National Academy of Sciences
National Academy of Engineering
Institute of Medicine
National Research Council
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At A Glance
 
Testimony
: Experimental Energy Efficient Automobile
: 06/06/2002
Session: 107th Congress (Second Session)
: Vernon P. Roan
Credentials:

Professor of Mechanical Engineering and Director of the Fuel Cell Training and Research Laboratory, University of Florida, and Vice-Chair, Standing Committee to Review the Research Program of the Partnership for a New Generation of Vehicles, Transportation Research Board and National Research Council, The National Academies

: House
: Committee on Energy and Commerce

A Brief Summary of Relevant Findings and Comments From the NRC PNGV Peer Review Committee
7th Report

Testimony of

Vernon P. Roan
Professor or Mechanical Engineering
and
Director of the Fuel Cell Training and Research Laboratory
University of Florida

And
Vice-Chairman
Standing Committee to Review the Research Program of the Partnership for a New Generation of Vehicles
Transportation Research Board and National Research Council
The National Academies

before the

Oversight and Investigations Subcommittee
Energy and Commerce Committee
U.S. House of Representatives

on the

FreedomCAR

June 6, 2002

The following is a brief summary of some of the Peer Review Committee comments and findings felt to be relevant to the Committee on Energy and Commerce FreedomCar hearings.

The Partnership for a New Generation of Vehicles (PNGV) was initiated on September 29, 1993, as a cooperative research and development (R&D) program between the federal government and the United States Council for Automotive Research (USCAR). The PNGV goals and basis for National Research Council (NRC) reviews, in summary, are:

Goal 1. Significantly improve national competitiveness in manufacturing for future generations of vehicles.

Goal 2. Implement commercially viable innovations from ongoing research on conventional vehicles.

Goal 3. Develop vehicles to achieve up to three times the fuel efficiency of comparable 1994 family sedans. (this goal implies up to 80 mpg)

The PNGV declaration of intent requires an independent peer review "to comment on the technologies selected for research and the progress made."

The review and reports focused on assessments of 1) the overall balance and adequacy of the research program to meet the technical goals and 2) efforts to develop commercially feasible low emission propulsion systems.

Goals 1 and 2 are qualitative in nature, but goal 3, in addition, to the technical targets, included time milestones calling for the development concept vehicles by the year 2000 and production prototype cars by 2004.

The Seventh Report of "Review of the Research Program of the Partnership for a New Generation of Vehicles" presents the latest findings and recommendations by the review committee. It is impractical to summarize all relevant findings from the report since to do so would essentially require reproducing the entire report. Therefore, the following material represents a brief summary, including a few excerpts from findings and recommendations, felt to be pertinent for the issues being currently considered.

The committee believes that the PNGV program has established a unique and a valuable framework for directing closely coordinated industry and government research efforts towards the development of technologies capable of solving important societal problems.

The year 2000 concept-vehicle milestone (for Goal 3) was met when the three manufacturers each introduced concept cars: the Daimler-Chrysler ESX3, the Ford Prodigy, and the General Motors Precept.

All three vehicles incorporated hybrid-electric power trains designed around small, turbocharged, compression-ignition, direct-injection (CIDI) engines, using diesel fuel. All three employed significant technical advances (reduced mass, improved aerodynamics, reduced auxiliary loads) developed in the PNGV program.

The committee believes that no reasonable amount of funding would ensure achievement of all aspects of Goal 3, including 80 mpg (and cost), and that has been clear for some time. Breakthrough ideas and talented people are more stringent constraints than money in achieving this goal.

The CIDI engine operating on diesel fuel continues to be the major focus of PNGV power plant development for near term application. Current PNGV activity centers on the challenge of meeting new emission standards and is being pursued in engine combustion, exhaust-gas after treatment, and fuels development programs.

Fuel cells continue to show promise of high efficiency and very low emissions with continuous progress towards targets that are very difficult to meet for any general-purpose, high-volume automotive application.

The PNGV concept vehicles made public (in the year 2000) made extensive use of lightweight materials and new body construction techniques to achieve major reductions (20 to 31 percent) in curb weight. The high cost of these lightweight materials and the associated manufacturing costs represent a significant part of the affordability challenge faced by the program.

High prospective cost is a serious problem in almost very area of the PNGV program.

As noted earlier, affordability is the linchpin of the PNGV program. For the benefits PNGV intended to be realized, the economics must favor large-scale purchases of these vehicles.

