TNEI hosted four Durham University students in the Newcastle office last week to work on two mini projects, including one which expanded on some shadow flicker work TNEI had previously carried out on quantifying the density of shadows, putting it into context on the available literature on human response.
Shadow flicker from proposed wind farm developments can be accurately predicted using specialist software. Whilst, in theory, shadows can be cast great distances from turbines the intensity of the shadows does decrease with distance. Accordingly, guidance in the UK and Ireland is based on the assumption that, normally, shadow flicker occurring at distances greater that 10 Rotor Diameters (RD) away from the turbine(s) is negligible.
The study carried out by students Lewis and Thomas used available literature and site data to analyse the validity of the 10 RD study area. Their project involved calculation of shadow density (the percentage of the sun that could be covered by a turbine blade at any given distance), comparison with real measured light intensity data measured at a receptor near an operational wind farm in England and a review of evidence relating to human response to changes in light levels. Some evidence was found suggesting that a shadow density of 10% could be a suitable threshold above which shadows are generally considered to be observable by a human.
The results concluded that there is an opportunity to refine the approach to assessing shadow flicker taking into account not just set back distances, but also shadow densities. It may also be possible to propose an approach which can be used to investigate complaints.
The students presented their findings at the end of the week, and the study, which made great progress in just 4 days, was so successful that Thomas would like to pursue this project for his main masters project. We are excited to see where this project will lead!
TNEIs Head of Technical Services, James Mackay, noted:
“It was great to work with all four of the students from Durham University, they took on the projects with real enthusiasm, picked up the technical aspects really quickly and their findings have been of real interest to us and our clients. We hope to have the opportunity to work with students from Durham again in the future.”
If you have any questions regarding the mini projects, or would like to know more about how TNEI model and assess shadow flicker please get in touch.