Even if perfected it still wont be free. Creating it and then sending it all over the world will cost quite a bit of money. So we'll probably (hopefully!) just get cheaper energy.

And that's why I don't think it will impact economic growth that much. But it will hopefully reduce our CO2 emissions.

The reduced CO2 should make the climate colder. Continued economic growth will dump more heat into the air. But as we expect global population to peak at only a couple more billion people, would the energy humanity dumps into the air be comparable to how much the sun dumps into each square meter of the earth every day?