This section provides answers from AST experts to the questions most frequently asked about connections to the transmission network.
1. In which cases does the TSO deem an application to have not been submitted or to be incomplete?
Answer: If the application does not contain all the necessary information about the connection and the project as a whole. Not all of the required documents are enclosed with the application in its annex. The application was not signed by the person authorised to sign it, or no document certifying the authorisation to sign was enclosed with the application.
2. If an incorrect application is submitted, how long does it take AST to provide information about the application’s deficiencies?
Answer: AST provides this information within 20 days after receiving the application.
3. How much time does the drafting of technical requirements take?
Answer: 60 days after the receipt of a complete application and the required documentation. If the drafting of the technical requirements is complicated and needs more time, or the application does not include all the necessary information, the system operator informs the system participant of the deadline for issuing the technical requirements in writing within 20 days after receiving the application.
1. In what cases must the party requesting a connection obtain the respective property rights or development rights?
Answer. If the connection involves the construction of a new substation or the expansion of an existing substation, the party requesting the connection must provide a plot of land for the construction or expansion of the substation.
2. What must the course of action of the party requesting a connection be to ensure the acquisition of property rights or development rights for building AS “Augstsprieguma tīkls” part of the substation, and within what time?
Answer. The course of action and time involved are described on the AST website, in step 10 of the process: Connections to the transmission system.
1. Is it possible, during or after setting up a connection, for a different legal entity to act on behalf of the party requesting the connection?
Answer: Yes, this is possible if a different legal entity is the successor of the rights and obligations of the party requesting the connection.
2. Is it possible to change the location of the land intended for the planned connection location (new substation)?
Answer: Yes, this is possible. Changing the land is possible if the change does not involve a substantial modification of the construction design. The information in the application and the list of enclosed documents must be amended, and a formal application for amendments to the existing technical requirements and design terms of reference (if any are designed) must be submitted to AST. AST then assesses the amendments and, if the installation of the connection is technically feasible, changes will be made to the technical requirements and the design terms of reference (if any are designed). The concluded agreement will have to be amended as well. It must be kept in mind that the changes must not affect other candidates for a connection. The processing of changes to the land does not extend the deadlines for the installation of a connection.
3. Can the number of connections be changed during the installation of a connection?
Answer: Yes, it is possible if the size of the land plot permits such. Changes to the number of connections can be formalised before the connection contract is signed. If the size of the land plot does not permit this, all matters pertaining to increasing the size of the land unit must be resolved first. The information in the application and the list of enclosed documents must be amended, and a formal application for amendments to the existing technical requirements and design terms of reference (if any are designed) must be submitted to AST. AST then assesses the amendments and, if the installation of the connection is technically feasible, changes will be made to the technical requirements and the design terms of reference (if any are designed). The concluded agreement and other binding contracts with AST will have to be amended as well, and updated technical specifications will have to be obtained for the procurement of the equipment. The processing of changes to the number of connections does not extend the deadlines for the installation of a connection.
4. Does amending information about the planned connection location (new substation location), the number of connections at the connection point, or other information related to the connection and the applicant affect the time provided for the installation of the connection?
Answer: No, the deadline for installing the connection does not change if amendments are made to the technical requirements.
1. What is the minimum distance between a wind turbine of a Producer and an AST substation or transmission line?
Answer: The minimum distance from the wind turbine tower to the outer wires of an overhead line or to the fence of a substation is equal to the height of the wind turbine (including the length of the rotor blades) plus 10 metres.
2. What is the minimum distance between a solar panel of a Producer and an AST substation or transmission line?
Answer: The minimum distance from a solar panel to a substation is 1 m from the substation fence or AST land plot. The minimum distance between a solar panel and the outer wire of a power transmission line is: 12 m from the outer wire of a 330 kV PTL, and 7 m from the outer wire of a 110 kV PTL.
3. At what point is the party requesting a connection required to supply 10% of the installed capacity, and why is this requirement in place?
Answer: In order for the AST connection test (72-hour test) to be carried out, the owner of the power-generating facility, demand facility, or distribution facility must supply a load equal to at least 10% of the installed capacity specified in the technical requirements or at least 5 MW, whichever is greater. The 72-hour test is deemed passed if the equipment operated for 72 hours without load disruptions. Without this testing, AST cannot verify if the equipment of the connection works properly, and the connection contract cannot be completed.
4. What are the conditions and options for building a connection in phases?
Answer:
- Installation of the connection in phases must be specified in the technical requirements in writing, with the phases defined.
- Installation of the connection in phases must take place as part of a single connection contract. The deadlines for the installation of the connection set in prior contracts between AST and the party requesting the connection remain unchanged. The deadlines for each phase are to be specified in the connection contract.
- If, at the time of the conclusion of the system service contract, not all of the phases of the connection specified in the technical requirements are installed, the issued technical requirements are amended again, making corrections in line with what has already been built, and only then is the system service contract concluded with AST and the party that requested the connection. The reserved connection capacity for the part that has not yet been built no longer remains reserved for the party requesting the connection.
- It should also be pointed out that the installation of each successive phase may require disconnections from within the power transmission grid, which will limit the operation of the facility installed during the initial phase. It is more efficient to conduct the construction of both phases at the same time.
5. What are the conditions and options to continue building up the utilisation of capacity (through the installation of generation facilities) after the installation of a connection, with gradual implementation of the project?
Answer:
- Once the connection is installed, the generation capacity may be built up gradually in accordance with the deadlines set in the Technical Requirements, the agreement on the installation of the connection, and the Bureau permit for the implementation of a new power-generating facility as per Section 22(1) of the Electricity Market Law (effective at the time the agreement is concluded), as well as the conditions for installing the connection.
