James S. Rhodes, Ph.D.

Trestle Energy LLC

5580 La Jolla Blvd. Suite 429

La Jolla, CA 92037

July 27, 2015

Air and Radiation Docket and Information Center

Environmental Protection Agency

Mailcode: 2822T

1200 Pennsylvania Ave., NW

Washington, DC 20460

Docket: EPA–HQ–OAR–2015–0111

Dear EPA:

I appreciate the opportunity to provide comments on the Notice of Proposed Rulemaking entitled 

“Renewable Fuel Standard Program: Standards for 2014, 2015, and 2016 and Biomass-Based Diesel 

Volume for 2017,” dated June 10, 2015 (“2015 NPRM”), which represents an important step in 

implementing the Renewable Fuel Standard (“RFS”). I recognize and appreciate EPA’s thoughtful efforts 

in developing this proposed rulemaking, particularly in terms of the substantial evolution in EPA’s 

approach since the proposed rulemaking from November, 2013.

My comments address a variety of issues discussed in the proposed rulemaking and reflected in the 

underlying policy objectives, and provides suggestions for advancing those objectives through EPA’s 

rulemaking authority. They build directly on the comments I provided to the 2013 NPRM entitled “2014 

Sandards For The Renewable Fuel Standard Program,” dated November 29, 2013 (“2013 NPRM), which 

is attached only for ease of reference. These comments are based on my professional experience with 

transportation fuel policy, both in academia and in the private sector, which is summarized in my 

comments to the 2013 NPRM. My academic work focuses broadly on engineering and economic 

analysis of technologies for mitigating anthropogenic GHG emissions and on policy analysis at the 

intersection of energy, environment, and climate change. My private sector work focuses on using 

existing policy incentives to support development of low emission energy systems.

Of particular relevance in this context is my experience from my most recent academic position, in 

which I served for two years as the Managing Director for the National LCFS (“N-LCFS”) Study, and from 

my current position as President of Trestle Energy LLC. The N-LCFS Study was a collaborative initiative 

led by a group at the University of California, Davis and included researchers from six research 

institutions. Trestle Energy is small energy company developing low carbon transportation fuels in 

response to established policy instruments. In the context of the RFS, Trestle Energy is developing 

systems to dramatically reduce lifecycle carbon emissions from biofuel production. Integrating these 

systems with bio-refineries producing butanol or sorghum ethanol, for example, can enable rapid 

expansion of economically efficient advanced biofuel production. In so doing, these systems will seed 

development of whole new industries for domestically produced renewable energy that can drive down 
greenhouse gas emissions and improve environmental quality while creating demand for new green jobs 

and new opportunities for economic development. 

Trestle Energy’s systems provide an opportunity to make big gains toward the policy objectives 

underlying the RFS—expanding domestic production of low carbon renewable fuels, driving down 

greenhouse gas emissions from domestic sources, improving energy security, creating jobs, and 

accelerating economic growth. 

General comments on the 2015 NPRM

As a whole, the 2015 NPRM reflects a balanced and well-reasoned approach to addressing the diverse 

issues that have recently challenged effective implementation of the RFS. EPA deserves substantial 

credit for the significant evolution in its analysis and rationale underpinning the volumes proposed in 

this NPRM. In particular, I commend EPA for: 

1. Setting volumetric mandates at levels that aim to balance the fuel volumes achievable in the 

market with the growth in supply envisioned in the statutory volumes established by congress;

2. Providing continued support for investments made in good faith to advance the policy 

objectives by providing steady increases—and avoiding absolute decreases—in RVO volumes;

3. Crystalizing pressure on the so-called “ethanol blend-wall” by establishing volumes that can be 

met by either (i) increasing ethanol beyond the blend-wall or (ii) increasing supplies of nonethanol renewable fuels;

4. Signaling a shift in supply growth—consistent with the statutory volumes established by 

congress—toward advanced biofuels with increasing greenhouse gas emissions benefits;

5. Recognizing the contributions to key policy objectives of competition among fuels within the 

implied pool for “unspecified advanced biofuels”, and advancing these objectives by growing 

this pool through an increasing gap between the sum total of the RVOs for D3 RINS, D4 RINS, D7 

RINS, and the RVOs for Advanced Biofuels;

6. Recognizing the diverse compliance pathways available to market participants and the 

implications of competitive dynamics for increasing renewable fuel supplies, as reflected in the 

analysis underlying Table II.D.2-2 in the 2015 NPRM, for example;

Two additional sets of comments focus on the following issues:

1. Establishing RVOs that reflect the maximum achievable volumes of renewable fuels (in response 

to requests for comments on pages 33122 and 33123); and 

2. The relative growth in fuel volumes for Biomass-Based Diesel, unspecified advanced biofuels,

and total renewable fuels (in response to requests for comments on pages 33122, 33123, 

33137);
Comment on establishing RVOs that reflect maximum achievable fuel volumes: EPA should consider 

increasing the 2016 RVO for Advanced Biofuel by approximately 650 Million ethanol-equivalent gallons 

and increasing the 2016 RVO for Renewable Fuels by approximately 340 Million ethanol-equivalent 

gallons.

Through a number of statements, the 2015 NPRM makes clear EPA’s intention to use its waiver 

authority only to the extent required to bring the RVO’s within the market’s reach and to establish RVOs 

that target maximum achievable renewable fuel volumes. I generally support this basic approach for 

setting the RVOs, which appears to be broadly consistent with the legislative intent and underlying 

policy objectives. I also appreciate that the timing of EPA’s issuance of 2014 and 2015 RVOs inherently 

limits their ability to influence fuel supplies delivered in the 2014 and 2015 compliance periods. That 

said, analyses contained within the 2015 NPRM and the 2013 NPRM seem to suggest that the proposed 

2016 RVOs are significantly below the maximum achievable renewable fuel volumes.

For example, the 2015 NPRM projects the volume of ethanol that can be supplied as E10 is 13.69 Billion 

gallons [2015 NPRM pp. 33115], and the 2013 NPRM projects that the maximum volume of biodiesel 

that can be consumed by the existing vehicle fleet is 2.7 Billion gallons [2013 NPRM pp. 71764-71765 of 

the 2013 NPRM, and summarized on page 13 of the comments attached]. The ethanol-equivalent 

volume of this biodiesel is 4.05 Billion gallons, which approximates the maximum achievable volume for 

the current vehicle fleet and is 650 Million ethanol-equivalent gallons more than the RVO for Advanced 

Biofuel proposed in the 2015 NPRM for 2016. Adding this ethanol-equivalent volume to the volume of 

ethanol that EPA projects can be supplied as E10 suggests a total achievable renewable fuel volume of 

17.74 Billion ethanol equivalent gallons, which is 340 Million gallons more than the RVO for Total 

Renewable Fuel proposed in the 2015 NPRM for 2016. 

