Energiabilansi

Energiabilansi is a concept that describes the balance between energy inputs and outputs in a defined system. It is rooted in the principle of conservation of energy, which states that energy can neither be created nor destroyed but can change form. An energy balance accounts for all energy entering, leaving and being stored within a system, and is used across disciplines to analyze performance, efficiency and sustainability.

In physics and engineering, an energy balance quantifies fluxes such as heat transfer, work, and stored internal energy, typically expressed in joules or watts. In ecological and environmental contexts, energy budgets describe flows between organisms, ecosystems and the atmosphere, helping to assess productivity and trophic dynamics. In nutrition, energy balance refers to the relationship between dietary energy intake and energy expended through basal metabolism and activity; a positive balance leads to energy storage, while a negative balance leads to energy deficit. In building science and energy policy, energy balances are used to evaluate consumption, losses and gains to improve efficiency and reduce emissions.

Performing an energy balance requires defining system boundaries, identifying all relevant input and output terms, and using measurements or models to quantify them. Uncertainties arise from incomplete data, temporal variability and system interactions. Energy balance analyses inform decision making in design, management and policy by highlighting inefficiencies, opportunities for conservation and pathways to meet energy goals.