Latvia provides a comprehensive overview interactive map of hosting capacity through regularly updated publications by the Latvian TSO (AST). At the TSO level, hosting capacity is calculated and published weekly on the AST website in accordance with legal requirements. The published information reflects the available capacity across the entire AST transmission grid and is detailed at the substation/grid sector level. In the interactive map, a distinction is made between gener ation and consumption. A hosting capacity of 0 MW indicates that for at least one hour of the year no power can be injected or consumed without (possible) congestion-related constraints imposed by the TSO. The calculation is based on grid simulations aligned with the Ten-Year Network Development Plan (TYNDP). The published hosting capacity is independent of switching bay availability and dynamic aspects like short-circuit currents. The calculation is made by TSO, based on a uniform methodology defined in a regulation by the national regulatory authority (NRA).

At the distribution level, the hosting capacity map of Sadales Tikls, a Latvian DSO covering the vast majority of the country’s territory, provides available firm connection capacity at the primary substation (nodal) level. 

Hosting capacity covers both the generation and demand sides. On the generation side, available hosting capacity is calculated as the difference between the largest 110 kV transformer capacity and the sum of installed and reserved generation capacity. Information on the technology and capacity of each generation that has reserved capacity for each primary substation is publicly available. For substations with no available demand-side hosting capacity, the map shows <0.5 MW. For generation, it shows <0.011 MW (the maximum microgeneration installed power), encouraging new customers to submit an application so Sadales Tikls can examine potential line reconfigurations or other network operations to provide the desired capacity. 

The map/website also encourages business customers to submit an application, allowing their requests to be examined under flexible connection agreements for both demand and generation. Energy storage is not considered in calculations, but rather follows the rules of non-firm capacity. In the future, we plan to add a preliminary curtailment assessment for all substations, giving customers a rough estimate of potential energy losses based on the required capacity and location.