If it's any consolation, CARB may think about regulating methane emission from dairies directly, and once that happens no new LCFS pathways with avoided methane credits could be granted. In that case, the higher price of milk would occur instead of carbon market stuff, not on top of it.

The CA Low Carbon Fuel Standard currently has a 15 day regulatory comment period open right now (13 days left) and there will be one more public comment opportunity final hearing Nov 8th, though those are more about finalizing the public record, rather than actually improving the proposal.

Ultimately, it seems an odd fit to have gasoline consumers pay for dairy digesters. "Polluter pays" is a good general principle. I really wish someone would do a study that tries to identify whether there's less regressive risk from using fees on gas to fund digesters rather than more expensive milk

But I've also seen studies that say carbon credits can make up about half as much revenue as they get from milk, which seems like enough to affect decisions. Those estimates usually rely on high LCFS credit prices, which are likely a thing of the past, though.

It's hard to say how much dairy operators are changing their behavior to maximize gas production (though anecdotally, it does occur). I've seen studies that say the biggest economic benefit they get from digesters is self-producing bedding material, and carbon credits are an afterthought

Yeah, policymakers have been very reluctant to impose any costs on farmers, across the country. That's why CA chooses to persist with the current system of letting LCFS incentives (paid for by gasoline consumers) drive the installation of digesters at dairies, despite EJ groups' strong opposition

I haven't really played with the math as much as I want, but I suspect there are some scenarios where the assumptions made in LCFS credit quantification actually allow this to result in more credits for making electricity from biogas than if you just used it to fuel natural gas vehicles

So if a dairy chose to make electricity, the loss due to the efficiency of the generator would be reflected in the fact that only about 30% of the energy from the input biomethane comes out as electricity, but the efficiency of the EV comes close to making the producer whole.

LCFS credits are based on total avoided emissions compared to what would have happened if the fuel merely met that year's target. So it's calculated based on fuel energy delivered to the vehicle, but adjusted for the vehicle's efficiency (i.e. EVs get a big bonus because they're more efficient)

In truth, I'm (sadly) confident that policy makers will hand-wave around this by saying that GHG inventories only look at direct real-world emissions and then giving transportation special dispensation to keep claiming the value of LCFS credits, but that's blatant double-counting.