Energy cost can be theoretically lower than on earth IF launch costs and additional hardware costs are low enough. Because solar is about 5x better on space than on earth. That's basically it.
If we wanted to launch the Stratos Hyperscale AI Data Center, which will take 40,000 acres of land, to space, we're looking at roughly 3 million tons of equipment, or 3 billion kilograms. SpaceX charges $1520 per kilogram, so it would be about $4.5T to launch all of that into orbit. We'll just assume the space station already exists and labor is free to hook it up, given that we've already hit the annual budget for the US federal government in launch fees. And it'll take about 47,000 launches to get the equipment there, or roughly 300 years.