The dualism of the authors you mentioned is perfectly compatible with the principle of conservation of energy. Though I am not directly answering your question, I may help with some misconceptions in your question.
According to dualists, the mind is not fully physical, but there are many types of dualism. Some of them are compatible with the principle of conservation of energy and some of them are not (i. e. Descartes). First, I will explain the ones that you cited, which are compatible.
What Thomas Nagel suggests in What Is It Like To Be A Bat? is that we need new concepts to understand the mind, that "the physical" and "the mental" may not be the best cathegories. This is because the subjective mind, the one that perceives qualitative phenomena (such as "what it is like" to be a bat), cannot be reduced to the objective and the physical.
The perception of qualitative, subjective phenomena (or qualia) is the core of the hard problem of consciousness. The hardest problem is not to explain how consciousness is produced (that can be explained in science), but how physical phenomena and consciousness' qualia are connected. Does Mary learn something the first time she perceives the quale of the color red? Frank Jackson says that she learns how others perceive the world, more than learning something in virtue of the quale itself.
But that isn't incompatible with the law of conservation of energy, as David Chalmers points out in The Conscious Mind, when he exemplified what he calls the "hard problem of consciousness" in his famous argument of philosophical zombies. Can you imagine a world physically identical to ours, where each neuron cell is connected to the same as in ours, where there is no consciousness? Where people do not perceive "red" or "rough" qualia? Where they are not conscious of their experience at all? Chalmers claims that you can imagine this world of "philosophical zombies" without modifying our knowledge of physics at all. Every law of physics applies exactly in the same way; the point is that conscious experience is not necessary. So, why does it even exist?! That's the hard problem of consciousness.
The idea of these dualists is that the mind cannot be reduced to the physical, but, as you can see, that does not imply that the principle of conservation of energy is violated. What they claim is that physicalism is not necessarily wrong, but incomplete. We cannot even draw a physical connection between physical causes and the qualia, we cannot even measure the qualia, so we wouldn't be able to measure the quantity of energy they take in a physical process. As long as qualia don't play a determinant role in the actions of an individual, there will be no problem. (Is it the "redness" of red [subjective] the thing that changes our mood, or is it the intensity of the light of this frequency [objective, physical]? Note that they are in different worlds. Physical is only affected by the physical.)
However, if you held a view in which there is a mental substance (res cogitans) not affected by physical laws, separated from a physical or material substance (res extensa) affected by physical laws, and that the first causes effects in the second, yes, there would be a problem with the principle of conservation of energy, because you would be introducing new energy in a world, "creating" energy. But then you'd have to hold that an important part of the mind is separated from the body, and not only its qualitative aspect.
I hope this will help