As has been mentioned in both comments and in another answer, 'energy' is a subjective term to use for this.
Red Bull cans vary in size, but the European can size (250ml) delivers 112.5kCal of energy. A cup of Starbucks Americano (Grande) coffee contains 72kCal, meaning that in the scientific defintion of 'energy', the Red Bull contains more.
The point that this is missing is energy in the calorific sense does not equal feeling energetic, it just equals having more energy to use. For example, a slice of bread typically contains 80-120kCal of energy, so a similar amount to a can of Red Bull, but it will not make you feel energetic in the same way.
I think it's a fair given that Red Bull will make the majority of people feel more energetic, and that coffee also helps most people feel alert. Some of this affect may of course be placebo.
The significant difference between coffee and Red Bull, nutritionally and physiologically, is that, whilst coffee contains one significant ingredient that has an 'energising affect' on the body (Caffeine), Red Bull has 2 (Caffeine and Taurine). Both, potentially - depending on how you like your coffee, also contain Sugars of one sort or another, mainly Glucose.
Caffeine is a vasoconstrictor and cardiovascular agonist. The vasoconstriction caused by caffeine will cause the peripheral network of capillary blood vessel to become smaller, and thus move less blood, the effect of this is that the volume of blood within the body will be held in a smaller space, and thus the Arterial Blood Pressure will increase, increasing perfusion to the organs, including the brain. Thus, caffeine causes a feeling of alertness through a greater bloodflow to the brain.
Caffeine also causes a release of Adrenaline and Noradrenaline within the body. Adrenaline and it's derivatives are Beta-agonists, which raise blood pressure, and heart rate, so blood flow is further increased by heighten cardiac output.
Taurine is an amino acid used in the formation of proteins, which is especially useful to the brain, which is a primary consumer of taurine. Although its affects on the cardiovascular system aren't fully understood, they are observed. It has a calming affect on Cardiac Output, and thus may help recovery from a large amount of caffeine.
The long and short of the question is that in pure energetic terms, Red Bull has slightly more energy, but that this isn't necessarily what makes drinkers feel energised. The affects of the ingredients of coffee and Red Bull will act differently on different people, so it's not possible to say which makes people more energised, as different people will react differently.