Burning biomass causes high levels of particulate emissions, which are a very significant health risk (Burning firewood is the most important source of air pollution in much of the developing world).

Hydro is completely safe most of the time, but when a dam fails, it typically kills a lot of people really quickly.

It would be really hard to collect figures for non-rooftop solar -- simply because there is so little of it. (They would be very favorable.)

Biomass - comprehension error on my part, I thought that it was using dung in fermenters and like apparatus.

There seems to be enough solar farms to make the same sort of estimates as have been used in the article though.

I think what would be most helpful would actually be a comparison for a large country with similar safety standards across all industries looking at facilities over a fixed period. That would help, IMO, to rule out problems like people continuing with a hydro project even though the dam is cracked from the off ...

Think about what happens when a dam fails. For example http://en.wikipedia.org/wiki/Banqiao_Dam