Could there be nuclear fusion with carbon instead of hydrogen?

Yes. As far as I know, you can fuse any two atoms, if you had enough heat and density. Carbon fuses in the core of stars which are at least 8 times the size of our sun. Here are the relative size of stars (the earth's orbit is in red). read more

While many forms of nuclear are carbon neutral, and produce no CO2 while they operate, Carbon Detonation Fusion is one of the very few techniques that actually permanently takes carbon out of the air and ocean while producing large amounts of energy (not just using up energy as many other carbon reduction approaches do). read more

Nuclear fusion - Wikipedia lists the ten easiest fusion reactions for power reactors. There are two without hydrogen isotopes, the easier of these being a He3-He3 reaction. read more

If we could build nuclear fusion plants that make as much electricity as today's coal or nuclear fission plants, with none of their drawbacks, we could potentially solve Earth's energy problems forever, making all the power we need without wrecking the environment. read more