The simplified calculations above suggest that potentially significant increases in the RVOs for Advanced 

Biofuel and Total Renewable Fuels may be possible within EPA’s proposed framework to target 

maximum achievable volumes of renewable fuels. The 650 Million ethanol-equivalent gallons would 

represent a more than doubling of the 500 Million gallons of “unspecified advanced biofuels” implied by 

the 2016 RVOs proposed in the 2015 NPRM [pp. 33136]. Importantly, these simplified calculations 

should yield a conservative estimate of the maximum achievable volumes, because they ignore potential 

contributions from higher ethanol blends (e.g., E15 and E85) and from other non-ethanol renewable 

fuels (e.g., renewable diesel, butanol, biomass based heating oils, renewable jet fuels, etc.).

On this basis, and specifically in response to requests for comments on pages 33122 and 33123 of the 

2015 NPRM, I respectfully submit that EPA consider increasing the 2016 RVO for Advanced Biofuel by 

approximately 650 Million ethanol-equivalent gallons and increasing the 2016 RVO for Total Renewable 

Fuels by approximately 340 Million ethanol-equivalent gallons. 

Comment on the relative growth in fuel volumes for Biomass-Based Diesel, Advanced Biofuels, and 

Total Renewable Fuel: EPA should consider shifting annual increases in RVOs toward the fuel pool 

implied for unspecified Advanced Biofuels.

Integrating various concepts expressed in the 2015 NPRM highlights the importance of relative growth 

across renewable fuel types, particularly across Biomass-Based Diesel (“BBD”), unspecified advanced 

biofuels, and conventional biofuels. In particular, the 2015 NPRM discusses the importance of 

continued growth in both the implied pool for conventional biofuels and in the Advanced Biofuel carve-
out for Biomass-Based Diesel (“BBD”) in order to support the health and continued development of 

these fuel industries, which have delivered the greatest contributions to the RFS policy objectives. EPA 

also notes the important contributions that result from the implied pool for unspecified advanced 

biofuels—i.e., from having an RVO for Advanced Biofuels that is greater than the sum of the carve-outs 

for Cellulosic Biofuels and BBD. EPA further notes both the benefits of increasing the implied pool for 

unspecified advanced biofuels over time and the increasing difficulty of supplying each increment of 

additional renewable fuels. 

Integrating these comments highlights the importance of balancing growth in fuel supplies across these 

key fuel pools in order to effectively advance the underlying policy objectives. The proposed RVOs 

reflect one way that growth across these fuel pools may be balanced. Specifically, considering the RVOs 

proposed for 2015 and 2016 suggests increases in the required volumes of BBD, unspecified advanced 

biofuels, and conventional renewable fuels of 100, 250, and 600 Million gallons, respectively. The 

growth in these pools is directionally correct and seems reasonable given the historical volumes in each 

of these pools, the congressional intent underlying the RFS, and the trend to systematically increase

contributions from advanced biofuels. 

That said, as discussed in the 2015 NPRM (and on pages 5-6 and 9-13 of the attached comments to the 

2013 NPRM), the unspecified Advanced Biofuel pool has a particularly important role. It encompasses a 

broad range of fuel types that deliver systematic increases in both climate benefits and diversification of

feedstock or fuels. The diversity of fuel types within this pool supports a healthy level of competition, 

thereby providing strong incentives for innovation to advance both economic and environmental 

performance. In particular, as the implied pool for conventional biofuels approaches its statutory limit, 

the growth in renewable fuels may be shifted to the unspecified advanced pool to further incentivize 

innovation, diversification, and additional climate benefits from continued expansion of renewable 

fuels. Moreover, inherent qualities of Advanced Biofuels (e.g., minimum carbon intensity reductions) 

provide a concrete means of achieving measurable progress toward the program’s underlying policy 

objectives despite recent delays in the scale up in Cellulosic Biofuel supplies.

On this basis, and specifically in response to requests for comment on pages 33122, 33123, 33137 of the 

2015 NPRM, I respectfully submit that RVOs increasingly shift growth in required fuels supplies toward 

unspecified Advanced Biofuels. 
James S. Rhodes, Ph.D.

Trestle Energy LLC

5580 La Jolla Blvd. Suite 429

La Jolla, CA 92037

December 20, 2013

Air and Radiation Docket and Information Center

Environmental Protection Agency

Mailcode: 2822T

1200 Pennsylvania Ave., NW

Washington, DC 20460

Docket: EPA–HQ–OAR–2013–0479

Dear EPA:

I appreciate the opportunity to provide comments on the Notice of Proposed Rulemaking entitled “2014 

Sandards For The Renewable Fuel Standard Program,” dated November 29, 2013 (“NPRM”), which 

represents an important step in implementing the Renewable Fuel Standard (“RFS”). I recognize and 

appreciate EPA’s thoughtful efforts in developing this rulemaking, which aims to leverage the policy 

mechanisms available under the regulation to put the RFS on a “manageable trajectory” that balances

the fundamental policy objectives, the practical challenges to achieving those objectives, and the 

broader challenges inherent to motivating industrial scale innovation in transportation fuel supplies.

My comments address a variety of issues discussed in the proposed rulemaking and reflected in the 

underlying policy objectives, and provides suggestions for advancing those objectives through EPA’s 

rulemaking authority. They are based on my professional experience with transportation fuel policy, 

both in academia and in the private sector. My academic work focuses broadly on engineering and 

economic analysis of technologies for mitigating anthropogenic GHG emissions and on policy analysis at 

the intersection of energy, environment, and climate change. My private sector work focuses on using 

existing policy incentives to support development of low emission energy systems.

Of particular relevance in this context is my experience from my most recent academic position, in 

which I served for two years as the Managing Director for the National LCFS (“N-LCFS”) Study, and from 

my current position as President of Trestle Energy LLC. The N-LCFS Study was a collaborative initiative 

led by a group at the University of California, Davis and included researchers from six research 

institutions. Trestle Energy is small energy company developing low carbon transportation fuels in 

response to established policy instruments. In the context of the RFS, Trestle Energy is developing 

systems to dramatically reduce lifecycle carbon emissions from biofuel production. Integrating these 

systems with bio-refineries producing butanol or sorghum ethanol, for example, can enable rapid 

expansion of economically efficient advanced biofuel production. In so doing, these systems will seed 

development of whole new industries for domestically produced renewable energy that can drive down 

greenhouse gas emissions and improve environmental quality while creating demand for new green jobs 

and new opportunities for economic development. 

