Global energy efficiency transition tendencies: Development phenomenon or not?

I assessed energy efficiency performance and investigated transition tendencies for economies at different development levels. I found that energy efficiency performance is tied to the level of economic development, with developed economies exhibiting higher performance than developing economies. Furthermore, developed economies are more likely than developing countries to transition out of a low energy-efficient (LEE) state. Consequently, achieving higher energy efficiency (HEE) status is expected to be highly sustainable in the short-, medium-, and long-term for developed countries. However, for similar achievements, I found moderate sustainability in the medium-to long-term for upper-middle-income countries and higher unsustainability in the medium-to long-term for lower-middle-income countries. Addressing the gap in the global energy efficiency system requires a ‘big push’ investment in energy efficiency, particularly in developing countries, in addition to implementing a broad policy overhaul aimed at eliminating or reducing market barriers and inefficiencies in energy efficiency.