"certain amount of energy" is correct and usable in written English.
You can use it to describe any measured amount of energy, either physical or mental. For example, "There is a certain amount of energy required to run a marathon."
Each square on the grid requires 1 Energy to move to, and each character has only a certain amount of energy.
Being young, they still had a certain amount of energy.
"Rock 'n' roll requires a certain amount of energy," he explained.
I had to expend a certain amount of energy on tics each day.
The meteor has a certain amount of energy as it enters the atmosphere, Dr. Binzel said.
To be depressed you need to have certain amount of energy, to go hunting through the weeds.
An atom can possess only certain amounts of energy, so its internal states form a ladderlike arrangement of increasing energy.
Most of the scattered photons have the same energy as the incident photons (i.e., Rayleigh scatting), but a small fraction of the scattered photons lose or gain certain amounts of energy due to energy exchange between the scattering partners.
In this condition, when the air layer is formed a certain amount of extra energy is required to overcome the energy barrier and further collapse in W-CB state (thermodynamically stable).
In particular, among the small size bottoming cycle technologies, the identified solutions which could allow to improve the energy saving performance of an existing plant by generating a certain amount of electric energy are: the Organic Rankine Cycle, the Stirling engine and the Inverted Brayton Cycle; this last is an original thermodynamic concept included in the performed comparative analysis.