Page 1 of 15
Trestle Energy’s systems provide an opportunity to make big gains toward the policy objectives 

underlying the RFS—expanding domestic production of low carbon renewable fuels, driving down 

greenhouse gas emissions from domestic sources, improving energy security, creating jobs, and 

accelerating economic growth. We very much look forward to working with the EPA to advance these 

objectives and the Administration’s broader policy goals for energy, the environment, and economic 

development. 

My comments on the NPRM are organized as follows:

1. Comments on EPA’s approach to putting the RFS2 on a “manageable trajectory” (in response to 

requests for comments on page 71738) , with recommendations that:

a. Any shifts in EPA’s implementation should reflect the public-private partnership implicit 

to the RFS and continue support for private sector efforts to advance EPA’s policy goals;

b. Any shifts in EPA’s implementation should maintain strong incentives for innovation to 

advance the underlying policy objectives, particularly in advanced biofuels;

c. The “manageable trajectory” be supported in the rulemaking process for establishing 

new fuel pathways by:

i. Integrating industry-analysis of proposed fuel pathways that are consistent with 

and appropriately leverage EPA’s considerable analytic efforts to date; and by

ii. Prioritizing fuel pathway petitions according to the potential scales of their 

contributions to volumetric mandates, as well as their time to deployment.

2. Comments on supply constraints related to the so-called E10 blendwall (in response to requests 

for comments on pages 71734, 71754, and 71778), with recommendations to adopt a 

framework that:

a. Maintains incentives to overcome the E10 blendwall;

b. Supports continued innovation in fuel supplies required to advance the policy 

objectives; and

c. Is achievable even if the E10 blendwall proves to be a binding constraint.

3. Comments on EPA’s approach to setting the advanced biofuel volumetric mandates (in response 

to requests for comments on pages 71738), with recommendations that:

a. The volumetric mandates retain the policy’s strong emphasis on developing innovative 

fuel supplies required to advance the policy objectives;

b. The implied preference ordering for ethanol prioritize advanced biofuel ethanol at least 

as highly as “conventional” biofuel ethanol; and

Page 2 of 15
c. The advanced biofuel mandate reflect quantities of advanced biofuels, including 

biomass-based diesel that “could reasonably be achieved”, without regard to the RVO 

for biomass-based diesel or to potential changes to the biodiesel tax credit.

If I were to condense these various comments into a single, actionable recommendation for the 2014 

RVOs it would be this: define RVOs for advanced biofuel and total renewable fuels at levels reflecting 

EPA’s expectation for advanced biofuel supply, including biodiesel supply, without regard to potential 

interactions with the biodiesel tax credit. The NPRM provides a number of reasons why the biomassbased diesel RVO is set below the expected supply. These reasons may be appropriate in that context, 

but they do not appear to be appropriate for defining the advanced biofuel or total renewable fuel

RVOs. Moreover, while potential changes in the tax code (e.g., elimination of the biodiesel tax credit) 

may affect the economics of renewable fuel production, and therefore the volume of biodiesel available 

absent the RFS, it will not affect the currently available capacity to produce or supply the fuels to 

vehicles. Integrating this recommendation with the framework recommended in the NPRM & EPA’s 

projection for ethanol consumption in 2014 might yield, for example, the following target volumes:

 Table 1. Summary example for 2014 RVOs

Cellulosic biofuel 8 – 30 million gallons a

Biomass-based diesel 1.28 billion gallons b

Advanced biofuel 2.4 – 5.2 billion gallons c

Total renewable fuel 15.4 – 17.3 billion gallons a

a Ethanol-equivalent gallons.

b Physical gallons, equal to 1.92 ethanol-equivalent gallons.

c Ethanol-equivalent gallons, equal to 1.6 – 2.7 billion physical 

gallons of biomass-based diesel plus up to 1.1 billion gallons of 

other advanced biofuels (30 million gallons cellulosic, 132 million 

gallons of non-ethanol non-cellulosic, and up to 942 million gallons 

of non-cellulosic advanced ethanol).

Page 3 of 15
Comments regarding EPA’s approach to put the RFS on a “manageable trajectory”

(Per request on page 71738)

The Notice of Proposed Rulemaking for the 2014 standards (NPRM) reflects EPA’s intentions and 

thoughtful efforts to define a framework that puts the RFS “on a manageable trajectory while 

supporting growth in renewable fuels over time” and that advances the “central policy goals underlying 

the RFS program: reductions in greenhouse gas emissions, enhanced energy security, economic 

development, and technological innovation” (NPRM Pp 71732 and 71734, respectively). It is important 

that such a framework be clearly defined, both to enable effective future rulemaking and to support the 

continued private investments required to achieve the underlying policy objectives. The NPRM

generally reflects a thoughtful approach by EPA in this regard. The comments and suggestions provided 

here are respectfully submitted with the intent of supporting EPA’s ongoing efforts refine its approach

to implementing the RFS.

Any shifts in EPA’s implementation should reflect the public-private partnership implicit to the RFS and 

continue support for private sector efforts to advance EPA’s policy goals. To be successful, 

implementation must take a balanced and coordinated approach that reflects the public and private 

sectors’ respective roles under the RFS. Generally speaking, the role of the public sector (i.e., Congress 

and the EPA) is to clearly define the policy objectives and the policy incentives for advancing them (e.g., 

RVOs). The private sector’s role is to harness market forces and mobilize private resources in order to 

respond effectively to the policy incentives and advance the policy objectives. While a balanced and 

coordinated approach is required for effectively implementing any such market-based environmental 

policy, it is particularly important for the RFS because advancing its ambitious policy objectives requires 

that large investments in technology development and infrastructure be sustained over extended 

periods of time in the face of large technical and economic uncertainties.

In this context, policy uncertainty should be minimized as much as is practical in order to support 

effective private-sector engagement. Any shifts in policy implementation—which may well be 

appropriate in light of evolving dynamics—should be designed to support continued private-sector 

engagement, particularly by parties that have already invested in the policy’s success. With this in mind, 

policy shifts should, among other things, strive to:

 Limit stranded capital, particularly where associated investments were made in a good faith 

effort to advance the policy objectives; 

 Support opportunities to realign private sector resources in ways that progressively advance the 

underlying policy objectives;

 Provide sufficient notice for such realignments to be implemented.