- If the Producer obtains an interim operational notification (IOM), then its deadline must be complied with, which is two years for testing the Producer’s power plant and for completing its installation; during these two years, additional power-generating facilities may be added, amending the IOM, taking that which is stated in the previous paragraph into account.
- Interim operational notifications are issued for the purpose of conducting verifications and tests, in accordance with the procedure for the acceptance of type D power-generating modules, drafted in line with Regulation 2016/631 and Regulation 2016/1388, as well as the Power Industry Network Code.
1. What needs to be done to obtain an energisation operational notification (EON)?
Answer:
- The Producer must follow the operational notification procedure for type D power generation modules, demand facilities, and distribution facilities. It describes how to receive an EON and what documents need to be submitted for it. The procedure is publicly available here: Operational notification procedures and inspection procedure.
- According to Section 34 of Commission Regulation (EU) 2016/631 of 14 April 2016, establishing a network code on the requirements for the grid connection of generators (‘Regulation 2016/631’): ‘An EON shall entitle the power-generating facility owner to energise its internal network and auxiliaries for the power-generating modules by using the grid connection that is specified for the connection point.
An EON shall be issued by the relevant system operator, subject to the completion of preparations including an agreement on the protection and control settings relevant to the connection point between the relevant system operator and the power-generating facility owner.’
2. What needs to be done to obtain an interim operational notification (ION)?
Answer:
- The Producer must follow the operational notification procedure for type D power generation modules, demand facilities, and distribution facilities. It describes how to receive an ION and what documents need to be submitted for it. The procedure is publicly available here: Operational notification procedures and inspection procedure.
- According to Section 35 of Commission Regulation (EU) 2016/631 of 14 April 2016, establishing a network code on the requirements for the grid connection of generators (‘Regulation 2016/631’): An ION entitles a power-generation facility owner to operate a power-generating module and generate power using the grid connection for a limited time of 2 years. All the necessary checks and tests are carried out while the ION is valid.
3. Can an interim operational notification (ION) be extended?
Answer: In accordance with Section 35(4) of Regulation 2016/631:
‘The maximum period during which the power-generating facility owner may maintain ION status shall be 24 months. The relevant system operator is entitled to specify a shorter ION validity period. An extension of the ION shall only be granted if the power-generating facility owner has made substantial progress towards full compliance. Outstanding issues shall be clearly identified at the time of requesting an extension.’
4. What needs to be done to obtain a final operational notification (FON)?
Answer:
- The Producer must follow the operational notification procedure for type D power generation modules, demand facilities, and distribution facilities. It describes how to receive an FON and what documents need to be submitted for it. The procedure is publicly available here: Operational notification procedures and inspection procedure.
- According to Section 36 of Commission Regulation (EU) 2016/631 of 14 April 2016, establishing a network code on the requirements for the grid connection of generators (‘Regulation 2016/631’): A FON shall entitle the power-generating facility owner to operate a power-generating module by using the grid connection.
1. Where is it possible to see the available capacity?
Answer: The capacity available for Producers/Users can be found on the capacity map available for the continuous service on the AST website and, for the flexible service, in the published PDF file (since 2 June 2025): Connections to the transmission system.
2. Can the TSO refuse to issue technical requirements and in what cases does it do so?
Answer:
- According to Section 9(4) of the Electricity Market Law: ‘The system operator has the right to refuse a connection to the relevant system if the network capacity thereof is not sufficient. The system operator shall provide justification for the refusal in writing within 30 days after the receipt of an application from a system participant.’
- In accordance with Section 15.2(3)(4) of the Electricity Market Law ‘Types of Transmission System Services’: ‘(3) In order to provide a flexible transmission system service, the transmission system operator: ... 4) does not conclude a connection contract and does not reimburse the electricity producer for the costs associated with the connection of the power-generating facility if, once the requirement referred to in Paragraph 3 of this Section is met, the free available transmission system capacity is less than the capacity specified in the technical requirements for the connection of the electricity producer’s power-generating facility to the electricity system (unless the technical requirements can be amended, with the consent of the electricity producer, and the technical solution for the connection does not change due to the amendments).
3. Which party covers the connection costs, and in which cases does the TSO contribute to the coverage of the costs?
Answer: According to the connection regulations approved by the Public Utilities Commission, all costs are covered by the party requesting the connection. If the party requesting a connection intends to set up a connection to an existing substation and its rebuild is included in the 10-year development plan, and the planned deadlines of the projects match, then AST contributes to the rebuild using its own financial assets earmarked for the implementation of the solution foreseen in its development plan.
4. Based on AST’s experience, what is the average time for building or rebuilding substations?
Answer: The average time for building or rebuilding a substation is 3 years, counting from the start of the procurement procedure.
5. What critical points need to be considered when setting up a connection? What are the common stumbling blocks?
Answer:
- Failure to resolve the land-related affairs in time. No connection contract can be concluded unless AST and the party requesting a connection sign a land development contract or a land sale contract.
- Failure to take the long time necessary for the production and delivery of equipment into account.
- Failure to coordinate the deadline for the construction of the producer’s power plant and the installation of the connection.
6. What needs to be taken into account to make the connection costs as low as possible?
Answer: Plan installing the connection with an existing substation that still has free capacity for new connections. For such facilities, the costs of a new connection are limited to the connection/connections themselves, with no new substation having to be built, or an existing substation to be rebuilt.