[ktal]

Until there exists 100% clean options for the entire pipeline of resource extraction, transport, assembly, distribution, etc., there will still be fossil fuel involvement in 'clean energy generation'. Can't really make clean energy cleanly unless we have clean energy to make it in the first place.

Resource extraction / recycling is a whole other issue of course.

[avmich]

We have that technology for decades - for example, Tu-155 flew on hydrogen in 1988 - and we gradually replace existing usage with more and more clean options. Don't worry - we won't turn off pollutions overnight, but will gradually drive them to zero. And then to net negative values, restoring some losses in the environment.