For a long time, I have been saying that, invariably, new technology developments bring with them not only highly tangible benefits, but also, quite frequently, undesirable side effects that are not that tangible at first. I have said that it is the duty of technology developers to look for the negatives in a new technology before launching it on the public.

Who would have thought, initially, that the development of Facebook on the Internet would lead to murders or that cellphones would be used to detonate bombs?

I was reading the African Birdlife magazine, an excellent publication, when I saw an article by Samantha Ralston concerning solar energy. She discussed the rather dramatic statistics of birds that solar energy kills.

First, let me explain a bit of physics. When sunlight comes from the sun, it is, in effect, white light. If you take a triangular glass prism and pass a beam of white light through it, the beam splits into all colours of the rainbow. Red is at one side and blue and violet at the other. The red part of the light is the heat part and the blue end is the high-energy part. The red makes you feel hot outdoors, but it is the blue end which gives you sunburn.

When solar energy systems are made, there are essentially two types: the red-end type, which makes something hot, and the blue-end type, which produces electricity. The red-end type is called concentrated solar power (CSP) and is the same as what many schoolboys do when they take a magnifying glass and concentrate sunlight onto paper to ignite it.

Blue-end systems are called photovoltaic (PV) and the blue light carries enough energy to knock electrons off atoms and so induce an electric current to flow.

Ralston points out that a huge number of birds are killed by both these types of systems. Clearly, Ralston is worried about the bird deaths at solar plants. She says: “Realistically, one would be hard pressed to argue that fossil fuels are a more environmentally sustainable solution.” I do not agree with her on that because I do not believe that man-made carbon dioxide has anything to do with climate change. She also states: “Renewable energy may be clean, but we have our work cut out to make sure it is green.” I agree totally with this statement.

Ralston says that, as early as 1986, this bird kill problem was realised in the US. The Solar One CSP power tower facility, in the Mojave desert of California, was examined by Michael McCrary. It is a 10 MW facility which was large back then but is quite small now. In South Africa, we have a 50 MW plant near Upington, Khi Solar One, and the 100 MW KaXu Solar One CSP facility, near Pofadder.

How do the birds die? In the case of CSP, there are two ways, one of which is that the birds fly into the shiny mirrorlike collectors and either die on impact or get injured and are then eaten by ground predators like snakes and jackals. The other CSP injury cause is the intensely hot beams of sunlight. Some CSP systems are designed to heat a target heat transfer fluid to 1 000 °C. Birds fly through the beams and are burnt. Some observers have reported seeing puffs of smoke in the air as birds are instantly grilled. Some birds will have a wing burnt enough to induce them to crash and become food for predators.

In the case of the PV systems, there are no hot beams, but birds still fly into the shiny collectors. An additional complicating factor is that the shiny mirrors look like water to insects. This then attracts an abnormal number of insects, which are food for the birds. So the collectors have the effect of being a ‘bird magnet’.

Ralston points out that not very much scien- tific work has been carried out on the solar ‘bird kill’ problem. So, with solar, we are groping in the dark.

The US National Fish and Wildlife Forensics Laboratory has examined some solar plants, including the 550 MW Ivanpah CSP plant. Just less than half the dead birds found had burn wounds. This figure, of course, excludes those carried away by predators. The observed fatalities at Ivanpah represent only a fraction of the total kill, since only 20% of the plant is surveyed. Even so, the yearly bird kill there is estimated at between 1 000 and 28 000 a year.

Ralston points out that the Northern Cape has some really valuable endangered birds. So, she urges that serious attention be given to the bird kill problem associated with solar as well as wind plants.