When I was in college during the last millennium, there was a standard text on this. I believe it was "Why Nations Go to War" by Stoessinger; things may have changed in the new millennium. IO9 provides a traditional top 10 list, which is worth what you pay for it.
As the comments have pointed out "power" is a weasely word that can be construed to mean anything- kind of like the ultimate cause of death is heart failure, it is fair to retro-fit "power" to any conflict.
You've also used the term "factions" rather than "nations"; I'm not sure why, but let's assume that you want to include civil wars.
And finally, why people go to war is often not the reasons they state. The grade school narrative today is that the US Civil War was about slavery, but I think a responsible historical analysis would have to include conflicts that began before the Constitutional convention and that might include differing economic systems (and mutual contempt for one another's economic systems), differing alliances (and mutual contempt thereof), differing agendas (and mutual contempt), etc. Culture, tradition, and isolation all played a part; fundamentally they had divergent, incompatible visions for the future. If I wanted to, I can make the argument that the two factions went to war over the power to determine their own futures, but I don't think that would help me to understand why these two factions went to war.
The other weakness with the "power" thesis is that it doesn't help us to predict. What was it that finally forced faction X over the edge from resistance and debate to war? There are endless pages written on the significance of the Archduke Ferdinand to the start of WWI. (I don't know if it is true, but I'm told more people went to the assassin's funeral than the Archduke's.)
Matter of fact, WWI might be the counterexample you're looking for. I think the general consensus (with much debate) is that none of the players wanted war, but they all made commitments that wound up making it easier to participate in war than to avoid war. From that standpoint, WWI was not about power.
The Revolutionary war would be another good case study; neither side wanted a war. Neither side wanted "power". You could force fit the situation to claim that the Colonials wanted the power of self-determination and Parliament wanted the power of taxation, but I don't think that is a useful framework.
OP has edited the question to emphasize power as "energy" - energy was not involved in the start of any of the three wars I've discussed. (the case for backfitting energy into the any of these is even weaker than the case for power).
Final comment; there are an infinite number of analytic frameworks one can use to study history. The measure of a good analytical framework is not whether you can or cannot fit examples to the theory, but rather whether the framework improves the understanding. Does it have predictive power? does it help to isolate the critical factors from other factors which are present?
I doubt that either "power" or "energy" provide these properties.