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On-grid System

The most widelystem with the lowest cost and least maintenance requirements.

Key features

The name of the system itself comes from the way it operates, namely – in parallel with the grid. It consists of solar PV panels, an inverter (one or several) and a switchboard. It contains no batteries. The power capacity of these systems can range from 250Wp to infinity, depending on customer needs.

The size of an on-grid system is determined mainly by two factors: the area which the customer has available for construction and the investment they are willing to make.

It is important that the location of the plot or building has southern exposure to the sun and does not to have any overshadowing from trees, buildings etc. at any given time during the day.

On-grid systems can operate under two main scenarios: entirely for the sale of the electricity produced or for own consumption.

Scenario 1

In the first scenario, the solar PV system is connected directly to the power grid by means of a meter and the entire quantity of electricity produced is fed back into the grid.

At the end of each month, a report is issued by the local electricity company which indicates the total amount produced and fed into the grid. Based on this report, the investor issues an invoice for this amount, which is  priced at a special tariff, indicated in the purchase agreement.

Currently, the most common size for an on-grid solar PV system in Bulgaria is 30kW. This is because of the feed-in tariff at which the electricity produced by systems up to this size is purchased at. This tariff is set anually by the Bulgarian Commission for Energy and Water Regulation (CEWR).

There are currently three main requirements for the status of the property on which such a solar PV system can be installed:

Feed-in tariff for solar PV systems at 01.07.2020, set with Decision Ц-27 by CEWR:

Scenario 2

In the second scenario, the solar PV system is connected to the internal grid of your home. When the system is generating electricity, the energy produced enters the system and is utilised by the household. At this time, household consumption is satisfied primarily by the energy produced by the solar PV system. However, if the production of the system fails to meet the needs of the household , the amount of energy that is not enough is supplemented by the main grid.

On the other hand, if the amount of energy produced is greater than what the household is currently consuing, then there are two options:

Option 1

The excess electricity is fed into the grid through a bi-directional meter, installed by the local EDC. This eletricity is costed at a tariff, which is different from the feed-in tariff in scenario 1 and is determined by the local EDC.

Option 2

Production is limited through the use of a smart  meter which detects the presence of excess electricity. This way, no coordination or a relationship with the local EDC is necessary.

With this option it is recommended that the investor calculate well, so that the excess electricity should not be equal to more than 15% of the operational time of the system, because then the losses will be unreasonably large.

For Bulgaria, the average operating time of a photovoltaic system on an annual basis is about 1300 hours. Which means that if, for example, you have a photovoltaic system of 5kWp, then 5 x 1300 = 6500 kW energy yield can be expected on an annual basis. It should be taken into account that in summer the production of a system is about 3 times more than in winter.

The optimal angle for mounting the solar PV panels is at 30 ° – 35 °, but a deviation of up to 10 ° does not have such a large impact on yield.

It is important to remember that an on-grid system ALWAYS works ONLY in sync with the main grid, which means that if the grid falls out (i.e. the power supply is out), the system will also stop working. This is a European safety directive, which aims to prevent the supply of voltage to the grid during repairs.

What you get with us:

Expert Consultation

We will aim to answer all of your questions. If we don't have the answer at hand, we will do the work and find it for you as quicly as possible.

Certified Products

All materials and components which we use comply with the highest quality and safety technical standards. Each and every product has been approevd for use within the EU.


We will clarify all requirements regarding the necessary documentation: how to obtain them, where and when to submit these. We will assist in filling out all forms.

Right on Time

We complete our work exactly within stipulated timelines. They will be detailed within our contract and will be our first priority.


Every product which we work with carries a technical warranty. Any technical issues arising within this period will be serviced as soon as possible or components will be replaced as needed.

High Quality

Our biggest priority: high quality. We strive to achieve this at all cost.