​These data from the US Energy Information Agency show that, for the first four months of 2015, renewables provided 84 % of new capacity added to the grid, while gas added the remaining 16 %.  Oil coal, and nukes had no added capacity so far this year.  Renewables was 100 % f new capacity for the month of April.

These data count utility scale generation, and do not include distributed generation such as residential roof-top solar.  Full story at:

http://ecowatch.com/2015/05/26/wind-solar-april-capacity/