From the inception of PNGV, practical automotive fuel cell power plants have been considered to be well beyond the 2004 time limit of the program. Nevertheless, because of their potential for high-energy efficiency and no onboard emissions of any regulated pollutants when using hydrogen as a fuel, the development of these systems has remained a major part of PNGV.

The original targets for the year 2000 for the fuel cell systems were not met---the dates for meeting these targets should be extended substantially. Size and weight need to be reduced by at least a factor of two (to meet 2004 targets) and (projected) cost is roughly six times the target value (for 2004 PNGV-type vehicles).

The need to reduce fuel consumption and carbon dioxide emissions of the U. S. automotive fleet is more urgent than ever. Since 1993 (when the PNGV was formulated) there has been a 20% increase in the petroleum used in highway transportation, the percentage of U. S. petroleum from imports has risen to 52 percent----.----- during this time (since 1993) the demand for SUV’s, vans, and pickup trucks in the U. S. has drastically increased ----- now make up 46 percent of new light-duty vehicle sales (note, it was recently announced that for the past year they exceeded 50 percent).

In view of these facts and as a new energy policy is being developed for the nation, it is the committees belief that priorities and specific goals of the PNGV program should be reexamined.

Recommendation. Taking into account the successes, degree of progress, and lessons learned in the PNGV program to date, government and industry participants should refine the PNGV charter and goals to better reflect current societal needs and the ability of a cooperative, precompetitive R&D program to address these needs successfully.

Recommendation. The PNGV should continue the aggressive pursuit and development of lean-combustion exhaust-gas after-treatment systems.

Recommendation. Because of the potential for near-zero tailpipe emissions and high-energy efficiency of the fuel cell, the PNGV should continue research and development efforts on fuel cells even though achievement of performance and cost targets (simultaneously) will have to be extended substantially beyond original expectations.

Recommendation. Because affordability is a key requirement ----- the committee believes that more attention should be paid to the design and manufacturing techniques being worked up by the American Iron and Steel Institute in the Ultralight Steel Auto Body Advanced Vehicle Concept Project.

Recommendation. High priority should be given to determining what fuel sulfur level will permit the preferred compression-ignition direct-injection (CIDI) engine and its after-treatment system to meet all regulatory and warranty requirements.

The power train with the highest probability of meeting the vehicle fuel-economy target of 80 mpg by 2004 is the hybrid-electric power train powered by a CIDI engine. (It was pointed out, however, that the EPA tier 2 emission standards for NOx and particulates promulgated in 1999 ---- brought into question the possibility of meeting these new requirements in a CIDI production prototype engine by 2004).

From all the evidence the committee has seen during past reviews, the cost premium of a PNGV-type vehicle with a fuel economy close to 80 mpg will likely be several thousand dollars more than a competing conventional vehicle.

In the committees view the PNGV program has been a success largely because:

The committee indicated that it believed that future activity could benefit from:

Other questions posed: note: The following questions were not specifically addressed by the panel and the responses represent my personal opinions.

What were the advantages and disadvantages of PNGV having an explicit goal of a deliverable product integrating a variety of technologies, i.e. a mid-size sedan that would get up to 80 miles per gallon? Regardless of whether the particular goal of PNGV was appropriate, how important is it that government-industry partnerships have a concrete, integrated deliverable product as a goal?

I believe that in the early stages of the PNGV, there were big advantages to having such an explicit goal. This approach allowed quantification of potential energy-efficiency benefits associated with:

• mass reduction

• aerodynamic improvements

• auxiliary load (heating, A/C, power steering, etc.) reduction

• power plant energy conversion efficiency

• system configuration and optimization

• on-board energy storage systems

It also allowed approximate "sizing" of major components for many vehicle configurations and system options with a result that all technology developers were working towards common goals. In short, it provided much needed focus and consistency to the early analysis and development efforts.

The major disadvantages, in my opinion, were:

• The targeted "family" car was a very price-competitive vehicle with good fuel mileage (~27 mpg) and several generations of evolution to reduce mass and otherwise increase fuel efficiency. Thus, it was a very difficult "target" vehicle.

• Now (as at the beginning of PNGV) fuel expense represent a relatively small fraction of the cost of owning a family car, and as such there is little incentive for a buyer to choose fuel economy as a high priority item.

• ·In some ways, the fixation on 80 mpg detracted attention from the original primary objectives of reducing U. S. petroleum consumption and reducing CO2 emissions.

