Probably should cost more than 1 |0.
Consider the upgraded vs a Tower. Tower is +1 quanta on turn 1. Nuclear Energy is tied on turn 2 but has a second effect. On later turns Nuclear Energy has a clear advantage.
2 |1 might be enough
Ok. Sounds fair enough.
EDIT: Modified.
Also, keep in mind that though the quanta generation of Nuclear Energy stack and their card transforming is virtually unaffected, you can only have them "stack" -if- the next "Nuclear Energy"s you draw after having played the first one are not transformed, or if you receive more from transformations.