These principles are intended to buttress the integrity and credibility of the RFS and of other federal 

environmental policy instruments. Advancing environmental policy priorities of all types requires 

considerable investments by the private sector. These investments are subject to large risks from a 

variety of sources, which must be internalized by the private sector. Policy shifts—even those viewed as 

appropriate course corrections—risk devaluing, or even stranding, private sector investments made in

good faith to advance the policy. Such impacts will generally increase the perceived policy risk 

associated with environmental policy initiatives and may substantially compromise the private sector’s 

Page 4 of 15
ability to respond effectively to future policy initiatives. This, in turn, risks undermining the 

government’s ability to leverage market-based policy mechanisms to advance key environmental policy 

objectives. 

This dynamic creates an implicit public-private partnership in advancing the RFS and other market-based 

environmental policy instruments. Among other things, it creates particular responsibility for public 

sector agencies that any shifts in implementation be thoughtfully designed and executed in a way that 

respects the implicit partnership with the private sector. The importance of this dynamic, and the 

principles suggested above, should not be overstated; however, they do seem relevant to potential

shifts in EPA’s implementation of the RFS.

The NPRM’s aim to define a clear framework for prospective rulemaking is broadly consistent with these 

principles, particularly in signaling how issues related to the E10 blendwall will be addressed moving 

forward. Potential compromises to private capital deployed to advance the policy could be further 

limited by minimizing any absolute reductions in renewable fuel volume obligations (RVOs) from prior 

year (e.g., 2013) values. Structuring RVOs to support realignment of private sector resources by, for 

example, converting facilities producing “conventional” renewable fuels to advanced biofuel, could both 

protect capital investments while supporting continued progress toward the policy’s underlying 

objectives. Further suggestions for how these principles might be operationalized in the RVOs for 2014

and beyond are provided in the comments and recommendations below.

Any shifts in EPA’s implementation should maintain strong incentives for innovation to advance the 

underlying policy objectives, particularly in advanced biofuels. Innovation is critical to advancing the 

policy objectives underlying the RFS. The RFS was specifically amended in the Energy Independence and 

Security Act of 2007 to establish a market “pull” for domestically produced renewable fuels that 

advance the underlying policy objectives. Accomplishing this requires substantial innovation in 

renewable feedstock supplies, fuel production, and distribution systems. Innovation on this scale 

requires sustained investments over an extended period of time in the face of inherently unpredictable 

outcomes. The RFS accommodates these characteristics by adopting clear, technology-neutral 

performance metrics, by projecting a coherent set of targets for renewable fuel supply, and by enabling

EPA to adjust that trajectory in response to evolving market dynamics.

While important innovations continue to develop in the production of so-called “conventional” biofuels, 

the innovation required to achieve the policy’s underlying objectives must ultimately come from the 

advanced biofuel pool. It is advanced biofuels that ensure increasing climate benefits and continued

growth in renewable fuel supplies over time. As such, advanced biofuels will, by design, do much of the 

“heavy lifting” required to advance the policy’s underlying objectives moving forward. 

The market signal to develop advanced biofuels, transmitted through the Renewable Identification 

Number (“RIN”) market, responds rapidly to EPA’s rulemaking and to expectations regarding future 

rulemaking. An implementation framework yielding RVOs that emphasize contributions from advanced 

biofuels (e.g., the 2013 RVOs) signals industry to supply more of these fuels, which is translated into

premium RIN values for advanced biofuels that enable investment into increasing production capacity. 

Conversely, an implementation framework yielding RVOs that de-emphasize advanced biofuels signals 

industry not to increase supplies of these fuels, which is translated into relatively low RIN values for 

advanced biofuels that cuts investments to increase production capacity. In this way, RVOs that dePage 5 of 15
emphasize advanced biofuels effectively close opportunities to investment in developing advanced 

biofuels and can undermine the value of prior investments made to advance the policy. 

On the one hand, the presence of this dynamic is generally a positive sign, indicating that RIN markets 

are responsive to RFS policy signals to increase the supply of fuels with improved environmental 

performance (e.g., advanced biofuels). At the same time, it means that the role of advanced biofuels 

must be consistently emphasized within the implementation framework and associated RVOs in order to 

realize the environmental benefits and policy objectives associated with advanced biofuels.

This is a dynamic that I witness first-hand in my efforts to develop low emission energy systems—capital 

investments flow into and away from advanced biofuel production according to the expected RVOs. As 

a result, industry’s ability to invest in low emission advanced biofuels depends on the RVOs and broader 

implementation framework that EPA adopts. Adopting the RVOs and implementation framework 

proposed in the NPRM, which effectively de-emphasize advanced biofuels, will substantially reduce my 

ability—and the ability of industry as a whole—to commercialize production of low emission advanced 

biofuels. 

In addition, the ability for diverse types of emerging renewable fuels to qualify as advanced biofuels 

ensures a competitive market for satisfying advanced biofuel RVOs, thereby enhancing the policy’s 

economic efficiency. The NPRM notes the flexibility resulting from the ability of biodiesel to compete 

with other advanced biofuels in satisfying the advanced biofuel RVOs (Pp 71753). It does not, however,

discuss the broader implications of this flexibility for setting and satisfying advanced biofuel RVOs, which 

can be met with a variety of fuel types. Some are currently available in large volumes (e.g., biodiesel 

and sugarcane ethanol), while others are more emergent (e.g., reduced emission sorghum ethanol, 

reduced emission butanol, renewable diesel, renewable CNG, etc.). This diversity ensures a competitive 

market for supplying advanced biofuels. 

In addition to enhancing the policy’s economic efficiency, this competitive environment also provides a 

clear market opportunity for innovation in supplying advanced biofuels. The marginal costs of supplying 

advanced biofuels that are currently available in large volumes (e.g., biodiesel and sugarcane ethanol) 

set a clearly defined target for emerging advanced biofuels. Adopting RVOs that maintain pressure to 

supply these currently dominant fuel types ensures that RIN markets accurately reflect marginal costs of 

production, thereby providing a meaningful price signal to developers of emergent advanced biofuels. 

