Does Solar PV in half of Europe make more energy than it consumes?

via JoNovahttp://joannenova.com.au

You might think we’d know whether a solar PV system produced energy before we installed 1,000 Megawatts of it. But it’s hard to even know after the fact. Dr John Constable points us at an interesting new paper that discusses the odd creature called EROEI. This stands for energy return on energy invested. If you get back less than “one”, it sucks.

That sounds like a fine idea except everyone seems to get different answers to the same question. Solar PV in Switzerland achieves either a tenfold return or it costs a fifth of your energy. Plan your national policy with a Ouija Board?

Constable comes to the conclusion that the whole calculation is so uncertain it’s useless. There are so many subjective estimates on the “energy invested side” that the answer is almost irrelevant. Constable points out that what we really need to know is how the whole system responds to the addition of a new generator –but the whole grid analysis is even harder than just the EROEI to calculate.

His conclusion, it that we really need something more like a neural net to calculate the costs. Luckily we have one — us — and the contractual free […]