English is not my native language so there might be a better word for what I meant: An energy that can be "produced" (physically transformed is more accurate)

English is not my native language so there might be a better word for what I meant: An energy that can be "produced" (physically transformed is more accurate) whenever you want and at whatever power you want (with the upper bound of its max power obviously). In practice there is no such energy: there is always a delay between your choice of delivering a certain amount of power from a hydroelectric dam, a nuclear plant or a coal plant. Some behave better than others in this regard. However with this delay taken into account, you can schedule production according to estimated demand. With pure renewables without a large storage system this is not possible. Please note that "drivable" energies also need some storage (hydroelectric dam for instance) to help balancing the production/demand. However it is marginal