What is net billing in Greece?

It is simultaneous netting: solar energy consumed at the same moment reduces what you buy from the grid, while surplus injected into the grid is paid at the Day-Ahead Market price for the hours it is injected.

What is the difference between net billing and net metering?

Under net metering, production was offset against consumption over time, so every kWh had roughly the same value. Under net billing, netting happens in the same hour and surplus is paid at wholesale prices, so value depends on when you consume.

How much is surplus solar paid under Greek net billing?

The hourly Day-Ahead Market price. At sunny midday hours this price is often very low or even negative. A Ministry of Environment and Energy bill under consultation (October 2026) provides that at negative prices the compensation counts as zero rather than as a charge.

What is the power limit for a household solar system under net billing?

Up to 10.8 kW per supply point for households. The netting contract lasts 20 years and the value of the surplus is credited on the electricity bill.

Do I need a battery with net billing?

Not necessarily. It is usually cheaper to first shift large loads (water heater, heat pump, EV charger) into production hours automatically. A battery then covers evening consumption once load shifting is exhausted.

How do I increase solar self-consumption?

Measure the power flow at the grid connection point and use automation to switch on loads when there is surplus: water heater, heat pump pre-heating or pre-cooling, solar EV charging, washing machines, pool pump.

Smart Home and Solar in Greece: How Automation Raises Self-Consumption Under Net Billing

In short: Under net billing every solar kWh has two very different values. When you use it the same moment, you avoid the full retail price with all its charges. When you send it to the grid, you are paid the hourly wholesale price, which at sunny midday hours is often close to zero. The practical takeaway: a home solar system's return now depends on how much of its production you consume yourself. That is a job for automation, not for reminders.

Net metering vs net billing at a glance

	Net metering (old)	Net billing (new)
How it nets	Production and consumption over time	In the same hour (simultaneous)
Value of surplus	Roughly equal to consumption	Hourly wholesale price
What matters most	Total annual production	When you consume
Role of automation	Useful	Decisive

How net billing works today

Self-consumption: Energy produced and consumed at the same time simply reduces what you buy from the grid.
Surplus: Whatever is injected into the grid is paid at the Day-Ahead Market price for the hours of injection.
Household systems up to 10.8 kW: The value of the surplus is credited on the electricity bill. The netting contract lasts 20 years.
Regulated charges: Calculated on energy drawn from the grid. The less you draw, the lower they are.
New contracts: With the September 2026 ministerial decision (ΦΕΚ Β 5573), the three-party contract is replaced by two bilateral ones and the process goes digital.

What happens when prices go negative

At sunny midday hours the wholesale price often drops very low, and some hours it turns negative. A Ministry of Environment and Energy bill under public consultation (October 2026) provides that in those hours small self-producers' compensation counts as zero rather than as a charge, and that energy from those hours is not taxed. It is an important protection, but it also shows something else: at peak production hours, surplus may be worth exactly zero.

A simple example

Assume, with illustrative prices, that you pay a final price of €0.22/kWh for grid electricity and that the wholesale price at 13:00 is €0.03/kWh.

If the water heater heats water at 13:00 using 3 kWh of solar, you save €0.66.
If the same 3 kWh go to the grid and the water heater runs at 20:00 from the grid, you receive €0.09 and pay €0.66.

Same energy, same day, different hour: roughly a 7x difference. Multiply that by every load and every day of the year and it is clear why self-consumption decides the payback.

The Hellenic Association of Photovoltaic Companies (ΣΕΦ), in its new guide, gives an illustrative example of a household using 8,500 kWh a year, with a heat pump or air conditioners, a 5 kWp solar system and a 5 kWh battery, with a 53.4% bill reduction. The guide itself stresses that results depend on each home's consumption profile.

Which loads move to solar hours

Not every consumption can move. The largest loads in a home usually can:

Water heater or boiler: The easiest "storage". It heats water with midday surplus and keeps it for the evening.
Heat pump: Domestic hot water, plus pre-heating or pre-cooling the home while there is production. The building's thermal mass does the job of a battery.
Electric vehicle: "Solar charging", with a charging current that follows the surplus, instead of charging at full power the moment it is plugged in.
Washing machines, pool pump, dehumidifiers, electric towel rails: Smaller loads that add up.

How a KNX system does it

An energy management system built on KNX works with simple, predictable logic:

Measures at the grid connection point. A bidirectional energy meter in the panel shows at every moment whether the home is drawing or exporting, and how much.
Knows what is produced. The inverter is connected to the system (usually via Modbus and a gateway), so production and battery state are known.
Switches loads on by priority. When surplus exceeds a threshold for several minutes, it starts the first load on the list (for example the water heater). If there is still surplus, the next one. Time hysteresis prevents constant switching when a cloud passes.
Respects comfort. Water is not heated above a limit, the home is not cooled below a set temperature, and the user can always override the automation from a switch or the app.
Works with the battery. It decides whether surplus goes to loads or to the battery first, depending on the time and the forecast. With a dynamic tariff, it also takes tomorrow's prices into account.
Shows the result. Self-consumption rate, kWh from the sun and savings, on a touch panel or app.

Advice before installing (or upgrading) solar

Size for your consumption, not your roof. Under net billing, a large system that sends half its kWh to the grid at midday pays back more slowly.
Automation first, battery second. Shifting large loads costs less than a battery of similar "capacity" and does not wear out with cycles.
In a new build or renovation, plan now for an energy meter in the panel, separate circuits for the water heater, heat pump and EV charger, and communication cabling to the inverter.
No roof of your own? See what the new framework allows for balcony solar and batteries without solar.

The Sync-Teq approach

Under net billing, solar is no longer "install panels and forget". It pays off when the home knows when to consume. Sync-Teq does not install solar panels: we handle the home automation and work alongside your solar installer, so that the KNX system measures, prioritises and shifts loads automatically and as much sunshine as possible stays yours. Contact us for an assessment of your home or project.

Sources

Energymag: The new ΣΕΦ self-consumption guide (in Greek)
Alphafreepress: New protection for household solar (13/10/2026, in Greek)
Joint Ministerial Decision ΥΠΕΝ/ΔΑΠΕΕΚ/102876/1958/2026, ΦΕΚ Β 5573/14.09.2026, via e-nomothesia.gr
ered.gr: Net billing replaces net metering