Because he is selling antinuclear have-your-cake-and-eat-it renewable energy studies that he asserts "find" least-cost energy systems with little or no nuclear energy, while in fact he simply assumes it, hidden in the fine print of his papers.
Note how I try to evaluate Clacks storage cost assumption by comparing to the *best* current storage cost quote I could find.
In his effort to support his nuclear cost assumptions, he refers to the *worst* project he could find.