Elektrilevi

DSO - Estonia

Publication info

Publication status Published
Access link to GHC publication of the SO
Access type Open
Geographical Coverage No additional filters are available to view specific regions; only feeders across the entire Elektrilevi grid can be displayed
Spatial granularity Distribution lines. The TSO map includes substation nodes.
Voltage Level Coverage DSO network up to 35kV
Time Horizon (e.g. Y+1, Y+3 / 202x / snapshot) Snapshot
Data Format (Table, Map, etc.) Map
Grid user types covered Wind, solar, and other production
Displayed Capacity Type (e.g. available/requested/reserved/connected etc.) Available
API Availability Openly available
Grid hosting capacity downloadable & format No
Update Frequency Monthly
Available language National language(s) + others including English

Hosting capacity assessment

Capacity type considered for available hosting capacity information (e.g., Firm and/or Flexible)

Firm
Description of what firm capacity means

Offered capacity is available all the time
Description of the aspects/methodology that leads to firm capacity results

The formula calculates available production hosting capacity in the MV grid, considering only feeders supplied from 110 kV or higher voltage transformers, which is why the whole grid is not visible. The calculation is based on the maximum permitted output of existing and soon-to-be connected producers. The hosting capacity is derived using the active resistance (R) of the MV network (including transformer resistances), with cos(φ) = 1, i.e. reactive power is not considered. The starting voltage is taken from our guideline, and the permissible voltage increase is calculated as a percentage. Consumption is assumed to be zero, meaning only maximum generation is considered. The total transferable generation capacity (W) is calculated using:

  • ΔU = relative voltage rise (%)
  • U = starting voltage
  • R = total active resistance of the MV network including transformer impedances

The available capacity is then obtained by subtracting the already installed generation capacity from this result. Additionally, the maximum permissible transfer capacity of the supplying MV line is taken as a boundary condition. Final available hosting capacity is calculated by: 

  • Imax = maximum transfer capacity of the upstream line (W),
  • Pallowed = calculated hosting capacity limit (W),
  • Pinstalled = currently installed generation capacity (W).
Description of what flexible capacity means (if applicable)

This is not directly applicable. However, in Elektrilevi grid, flexibility should initially be applied against reserved capacity. In other words, flexibility is not intended to replace or cover the main required capacity. It represents a form of “virtual” capacity that can be allocated to clients or used by grid planners as if it were real capacity, without the need to build or secure additional physical capacity. Reserved capacity is needed to provide the grid service mandated in grid service quality standards (outage hours).
Main assumptions/disclaimers behind calculations
  • Maximum production all at once
  • Consumption doesn’t help available capacity. Consumption = 0
  • Primary substation is not a limit
  • TSO connection point capacity is not a limit

Additional information for connection request and hosting capacity information

Connection request procedure

Tingimused - Elektrilevi (https://elektrilevi.ee/et/tingimused/liitumine). The connection request process begins with submitting an application, including technical parameters and necessary documentation. Elektrilevi evaluates the request based on network capacity, development plans, and legal requirements, issuing a connection offer within 30 days. The connection fee is calculated using a methodology that considers actual or forecasted costs, regional development, and available capacity. For B-type producers (over 500 kW), additional guarantees and technical compliance (SCADA) are required, indirectly supporting grid stability and energy transition goals.
Available options for the investors if the map shows“no capacity available” in their interested area

Option to pay for the grid reinforcements. Elektrilevi has a cost-based connection fee. For low voltage consumers the fee is amper-based (with exceptions). Depending on the size of the client, they can also ask for a connection from the TSO. In some cases, Elektrilevi offers longer outage hours for clients, making it possible to avoid reinforcements that provide reserved capacity. This is a form of flexible connection that gives the client the option of paying less, although it may have longer outages. This is only meant for producers, depends on the grid situation and is not an official service.
Connection request rules/principles

First-come-first-serve
Information published for volumes of connection requests/waiting lines

On Elektrilevi’s website, applications from electricity producers that have been accepted for processing (awaiting a connection offer or under construction) are publicly available.

Relevant references/Links/Additional material

Calculation method, disclaimers, and boundaries

https://public-docs.elektrilevi.ee/2/10/tasude_arvutamise_metoodika_66d2e3cb6d.pdf

Connection request process

Tingimused - Elektrilevi - https://elektrilevi.ee/et/tingimused/liitumine

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