Interesting and thought provoking article!

But How Would It Work? We buy solarcoins with gridcoins through voluntary actions? I would expect only a tiny drive to do so. Apart of the direct bridge omitting bitcoin, which should be quite straightforward to do, what else we need for this idea to work?
Also, both coins have lost close to 95% value since the peak a year ago. Rewarding anything is, at ~1M market cap for each, rather symbolic.

What about if coins would merge into one and reward both crunchers and energy producers? Or one of the coins would also start rewarding what the other one does? This would be a more user friendly solution, as one doesn't need two running wallets and two sets of keys / backups to worry about.

Another idea for offsetting carbon emissions: Run a BOINC based scientific or engineering project that solves some fundamental or design / construction challenges in green energy field (similar to DHEP).