It's not clear to me why the reference points need to be a couple hundred years ago, and a couple decades ago. Was the intent to point out that the dollars are

It's not clear to me why the reference points need to be a couple hundred years ago, and a couple decades ago. Was the intent to point out that the dollars are a one-off, where the kWh's keep on coming as long as the equipment works? Even in my relatively wet and grey corner of the world, I'm confident that if I spent $X on PV vs hydro, the PV would produce more electricity and require less maintenance.