What is high-quality energy?

Answer 1

Hi

The quality of energy is a perception, and it is necessary to grade the tasks for which the energy is used to understand it better.

One perception is that You require High quality energy to do high quality task. Low quality energy cant be used to do a high quality task, where as high quality energy can be used to perform any task ,low or high quality.

Another perception is that, High quality energy can be transformed into several forms of energy with great efficiency (without much loss of energy when changing form)

Take the example of electricity, which is a high quality form of energy. It can be converted to mechanical energy (in running electric motors), Thermal energy (in heating water), Electromagnetic radiation (in Radio broadcast) with little loss of energy while changing form.

Here Water heating is a low quality task, which can be met by a low quality energy such as heat (from burning fuel). Only Electric energy which is a high quality energy can be used in high quality tasks such as running a motor.

So Electricity is high quality energy and heat is a low quality energy. Even among heat, the heat from solar radiation as received at earth is supposed to be of lowest quality, because of lower temperature and being diffuse (not concentrated). Blue flame heat (from burning Natural Gas) is a better quality energy because of its higher temperature, than say heat from burning wood or paper which is of lower temperature reddish flame. The higher temperature heat source ensures better heat transfer coefficients and thereby faster heat transfer to bodies at lower temperature.

The environmentalists say "use high quality energy for only high quality tasks and don't use it for low quality tasks". The logic behind this is high quality energy is produced at great energy cost and environmental cost. Avoid use of electrical energy for room heating and cooling, instead use fuel energy or solar energy for heating and use thermal design such as passive cooling for the buildings, which lowers the room temperature by 5 to 7 degrees centigrade.