• Due to the shift in car sales away from family sedans and towards SUV’s and light trucks, more petroleum could be saved with a smaller fuel efficiency increase if these larger vehicles were targeted.

All things considered, however, I believe that the original Goal 3 was a reasonable and proper approach, especially at the time the program was initiated.

I think that is now less important that the government-industry partnerships have a concrete, integrated deliverable product as a goal than it was at the beginning of PNGV. However, I still believe that the best way to achieve consistency and to minimize confusion during technology development is to have a common focus.

2. Did PNGV focus too much on shorter-range research on technologies that were already in reach? If so, what areas of research were neglected? What is the appropriate balance between shorter- and longer- term in the research portfolio of a government-industry

partnership?

I think that very little of government-supported research focused on technologies that were already in reach. On the other hand, with the exception of the fuel cell, most technologies perceived to be significantly beyond the 1994 timeline were not retained in the active

program.

While I don’t know of any areas of research that were totally neglected, there are some which might justify more priority on the basis of a longer-term approach, such as:

In my opinion, the appropriate balance between shorter- and longer- term research in this context, is that priority should be given to research that has clear societal benefits but would not likely be successfully pursued by industry alone. For the most part, I believe that this translates into a combination of higher risk and/or longer term research. I hesitate to put numbers on the distribution since it must be put in context, but typically, I think that more than half of the effort should be for the longer term activities.

3. What areas of research should the government focus on to move toward a hydrogen-based transportation system? To what extent did PNGV focus on those areas? Is it more important for the government to invest in areas related to vehicles or in areas related to the distribution system and other ancillary areas that could stall a shift to fuel cells?

There are three major areas of fuel availability-related (as opposed to utilization related)research areas to move towards hydrogen-based transportation

1) Hydrogen production. Currently, essentially all hydrogen is produced from steam-reforming of natural gas. Further, this is an endothermic process resulting in the heating value of hydrogen obtained being less than that of the feedstock natural gas. Additional energy is required for compression or liquification as well as for transportation. For large scale hydrogen production, a large new supply of national gas or other primary feedstock would be needed if production techniques are used.

The dissociation of water to produce hydrogen utilizes an almost unlimited supply of feedstock, but the electrical energy required to produce a unit of hydrogen is at least double that of the electrical energy which would be produced by consuming that unit of hydrogen in a fuel cell. Consequently, innovative and inexpensive primary energy sources, such as renewables or perhaps nuclear will have to be exploited to produce the hydrogen. Even with acceptable primary energy sources the total power requirements and production facilities, to replace even a fraction of current petroleum energy are staggering.

2) Infrastructure. For hydrogen-powered vehicles to be commercially viable, fuel must be readily available to the consumer, nationwide. There are currently perhaps around 200,00 refueling stations for gasoline. These refueling stations accommodate vehicles which have ranges in excess of 300 miles and can be refueled in minutes by persons with no expertise or training. Thus, it is likely that at least tens of thousands (perhaps many more) refueling sites for hydrogen, distributed all around the united States will be needed to support large-scale production and sale of hydrogen-powered vehicles. Since there is currently virtually no infrastructure to provide this capability, clearly some innovative infrastructure approaches are necessary.

3) Vehicle refueling and on-board storage of hydrogen. The energy density of hydrogen (energy stored-per unit of storage volume) is much less than for gasoline or other alternative fuels. For example, to store on-board the same energy available from the typical 16-gallon gasoline tank would require about a 200 gallon volume for compressed (5000 psi) hydrogen gas or about 60 gallons for liquid hydrogen (at -423F). Even if the on-board energy efficiency is assumed to be doubled (for a non-hybrid system) or tripled (for a hybrid system), the resulting volume of about 70 gallons for compressed hydrogen would likely present a severe challenge to vehicle designers. The use of liquid hydrogen would ease the storage volume problem, but producing liquid hydrogen is very energy intensive, and handling it at 423F presents obvious safety problems.

Materials such as metal hydrides or carbon fibers offer the potential for reducing hydrogen storage problems, but the design of practical systems with clear advantages over pressurized hydrogen are thus-far elusive. Clearly, some highly innovative approaches to improve the practicality of hydrogen from both refueling and on-board storage standpoints will be essential to the ultimate success of hydrogen-fueled vehicles.

