as a result tgc price can fluctuate over time however as administrative costs for tgcs can be higher than for fits actors may require capacity building before engaging in such markets economic performance will also depend on other parameters including how close the technology comes to competing with fossil fuel technologies and its stage of market development studies by the iea show that differences in impact and costeffectiveness among the various economic support systems tend to be smaller than the differences among countries that have the same system iea a