International Day of Energy Efficiency
According to the first law of thermodynamics, “energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another”. However, in the current context where the geopolitical landscape is constantly shifting, and access to essential resources is increasingly uncertain, it is essential to use energy as efficiently as possible. Energy efficiency is not just about the typical “no spending” or “spending less”, as it also involves optimising and therefore improving processes to maximise resource use while minimising losses.
From industries to households, including the transport sector, energy-saving strategies can be implemented at multiple scales and in different forms, as reflected in the Energy Efficiency 2025 report by the International Energy Agency (IEA). In the industrial sector, for instance, a significant share of energy is devoted to heating, but part of it is dissipated as residual heat or lost due to inefficiencies. Similarly, buildings experience energy losses due to poor insulation, not only when heating, but also when cooling in increasingly hot summers. In this regard, electrifying cooling systems and low-temperature heating processes can improve efficiency while reducing both emissions and operational costs. Electrification can also benefit the transport sector, particularly road transport, which accounts for 90% of domestic transport energy demand. The aviation and marine sectors, which together with rail transport account for the remaining 10%, face greater technological barriers to full electrification. For these two sectors, integrating biofuels may serve as an intermediate step towards reducing their dependence on fossil fuels.
Today, on the International Day of Energy Efficiency, we celebrate that the energy we save or do not need to produce is the most valuable. Enhancing efficiency is key to energy sovereignty, competitiveness, and sustainable development. Still, addressing this paradigm shift is not only something for governments, industries, or large investors: our individual actions and choices have the power to shape the change we want to see.
Ph.D. Candidate, Chemical Engineering Department, Universitat Rovira i Virgili.