You are right, storage is not required to integrate variable energy, such as wind energy, to the grid, BUT, as has been PROVEN in Ireland with 15-minute Eirgrid operating data and by Wheatley, using even more accurate date for each generator on the grid, at about 17% wind energy on the grid, the OTHER gas-fired generators are operated so inefficienctly (more Btu/kWh, more CO2/kWh), that that extra fuel and CO2 offset about 50% of what wind energy was supposed to save, as claimed by the AWEA, et al.
What you may not yet know, the interesting development in the past few months is that Eirgrid has, after many years of obfuscation, PUBLICLY admitted that this is indeed the case, and informed the EU in Brussels of that fact.
Government officials and wind energy promoters, such as the EWEA, BWEA, etc., usually claim one MWh of “clean” wind energy offsets one MWh of “dirty” fossil fuel energy, which is true regarding energy, but not regarding CO2 emissions, because of the inefficient operation of the other generators on the grid due to wind energy.
Below is summary of wind energy CO2 emission reduction effectiveness versus annual wind energy percent, for various grids:
1.0 at 0% wind energy on any grid.
0.97 (my assumption) at 1.0%, New England grid.
0.70 (calculated by Dr. LePair) at 3.36%, the Netherlands grid; based on at least 10 years of actual fuel and production data.
0.706 (calculated by Dr. Udo) at 12.6%, Ireland grid; based on deficient EirGrid data.
0.526 (calculated by Wheatley) at 17%, Ireland grid; based on SEMO data of individual generators, including increased start/stop CO2 emissions, and increased capacity and hours of spinning plant CO2 emissions, i.e., better than Eirgrid data.
Wind energy CO2 reduction effectiveness of Irish Grid = (CO2 intensity, metric ton/MWh, with wind)/(CO2 intensity with no wind).
Ireland = (0.279, 17% wind)/(0.53, no wind) = 0.526, based on SEMO data.
If 17% wind energy, promoters typically claim a 17% reduction in CO2, i.e., 83% is still left over.
If 17% wind energy, actual performance data of the Irish grid shows, 0.526 x 17% is reduced = 8.94%, id est, 91.06% is still left over.