Law of conservation of energy !!?

Ah...that's conserving total energy in the COE law...not just useful energy. Total energy TE = H + S = constant. where H is low entropy useful energy and S is high entropy useless. From the First Law, H --> S which means useful energy diminishes as useless energy increases.

And it's conserving useful, low entropy energy that we should be concerned about. There is only so much of that available on our planet. When all that is converted into high entropy, useless energy there will be no more. And by definition we can't use high entropy energy.

Because there are 2 different meanings to conserving energy .

In physics, energy is always conserved. If you start with 100J of energy you must finish with 100J of energy. The types of energy could be different - e.g. you could start with 100J electrical energy and end up with 100J of heat energy. This is the law of conservation of energy.

But in the environmental sense, conserving energy means something totally different. If means controlling the use of energy *resources* such as coal, oil and gas. So it has nothing to do with the law of conservation of energy.

Every energy transformation causes a greater entropy, and the excess energy is not utilized (e.g. car's engine exerts heat that is not being utilized)

Conservation of energy is in anlysing the details of physics and chemistry. Conserving energy is like surviving. If you do not have any thing to eat, then you starve. To avoid starving you need to look for conserving energy. This energy comes from animals, trees etc.