Carbonless Energy Carriers

Electricity is the highest quality energy carrier, increasingly dominant throughout the world's energy infrastructure. Ultimately electricity use can expand to efficiently meet virtually all stationary energy applications, eliminating stationary end-use carbon emissions. This approach is unlikely to work in transportation, however, due to the high cost and low energy density of electricity storage. Chemical energy carriers, such as hydrogen, can more effectively serve transportation fuel and...

Energy efficiency vs energy intensity

It is easy to confuse energy efficiency and energy intensity. Energy efficiency as we describe it above is a bottom-up view applied to individual activities. We describe energy intensity as a top-down or aggregated look at energy use in an economy. For consistency and clarity, the rest of this chapter will use the term efficiency for specific activities and intensity for aggregated energy use. However, the relationship between the two is far more complex and controversial than a simple...