5 Conclusions

Green Alternatives and National Energy Strategy: The Facts behind the Headlines

CHAPTER 5 Conclusions

What started as an investigation into green alternative vehicles quickly grew into an examination of energy and pollution, both traditional pollution and greenhouse gases, in general. Developing a successful vehicle that allows us to replace gasoline with a clean abundant fuel will affect all segments of the national energy system, and one cannot discuss automobiles without discussing the larger issues. In the preceding chapters, I have examined conventional and alternative energy sources as well as conventional and green vehicles. What follows is my take on the things that may work and the things we need to do to make them possible as we develop a national energy strategy. These are the things we should support with research and development (R&D) funding. You may interpret the information I have presented differently and reach different conclusions about where we should focus our R&D funding. Feel free to do so. Just let the facts, rather than the hype, guide you.

Energy

The United States and the world at large have gotten into a situation from which extrication will be difficult. After a century of ready availability of oil and gasoline, we have gone down a path that has boxed us in. Gasoline is a magnificent fuel for mobile machines and vehicles. It packs a lot of energy for its storage size and weight, is easily transported and stored, and has been, until recently, abundant and cheap. Easy and cheap transportation of people and goods has shaped worldwide behavior. At current rates of production and with increasing consumption resulting from growing populations and growing industrialization by more and more countries, the window of opportunity for action before fossil fuels run out is decades rather than centuries.

The United States imports over half of its oil, and our proved reserves are a miniscule fraction of world oil reserves. Our proved reserves will last only seven years at current rates of production, consumption, and importation. Halting imports of foreign oil by increasing domestic production does not seem to be possible, as that would require tripling production, which would be difficult. Even if it could be accomplished, our reserves would then last only three years. Our only hope for reducing greenhouse gas emissions from oil and reducing foreign imports is to reduce consumption, which is the goal of engineering green vehicles. Reducing oil consumption is more complicated than developing alternative vehicles, however. Green vehicles will reduce oil consumption if they use some other fuel, but they will reduce greenhouse gases only if the replacement fuels produce fewer emissions. Finally, one must remember that oil provides critical non-automotive-fuel products such as plastics and pharmaceuticals. Until we find replacements or other sources for these, we will need oil.

The United States imports 66% of its oil, 16% of its natural gas, and 80% of its uranium. Moreover, the United States has very little of the world’s proved reserves of these resources: 2% of the oil, 4% of the natural gas, and less than 6% of the uranium. US proved reserves will not last long at current rates of production, consumption, and imports: seven years for oil, ten years for natural gas, and two hundred years for uranium. The situation with oil is even worse because US production is declining. If this trend continues, US reserves will last longer, but imports will have to increase faster to offset declining production. Reserves of oil and natural gas will probably last longer than I have stated because of undiscovered technically recoverable reserves (UTRR). The most optimistic estimates might extend sixfold the time we have before the United States runs out.

The situation with natural gas is better. The United States imports natural gas but not as large a percentage of consumption as oil. Indeed, increasing production 20%, which would be tough but feasible, would allow us to stop importing natural gas. However, in that case our domestic reserves would last only ten years. Since natural gas is cleaner than oil, it is a possible fuel for green vehicles, but using it as such would lead to increased and protracted demand, which cannot be satisfied by domestic reserves. It is doubtful that we can stop importing natural gas.

Nuclear power presents an interesting situation. Domestic reserves of uranium will last over two hundred years at current rates of production, consumption, and importation. However, we import almost 80% of our uranium. We could stop importing uranium if we were able to increase production more than tenfold, which is not possible, and even if it were, it would exhaust our domestic reserves in less than twenty years. Nuclear power provides electricity, and demand for electricity will double or triple soon in response to the demands of a growing population, the proliferation of Internet-related electronics, and the development of electric vehicles. It is doubtful that we can stop importing uranium.

Coal is also interesting. We have a lot of coal, more than any other country. Indeed, the United States exports coal, and our domestic reserves should last well over two hundred years, even if we keep exporting coal. Coal currently provides about half of our electricity, and as demand for electricity grows, domestic coal is a straightforward means of increasing generating capacity. Unfortunately, coal-fired power plants produce a large quantity of pollution and greenhouse gas emissions. Unless clean coal technology is developed successfully, replacing gasoline vehicles with electric cars powered by coal-fired power plants would produce a huge increase in noxious emissions. Even if coal is not an acceptable source of electricity, it can be used as a source of gasoline and similar fuels through the Fischer-Tropsch process. Production of gasoline from coal could help reduce imports of oil, but it would be expensive, and greenhouse gas emissions would inevitably increase.

If our abundant domestic coal is to come to the rescue, we must first get control of coal emissions, improve mining techniques to limit environmental damage, develop techniques for extracting fuel from coal, and figure out how to obtain the nongasoline petroleum products we rely on. Now, the dominant source of noxious emissions is coal-fired electric power plant turbines. Emissions will double or triple with the expected increase in demand for electricity. We should pursue efforts to reduce greenhouse gas emissions from coal. The first step, removing CO₂ before burning the fuel in an integrated gasification combined cycle plant turbine, has been demonstrated. The second step, carbon collection and sequestration, which involves capturing carbon dioxide and storing it underground permanently, has not been successfully demonstrated. The challenges of developing clean coal are daunting. Success is uncertain and, if successful, the cost will be high; clean coal will double the price of electricity. Safety is questionable; the suffocation and global warming potential of CO₂ lasts forever. I have trouble with the idea that we can store half of all the CO₂ we produce from now to eternity in hundreds of underground repositories forever. By comparison, storing comparatively small amounts of highly radioactive waste from nuclear reactors, with a dangerous half-life measured in thousands of years, in a repository we spent decades selecting and preparing, is easy.

