The big debate about the periodic cut-off in the operation of residential photovoltaic systems does not just have an answer, but also a solution, according to what is conveyed to "F". Now, whether this solution is financially advantageous for consumers is something that must be evaluated separately by each citizen and entrepreneur, since, as it seems, contrary to the general perception, the cuts are limited for homes and do not have such a large economic impact on households.
In particular, it is now possible for residential and small commercial photovoltaic systems to legally avoid cuts. This can be done through an application to convert the connection to a zero-injection regime into the network, or as it is better known, for "zero export".
That is, there is the possibility that the electricity produced is used exclusively for self-consumption.
The two ways that exist
According to the EAC, "zero export" can be implemented in two ways:
1. Permanent zero injection into the grid: In this case, the PV System operates exclusively for self-consumption, without exporting electricity to the grid. The energy generated is consumed within the installation and the control system ensures that no injection is made into the grid. In this form of operation, the installation is generally not subject to production restrictions, except in exceptional cases related to network security or stability issues.
2. Occasional zero injection into the grid: In this case, the PV installation can export energy to the grid when the operating conditions of the System allow it. However, when required, to maintain the balance and safe operation of the electrical system, the system receives a zero-injection state mandate, temporarily limiting the export of energy to the grid.
It should be noted that in order to implement this function, a conversion to the photovoltaic system must be made, with the installation of a "smart meter". This conversion can also be done in an existing photovoltaic system.
It will cost about €500 to "save" €20 (at most) per year, according to calculations by technocrats.
The amount for special equipment may not sound prohibitive in order to avoid the cuts, however, the cost for the conversion in relation to the final benefit for the consumer, is not only large, but even seems to be greater in relation to the economic impact it will have, even with cuts.
The mathematics of cuts
In this equation we asked for the knowledge of Michalis Drakoudis, CEO of Dracoudis Energy and an expert on energy issues.
Mr. Drakoudis, through his knowledge, clarifies the real cost and benefit for a household. As he explained, an average consumption in a house, when the tenant is absent, ranges between 200 and 500W (provided that some appliances are working, such as the refrigerator). This means that if a house consumes about 300W per hour, then in a four-hour cut-off, the "damage" in electricity for the owner will be a few cents of the euro, about 34 cents, even giving a specific example of how one can calculate what one loses in energy and how much is the economic impact of cutting off the operation of the photovoltaic.
More specifically, as he explained, if we assume that every hour a house consumes 300W and photovoltaics are cut off for four hours, then, based on the price of a kilowatt hour at 29 cents, the citizen will "lose" about 34 cents. If we now take these 34 cents for every four hours of cuts and multiply them by the times it is decided to stop the operation of photovoltaics, then the cost, even roughly and with the addition of even weekends, does not exceed €20 for the whole year.
Now, in case someone wants to avoid cut-offs, they should install a "smart meter", at a cost that can even reach €500. Essentially, a citizen, with deductions close to 7-8% throughout the year, will need more than 20 years to amortize the amount for this conversion!
The cost of the "smart meter" and battery
In particular, the "smart meter" as a device costs close to €150 + VAT, an additional €80 for other materials needed for its installation and an additional about €150 for labour.
For new PV systems to be installed, the cost may be a little lower, however, it is still high in relation to the benefit.
Asked whether the solution can be the use of batteries, Mr. Drakoudis noted that their price is close to €700 to €800 per kilowatt hour. A cost that amounts to a few thousand euros and is certainly not justified in relation to the financial loss of a few euros per year from the cuts.
In conclusion, as he noted, the installation and conversion of a photovoltaic system to "zero export" can only be advantageous in some exceptional cases of commercial systems, for industries that may be working their machines at noon and based on cost-benefit to benefit from this conversion.
