ENcome evaluates glaring behaviour of photovoltaic installations

Klagenfurt/Wörthersee (07.04.2015) – Glaring caused by photovoltaic installations is a peripheral topic that often becomes important, when it’s nearly too late. While some only feel disturbed by the glaring of PV plants or other glass surfaces, glaring in road traffic and public transport by plane and train can become a serious safety risk.

People driving a car are reliant on good visibility. However glaring can reduce “drive on sight” and the recognition of signals leading to traffic obstructions or, in the worst case, accidents. ENcome is therefore regularly commissioned by plant constructors and investors to provide glaring reports. This, for example, for plants close to airports where the potential glaring during landing and in the tower has to be evaluated. “In many cases all-clear can be given very quickly after having checked all local circumstances and calculated the glaring behaviour. That is the case if glaring occurs but the sun has the same direction at the time of glaring like the PV installation. The glaring effect caused by the photovoltaic installation will not be increased considerably”, explains DI Jakob Zehndorfer, Sales Director at ENcome Energy Performance and court-certified expert for photovoltaics.


The question for glaring can only seldom be answered with a “Yes/No”. Nearly every glass surface will cause glaring at specific locations and time periods. The question is, if the affected individuals feel disturbed by this glaring or if the glaring effect is comparable with the normal sunlight at that time. All of us know those glowing dots on ground level when looking out of the airplane resulting from reflections on roof surfaces, glazed roofing tiles or car windows. These reflections normally do not constrain pilots as long as they do not have to land close to such a glowing dot.

A proper glaring report does not only calculate the intensity, moment and direction of glaring but also considers the condition and needs of the glared individuals (e.g. pilots). The calculation then delivers data, represented in graphical or numerous formats. Furthermore a glaring report should include effective anti-glaring measures in case that the PV installation is already completed and does cause glaring. Walls, fences and trees can improve the situation as well as local shading measures. Thus, ENcome could identify several countermeasures for a glaring report of a PV installation located close to a railway line. Due to intense reflection in the morning hours causing a strong backlighting, the train driver missed a stop signal. The proposed countermeasures include local shading, signposts, a relocation of the existing signal and other measures, which are currently under evaluation of the involved parties with respect to costs and acceptance.

The ENcome group is a pan-European leading and independent provider for the operation of photovoltaic power plants with focus on technical Operation and Maintenance (O&M), technical Asset Management (TAM) and the compilation of technical expertise. At present ENcome operates power plants with a nominal capacity of several hundred megawatts in different countries. Well skilled engineers ensure the best yield for every renewable energy park in any grid environment. Furthermore ENcome offers other services along the asset lifecycle of photovoltaic installations partnering amongst others with renown law firms, tax advisers and security centres.