METHODOLOGICAL DESCRIPTION (a) Underlying Definitions and Concepts: Energy use per unit of value added or per
unit of floor area in the service/commercial sector is one way to measure energy
requirements and trends of service buildings. These buildings include both public and
commercial services such as offices, schools, hospitals, restaurants, warehouses and
retail stores. Energy use in services is challenging to analyse in the aggregate owing to
the large differences among building types and the wide range of activities and
energy-related services offered in any given building. That buildings house different
kinds of enterprises and a given branch of enterprises may be found in many different
kinds of buildings makes the situation even more complex. Thus the
service/commercial sub-sectors are diverse and difficult to classify. They include sub-
sectors that require a great deal of electricity per unit of output (retail trade), those that
use large quantities of fuel for water and space heating (health care establishments)
and those that by their nature consume little energy (warehouses, parking garages).
Energy efficiency in this sector is more directly related to the efficiency of general
energy services (lighting, ventilation, computing, lifting, etc.) than to the efficiency of
the particular sectoral activities. However, there are almost no data on actual energy
service outputs per unit of energy input (lumens of light, cubic metres of air moved,
computing power or use, tonnes raised in lifts, etc.). Hence, the usual measure of
energy intensity, toe per unit of output in economic terms (toe /US dollar), can be a
useful indicator, provided it is clear that this indicator summarizes many processes
and types of buildings. Because of the differences in processes, it is very important to
separate electricity from fossil-fuel and purchased heat.
Changes in intensities are affected by factors other than energy efficiency; therefore,
analysing intensity trends provides important insights into how energy efficiency and
other factors affect energy use. Annex 3 includes a decomposition method for energy
intensities.
