Globally, hydro is three times as risky as rooftop solar, there were ~171,000 dead from the Banquio Dam failure alone - http://www.nuceng.ca/refer/risk/risk.htm

Also, I keep seeing figures for rooftop solar and not solar in general, and the risk for rooftop solar is due to the risk of working on a roof. If solar was mandated in new build and major roof repair, wherever it made sense to install it, this risk can be greatly reduced as the largest risk is during putting the scaffolding up and taking it down again.