The two main energy currencies are electricity and gasoline, seen in Figure 1, as they are extremely versatile in their use and provide extraordinary services. These forms of energy allow people to communicate across the world, move vast distances, and much more, however in their raw form they are essentially unusable. They require the use of such technologies listed above in order to achieve these tasks.
Many energy service technologies take a tremendous amount of energy to create. Their materials must be mined and refined, smelted, reprocessed, and manufactured. The end product must also be transported to where it can be made useful. All in all the energy it takes to make a technology adds up, far beyond what a consumer could imagine. This is known as a technology's embedded energy - the energy that was required to make it is "embedded" within it.