Reducing the RVOs from such levels collapses the premium value of advanced biofuels, which creates

slack in the market, obscures the market-clearing price, and effectively distorts the price signal for 

developers of emergent fuel supplies. In this way, RVOs that emphasize advanced biofuels provide 

critical support for emerging renewable fuels, even if they are initially satisfied with currently dominant 

sources of biodiesel and sugarcane ethanol. 

For these reasons, I respectfully suggest that EPA adopt RFS RVOs that maintain consistently strong 

incentives for advanced biofuel production. Such incentives are important for supporting sustained

investments in innovative production systems that advance the underlying policy objectives. 

More broadly, I suggest that the framework adopted by EPA to put the RFS on a “manageable 

trajectory” reflect a strong and increasing emphasis on innovation in supplying advanced biofuels. 

Specific suggestions for how this might be operationalized with respect to the proposed 2014 RVOs are 

provided in the comments and recommendations below.

Page 6 of 15
The “manageable trajectory” adopted by EPA should be reflected in the rulemaking processes for

establishing new fuel pathways. The notion of establishing a “manageable trajectory” for the RFS is an 

important one, and one that should be reflected throughout EPA’s implementation of the policy. There 

are many areas where this notion could be applied. The processes for establishing new fuel pathways

stand out as being particularly relevant and suitable for applying this principle in clear, actionable ways.

Establishing new fuel pathways represents a critical aspect of the RFS. It enables fuels to contribute 

toward the volumetric mandates and is a key step in commercializing new renewable fuel production 

systems. It is a prerequisite for accessing RIN markets, which provide economic incentives for fuel 

production, and as a result it can be a key factor in financing development of novel production 

systems—from research through commercial deployments. Uncertainty in the ability to qualify a fuel

under particular renewable fuel categories can substantially compromise development efforts. 

Therefore, accelerating the process for establishing new renewable fuel pathways—particularly those 

capable of making substantial contributions to near-term volumetric targets—could substantially 

accelerate commercial production of fuels that advance the underlying policy objectives. This could 

provide important contributions toward putting the RFS on a “manageable trajectory.”

Accelerating petition processing requires a strategic approach by EPA due to the resource intensity and 

administrative demands associated with lifecycle assessment and related analytic requirements. There 

is no substitute for diligent analysis and the potential benefits of accelerated processing do not justify 

compromises in technical rigor. That said, at least two strategies may help accelerate EPA’s petition 

processing and better align EPA’s efforts in this process with the stated intent of establishing a 

“manageable trajectory” for the program. 

The first strategy is to incorporate industry-developed lifecycle assessments of proposed fuel production

systems within petition processing, so long as those assessments are consistent with and appropriately 

leverage EPA’s considerable analytic effort to date. Industry has substantial capacity to conduct 

technically rigorous analysis, including lifecycle assessments of potential renewable fuel pathways. EPA 

could leverage this capacity by enabling industry to develop lifecycle assessments of fuel production 

according to novel pathways using assessment methods and assumptions appropriate to EPA’s petition 

processing requirements. While EPA’s framework for assessing lifecycle impacts of feedstock supply 

may not lend itself to industry analysis, lifecycle assessment of the biofuel production stage can arguably 

be developed as credibly by industry as by EPA staff. This approach has been adopted by California’s Air 

Resources Board in implementing the lifecycle assessment requirements of the California Low Carbon 

Fuel Standard. California’s experience to date suggests that the approach can be effective in leveraging 

relatively limited agency resources to provide technically rigorous lifecycle assessments for many 

potential fuel pathways. 

EPA could adopt a similar approach, in which industry is encouraged (or perhaps even required) to 

develop lifecycle assessments of proposed fuel production systems as part of a petition to EPA. EPA 

staff could then critically evaluate the industry-developed assessment to ensure it is consistent with 

EPA’s requirements and analyses to date. Upon the satisfaction of EPA’s staff regarding the methods, 

assumptions, and technical rigor of industry-developed assessments, the results could be integrated 

with results of EPA’s internally developed lifecycle assessments of feedstock supply.

This approach could be facilitated by adopting a specific lifecycle modeling framework for assessing the 

fuel production process, such as the GREET model, which EPA adopted for determining emissions factors 

Page 7 of 15
within its established lifecycle assessment framework. Industry-developed assessments could then be 

required to clearly specify any modifications to the standard model that are required to effectively 

characterize the fuel production process of interest. This would substantially simplify EPA’s critical 

review of industry-developed lifecycle assessments. 

The benefit of this approach is that it would limit EPA’s analytic requirements of specific production 

systems to critically reviewing industry-developed analyses. While this is a non-trivial task, it is 

substantially less resource-intensive than developing original assessments for each potential fuel 

pathway. As a result, this approach could substantially increase the processing capacity of EPA’s existing 

analytic staff and consequently accelerate petition processing. 

The second strategy is for EPA to prioritize petitions for processing according to the scale of potential 

contributions toward volumetric mandates (in addition to the expected time to commercialization). EPA 

has a considerable backlog of petitions to evaluate and process. This is understandable, given the 

unlimited number of potential fuel pathways and the substantial resources requirement to develop

assessments with the appropriate technical rigor, as discussed above. In this context it is sensible that

EPA prioritize petition processing according to particular attributes of the proposed fuel pathways. The 

regulation currently stipulates that petitions for fuel pathways that are “...closer to the commercial 

production stage than others” be prioritized (EPA. 2010. Final Rule. Pp 14681). This criterion is 

appropriate, but not sufficient for putting the program on a “manageable trajectory,” because it may 

prioritize fuel pathways that can be commercialized in the near term, but are not capable of producing 

fuels in the quantities required to achieve the policy’s proximate volumetric targets or to substantially 

advance the underlying policy objectives. For this reason, I respectfully suggest that EPA prioritize fuel 

pathway petitions according to both the expected time to commercialization and the scale of potential 

contributions to volumetric targets.

Comments on supply constraints recognized in the proposed rulemaking

(Per requests on pages 71734, 71754, and 71778)

A substantial portion of the NPRM, and a key aspect of the proposed framework for putting the RFS on a 

“manageable trajectory,” relates to the E10 blendwall, which refers to the ethanol volume equivalent to 

blending all gasoline with 10% ethanol by volume. The E10 blendwall has been an important 

consideration in the context of the RFS at least since the program amendments in EISA2007. While the 

E10 blendwall may be reached earlier than originally envisioned, EPA’s current expectations (as 

indicated in the NPRM) appear to be consistent with those indicated in the Regulatory Impact Analysis 

dated February 2010, which projected the E10 blendwall to be reached in the 2013 to 2015 timeframe 

(EPA 2010. Figure 1.7-3).

