What little I do know of clean coal indicates it's a pipe dream. Google "clean coal power plant over budget" to get an idea.
Read here http://reneweconomy.com.au/flagship-clean-coal-project-abandoned-despite-10bn-investment-84327/
A snippet from the article.
The 582-megawatt plant, initially projected to cost $US1.8 billion, has so far run up a bill of over $US7.5 billion ($A10 billion) in construction and engineering expenses. In comparison, a typical 700-megawatt natural gas plant would have cost roughly $US700 million to build.