Solar panels in the Sahara could damage global climate


The world’s most dangerous deserts could be the best places on Earth to harvest solar energy – the most abundant and cleanest source of energy we have. Deserts are spacious, relatively flat, rich in silicon – the raw material for the semiconductors from which solar cells are made – and never short of sunlight. In fact, the ten largest solar power plants in the world are all located in deserts or dry regions.

The researchers imagine that it would be possible to turn the world’s largest desert, the Sahara, into a giant solar farm, capable of meeting four times the world’s current energy demand. Plans were drawn up for projects in Tunisia and Morocco that would provide electricity to millions of homes in Europe.

While the black surfaces of solar panels absorb most of the sunlight that reaches them, only a fraction (about 15%) of this incoming energy is converted into electricity. The rest is returned to the environment as heat. Panels are usually much darker than the ground they cover, so a vast expanse of solar cells will absorb a lot of extra energy and release it as heat, affecting the climate.

If these effects were only local, they might not matter in a sparsely populated and barren desert. But the scale of the facilities that would be needed to reduce global fossil fuel demand would be vast, covering thousands of square kilometers. The heat re-emitted from an area of ​​this size will be redistributed by the flow of air into the atmosphere, having regional and even global effects on the climate.

A satellite view of four different solar farms in the deserts.