A white paper from the International Energy Agency details how hydropower can help ease the global addition of wind and solar to the resource mix on power grids. Argonne’s Audun Botterud offered his expertise as a co-author. As the world adds fields of wind turbines and solar panels to generate more clean energy, electric grid operators are looking for ways to smooth out the variability that comes with renewables. Amid this quest for increased flexibility, the International Energy Agency (IEA) has issued a reminder, of sorts: Don’t forget hydropower. One of the largest sources of renewable electricity today, hydropower can help balance fluctuating output from wind and solar farms. To explain this potential, IEA recently published the first in a series of white papers on valuing hydropower services, outlining their potential role in an evolving energy system.