Can we make usable energy from subnuclear particles? I understand mass and energy are the same, but in this question I will be talking about mass being turned into usable energy (electricity/heat/etc). We can make our energy through chemical reactions like burning coal. We can also make energy from nuclear decay (and soon the fusion) of atoms. 
But is there any know way to take subnuclear particles and turn them into energy? How about quarks and other particles that make up protons/neutrons/electrons? 
More specifically, I have heard (and know little) about Quantum Field Theory. Do we know any way to take the energy form an excited field of, lets say a quark and transfer it into the electron field?
I hope this is not a silly question and thanks.
 A: The problem is that the word energy is bandied around without clearly defining what it means, and in particular non-physicists tend to equate the word energy with the electricity that runs their iPhones.
In the context of elementary particles energy basically means kinetic energy i.e. energy of motion, and pretty much all you can do with this energy is use it to heat things. For example all sorts of complicated particle reactions are going on in nuclear power stations, but all we do with the resulting energy is heat water, turn it to steam and use it to drive turbines and generate electricity. If we ever get hydrogen fusion to work we'll probably just use this to boil water and generate electricity in the same way.
You ask:

Do we know any way to take the energy form an excited field of, lets say a quark and transfer it into the electron field?

and I'm guessing you're thinking of the discussion in What keeps mass from turning into energy?. What you describe is exactly what happens ever time we collide protons in the LHC. Quark-quark collisions excite lots of quantum fields, including electrons, and a huge shower of the created particles emerge from the collision. But the created electrons don't constitute electricity in the sense of the electricity you use at home. All the created electrons can be used for is to heat things.
Heating things is good of course, and the industrial revolution started with heating water by burning coal. A large fraction (two thirds?) of the electrical power you and I use every day is still generated by burning coal to heat water. Who knows what future nuclear fission and fusion have, but even in the best case scenarios I'm afraid we aren't going to be doing anything more glamorous than boiling water.
A: Sub nuclear particles, i.e. quarks, are bound within the proton. If the proton had a decay mode, then all of matter as we know it would be in a higher excited state and could by spontaneous decay release a lot of radiation finally ending up in photons and neutrinos. If this decay could be stimulated one might try thinking of how to use the energy produced. Fortunately experimentally the limits of proton decay are such that the probability of this happening is zero. Theoretically the probability of proton decay is very tiny and thus our stable macroscopic world can exist.
All other known subnuclear particles need much  more energy in order to be produced than can be garnered by any method.
I agree with John that  large scale energy production ends up in heating water, except of course for wind and solar, which go directly to electricity.
Possible future  energy uses coming from the in depth study of elementary particles and their interactions could come if a theory of everything, i.e. a theory including quantized gravity, is found. For example  it might prove possible to get energy out of the  Quantum Field Theoretical vacuum. This, of course,  is at the science fiction level at the moment as far as research goes.
