Axis camera station yellow dot continuous recording

D) Top of a solar power tower being heated by solar flux and multiple, small smoking objects in the closely surrounding airspace. B & C) Closer views (approximately 2 km and 400m away, respectively) of towers being lit with sunlight, as well as the machinery associated with power generation. Images of the solar power towers: A) Far view of a solar tower facility showing a foreground of mirror РІР‚СљheliostatsРІР‚Сњ used to reflect sunlight toward the РІР‚СљreceiverРІР‚Сњ towers (yellow arrows). Rather, solar flux is converted to heat energy when striking an object, which can be problematic for animals flying through sufficiently powerful flux fields.Р”Вifferent views of a solar power tower facility. As radiant energy, flux does not substantially heat air through which it travels. Sunlight reflected from heliostats toward the tower is referred to as РІР‚Сљsolar flux.РІР‚Сњ Solar flux is not thermal energy but rather concentrated light, and the intensity of flux is greatest at the tower receiver, where surface temperatures can reach more than 500РІВРЉ. The receiver heats water inside the tower, creating steam that is then piped to a conventional turbine to generate electricity.

These facilities generate electricity using an array of large, pivoting mirrors, called heliostats, to concentrate energy from the sun onto a РІР‚СљreceiverРІР‚Сњ at the top of a central heat-absorbing tower ( Fig 1). Solar thermal energy facilities incorporating mirrors and concentrating towers (hereafter РІР‚Вsolar towersРІР‚в„ў) produce electrical energy from sunlight at an industrial scale. Some of the methods we tested (e.g., video surveillance) could be further assessed and potentially used to automatically detect and observe flying animals in the vicinity of solar towers to advance understanding about their effects on wildlife. Traps did not tend to sample the larger insects we sometimes observed flying in the solar flux or found dead on the ground beneath the towers. Insect trapping on the ground was somewhat effective at sampling smaller insects around the tower, and presence and abundance of insects in the traps generally trended with radar and video observations. Also, we occasionally detected birds flying in the solar flux but could not accurately identify birds to species or the types of insects and small objects composing the vast majority of smoking targets.

Video revealed what appeared to be mostly small insects burning in the solar flux. We detected and broadly differentiated animals or objects moving through the airspace generally using radar and near solar towers using several video imaging methods. During site visits in May and September 2014, we monitored the airspace surrounding towers and observed insects, birds, and bats under a variety of environmental and operational conditions. In this observational pilot study at the worldРІР‚в„ўs largest solar tower facility, we assessed the efficacy of using radar, surveillance video, and insect trapping to detect and observe animals flying near the towers. Smoking objects are sometimes observed co-occurring with reflected, concentrated light (РІР‚Сљsolar fluxРІР‚Сњ) in the airspace around solar towers, but the identity and origins of such objects can be difficult to determine. Little is known about the effects of this technology on flying animals and few methods exist for automatically detecting or observing wildlife at solar towers and other tall anthropogenic structures. Solar power towers produce electrical energy from sunlight at an industrial scale.

Axis camera station yellow dot continuous recording