According to the U.S. Energy Information Agency (EIA), April marked the eighth consecutive month that the nation's total monthly non-hydro renewable generation exceeded hydropower generation.
The recent growth in wind and solar, which reflects policies such as state renewable portfolio standards and federal tax credits as well as declining costs of technology, has been the primary driver in the increasing market share of non-hydro renewable generation, the EIA says.
October 2012 was the first month on record in which non-hydro renewable generation exceeded hydropower generation, although significant month-to-month variation kept the trend lines crossing back and forth. The most recent ascent of non-hydro renewables, lasting from September 2013 through April 2014, has been the most enduring.
The data used to develop the EIA's trends analysis includes only generation from plants whose capacity exceeds 1 MW, and as a result, does not include generation from most distributed generation (DG) solar PV capacity. Inclusion of DG solar, which the EIA estimates at roughly 10 billion kWh hours in 2013, modestly accelerates the timing of the crossover between hydro and non-hydro renewable generation.
The EIA projects that 2014 will be the first year in which annual non-hydro renewable generation surpasses annual hydropower generation. By 2040, non-hydro renewables are projected to provide more than twice as much generation as hydropower.