Does SunPort only work when the sun is shining?

No, you can get solar energy any time you want. SunPort treats the grid like a huge solar reservoir. Solar energy pumps into the grid whenever the sun shines on the panels that generate our solar, so we always have new solar waiting in the grid before you demand it. When you use solar, our SunPort technology keeps your power 100% matched against this actual solar production, regardless of time of day or weather conditions. The solar energy is only made during the day when the sun is shining, but you can create demand for solar, any time day or night and without any consideration to weather conditions.