What applies in Germany

800 watts of inverter, 2,000 watt-peak of modules

Plug-in solar devices may run up to 800 W of inverter AC output; installed module power may reach 2,000 Wp.

Inverter

max. 800 W AC

Modules

max. 2,000 Wp DC

Oversizing

Permitted, up to 2.5:1

The first solar package raised the former 600 W limit to 800 W. What counts is the inverter's output, not the module power — which is why oversizing is explicitly allowed and sensible in practice, since rated power is reached in only a handful of hours per year.

The limit applies per metering point, not per device. Running two devices means their combined output must stay within 800 W.

One registration, not two

Registration is a single entry in the market master data register, due within one month of commissioning. Registration with the grid operator has been abolished.

Deadline

1 month after commissioning

Grid operator

no longer required

Cost

none

The register now asks plug-in devices for only a few items: location, commissioning date, module and inverter power, and the meter number. The grid operator is notified automatically.

Commissioning means the first time the system generated and exported electricity — not the purchase, and not the mounting.

An old meter may keep running backwards for now

A Ferraris meter without a backstop may stay in place until the metering operator replaces it during the smart meter rollout.

The meter used to have to be swapped before the system could run. That requirement is gone: you need to arrange nothing and pay nothing.

Until the swap, the backwards-turned share is effectively credited at the household electricity price — an advantage that ends with the new meter, so do not build it into your calculation.

Landlords and owners' associations can no longer refuse outright

Plug-in solar counts as a privileged structural alteration. Others may have a say in how it is installed, not whether.

Since the reform of tenancy and condominium law there is an entitlement to consent. Landlords and associations may decide on the fixing method and appearance, but may not refuse the installation as such.

There is no entitlement to a particular mounting method. Obtain consent in writing and document the fixing. Above the fall edge, proof of structural stability is sensible.

Zero VAT and income tax exemption up to 30 kWp

Supply and installation of PV systems up to 30 kWp on residential buildings carry no VAT, and the income is exempt from income tax.

VAT

0 % up to 30 kWp

Income tax

exempt up to 30 kWp

The zero rate covers modules, inverter, storage and installation. You pay the net price without needing to reclaim input tax — the old optimisation via standard taxation is obsolete.

The income tax exemption applies per taxpayer for up to 100 kWp in total and usually removes the need for a trade registration.

The feed-in tariff is guaranteed by statute

Surplus from systems up to 10 kWp earns a statutory rate, guaranteed for 20 years plus the year of commissioning.

Surplus up to 10 kWp

around 7.9 ct/kWh

Guarantee

20 years + commissioning year

The rate falls every six months for new systems; once set, it stays fixed for the whole term. Full feed-in earns higher rates but rarely pays where self-consumption is high.

During extended periods of negative exchange prices, newer systems lose the tariff for those hours. So far this affects a low single-digit percentage of annual output.

Bidirectional charging: not banned, but still awkward

Feeding electricity from an electric car back into the house is not prohibited in Germany. What blocks it is certification, metering and the treatment of levies.

This is the most frequently misreported point in the field. It is not "forbidden" — it is regulatorily unfinished, and the position is moving quickly.

A bidirectional wallbox exports into the house circuit and therefore counts as a generation unit. It must be certified to VDE-AR-N 4105 and registered with the grid operator. For a long time, certified vehicle and wallbox combinations simply did not exist.

The second obstacle is metering: vehicle-to-home needs a metering concept that separates drawn from returned electricity, otherwise the same kilowatt hour risks being charged grid fees, levies and taxes twice.

Third, § 14a of the Energy Industry Act applies: wallboxes above 4.2 kW are controllable consumers, which earns reduced grid fees but lets the operator throttle them.

For the calculators here that means we deliberately do not model vehicle-to-home as a revenue item. Anyone counting on it should get the certification of their specific vehicle and wallbox pairing confirmed in writing first.

Up to 70 percent towards a heating replacement

The BEG subsidy combines a base grant with speed, income and efficiency bonuses, capped at 70 percent and €30,000 of eligible cost.

Base grant

30 %

Speed bonus

20 %

Income bonus

30 %

Efficiency bonus

5 %

Maximum grant

€21,000

The speed bonus requires replacing an old but still functioning system. The income bonus applies to owner-occupiers below €40,000 of taxable household income. The efficiency bonus covers natural refrigerants or ground source.

The application must be filed before the work is commissioned — strictly, a supply or service contract with a condition precedent is required.

The carbon price on oil and gas keeps rising

Fossil fuels carry a national carbon price that is scheduled to rise and to move into European emissions trading from 2027.

The price is already inside the fuel price and, in tenancies, is split between landlord and tenant on a sliding scale — the worse the building's efficiency, the larger the landlord's share.

For the economics this means the gas-versus-heat-pump comparison shifts further towards the heat pump every year, even without any rise in the gas price itself.

Notice periods and the right to price changes

Basic supply carries a two-week notice period. A price increase triggers a special right of termination.

Special contracts usually run twelve or twenty-four months with three months' notice. After the initial term they roll over, but may then be cancelled with at most one month's notice.

A supplier raising prices must give at least six weeks' notice in text form; the special right of termination runs from receipt.