# Power Quality Impact and Its Assessment: A Review and a Survey of Lithuanian Industrial Companies
## 2 Literature Review
### Environmental Impact
According to the results presented in the \"LIFE Birds on Electrogrid\" final report [56], 254 birds were found beneath the investigated power lines of the Lithuanian TSO (Litgrid AB) during the project period between June 2014 and December 2018, including 112 mute swans (_Cygnusolor_)--852 km were monitored walking on foot. Concrete conservation actions were: (1) installation of bird collision mitigation measures in bird staging areas (see [56; 57] for more details); (2) installation of line markers in the most critical areas (see [56; 58] for more details); (3) installation of bird protection measures--\"wishbone\" type (prevents birds from making a touchdown on the insulators) and \"saucer\" type (prevents bird excrements from falling on the insulators) installations--on the utility poles, aiming to reduce the mortality rate of the white stork (_Ciconia ciconia_) due to electrocution (see [56; 59] for more details); (4) improvement of breeding conditions of the common kestrel (_Falco tinunculus_) by erecting nest boxes on the pylons of the HV lines (see [56; 60] for more details). The interim activity report [61] underlines the effectiveness of the measures by comparing the situation in 2014 (ex ante) with 2015 (ex post): (1) it is not always possible to find bird remains; therefore, cases where the cause of disconnection is not determined are relevant as well, because it is probable that they occurred due to bird impact; (2) in 2014, 79 disconnections were recorded due to bird impact or undetermined causes, and most of them occurred during stork migration (automatic circuit reclosing was triggered in almost all cases and was mostly successful); (3) in 2015, only 2 disconnections due to bird impact were recorded in sections where the mitigation measures were installed. The final report [56] concluded that only 12 cases of disconnection of the HV lines were registered in 2017, in comparison to 79 disconnections before the project started. According to experts, in Lithuania, the annual toll of up to 45 thousand bird deaths caused by collisions with the HV lines occurs: the annual toll of 11.1 deaths per 1 km occurs when visibility increasing measures are not installed, and the annual toll of 3.6 deaths per 1 km--when visibility increasing measures are installed [2; 56]. To continue, a comprehensive overview of up-to-date knowledge of electrocutions and collisions of birds across 27 European Union member states is presented in [48]: the Slovak report provides information about the relevant characteristics of the electricity networks, bird electrocution mechanism, most vulnerable species, mitigation measures and their effectiveness, as well as legislation and policy framework. After interviewing the national experts, the collected data about most frequent bird victims are summarized in Table 1--the risk of collision depends on weather, visibility, and location of the power lines sections (whether they cross important bird habitats/breeding areas, main migration routes, etc. ), whereas the risk of electrocution depends primarily on technical construction of power facilities. In addition to the already mentioned mute swan and white stork, the wild duck (_Anas platyrhynchos_), common buzzard (_Buteo buteo_) and European golden plover (_Pluvialis apricaria_) are also marked in the Lithuanian column, whereas the already mentioned common kestrel is not. Summing up the total result, most votes were for the white stork: in Lithuania, together with some other countries like Belarus, Latvia, Poland, Ukraine, and Spain (e.g., see [62]), many (more than half) of them nest on power poles during their breeding season (Figure 5a), and then, with the onset of autumn, migrate to Africa as well as some regions of both the Arabian Peninsula and the Indian subcontinent to spend the winter. All bird species breeding and (or) found annually in Lithuania are listed in, for example, [63].