A question about EROEI. It has been noted that solar PV systems often show an ‘energy returned on energy invested’ (EROEI) ratio of about one. But is a figure of 1 or less actually a problem? As with so many economic and technological issues, the key question is not so much about absolute amounts or ratios as the conversion of a low-value resource into a high-value asset. That’s why it makes any sense at all to invest 1 calorie of oil to create 1 calorie of food – because you can’t eat oil, but you can eat food. If the simple calorific value were significant, we would never have made an entire industry of converting oil into food.
Likewise for many other technologies – we are surrounded by energy, but not all of it in forms that are usable to us, given everything from our current metabolisms to our current economic systems. But so what? An EROEI of less than one would make perfectly good sense if the energy invested were derived from a clean, widely accessible source and the energy returned were in a usable form that did not perpetuate other destructive forms of activity.