You don't have to actually remove carbon with excess power. In fact that would be bad environmentally since all you accomplish is removing carbon but you still

You don't have to actually remove carbon with excess power. In fact that would be bad environmentally since all you accomplish is removing carbon but you still have process inefficiency. Your statement is globally equivalent to doing something that would be done anyway but is tolerant to interruptions. There are power consumers that can do this and they have a power preferential rate (i.e. they're willing to shut down when the power company calls). Also, what you're saying can be done by, for example, electrolysis of water to make hydrogen. I'm currently working on fuel cells that can be operated in reverse; that is they generate electricity from fossil fuels when needed (at very high efficiency) but absorb excess electricity by producing hydrogen. Really what you're proposing is accomplished more efficiently by stored energy. The problem is that we've tapped out the easy ways to redistribute load, or store energy decades ago.