Fortunately, rocks can be crushed with power from solar panels. There remains the issue of whether those panels are better used, just now, to displace natural gas burners emitting new CO2 than to crush rocks to absorb CO2. Or, equivalently, if NG-generated power used to crush rocks makes more CO2 than would then be absorbed by the rocks.

In a near enough future, it won't matter, because the NG will all have been displaced already.