Today, net billing is the main settlement mechanism for new photovoltaic systems in Greece. Although it is often confused with net metering, it is a different model, with a different approach, economic logic and technical requirements.
In this article, we explain in detail how net billing works, what you pay, what is credited, when it makes sense, and the role of the battery.
What is net billing?
Net billing is a system where:
- the energy you use directly from your photovoltaic system is free
- surplus energy is sold to the grid
- the energy you need from the grid is charged at the regular rate
The settlement is calculated in monetary value (€), rather than in kWh, as it was under net metering.
How it works in practice
A photovoltaic system with net billing operates in three situations:
1. Direct consumption
When the home or business uses electricity at the same time as the photovoltaic system is generating power:
- the energy is used directly
- it does not pass through the grid
- it is not charged
This is the greatest financial benefitof a photovoltaic system.
2. Surplus generation
When generation exceeds consumption:
- the surplus energy is fed into the grid
- it is recorded by the meter
- it is compensated at the energy purchase price
This price is lower than the retail price, making correct system sizing crucial.
3. Consumption from the grid
When there is no generation (at night, in cloudy weather, or in winter):
- electricity is supplied by the grid
- it is charged at the regular tariff rate
- the value of the energy you have sold is deducted
The final bill is calculated as charges – credits.
Difference between net billing and net metering
The main difference is how the settlement is calculated:
- With net metering, kWh were offset (generation against consumption)
- With net billing, the value of the energy
is credited
This means that:
- installing excessive capacity is not worthwhile
- priority is given to self-consumption
- the battery becomes genuinely worthwhile
When does net billing make sense?
Net billing makes sense when:
- there is daytime consumption
- the system is designed using actual data
- overproduction is avoided
- it is combined with a battery or smart load management
For most homes, 4–7 kWp is often a more efficient choice than larger systems.
The role of the battery in net billing
The battery:
- stores surplus energy
- significantly increases self-consumption
- reduces the need to buy electricity at night
- protects against future price increases
In many cases, a smaller photovoltaic system with a battery performs better than a larger system without storage.
Common mistakes with net billing
- Choosing a system based only on kW
- Ignoring the consumption profile
- Relying too heavily on selling energy
- No monitoring
- Unrealistic expectations of a “zero bill”
Today, net billing is the right way to make the most of photovoltaicsin home or business, provided the design is done correctly. This isn’t a “put up lots of panels and you’re done” system, but a solution that requires careful planning, data and experience.
At Solar Home, we design net billing photovoltaic systems based on actual consumption, not general rules.
