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Ellen Williams served as Director of the US Department of Energy's ARPA-E (Advanced Research Projects Agency–Energy) from December 2014 until January 2017. Nature Energy caught up with her shortly before the end of her tenure to learn more about the agency's role in energy technology innovation.
Recent announcements highlight the increasing competitiveness of renewable electricity sources and signal that the need for subsidies may be approaching an end.
Private sector investments in African power generation play an increasingly important role in addressing the continent's electricity supply shortages. Our analysis of investment trends in sub-Saharan Africa reveals some key success factors.