Spyder Energy is your achievements result in the Spyder project from training forces, completing research, and upgrading buildings; for every mission you complete, you will get 1 energy (inside the Spyder Rewards screen that you can reach from the Central Control Room inside the Spyder building or by clicking on the triangle icon to the left corner of the screen) where you can collect a maximum of 5 and more than this will be destroyed!
You can use it by clicking on the "open all" icon, after which you will get growth bonus rewards, resources, and Spyder points.