What is an "energy" of God?

It seems to me that translating the term ενέργεια as "energy" does more to obfuscate the meaning of Palamite distinction between God's essence and His activity than it does to clarify it. Eric Perl makes a similar observation when he writes in his article "Gregory Palamas and Metaphysics of Creation" that:

"If the divine energies are real but are not 'things,' what then are they? As their name suggests, they are the activities of God, God acting in and for creation. (It would indeed be desirable to replace the conventional translation 'energies' with 'activities' which more accurately conveys Palamas' meaning in English and makes the entire doctrine sound rather less exotic. I propose therefore to use the latter term henceforward.) This is why they do not introduce composition into God, for 'nothing is ever said to be compounded with its own activity.' To say that God's essence and activity make up two things would, St. Gregory argues, be like saying that a man has two minds because we speak of 'mind' and 'understanding.' Understanding is not another substance, or a part, but is what the mind does. Activity cannot be co-numerated or added to substance. To say that God 'has activities' is simply to say that he acts: 'As he who calls [God] voluntative makes clear that he has a will, so also he who calls him active (ενεργή) shows that he has activity.'" (p.112-113)(emphasis mine)

I'm not entirely sure what the motivation has been in the Orthodox world for translating this term or even framing the debate in the way it has been. Perhaps I am cynical but I fear that this may stem from a desire on the part of Orthodox scholars to differentiate themselves first of all from the Roman Catholic tradition of Thomism which also utilizes the Aristotelian terminology of activity but instead has come down to the English langauge by means of the Latin-derived terms such as activity, actuality, or even operation. Then we also have Orthodox scholars such as Metropolitan Ierotheos of Nafpaktos who, following Fr. John Romanides, are loath to admit that Orthodoxy has anything to do with the classical tradition of metaphysics at all, a tendency which has crept into the English speaking world. 

Theodor Tollefsen, who has written an excellent volume on this exact subject, seems to have less of a problem with this strange new translation but also points out the dangers inherent in it and chooses generally to  avoid these pitfalls altogether:

"...now and then one gets the impression that energy is a kind of quasi-material force almost flowing into the human recipient. Of course, the saying that divine power is somehow flowing into the recipient is often a quite adequate description of what is experienced. But one should not conceive of or think about this divine power as if it was some kind of material force or fluidum. This is not to deny that divine energy is manifested in the nature of material being, but one should beware of interpreting the divine power itself as a material force. Against the background of these considerations I choose to translate energeia as 'actuality, activity', or---now and then---'energy', depending on the context, and the trascribe dfrom of the Greek will be used as well." (p. 5 Activity and Participation in Late Antique and Early Christian Thought)

In general, I think this is an intelligent move that helps us to realize that St. Gregory Palamas is working within a long and well-established tradition of metaphysical realist discourse about participation and activity which fundamentally begins with Plato. By translating energeia as energy we obscure this connection unnecessarily and in the hands of many less capable metaphysicians, a rather gross, even materialistic conception of the divinity ends up being put forth.

"The West today has need of the Roman tradition..."

"Today the western countries are thought to be cultured, enlightened, because in this area science was cultivated as well as technology. No one can doubt this, but the problem remains, however, to what extent science and technology constitute a complete civilization. When several external features based simply and exclusively in logic are cultivated and other aspects of the personality of man are ignored, this cannot be called civilization.

During the Renaissance period in the West, ancient Greek philosophy was studied, many centers were created for the study of the problems which the ancient Greek philosophers posited. But when Hellenism is isolated from the Orthodox Tradition, when it ceases to be Romanity (Romaiosyne), then it is retrogressive and incapable of solving the existential problems of man.

Consequently, the contemporary European is spiritually and existentially crippled. He has a developed scientific thought, he is distinguished by his technical infrastructure, he has rules of behavior and good conduct, but he cannot solve his ontological and existential problems. Contemporary western civilization is one-dimensional. For this reason, we can say that there reigns a particular form of neo-barbarism in the West.

The West today has need of the Roman tradition which solves all of the problems of man. We must not go to Europe as their poor relatives with an inferiority complex, but as spiritual nobles, since we have the spiritual nobility of humanity, all of the best elements of authentic humanism.

- Metropolitan Hierotheos Vlachos of Nafpaktos (Born and Bred Romans)
(My translation)