skip to main content

→ Top Stories:
Clean Power plan
Safe Chemicals

Nathanael Greene’s Blog

Independent peer review confirms EPA's approach to biofuels

Nathanael Greene

Posted August 10, 2009

, , , , , , ,
Share | | |

On Friday, EPA released the findings of four independent peer-review panels that assessed the Agency's approach to measuring the lifecycle GHG emissions of different types of biofuels. All of the reviewers agreed that emissions from land-use change is an important impact from biofuels that we cannot afford to ignore. While the reviewers offered lots of helpful recommendations, they also broadly praised the quality of EPA's efforts. And while some reviewers ultimately concluded that EPA's models are not yet ready to be used in regulations, the majority endorsed EPA's basic approach.

The reviewers looked at the combination of models EPA used, the timeframe EPA used,  EPA's use of satellite imagery to determine land-use trends, and the emissions factors EPA used for international agriculture.

On the models the reviewers basically supported EPA's coupling of a pair of partial equilibrium models. While Dr. Michael Wang of Argonne National Lab agreed that the type of models should not be a problem he did raise concerns about transparency. On the other hand, John Sheehan at University of Minnesota and formerly at NREL stated: “EPA has, at this time, used the best available tools and approaches for assessing indirect land-use change effects of biofuels.”

On the timeframe, all of the reviewers agreed that EPA needs to shift from discounting time to discounting impacts. Dr. Kenneth Richards from University of Indiana raised some of the toughest questions about the ability of EPA's choice of a timeframe to be scientifically validated, but also stated: "I was pleased to see the extent to which EPA’s analysts had grasped both the conceptual and practical issues related to this type of work."

All of the reviewers assessing EPA's use of satellite imagery to predict land-use change patterns agreed that this was a scientifically valid approach and they all called for improvements over time such as more validation against local and regional ground truth.

EPA got the most general support for its assessment of international agriculture emissions. Dr. Kenneth Cassman from the University of Nebraska struck a common note when he said: “I believe the analysis uses the best available database for this analysis, and I do not know of any other data source.”

Unfortunately, the corn ethanol industry continued its campaign to suppress the science. Growth Energy, the newbie industry association set up by Poet, took a hear no evil approach and only focused on the portion of the comments that Growth agrees with. RFA and the National Corn Growers, unfortunately, must have decided that their attacks on the science had failed and so they should attack the messenger. They launched ad hominem attacks against the reviewers. (Here's RFA's and here's NCGA's.) Their logic seems to be that because there weren't any paid lobbyists for the industry on the review panel, it couldn't possibly be scientifically valid.

There's some irony here. RFA's rant largely boils down to the claim that because the peer review panel included noted corn ethanol skeptic, Tim Searchinger, "this is a perversion of what the peer review process is supposed to achieve." So how did Tim get on the panel? He was picked by an independent third party, the consulting firm ICF International. (See this explanation from EPA.) I'm sure EPA staff were groaning when they saw Tim's name on the list, but they were following the rules of good independent review, and ICF picked Tim because he knows more than almost anyone else about the models and issues involved. So basically RFA is trying to claim that there's bad science here because the peer review panel wasn't politically gerrymandered to their satisfaction.

Share | | |


Brooke ColemanAug 18 2009 10:43 AM


It is disheartening to watch your blog posts on this subject become more and more ideological, capped off by NRDC joining the Grocery Manufacturers, Big Oil and the meat industry coalition against biofuels, all in the name of protecting rainforests. Anyone will tell you that cattle and big food are at the top of the list as threats to the world's rainforests, and their call for "science" is based purely on getting biofuels out of their way.

On the peer review issue, you are misleading a great many people from a position of power (NRDC) when you call the ethanol industry's quite reasonable critiques of the economic modeling predicting indirect land use change as politics as usual and anti-science. I am not sure, exactly, when NRDC decided that economic modeling (which is notoriously inaccurate, especially as a forecast) became science, but there are a great many people unaffiliated with any industry group that scoff at the notion.

You rip RFA for crying about transparency, but it is simply fact that these models cannot be verified or run by RFA modelers. Think about that for a minute: the models used for direct regulation are completely inaccessible and unverifiable. The relationships between variables cannot be confirmed or cross-checked by the industry bearing the burden of the regulation. This is not how the Clean Air Act works, how gasoline regulations work, how cap and trade will work, etc.

You mention ICF as an independent consulting agency. Ok, here is their summary of Michael Wang's position on these models. Michael Wang works for DOE, has forgotten more about carbon accounting than most people know, served as an EPA peer reviewer, and is not linked to your corn villain:

"Dr. Wang ... noted that the consequential LCA approach in place of an attributional LCA approach in emissions regulation development is new. He questioned whether the use of a consequential LCA approach was sound enough for regulation development, and whether the underlying data and assumptions in the consequential approach were reliable and transparent. Although he mentions a few additional questions, Mr. Wang’s main concern was the transparency of the consequential LCA. He voiced that because consequential LCAs are in their early stage of applications for environmental evaluation, there are large numbers of inter-relationships in general equilibrium models, and aggregate emission co-efficients are used inside of these models, stakeholders may not be able to readily identify the effects of individual activities and new technologies on LCA results."

So Dr. Wang thinks there are transparency problems with these models. Is he influenced by big bad corn ethanol?

Sadly, NRDC has gone to the extreme on this issue, working side by side with the real enemies of the rain forest, all in the name of trying to establish dubious economic models as science so they can sink corn ethanol. Now they rip those who have tried, unlike NRDC, to lift the hood on these models in an effort to see what's inside. I guess at NRDC, like GMA and API, the ends justify the means. Not encouraging.

Comments are closed for this post.


Switchboard is the staff blog of the Natural Resources Defense Council, the nation’s most effective environmental group. For more about our work, including in-depth policy documents, action alerts and ways you can contribute, visit

Feeds: Nathanael Greene’s blog

Feeds: Stay Plugged In