have their own charges. On top comes a one-off conversion of the meter cabinet, whose cost depends on the individual case. Levies, electricity tax and VAT do not change with the choice of module.

The example shows the logic, not the price in your grid area. Energy prices differ considerably, as the provisional grid fees for 2027 show. According to the Flensburg price sheet, customers billed with load metering in the low-voltage grid can only choose Module 1.

What applies to installations fitted before 2024?

Existing installations enjoy grandfathering in two variants. Heat pumps commissioned before 1 January 2024 with a control agreement already in place, i.e. classic heat pump tariffs, continue on the previous terms until 31 December 2028 and move into the new rules on 1 January 2029 at the latest. Installations from that period without a control agreement remain permanently exempt. Switching early on a voluntary basis is possible but binding. There is no way back.

If an existing installation is substantially modified, for example a battery with considerably more power, the Bundesnetzagentur regards it as a new installation and the grandfathering lapses.

What owners and landlords should do now

1. Obtain your own grid operator’s price sheet for 2026 and, once final, for 2027, and look for the “§ 14a EnWG” section: Module 1 flat rate, Module 2 energy price, Module 3 time windows.
2. Estimate the heat pump’s annual consumption realistically and use the calculation above to check from when Module 2 beats the flat rate, including meter and conversion costs.
3. When building new or replacing a heating system, plan the separate meter position at the same time; retrofitting it costs more.
4. For existing installations on an old heat pump tariff, note the 1 January 2029 deadline and compare beforehand whether a voluntary switch pays off.
5. With PV and battery storage, consider control via an energy management system so that self-generated power is used first even when dimming applies.
6. In an apartment building, clarify who is the grid user and who pays, so that the discount reaches the operator of the installation and appears correctly in the heating cost statement.