The method of self-sufficiency according to the Act on the promotion of the use of renewable energy sources

Act on promoting the use of renewable energy sources (Ur. l. RS, No. 121/21, 189/21 and 121/22 – ZUOKPOE) (hereinafter: law) it is the foundation of the transition to a carbon-neutral society, as it regulates the implementation of the country's policy and municipalities in the field of renewable energy use, determination of a binding target for the share of energy from RES in gross final consumption in the Republic of Slovenia and measures to achieve this goal and methods of their financing, certificates of energy origin, self-supply with electricity from RES, use of energy from RES in the heating and cooling sector and in the transport sector, as well as administrative procedures.

 

The aforementioned law does abolish the net metering of produced and transmitted electricity (old Regulation), therefore introducing new rights and options for customers, who want to become self-sufficient in electricity.

The law stipulates:

• every end customer connected to the distribution network has the right to become an end customer with self-supply of electricity from RES. The end customer can exercise this right individually, in community self-care or through aggregation;
• end customers with self-supply, regardless of the method of implementing self-supply, have the right to produce energy from renewable energy sources also for their own consumption, store it and sell their excess produced electricity, sent to the distribution network, also on the basis of electricity purchase contracts from renewable energy sources through electricity suppliers and according to the rules of mutual exchange;
• regardless of the possibility of selling surpluses, the end user with self-supply will still maintain the status of a customer (there is no need to register the activity of selling electricity);
• with its active operation, it will be able to participate in the stabilization of the electrical energy network (when this becomes possible);
• the procedure for easy connection of devices to RES has been introduced;

• for electricity taken from the public grid, end customers with self-supply pay the network fee, which is non-exclusive and reflects the costs and benefits of self-supply and other public charges, which are calculated on the amount of electricity (kWh) taken from the public grid. When determining the amount of the network fee for the end customer in community self-care, the extent of network use is taken into account;
• for electricity supplied to the network, the end customer with self-supply does not pay network fees and other public charges.
• for self-produced electricity from renewable sources, which can also be stored and remain in his building, the end customer with self-supply does not pay network fees or other public charges.
• the self-sufficient community is no longer limited to the transformer station, but to the entire network in Slovenia;
• provides exemption from the payment of the contribution for increasing energy efficiency and exemption from the payment of the contribution for providing support for the production of energy in CHP and RES (partially or in full, depending on the case);
• makes it possible to obtain certificates of origin and subsidies for the production of electricity from RES according to ZSROVA;
• enables entry into the self-supply system for all end customers who are connected to the distribution network in the Republic of Slovenia (until now, self-supply was limited only to household and small business customers);
• enables investment assistance to be granted by the support center;

• in order to prevent electric shock, enable disconnection from the distribution network at any time and ensure that a low voltage (ELV) is provided in the self-service device in the disconnected state, which is a maximum of 50 V alternating voltage or a maximum of 120 V direct voltage.
• in the event of a failure of the distribution network or detection of exceeding the prescribed voltage and frequency limits in the distribution network, ensure automatic shutdown of the device and must not transmit electricity to the distribution network.

• They enable MPPT (maximum power point tracking) separately for each module => better yield;
• Smaller losses due to module mismatch (partial shading, production tolerance, dirt);
• Automatic shutdown of AC/DC voltage for greater safety of installers and firefighters;
• When the device is turned off, a safe low voltage (50 VAC or 120 VDC) is provided;
• The possibility of increasing the power of the device (modular approach);
• Advanced performance measurement and real-time device performance monitoring.

CLASSIC SOLAR POWER PLANT (FN modules + inverter) IT DOES NOT MEET SAFETY REQUIREMENTS FOR A SELF-SERVICE DEVICE!

Conclusion
Owners of SE for self-care, which are connected according to the principle of net metering, can switch to the self-care system at any time according to the new regulation, but the transition from the new method to net metering is not possible.

Show less

Mode of self-sufficiency until 2023/2024 - »net-metering«

At the beginning of 2016, the Regulation on Self-Supply with Electricity from Renewable Energy Sources entered into force (Ur. l. RS, št. 97/15), which was amended in 2019 and 2020 (Ur. l. RS, št. 17/19 and 197/20) (hereinafter: the old Regulation), and is in Slovenian legal order entered the so-called net metering of produced electricity. This accounting principle has been well known in the world for 15 years and intended for small customers, i.e. households. Due to changes in European legislation, the Regulation and such method are getting old billing is abolished by the Act on the Promotion of the Use of Renewable Energy Sources, which, in Article 72, extends its use until 31 December 2023. Due to the energy crisis in 2022, the application of the old Regulation was extended for one year by the Act on Measures for Managing Crisis Situations in the field of energy supply (Uradni list RS, št. 121/2022), which stipulates that an application for approval must be submitted by 31 December 2023, and the device registered/connected by the end of 2024.

