Agreed, it seems that the economics simply don't add up. The article is also particularly deceptive, as it claims that 4 metres are enough to power one househol

Agreed, it seems that the economics simply don't add up. The article is also particularly deceptive, as it claims that 4 metres are enough to power one household, and 1km to "light a settlement of 5000 people". However, that means just powering the streetlights of a settlement of 5000, as 1000/4 = 250 only. It's interesting at least as an example of environmental action purely driven by an attempt to get cheap political support (pun intended). I wonder if such an experiment could at least drive further research and innovation.