Materials and Energy: Energy Conservation and Dissipation

Energy is always conserved, this principle is known as the conservation of energy. It means that the total amount of energy in a closed system remains constant.
Energy can be transferred from one form to another (like from kinetic to gravitational potential energy) but it cannot be created or destroyed.
Some of the energy in a system can be usefully transferred and some cannot. This un-useable energy is often referred to as wasted energy.
Energy dissipation is the term for when energy spreads out and becomes less useful. For example, when a car brakes, the kinetic energy of the car is dissipated as thermal energy and sound.
The effectiveness of energy transfers can be improved by reducing energy wastage. Insulation, for instance, can reduce heat loss from buildings and consequently improve energy efficiency.
Devices can be rated based on their energy efficiency. This takes into following how much of the input energy is converted into useful output energy. The higher the ratio, the more efficient the device is.
Electricity is an extremely convenient form of energy for transfer and use, but it is often generated using non-renewable resources (like coal and gas).
Moving towards a sustainable future requires us to focus on conservation of energy and to reduce energy wastage.

-Increasing energy efficiency, expanding the use of renewable resources and developing new, sustainable technologies are keys to conserving energy for future generations.

The energy consumption of a country is closely tied to its economic and industrial development. As such, richer, developed countries typically have higher per capita energy consumption.
However, as awareness of environmental issues grows, many developed countries are now seeking ways to reduce their energy consumption and CO2 emissions. This can involve improving energy efficiency, shifting to renewable energy sources, and promoting behaviors that conserve energy.
It’s critical to know how to calculate energy efficiency using the formula: efficiency = (useful energy output / total energy input) * 100%. This allows us to compare and contrast different devices or systems.
The larger the proportion of energy that is ‘wasted’, the less efficient the system is. For instance, old traditional incandescent light bulbs only convert about 5% of the energy they use into light, the rest is ‘wasted’ as heat. LED bulbs, on the other hand, are far more efficient, converting around 90% of the energy they use into light.
A Sankey diagram is a useful tool for visualising energy transfers. It shows the amount of energy that is usefully employed and the amount that is wasted.
In most energy transfers, some energy is transferred to thermal energy stores and then dissipated to the surroundings, which is often considered as wasted energy.
Reducing energy wastage benefits both the individual consumer (lower costs) and the environment (lower environmental impacts). As such, energy conservation measures are a key part of moving towards a more sustainable future.