What will be the biggest change in power generation in the next ten years?

The power production potential of fusion has been in the news this year, as some promising experiments have been done. Also in the news are some promising new methods of power production. When we look back ten years from now ... what will have been the biggest change in power generation?  

When responding to the poll, select the BIGGEST change and add your comments as to why or if you think there are multiple changes in the works and why.