PNGV did include some efforts in all of the areas mentioned above. However, the time-scale for a hydrogen-based transportation system was (and is) felt to be far beyond the 2004 milestone and even beyond the recommended extended milestone (~2008) for the PNGV fuel cell activities. It was felt that within these time frames, hydrogen-fueled fuel cell vehicles would likely be produced in small numbers and limited to fleet or otherwise carefully controlled operations (including maintenance and refueling) and would have limited range (less than 100 miles). As such, most of the PNGV efforts were directed towards technologies felt to be within the PNGV timeframes and applicable to the target vehicle.

I believe that it is important for the government to be active in all three of the research focus areas mentioned since each will likely require highly innovative approaches for realistic solutions. Further, there must be satisfactory approaches within the same timeframe for all three major issues if the hydrogen-fueled consumer vehicle is to be a reality.

Of the three issues, those related to the refueling and onboard storage will probably require the most new technology developments and should, therefore, be given the largest share of government resources. New hydrogen-absorbing materials, higher strength tank structural materials, conformable container concepts, better and/or less expensive approaches to compressing hydrogen, new leak detection devices, possible hydrogen odorants, automated refueling techniques, and many potential problem areas need much study and much innovation to reach satisfactory solutions.

The issues of appropriate feedstocks, production energy sources, centralized versus local production facilities, etc. will require comprehensive overall system studies with great emphasis on economics to determine the most practical approaches to providing massive amounts of transportation hydrogen.

Providing hydrogen distribution throughout the United States while meeting all local/state/federal licensing/safety/environmental requirements will also require many studies, also emphasizing economics. Central versus localized production, pipelines versus tank trucks (or other transportation), liquid versus gaseous versus absorption material for on site hydrogen storage, etc. are all major issues which must be dealt with in resolving infrastructure issues.

The government, especially by utilizing some of the impressive resources at the national laboratories can, and in my opinion, should, help resolve many of these critical issues.

Additional Comments on The Freedom Car

By

Vernon P. Roan, Ph.D., P.E.
Professor or Mechanical Engineering
and
Director of the Fuel Cell Training and Research Laboratory
University of Florida
and
Vice-Chairman
Standing Committee to Review the Research Program of the Partnership for a New Generation of Vehicles
Transportation Research Board and National Research Council

The National Academies

before the

Oversight and Investigations Subcommittee
Committee on Energy and Commerce
U.S. House of Representatives

June 6, 2002

These comments are presented as an addendum to the brief summary of relevant issues from the NRC 7th PNGV Peer Review Report that I have submitted to the Committee. I also refer the Committee to the complete report for additional information. This addendum is not based on any type of consensus from the PNGV Peer Review Committee but represents my own observations and opinions.

Since no specific questions have been presented to me by the Committee on Energy and Commerce, I will offer opinions which I think relate to the probable areas of consideration by the Committee, namely:

1. The appropriateness of emphasis on hydrogen and fuel cells for transportation-related energy visions of the future.

2. The viability of the proposed FreedomCAR program as an approach for directing government-sponsored research and development in support of long-range transportation energy goals.

With respect to the first area of consideration, the ultimate transition from fossil fuels to hydrogen as the primary chemical fuel is essentially inevitable. Fossil fuels represent a finite resource which will become increasingly more difficult and expensive to utilize. Further, it seems likely that other technologies competing for limited fossil fuel supplies (especially petroleum) such as for textiles, plastics, medicines, etc., might achieve a higher priority than simply burning the fuel to produce heat. Hydrogen, on the other hand, can be produced without consuming fossil fuels through the electrolysis of water by using non-fossil primary energy to produce the electricity. The non-fossil primary energy sources include hydro, wind, solar, geothermal, tidal, and nuclear.

The downside of producing hydrogen through the electrolysis of water is that more electrical energy goes into producing the hydrogen than will be available from the hydrogen fuel. This fact emphasizes the importance of utilizing the hydrogen in the most efficient manner as a transportation fuel. The most efficient manner currently known is to use the hydrogen in a fuel cell-powered vehicle. It should be noted, however, that while electricity is still being produced for the national power grid using some fossil fuel power plants, it might conserve more fossil fuel and produce fewer greenhouse gases to put the renewable energy-produced power into the grid and take older power plants off-line. Another potentially more efficient alternative could be to use the renewable-energy-produced power to recharge batteries in electric vehicles.

