Balancing wind with multiple renewable resourcesincluding solar, which does not normally peak when wind does, and baseload power from geothermal and biomasscould mitigate the temporal variability in generation. Reaching the goal of 20 percent nonhydropower renewables by 2035 could be achieved by adding 9.5 GW per year of wind power and a total of 70 GW of solar PV and 13 GW each of geothermal and biomass. Using multiple renewable resources to reach this level would take advantage of the geographical variability in the resource base.
Electricity from Renewable Resources: Status, Prospects, and Impediments http://www.nap.edu/download.php?record_id=12619
"Reaching the goal of 20 percent nonhydropower renewables by 2035 could be achieved by adding 9.5 GW per year of wind power and a total of 70 GW of solar PV and 13 GW each of geothermal and biomass."
We now have more than 10GW of solar capacity in the US, so most of this boom will be added to that within another 2 years. That puts us around 70% of the way to the 2035 solar level mentioned by NAS 20 years earlier than they hypothesized.
We have 60GW of wind capacity installed, but the performance of the wind industry is still a problem in that it is responsive to the existence of the Production Tax Credit, which the Republican House is sure to allow to expire at the end of this year. Every indication is that wind could deliver the 9.5GW of capacity easily if the Republicans in the House would stop screwing with the them and passed a stable policy that developers could count on when planning.
(How many times have you heard them attack the ACA by saying stable government policies are required for business growth? They aren't screwing with the PTC by accident.)