Overcoming the E10 blendwall is an important milestone toward achieving the policy objectives

underlying the RFS. Scaling up renewable fuel supplies to the levels originally envisioned is only possible 

if the E10 blendwall is overcome, and leveraging such renewable fuel production to advance climate and 

other important policy objectives similarly requires overcoming the E10 blendwall. Reducing volumetric 

mandates to levels below the E10 blendwall, and codifying this approach in the implementation 

framework moving forward would therefor substantially compromise the ability to continue advancing

the underlying policy objectives. Such an approach would effectively remove all policy incentives for 

developing the strategies required to overcome the E10 blendwall. It would risk creating a self-fulfilling 

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prophecy, locking the country into a future falling far short of the regulatory intent, and truncating our 

ability to effectively advance the underlying objectives.

For these reasons, I respectfully submit that the framework adopted by EPA to implement the RFS 

moving forward should embody the following attributes:

1. It should maintain strong incentives for overcoming the E10 blendwall, as this is a prerequisite 

to advancing the underlying policy objectives;

2. It should be achievable even if the blendwall represents a binding near-term constraint on 

ethanol consumption; and

3. It should maintain strong incentives for developing innovative systems for producing renewable 

fuels that advance the underlying objectives.

RVOs for advanced biofuel represents a potentially important policy tool for accomplishing this in a way 

that is consistent with the comments provided above. A variety of factors support this view, including:

 Advanced biofuel volumes can be met with advanced ethanol or a variety of non-ethanol 

advanced biofuels that are unaffected by the E10 blendwall (e.g., biodiesel, butanol, and 

compressed natural gas produced from renewable feedstock);

 Many types of advanced biofuel produce more than one “ethanol-equivalent” gallon for every 

physical gallon supplied (e.g., one gallon of biodiesel yields 1.5 ethanol-equivalent gallons),

which provides additional leverage from available production capacity; 

 There is substantial under-utilized production capacity for advanced biofuel (the NPRM projects 

2013 biodiesel production below 1.8 billion gallons despite a total capacity of 3.6 billion gallons), 

which supports substantially increasing volumetric targets; 

 There is substantial potential to convert biorefineries from producing conventional biofuels to 

advanced biofuel (e.g., ethanol plants to butanol production and corn ethanol plants to sorghum 

ethanol), which provides opportunities to realign private capital investments; and

 There are a wide variety of pathways for producing advanced biofuels, providing an inherently 

competitive market for ongoing innovation to advance the underlying policy objectives.

Taken together, these factors suggest that RVOs for advanced biofuels can provide incentives to 

advance the underlying policy objectives and overcome the E10 blendwall, while providing enough 

flexibility to enable compliance even if the E10 blendwall represents a binding constraint. For example, 

the advanced biofuel RVO might be set near the upper end of the range that might be “reasonably 

achievable” using non-ethanol advanced biofuels, recognizing that these fuels would compete with 

advanced ethanol (i.e., ethanol qualifying as and advanced biofuel), to the extent increasing ethanol 

volumes can be delivered as E15 or E85. The availability of substantial excess biodiesel production 

capacity, the potential for ethanol plant retrofits (e.g., to butanol), and the potential for other advanced 

biofuels supports a robust, diverse, and competitive market for meeting ambitious volumetric targets.

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Comments on EPA’s approach to setting the advanced biofuel volumetric mandates 

(Per requests on page 71738) 

The advanced biofuel category is particularly important for advancing the underlying policy objectives. 

As noted above, it is designed to do much of the “heavy lifting” in that regard by providing continued

growth, diversity, innovation, and climate benefits in renewable fuel supplies. Industry’s ability to invest 

in advancing these policy objectives depends directly on the RVOs and on market expectations for the 

RVOs, as noted above.

In this context, I respectfully submit that RVOs should retain the policy’s strong and increasing emphasis 

on developing advanced biofuels.

The NPRM highlights the merits of a strong and growing role for advanced biofuels (Pp 71774), which I 

broadly support. I have two general observations regarding the framework proposed in the NPRM for 

defining advanced biofuel RVOs that are relevant in this context. The first is that the proposed 

framework for defining RVOs appears to codify a long-term preference for “conventional” ethanol above

advanced ethanol, which seems to be inconsistent with the policy’s objectives and legislative intent. 

The second is that the analysis used to define biomass-based diesel supplies toward achieving the

advanced biofuel RVO is not representative of the volume that “could reasonably be achieved” (NPRM 

Pp 71752), for reasons specified in the NPRM (NPRM Pp 71752-71753 and 71762-71766), and therefore 

does not appear to provide a reasonable basis for defining advanced biofuel RVOs consistent with the 

intent noted above, the legislative intent, or underlying policy objectives. These comments are 

discussed further below, after which an example is provided for how 2014 RVOs might be defined in a 

manner that seems on its face to be more consistent with both the principles discussed above and with 

the intent underlying the general approach recommended in the NPRM.

The proposed framework for defining RVOs appears to codify a long-term preference for “conventional” 

ethanol over advanced ethanol. Under the RFS, ethanol can be supplied within three different 

renewable fuel categories, depending on how it is produced: cellulosic biofuel (i.e., ethanol from 

cellulosic feedstock); non-cellulosic advanced biofuel (e.g., ethanol from grain sorghum or sugarcane); 

and “conventional” renewable fuel (including ethanol from a variety of feedstock types). As a result, the 

RVOs (and differences between the RVOs) for these fuel categories reflect an implicit allocation of 

ethanol production volumes across them. The implications of this allocation are substantially magnified 

under the approach recommended in the NPRM, which aims to accommodate challenges from the E10 

blendwall by systematically reducing the RVOs from the legislated targets.