An interesting and troubling likely outcome of the transition period where a significant portion of the electricity to produce hydrogen might come from fossil-fuel plants and/or where hydrogen is partially produced from steam-reforming natural gas (as almost all hydrogen is produced today) is that the consumption of fossil fuel per unit of fuel energy available for transportation will likely increase. In other words, there will probably be a period of time when we actually use more fossil fuel in our efforts to transition from fossil fuels to hydrogen in transportation systems. In addition, since hydrogen must be produced in an energy loss process, the total electrical energy consumption as we move towards a hydrogen economy is sure to increase dramatically. For example, an average American home uses around 1000 kWh of electricity per month. If this home has two fuel cell cars operating on hydrogen, it will take about an additional 1000 kWh of electricity to produce the hydrogen fuel for the cars. The implication is that a complete transition to electrolysis-produced hydrogen for transportation fuel will roughly require doubling the residential electrical generation capacity.

Thus, the DOE vision of proceeding towards a hydrogen economy with fuel cells becoming the preferred way to utilize the hydrogen for transportation certainly seems appropriate but there will be troubling events along the way.

The second area of consideration involves the path and some of the related priorities en route to the long-range vision. The path and priorities are extremely important since, even under the best of circumstances, there will likely be some very difficult issues. Fossil fuels, which have been essentially free except for the costs of extracting and processing them, will be replaced with hydrogen which must be "produced." Millions of megawatts of new, non-fossil, power generation plants will be needed to replace older fossil fuel plants and to provide electrical power to produce the hydrogen. This transition will take decades and will involve huge amounts of capital expenditures. During this lengthy transition period, it will become increasingly important to have an orderly evolution of technologies which can contribute to more fuel-efficient vehicles. It will also be important to use the available fossil fuels in the most appropriate manner. As an example of the appropriate use of fuels, consider natural gas.

Natural gas is the cleanest burning and has the highest mass heating value of any fossil fuel currently being consumed. It is the primary heat source for many electrical power plants including virtually all now under construction or in the planning stages. It is also used as a motor fuel in spark ignition, compression ignition (diesel), and gas turbine engines. In addition, it is the feedstock for many chemical processes including virtually all of the hydrogen currently being produced. Each of these uses of natural gas is related to transportation energy options. Specifically, some of the ways that natural gas could be utilized for transportation, are:

Adding to the complexity is the fact that the hydrogen produced by methods 5 or 6 could also be used in many ways for transportation purposes, including as a fuel for conventional vehicles, hybrid vehicles, or fuel cell vehicles. Interestingly, for the relatively near term, probably the most energy-efficient way to utilize the natural gas for transportation is directly as a fuel in CI hybrid vehicles. The least energy-efficient option is to use it to produce hydrogen by electrolysis and then to use the hydrogen in conventional vehicles. The successful development of enabling hydrocarbon fuel, fuel cell technologies could provide not only another energy-efficient alternative but also an alternative with extremely low emissions. However, once the hydrogen is produced (by any means), the most energy-efficient way to utilize it will be in hydrogen fuel cells.

Similar options obviously exist also for the most effective ways to utilize petroleum or any other form of fossil fuel. The options which are actually feasible will depend on many factors but certainly including the successes in developing many enabling technologies. Clearly, of high importance in technology development must be included the following:

As a final note, it should be emphasized that even with a good plan for achieving large-scale hydrogen production and infrastructure, it will be exceedingly difficult and expensive to implement. As an example, an Argonne National Laboratory study (ANL/ESD/TM-140) concluded that capital costs for production facilities capable of producing 1.6 millions of barrels of gasoline-equivalent hydrogen fuel per day, could be $400 billion for production and $175 billion for distribution. Their study was based on a "high" market penetration of hydrogen-fueled vehicles by the year 2030. Another study by Directed Technologies, Inc. (DE-ACO2-94CE50389, July 1997) was more optimistic but was partially based on assumptions of unlimited availability of very inexpensive natural gas and unlimited availability of off-peak electricity at 1.5 cents per kWh. There are also the inevitable problems with siting and licensing of facilities, as well as the obvious safety concerns of distributing massive quantities of liquid (-423F.) or high pressure (3000 to 5000 psi) hydrogen.

There are, of course, many other issues to be considered including many that should be fostered by the government en route to the long-term vision of a hydrogen economy and an efficient transportation utilization of the hydrogen. However, it is felt that the ones mentioned above are among the more important. In summary, with respect to the proposed FreedomCAR plan, it appears that it is reasonably well considered and includes the necessary elements to guide and support the more critical technology developments in a fashion appropriate for the government. Since the duration will involve many years of activities and many potential pitfalls, progress should be reviewed regularly and programs and plans changed as deemed appropriate.