The fusion breakthrough could mean carbon-free power, but not soon. And it's not going to be like 'Mr. Fusion' from 'Back to the Future II.'

<p>The fusion breakthrough could mean carbon-free power, but not soon. And it's not going to be like 'Mr. Fusion' from 'Back to the Future II.'</p>

Get the latest news, sports, entertainment, money and tech stories from USA TODAY through your voice assistant.

<p>Get the latest news, sports, entertainment, money and tech stories from USA TODAY through your voice assistant.</p>