Relevant aspects of the proposed approach are detailed on pages 71754 and 71775 of the NPRM, but 

are effectively summarized on page 71738 as follows:

“For total renewable fuel, we would project the volume of ethanol that could 

reasonably be consumed as E10 and higher ethanol blends, and would add to that the 

volume of all non-ethanol renewable fuels that could reasonably be expected to be 

available. For advanced biofuel, we would sum the ethanol-equivalent volumes of the 

cellulosic biofuel requirement [including cellulosic ethanol], the biomass-based diesel 

requirement, and the additional non-ethanol advanced biofuel that could reasonably be 

expected to be available and consumed.” [NPRM Pp28]

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As this excerpt indicates, the total renewable fuel RVO would account for all of the ethanol that is 

capable of being supplied within the constraints of the E10 blendwall, while the advanced biofuel RVO 

accounts only for ethanol provided as cellulosic biofuel. While excluding non-cellulosic advanced 

ethanols from the determination of the advanced biofuel RVO does not prevent them from contributing 

toward the mandate, it implies that there will be little room for them to contribute toward the RVOs 

once the separately mandated cellulosic and biomass-based diesel portions are satisfied. As a result, 

excluding non-cellulosic advanced ethanol from the determination of the advanced biofuel RVO 

implicitly allocates all ethanol supplied within the E10 blendwall into either the cellulosic biofuel 

category or the non-advanced “conventional” category. This implies preferences for ethanol as follows:

Cellulosic ≻ Conventional ≻ Advanced

A potential benefit of adopting this approach is to maximize the volume of conventional renewable fuels 

that can contribute to the total renewable fuel RVOs in the near term. This may be important for

preserving the value of capital already deployed to advance the RFS and for supporting continued 

investments to advance the underlying policy objectives, as discussed above. 

However, embedding this approach into the longer-term implementation framework adopted to put the 

RFS on a “manageable trajectory” risks codifying these preferences over the long term. This would 

effectively remove incentives for developing advanced biofuel ethanol and for continuing progress 

toward the underlying policy objectives (e.g., reductions in greenhouse gas emissions). As such, 

codifying such preferences would be inconsistent with the policy’s objectives and legislative intent, as 

articulated in the NPRM (NPRM Pp 71774).

With this in mind, I respectfully suggest that the framework adopted to put the RFS on a “manageable 

trajectory” reflect a progressive transition toward preferences for ethanol as follows:

Cellulosic ≻ Advanced ≽ Conventional

Or

Cellulosic ≻ Advanced ≻ Conventional

A rapid transition to such preferences may not be appropriate, given the intent to reduce total RVOs in 

response to challenges associated with the E10 blendwall, as this could substantially compromise 

private capital investments made in good faith to advance RFS policy objectives. However, it would be 

reasonable to embed a progressive transition toward these preferences in the framework adopted to 

put the RFS on a “manageable trajectory.” A transition toward advanced biofuels, even under a binding 

E10 blendwall, could support the growing set of options available for converting installed capital from 

producing “conventional” biofuels to advanced biofuel (e.g., butanol or sorghum ethanol with reduced 

carbon emissions) and advance associated policy benefits. Codifying a transition toward the suggested 

ethanol preferences could therefore signal the private sector to begin realigning installed capital 

without undermining prior investments made in good faith to advance the policy. 

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Implementing the recommended ethanol preferences could be accomplished by setting the advanced 

biofuel RVO at a level that reflects a fraction of the potentially available volume of advanced biofuel 

ethanol. The proposed 2014 RVOs include 0% of the potentially available supply in the advanced 

biofuels RVO (implying a strict preference for “conventional” ethanol). In contrast, including 100% of 

potentially available advanced ethanol supply within the advanced biofuel RVO would imply a strict 

preference for advanced ethanol. A progressive transition in ethanol preferences could be achieved by 

incrementally increasing the fraction of potentially available advanced ethanol that is included in each 

year’s advanced biofuels RVO.

This approach would be more consistent with the general approach proposed in the NPRM. It reflects 

the availability of advanced biofuels and the constraints associated with the E10 blendwall, stated 

objectives of the proposed approach (NPRM Pp 71775), and it reflects broader policy objectives and 

legislative intent to progressively increase supplies of advanced biofuels (NPRM Pp 71774). It is also 

broadly consistent with the balance of comments provided above.

The RVO for biomass-based diesel is not representative of the volume that can reasonably be achieved 

and therefore does not provide an appropriate basis for defining the advanced biofuel RVO. The NPRM 

describes considerable analysis by EPA regarding the factors relevant to defining the RVO for biomassbased diesel (e.g., NPRM Pp 71751-71754). In particular, this section discusses a variety of factors 

supporting the proposal to set biomass-based diesel RVOs for 2014 and 2015 below the volumes that 

could reasonably be achieved, including:

 The statutory minimum volume of 1 billion gallons;

 The statutory timing requirements for promulgating new volume requirements;

 The flexibility inherent to utilizing biodiesel production in excess of the biomass-based diesel 

RVO in order to meet the advanced biofuel RVO; and

 The uncertainty in expected biodiesel production volumes due to potential changes in the tax 

code (i.e., potential termination of the biodiesel tax credit).

These factors appear to be reasonable in the context of the biomass-based diesel RVO, with the possible 

exception of potential changes to the biodiesel tax credit. Prospective changes in the tax code could 

impact the economics of biodiesel supply, and therefore the volumes that might reasonably be available 

absent the RFS; however, they do not, on their face, appear capable of changing “. . . the volumes of all 

sources of advanced biofuel that could reasonably be achieved. . .”, which is the stated intent for 

defining advanced biofuel RVOs (NPRM Pp 71754). They cannot reduce biodiesel production capacity 

that is currently available, and they cannot change the volume that can be consumed by the current 

vehicle fleet. Moreover, the RFS is specifically designed to provide economic incentives for increasing 

renewable fuel production, irrespective of other policy instruments. In this context, it seems difficult to 

justify interpreting the definition of “reasonably achievable” volumes to be contingent upon unrelated 

changes in the tax code.

On this basis, I respectfully submit (in response to the request for comments on page 71763 of the 

NPRM) that changes in the biodiesel tax credit should not be considered in EPA’s projection of biodiesel 

volumes that could be available in 2014 or beyond.

Excluding potential changes in the biodiesel tax credit from EPA’s consideration does not necessarily 

affect the conclusions presented in the NPRM for biomass-based diesel RVOs, but would impact 

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conclusions for advanced biofuel RVOs. The other factors noted above may continue to support setting 

RVOs for biomass-based diesel in 2014 and 2015 below the volume that could reasonably be achieved,

but neither the statutory minimum volume for biomass-based diesel, nor the statutory timing 

requirements noted above, appear relevant to RVOs for advanced biofuels or total renewable fuels. 

The inherent flexibility from biodiesel’s ability to contribute toward advanced biofuels and total 

renewable fuel RVOs, above and beyond the biomass-based diesel RVOs, supports higher estimates of 

reasonably achievable volumes for these categories than is proposed for biomass-based diesel. Note 

that EPA’s analysis of the potential “biodiesel blendwall” indicates that at least 2.7 billion physical 

gallons of biodiesel (2.8 billion gallons, less 3% due to cold weather constraints, equivalent to 4.1 billion 

ethanol-equivalent gallons) could be consumed by the existing vehicle fleet (NPRM Pp 71764-71765). 

