Like, a lot of power. Scott Manley delves into the science of the planet destroying business and came up with the numbers that it would take to destroy a planet in Star Wars. To destroy an Earth-like planet which was like Alderaan, you’d need three trillion trillion trillion Joules of energy. There are five billion Joules of energy in a lightning bolt so yeah, you’d need a lot more energy.
Watch the science below. It’s so much more interesting than any other math or science class I’ve ever taken.