Energy efficiency technologies and benefits

Abstract

The term “energy efficiency” is interpreted differently in national and international literature as well as in various scientific disciplines. The working definition, which will be presented here, reflects the preliminary findings of an internal, interdisciplinary discussion held at the Wup- pertal Institute. While effectiveness marks the degree of achievement of objectives of an activity, efficiency refers to the ratio of benefits to expenses. Energy efficiency, therefore, describes the ratio between the benefit gained and the energy used. In this context, different levels and per- spectives can be distinguished concerning energy efficiency. They will be specified in the following: • the consideration of energy efficiency in the macro-economic aggregated perspective of the market-driven economy, • the perspective of the efficiency of energy conversion in the range of energy supply resp. energy provision, which is predominantly characterised by engineering science, • the end-use energy efficiency perspective on the demand-side with an increase in energy end-use efficiency achieved by technical, organisational, institutional, structural or behav- ioural changes, and • the energy end-use efficiency perspective of the caring economy that includes energy efforts of the human body during mainly unpaid household production.