This is substantially greater than projected production volumes, yet it remains substantially below the 

current biodiesel production capacity of 3.6 billion physical gallons (NPRM Pp 71763). Moreover, the 

variety of fuel types eligible to qualify as advanced biofuels—including advanced biofuel ethanol, 

butanol, renewable compressed natural gas, etc.—suggests that adopting advanced biofuel RVOs that 

are higher than proposed in the NPRM would support a competitive environment for advanced biofuels. 

This provides meaningful incentives to continue innovation toward advancing the underlying policy 

objectives.

On this basis, I respectfully submit (in response to the request for comments on pages 71734, 71738,

and 71763 of the NPRM) that the RVOs for total renewable fuels and advanced biofuels reflect the 

volumes of biomass-based diesel that can reasonably be achieved, without regard to either the biomassbased diesel RVO or to the fate of the biodiesel tax credit.

Example of 2014 RVO calculations consistent with the general approach proposed in the NPRM and 

with the recommendations provided in these comments.

The comments in this section provide an example of one way that the recommendations provided in 

these comments might be integrated with the general approach proposed in the NPRM to determine 

2014 RVOs. It is intended to illustrate how the various principles discussed above might be translated 

into RVOs, but it is not a recommendation for specific RVO values.

Implementing the recommendations above regarding the advanced biofuel RVO might imply adopting a 

range for achievable biomass-based diesel supply in the range of 1.6 to 2.7 billion physical gallons. 1.6 

billion gallons reflects the minimum projected supply in 2013. There is no reason to think that at least 

this much biodiesel cannot be delivered in 2014 as well. 2.7 billion gallons reflects the maximum 

volume that might be supplied in light of EPA’s assessment of the biodiesel blendwall (NPRM Pp 71764-

71765). This may be viewed as the binding constraint on supply, given total production capacity of 3.6 

billion gallons and falling feedstock prices (NPRM Pp 71764). This range in physical volumes of biodiesel 

is equivalent to between 2.4 and 4.1 billion ethanol-equivalent gallons. 

Adding this estimate of available biomass-based diesel to EPA’s estimated range for domestic nonethanol advanced biofuel available in 2014 of 24-132 million gallons (NPRM Pp 71776), implies a 

potential range for non-ethanol advanced biofuels of 2.4 to 4.2 billion ethanol-equivalent gallons. 

Adding to this estimate a volume equivalent to some portion (between 0% and 100%) of the 328 to 942 

million gallons of non-cellulosic advanced ethanol biofuels potentially available in 2014—in order to 

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signal a transition in ethanol preferences, as noted above—implies a potential range for the 2014 

advanced biofuel RVO of 2.4 to 5.2 billion ethanol-equivalent gallons. (2.4 billion gallons allocates zero 

non-cellulosic ethanol to the advanced biofuel pool. 5.2 billion gallons allocates 100% of the maximum 

volume EPA determined to be potentially available non-cellulosic advanced ethanol to advanced 

biofuels.)

According to the approach proposed in the NPRM, the RVO for total renewable fuels would be defined 

by adding the estimated volumes of cellulosic biofuels, biomass-based diesel, and other non-ethanol 

advanced biofuels to EPA’s estimate for total ethanol consumption for 2014, which is in the range of 

12.95 to 13.09 billion gallons (NPRM Pp 71762). This approach implies an RVO for total renewable fuels 

in the range of 15.4 to 17.2 billion ethanol-equivalent gallons, ignoring any potential adjustments to 

EPA’s estimate of total ethanol consumption that may be appropriate. These results are summarized in 

the table below.

Table 2. Example 2014 RVO ranges consistent with the general approach proposed in the NPRM and 

with the recommendations provided in these comments.

Proposed requirement for cellulosic biofuels 8 – 30 million gallons

Proposed requirement for biomass-based diesel 1.28 million gallons (1.92 ethanol-equivalent 

gallons)

Available volume of excess biomass-based diesel 0.32 – 1.44 billion gallons (0.48 – 2.15 billion 

ethanol-equivalent gallons)

Available volume of domestic non-ethanol 

advanced biofuel

24 – 132 million ethanol-equivalent gallons

Available volume of advanced ethanol (domestic 

ethanol and sugarcane ethanol imports)

328 – 942 million gallons

Total available volume of advanced biofuels 2.7 – 5.2 billion ethanol-equivalent gallons

Proposed requirement for advanced biofuels 2.4 – 5.2 billion ethanol-equivalent gallons

Total renewable fuels 15.4 – 17.3 billion ethanol-equivalent gallons

Note that the example ranges for advanced biofuels and total renewable fuels in Table 2 are 

systematically higher than those recommended in the NPRM Table I-2. This results from adopting 

ranges for biomass-based diesel supply that reflect reasonably achievable volumes, based on 

information provided in the NPRM, but excluding consideration of potential changes in the tax code and 

other issues that are specific to the biomass-based diesel RVO (rather than the advanced biofuel RVO). 

It also reflects allocating some portion (0% to 100%) of potentially available advanced ethanol to 

advanced biofuels in defining the advanced biofuel RVO.

The ranges presented in this example support RVOs that could provide the following benefits:

1. Support capital investments made to advance the policy’s success by minimizing absolute 

reductions from 2013 RVO levels;

2. Provide incentives for increasing development of advanced biofuels, which would:

a. Provide incentives for continued innovation to advance the underlying policy objectives, 

even absent absolute increases in renewable fuel production;

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b. Maintain pressure on the E10 blendwall, through potential supplies of advanced 

ethanol, while enabling compliance if the blendwall is not overcome;

c. Signal the private sector to begin realigning installed capital, where appropriate, toward 

advanced biofuel production;

The ranges in this example do not reflect recommendations regarding fuel pathway petitions to 

accelerate EPA’s processing and to better align EPA’s efforts with its intent to provide a manageable 

trajectory for the policy. This might increase the volumes EPA estimates for potentially available 

advanced biofuels.

Thank you again for the opportunity to share comments as part of EPA’s rulemaking process. I look 

forward to continuing to work with the agency on low-emissions energy systems that support the 

nation’s 21st century energy and environmental goals.

With kindest regards,

James S. Rhodes

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