I'm somewhat unsure of what you are asking, but in general:
You should be spending all of your metal as you acquire it, such that the metal resource bar appears empty. Yes, you can store some, but generally you want to build as fast as possible.
You should NEVER be limited by energy for build production. This is known as E-stalling and is bad, because energy buildings can be built directly, and it's easier to up energy production than metal.
In practice, you should expand your energy production throughout the game to match or be slightly above your metal production. A general rule of thumb is for every mex, you should have 1 solar.
Hope this helps :)