Seasonal leveling would be done by combining solar/wind (which tend to have opposite seasonality) and by use of overprovisioning and production of e-fuels, like

Seasonal leveling would be done by combining solar/wind (which tend to have opposite seasonality) and by use of overprovisioning and production of e-fuels, like hydrogen. To see how this would work, go to https://model.energy/ https://model.energy/ and find optimal solutions for synthesized constant output using solar, wind, batteries, and hydrogen storage. The cost optimizing solutions are found vs. real historical weather data.