Of the nine levels, TRL 3, 6, and 7 represent important development milestones for a technology. By achieving TRL 3, a technology has demonstrated proof of concept in a laboratory; further progress is reliant on further research funding. Commercial interest will be required to reach TRL 6 for both pilot plant siting, and construction support. Furthermore, this is the stage where technical issues will likely arise. However, advancement of successful pilot plant projects will require continued commercial support. Finally, the progression beyond demonstration scale (TRL 7) to commercial scale (TRL 9) is limited by financial support, and commercial interest.