Customers who will connect their SE for self-supply by the end of 2024 according to the old Regulation will retain their rights under EZ-1 and net metering, as long as they use the existing device and will not make changes to the measurement site.

Billing method for net metering

The basis of net metering is the compensation of a unit of electricity (kWh) sent to the public grid with a unit of electricity received from the grid. So the exchange of kWh for kWh, which is recorded on a two-way advanced electricity meter. Accounting period in which these exchanges are recorded, it is a calendar year, i.e. from 1.1. to 31.12. If the SE connection is in the middle of the year, the accounting period begins with the day the customer connects to it and ends on 12/31. For the sake of simplification and easier annual accounting, a single tariff (ET) method of electricity measurement is defined. SE in Slovenia produces more energy in the summer months than the household or small business customer (MPO) needs to cover own needs at this time of year. These peaks are transmitted (and of course recorded at the measuring point) to the public network, and are used in foggy autumn and short winter days. Therefore, it is essential that the power of the SE is dimensioned in such a way that it will produce as much electricity over the course of the year, as the receiving place needs throughout the year. Self-supply of electricity is intended to cover the own needs of the household or MPO according to electricity and not the sale of surplus electricity produced. For this reason, a correct assessment of the facility's electrical energy needs is very important for a period of one year: too much SE power for self-sufficiency also means a higher investment cost, and surplus energy cannot be sold after settlement (determined by the old Regulation). Therefore, if more energy is produced than was consumed in the household/MPO, the extras are given free of charge to the electricity supplier with whom the owner has a self-supply contract. In the event that the device will produce insufficient electricity to cover the needs of the household/MPO, the lack of energy is purchased from the electricity supplier. The old Regulation also stipulates the netting of the network fee, which is calculated on the electricity received, which means that in the case of an optimally dimensioned SE for self-sufficiency (production = needs), our electricity bill is reduced only to the costs of paying for the connection power of the measuring site and contribution to the support scheme for renewable energy sources. In summary, all items on the bill that are billed per "kWh" unit are equal to zero. We only pay items per "kW" unit. For purchased electricity (in case of insufficient production), both the energy and all contributions related to it (network fee ...) are charged.

Essential requirements of the old Regulation

The self-supply mechanism with net metering can include households and small business customers (MPOs), who can connect a solar power plant to their internal low-voltage electrical installation for self-supply of a maximum connected power up to the value of 0.8 times p of the power consumption of the measuring point (e.g., it is allowed to connect 13.6 kW SE to fuses 3 x 25 A). SE placement is enabled for self-sufficiency in individual houses, multi-apartment buildings and the installation of so-called community SE.

SE security requirements for self-care

Rulebook on technical requirements for devices for self-supply with electricity from renewable energy sources (Ur. l. RS, no. 1/16, 46/18) (hereinafter: the Rules) prescribes the safety requirements that must be met by SEs for self-care. SE for self-care must: in order to prevent electric shock, enable disconnection from the distribution network at any time and ensure that it is in a self-service device in the switched-off state, a guaranteed low voltage (ELV), which is a maximum of 50 V alternating voltage or a maximum of 120 V direct voltage. in case of outage of the distribution network or detection of exceeding the prescribed voltage and frequency limits in the distribution network ensure automatic shutdown of the device and must not transmit electricity to the distribution network. To fulfill both security conditions at SE, it is necessary to install the so-called electronics at the module level. The most widespread is the use of power optimizers, which, in addition to safety requirements, provide the following advantages:

• They enable MPPT (maximum power point tracking) separately for each module => better yield;
• Smaller losses due to module mismatch (partial shading, production tolerance, dirt);
• Automatic shutdown of AC/DC voltage for greater safety of installers and firefighters;
• When the device is turned off, a safe low voltage (50 VAC or 120 VDC) is provided;
• The possibility of increasing the power of the device (modular approach);
• Advanced performance measurement and real-time device performance monitoring.

Show less