Wednesday, November 17, 2021

Cellulosic ethanol's highly subsidized failure

Chart of actual vs targeted cellulosic ethanol production
Actual U.S. production of cellulosic ethanol and other cellulosic liquids compared to the targets for cellulosic biofuels specified in the Renewable Fuel Standard

Cellulosic ethanol, once a great green hope for cutting petroleum use and CO2 emissions, has been a bust. The chart above compares the volume of cellulose-based liquid biofuels (largely ethanol) actually used in the United States to the targets for such fuels set by Congress when it expanded the Renewable Fuel Standard (RFS) in 2007. Note the logarithmic scale on the vertical axis; the gap between promise and reality is so large that actual production would be barely visible on a linear scale. 

The fuel has been delivered at levels of no more than about 0.1% of (three orders of magnitude less than) the volumes on which the RFS was premised [1]. This chart does not include cellulosic biogas, which EPA re-classified to qualify for RFS compliance purposes and has seen recent production of around 500 million ethanol-equivalent gallons. However, such "renewable natural gas" is not in the spirit of the law, which envisioned liquid biofuels that could be readily used in motor vehicles. The 2019 RFS target for cellulosic biofuels was 8.5 billion gallons, set to reach 16 billion gallons by 2022. But in 2019, before the pandemic-related drop-off in 2020 for nearly all forms of energy, only 9.8 million gallons of cellulosic ethanol were tallied by EPA.  

Friday, August 6, 2021

Newly proposed auto standards hold promise

The Biden Administration is clearly making good on its pledge to revisit the automobile GHG emission standards weakened by the previous administration. The notice of proposed rulemaking issued by EPA on August 5, 2021 aims to cut model year 2026 car and light truck GHG emission rates 17% compared to the recent level, from 205 grams/mile (g/mi) in 2020 to a nominal target of 171 g/mi in 2026. 

The White House announcement just prior to the EPA proposal also states an ambitious goal for EVs to comprise half of U.S. vehicle sales in 2030. This non-binding target would include plug-in hybrid electric vehicles (PHEVs) as well as pure zero-emission vehicles such as battery electric and fuel cell cars. 

Monday, February 1, 2021

Fleetwide efficiency gains more important than electric cars over the next decade

For at least the next decade, the overall fuel economy of the entire car and light truck fleet will be more crucial for climate protection than the number of electric vehicles sold. That's the message of my recent online article in Scientific American: "Want Greener Cars? Focus on Fuel Efficiency." Read the discussion there (the article was first published in The Conversation under the title "To make the US auto fleet greener, increasing fuel efficiency matters more than selling electric vehicles").   

Friday, January 22, 2021

Personal trucks widen emissions gap over EVs

Excess carbon dioxide emissions from the rising popularity of light trucks, such as the Ram pickup, swamp many times over the potential carbon savings from increased sales of EVs, such as the Tesla Model 3, to date.  

Last fall, I posted an analysis showing that, even as electric vehicle sales had grown significantly over the past several years, the broader market shift to personal trucks (mainly SUVs and pickups) has overwhelmed the potential CO2 reductions from EV use by more than a factor of four. With the new EPA data now released, this ratio has increased to a factor of 5.6, as shown in the chart below. 

Tuesday, January 5, 2021

GM touts innovation while weakening regulation

My opinion piece published in The Detroit News points out the inconsistency of how some automakers have advocated for weaker fuel economy and GHG emission standards even as they promote their technology innovations. Taking General Motors' recent public statements as an example, it reminds readers that what ultimately matters for reducing emissions is the stringency of the regulations that apply across the entire vehicle fleet.