is this right?:

when a form of energy changes from one form to another some energy may transfrm into a useful form, those useful form of energy is high grade energy.while the rest of the energy will always change to form we cannot use.which is called the low grade energy.

if i am not right, can you please correct me?or is there any other things that i can add to about what is low grade and high grade energy?

There are not simply two grades of energy, high and low. There is a quantity called entropy, designated by S, and a quantity called available energy, and defined as H - TS. The quantity S increases or stays the same in all reactions involving closed systems, so that the available energy decreases or stays the same.

What you are trying to state is the second law of thermodynamics, which involves the tendency of entropy to increase, as available energy is degraded to heat. Heat (thermal energy) is not 100% available and is therefore of "low quality".

so what is high grade energy?

Energy that is 100% available to perform work. Potential energy and electrical energy are two examples.

High-grade energy refers to energy that is easily usable and has the potential to do work efficiently. It typically has a high energy density, is concentrated, and can be easily converted into different forms or used to perform tasks. Examples of high-grade energy include electricity, chemical energy in the form of fuel, or potential energy in the form of elevated objects.

To acquire high-grade energy, one needs to convert a raw form of energy, such as heat or sunlight, into a concentrated and usable form. This conversion can be achieved through various processes, such as using solar panels to convert sunlight into electricity or burning fossil fuels to release the stored chemical energy. In these examples, the resulting electricity or fuel can be readily used to power devices, run engines, or perform other tasks.

It's important to note that the concept of high-grade energy is relative and depends on the desired application. For instance, while electricity is high-grade energy when used to power electrical appliances, it would be considered lower grade if used to generate heat, as some energy would be lost in the conversion process. The distinction between high-grade and low-grade energy is significant in understanding the efficiency and limitations of energy conversion systems.