actually: efficiently: yes safely no a drop could destroy new york or something crazy like that
You're definetly thinking of something else, i dont know what though
And the cost would be ridiculous too, to make one single gram of the stuff would take 100 billion years and 100 quadrillion dollars and the current rates, and no im not making those numbers up cause they're huge
Actually they already have fusion plants that work, but not as much as they're supposed to, in a couple years they'll complete construction on one that will be more of a final version, so it wont take much longer
And it doesn't use heavy water, the only thing they use the water for is to power a steam turbine