There are no characters with 15 energy and no skills with a 1 energy cost, which is just a simplified example about Guild War Gold. Energy and even regeneration varies by character. The armor a character wears can include both bonus energy and bonus regeneration. A Ranger will have an extra 5 energy and 1 pip from most of their armor while Elementalists about Guild War Gold, Mesmers, Monks, and Necromancers – the so-called casters because they all use spells to cast - will have at least 10 energy and 2 pips. Regeneration is not available through equipment but energy is, items called foci and staves will grant some bonus energy to your character for Guild War Gold.

Those are innate bonuses, you do not have to do anything more to get them than to wear the armor or focus to have that bonus. Skills need to be cast, often taking some starter energy to establish but can bestow your character or another character with some extra energy or regeneration. A character is energy pool – the amount of both energy and regeneration they can call on – is very much determined by their profession about Guild War Gold. And since energy management is the concern of properly maintaining that energy pool, it is very much something that different professions deal with differently. 

From the above example you can tell that it is not so much the amount of energy you start with as the amount of energy you can regenerate. Energy determines what you can do in an instant but it is regeneration that determines what you can do over a prolonged period of time. The following table shows the basic energy and regeneration as well as the amounts of energy a character will regenerate over time based on their profession in order to compare the particulars of each profession needs. We will leave foci and skill concerns to the side for now because they add yet more complexity to the picture about Guild War Gold.