"The Concord" models often get speculated as the future, but as often the energy economics does not sustain. There is perhaps a very probable risk of rising en

"The Concord" models often get speculated as the future, but as often the energy economics does not sustain. There is perhaps a very probable risk of rising energy costs this decade, which might make such models unfeasible. In that light, your comment makes a lot of sense to me.