It’s been noted before that moving in a serious way to renewable energy sources is a formidable undertaking not just in the social, political and legal developments that would be required, but in the energy and materials demand it would impose. That is not to argue against such a move–which surely must be seen now as inevitable–but to recognise that it is not costless. Some accounting of embedded energy has been carried out, but this piece focuses on the requirements for mineral inputs, from sources which are not now heavily used. That likely demand will create its own set of realignments in international economics and politics, and will need to be managed carefully. It’s not clear on what basis this will be done: the international framework doesn’t appear to be in place, and the operations of the free-market will only exacerbate the situation, in giving new power for those nations fortunate enough to possess substantial supplies of these minerals.