Bidirectional counter – principles of operation

Before connecting the photovoltaic installation, it is necessary to install a bidirectional meter that will measure both how much energy was produced by the home power plant and allow reading how much of it was energy surplus and was sent to the general grid. Without this device, connecting the installation is not only illegal, but also completely unprofitable – connecting photovoltaics to a regular meter will cause it to treat the electricity produced as consumed, which will drastically affect the amount of energy bills.

Connecting the installation on-grid does not completely free us from the relationship with the energy company, so we will have to periodically settle the possible energy consumption from the general network or simply incur fixed network maintenance costs. In order to control the exchange of electricity between the photovoltaics and the general grid, a bidirectional meter is necessary, through which the electricity supplier will calculate the consumption exceeding the difference with the production of the surplus sent to the grid.

When designing installations, it is rare for customers to decide to select power based on minimum parameters, which would result in constant energy consumption from the network and the need to pay for the consumed electricity. In the case of the installation’s limit values, it is equally probable that the energy exchange balance may amount to 0, although of course it is difficult to precisely match the production to the demand due to, for example, variable weather factors. However, if this happens, in such a situation we will only be obliged to bear the fixed costs of maintaining the network, which amount to approximately PLN 20 per month and include, among others: meter fee.

The ideal situation is when more electricity is produced than is required by the household. In this case, if there are no energy storage units in circulation, the surplus is transferred directly to the grid, and the bidirectional meter records the exact number of kilowatt hours that were sent from the installation. Thanks to this, in winter, despite lower energy production, we can keep electricity bills very low, and often even at zero, if the surplus stored in the network covers the demand with reduced installation efficiency.

It does not matter whether the prosumer contract includes a single- or multi-zone tariff, because the bidirectional meter, in addition to indicating the current state of energy consumption and shipment, also allows reading the date, time and the current tariff, which can be deciphered with help. OBIS codes. Accordingly, we can read among the single-zone tariffs:

• code 1.8.0 meaning total consumption, i.e. the amount of energy specified in kWh that was taken from the network,
• code 2.8.0 denoting the amount of energy in kWh that was sent from the installation to the general grid.

In the case of multi-zone tariffs (including G12, C12, C22), these are the codes:

• 1.8.0 meaning total energy consumption in kWh including zone summation,
• 1.8.1, which determines consumption in tariff zone I,
• 1.8.2 suitable for zone II,
• 1.3.2 specifying electricity consumption in kWh in zone III,
• 2.8.0 – in total for zones means the total amount of kWh of energy fed into the network,
• 2.8.1 is the code for the amount of energy released in zone I,
• 2.8.2 similarly means shipment in zone II,
• 2.8.3 is the equivalent for measuring the amount of energy released in zone III.

The markings are not complicated, but it is worth having a cheat sheet near the meter if we want to be up to date with current consumption and our tariff is non-standard.

If we have not taken advantage of the opportunity to install a newer generation meter, which itself, using an internet communication system, sends measurement information in real time to the energy supplier with whom we have signed a contract, it will be necessary to write it down periodically based on the above-mentioned codes, so we will they had to provide its level in full kWh, and in the case of a multi-component tariff, it will be necessary to write down the meter reading for each tariff zone.

Apparently it may never be sent to the transmitter, but in practice the biggest difficulty is the time between billing to the power company. a failure is recognized on the basis of above-average consumption of electricity from the network despite the operation of the operating installation or a slightly faster one, based on the basic value: when the meter is too fast, the electricity consumption is charged or simply continues to be charged, when the installation can operate, achieve speed and only emit the surplus. network.

However, a fault will be signaled by a lit control diode, but we encourage you to periodically check the operation of the counter, even with a good control.

First of all, you shouldn’t try anything on your own. In this situation, we recommend caution and quick contact with the electricity supplier, who should send their technicians to the device within 14 days of reporting. If, after checking the meter, irregularities in its operation are indeed revealed, the cost of this visit is borne by the energy company.