Low carbon mandate could increase carbon emissions in Minnesota

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Last year, the Minnesota Legislature established the Clean Transportation Standard Work Group to explore the design and implementation of a Clean Transportation Standard in our state. This week, the group released its report, which states that such a standard “could be the largest single policy for reducing carbon pollution from transportation in Minnesota.”

This is incorrect. This sort of policy would be unlikely to reduce emissions; in fact, it would likely increase them.

To understand why, let’s start with how a Clean Transportation Standard, also known as a low carbon fuel standard, might work. First, each fuel available to Minnesotans — whether liquid or electricity — would be assigned a carbon intensity score, which is more-or-less akin to its carbon footprint. Second, the state would incentivize the use of those fuels with the lowest scores, thereby promoting their use and, as it is thought, reducing total emissions.

This may sound like a good idea, but in practice it is deeply flawed. The fundamental problem is that carbon intensity scores are calculated using a method of greenhouse gas accounting that is entirely not up to the task. Such a method leaves out important sources of emissions arising from fuel production and use.

When calculating carbon intensity scores for biofuels, for example, major sources of emissions from changes in energy and agricultural markets are commonly ignored. It’s as if in calculating your net worth, you were to forget about your home loan. Or if, when budgeting for your anticipated household expenses, you were to ignore inflation.

The consequence of this is that carbon intensity scores are essentially meaningless. A recent committee convened by the National Academies of Sciences, Engineering, and Medicine to explore standards such as the one being proposed here concluded that we should place little credence in the carbon intensity scores that these standards rely upon. All 16 members of the committee, myself included, noted that “the carbon intensities of fuels … are not necessarily equivalent to the full climate consequences of their adoption.” In other words, we should be skeptical.

The committee goes on to state, even more bluntly, that “increased use of a fuel with a low carbon intensity … could potentially decrease or increase carbon emissions.” Let the last part of that sentence sink in. A Clean Transportation Standard that promotes fuels that it deems to be “low carbon” may result in higher, not lower, greenhouse gas emissions.

It’s one thing to have a policy that is ineffective in achieving its goal. It’s another to have one that makes the problem worse.

Such has been the case in other states like California, where their Low Carbon Fuel Standard has led to increased use of corn ethanol, which has higher greenhouse gas emissions associated with it than gasoline but received a lower carbon intensity score. This may well happen here in Minnesota, too, where political pressure to use a locally produced product may supersede any scientific basis for excluding ethanol as a particularly dirty fuel.

So if a Clean Transportation Standard would likely take Minnesota in the wrong direction with respect to our climate policy, what can we do to reduce greenhouse gas emissions from transportation? The answer lies in improving vehicle efficiency, investing in public transportation, and rethinking the design and infrastructure of our cities and towns.

In short, we need to move away from thinking about how we can produce more fuel, which is what a Clean Transportation Standard does, and toward thinking about how we can use less. For the fuel that we must use, our focus should be on promoting vehicle electrification supplied by truly low-carbon sources of electricity such as wind and solar. Taken together, these actions would greatly reduce our use of highly polluting liquid fuels and help Minnesota meet its climate mitigation goals.

Jason Hill is a professor in the Department of Bioproducts and Biosystems Engineering, University of Minnesota. The views expressed here are solely his own.