Rules for switching to a back-up electricity and gas supplier for businesses

Importantly, the activation of reserve sales takes place automatically by law — the customer does not need to take any action, and the continuity of supply is maintained. This mechanism operates automatically in the background, protecting the customer from a situation where they would suddenly be cut off from electricity or gas.

What were the rules for reserve electricity sales before 1 July 2025?

Before the changes came into force on 1 July 2025, it was the customer’s responsibility to designate a reserve supplier themselves. This choice was usually made when concluding an electricity supply contract or a comprehensive contract, from among the entities listed in the registers published by distribution system operators. In practice, this meant that a business signing a contract for electricity or gas supplies had to simultaneously decide who would take over supplies in an emergency.

If the customer did not make such a choice, the distribution system operator would conclude a reserve supply contract ‘ex officio’, i.e. with the entity designated by default in the given area. Although this system provided formal protection, it required customers to be proactive and to manage their relationships with energy suppliers consciously.

In the event of reserve supply being activated, it was the distribution system operator (DSO) who acted as the coordinator of the entire process. If a customer wished to terminate the default supply arrangement and switch to a supplier of their choice, they had to give notice of termination with one month’s notice, effective at the end of the calendar month — which in practice could mean several weeks of being supplied under unfavourable pricing conditions.

What has changed since 1 July 2025?

The amendment to the Energy Law, linked to the launch of the Central Energy Market Information System (CSIRE), has brought about a number of significant changes to the mechanism for the reserve sale of electricity. These changes concern both the method of appointing the reserve supplier and the procedure for informing the customer, as well as the conditions for terminating the contract.

First and foremost, from 1 July 2025, the customer will no longer be required to designate a reserve electricity supplier themselves. This role is performed by a designated supplier, appointed by the President of the Energy Regulatory Office within the area of a given distribution system operator. Information on which specific entity acts as the designated supplier in a given area is available on the websites of the individual distribution system operators.

The second fundamental change is the transfer of the role of process coordinator from the distribution system operator to the Energy Market Information Operator (OIRE), operating within the framework of CSIRE. It is the OIRE that notifies the reserve supplier of the need to initiate reserve sales.

The terms for terminating a reserve supply contract have also undergone a significant change. Under the previous legal framework, a one-month notice period applied, effective at the end of the calendar month. Currently, the customer may terminate the contract with seven days’ notice. Furthermore, the contract is automatically terminated upon the customer entering into a contract with a new supplier of their choice — without the need to submit a separate notice of termination.

Changes to the above reserve electricity sales mechanism apply to entities joining the CSIRE – the deadline for implementing the system is scheduled for 19 October 2026.

What about natural gas?

The changes described above relating to the launch of CSIRE apply exclusively to the sale of reserve electricity (Articles 5ac–5ad of the Energy Law). In the case of natural gas, a separate legal regime applies, regulated by Articles 5aa–5ab of the Energy Law, which has not changed in connection with the implementation of CSIRE.

In the gas model, the end consumer independently selects a reserve supplier from among the entities included on the list published by the distribution system operator. The selection is made when the contract is concluded, whilst simultaneously authorising the operator to conclude a reserve contract on behalf of and for the benefit of the consumer in the event that the current supplier ceases supply.

The distribution system operator remains the coordinator of the process for initiating reserve gas sales. It is the DSO that informs the customer of the conclusion of the reserve contract within 5 days. The customer may terminate the reserve gas sales contract with 7 days’ notice, without incurring additional costs. A business using both electricity and natural gas should therefore be aware that, in the event of problems with the supplier, the procedure for initiating reserve sales will follow two different legal models.

When will the reserve supply of electricity not be activated?

The reserve supply mechanism, despite its automatic nature, will not operate in every situation. The regulations provide for a number of exceptions that businesses should be aware of. Reserve electricity supply will not be activated, for example, where the customer uses a prepayment billing system and has been in arrears twice within a twelve-month period, when energy supplies have been suspended for reasons related to grid security, when the customer has no legal title to the property to which the energy is supplied, and also when the customer is already using the reserve supply from another supplier. Another ground for exclusion is payment arrears to the distribution system operator exceeding 30 days.

What should a business owner do?

From the entrepreneur’s perspective, it is crucial to distinguish between two legal regimes. In the case of electricity, from 1 July 2025, the reserve supplier is the supplier who, within the area of the distributor to whose network the customer is connected, acts as the designated supplier – the entrepreneur does not need to make a choice themselves. In the case of natural gas, the obligation to independently designate a reserve supplier still rests with the customer, who makes this choice in the distribution or comprehensive contract. Regardless of the type of fuel or energy, it is worth verifying whether the current contracts are still in force – the expiry of a contract may automatically trigger reserve supply on unfavourable price terms. In the case of electricity, the reserve price can be up to three times the average market price for the previous quarter. Therefore, the priority should then be to conclude a contract with the chosen supplier on market terms as soon as possible.

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