The worldwide situation is slightly better. Proved worldwide reserves of oil should last forty years, natural gas sixty years, and uranium eighty years. The relatively small US domestic reserves are not an issue beyond their role in assuring that we will remain dependent on foreign sources. But the aforementioned projections assume that rates of consumption will remain constant. Any increase in consumption will decrease how long the reserves last. For example, an annual increase in consumption of 3%, the growth rate of US demand for oil over the past hundred years, would decrease how long worldwide proved reserves last to a couple decades.

These estimates of how long reserves will last are admittedly conservative, as they are based on proved reserves and ignore UTRR. The problem is that we don’t really know how large the UTRR are, and it would be foolhardy to depend on rosy guesses provided by industry. We could start having problems in a generation, or we could escape shortages for several generations.

Green Vehicles

What about a narrower goal of eliminating, or markedly reducing, gasoline consumption? I believe that we can meet this goal with green vehicles, but trying to do so has important implications for national energy strategy. Eliminating demand for gasoline is necessary if we want to eliminate demand for oil. It will not solve the problem, as we would still have to replace the other petroleum products. Nonetheless, reducing demand for gasoline would reduce greenhouse gas emissions and reduce pressure on oil imports. Conventional wisdom places great emphasis on developing green highway vehicles, but highway vehicles are not the only consumers of gasoline. Gasoline is a light, easily stored and easily transported fuel that packs a lot of energy in a small space. There are applications that depend on these attributes much more than road vehicles. Small boats, small airplanes, motorcycles, lawnmowers, garden tools, home standby generators, and off-highway military and exploratory expeditions all require small engines and efficient fuel storage. Vehicles that operate far off the beaten track, away from fueling stations, need an easily stored and transported fuel. We will still need gasoline for these applications long after we have converted the majority of on-road automobiles to other fuels.

The current collection of fuel-efficient standard gasoline cars improve fuel economy and reduce gasoline consumption. There is some room for additional improvement, but I believe we are approaching the point of diminishing returns. Gasoline economy of 35 to 40 mpg is probably as good as we can expect. However, we must keep in mind the logistics of improving fuel economy. The recently proclaimed 35 mpg CAFE standard will not become an on-road reality until new fuel-efficient models replace all the less efficient vehicles now on the road. Complete replacement will take about forty-five years. It will be 2055 before the average fuel economy of vehicles on the road comes even close to 35 mpg, reducing demand for gasoline 43%. That is, in forty-five years we will not even cut consumption in half. Simply improving the internal combustion engine will not solve the problem.

Switching to an E85 ethanol-gasoline mixture for use in flex-fuel vehicles could reduce gasoline consumption to 15% of what it is now, but only if every vehicle were converted to E85 and supplies of ethanol were great enough. Ethanol comes from growing plants. Currently corn provides the best yield per acre, but devoting arable land to corn for ethanol takes the land out of food production. Significant corn-ethanol harvests would have an unacceptable effect on world food supplies. Sources other than corn, such as cellulosic crops, would not affect food supplies, but yields are much lower, and the supply of cellulosic ethanol would be much smaller.

Engines and fuel systems have to be modified to burn E85. If only E85 were available, all portable power tools, snowblowers, and similar small engines would have to be modified, at great inconvenience and expense. To avoid modifying every small engine, gasoline has to be available in addition to E85. In that case, since E85 is more expensive than gasoline and fuel economy is poorer, many drivers would choose gasoline instead of E85. Raising the automobile engine’s compression ratio could prevent this by simultaneously improving fuel efficiency by taking advantage of the higher octane rating of E85 and dissuading drivers from filling up with gasoline. Unfortunately, it also would mean that the supply of E85 would have to be very robust to compensate for the fact that flex-fuel vehicles would no longer have the option of switching to E10.

Diesels have become clean, quiet, and fuel-efficient. New diesels get superior fuel economy. However, because of the nature of the crude oil refining process, a barrel of oil produces less diesel than gasoline. Even though diesels get more miles per gallon of diesel fuel, they get fewer miles per barrel of oil. They could actually increase the demand for oil if the number of diesels on the road increases sharply.

Biodiesel fuel could offset the increase in demand for oil, making diesels more attractive. Unfortunately, yields of the more common sources of biodiesel are so low that biodiesel cannot be the mainstay of the national transportation system. Estimates show that one should not expect much more than a few percent of total vehicle fuel from soybean biodiesel. This is certainly a step in the right direction but is hardly the entire solution. We can extract biodiesel from other crops, but the US climate favors soybeans, which have low yield. We can also import crops and biodiesel from foreign countries, but this runs contrary to becoming independent of foreign sources of energy. Biodiesel will not have a major effect on fuel consumption without a massive impact on food supplies and without our becoming dependent on foreign sources of biodiesel. This could change if algal biodiesel becomes as practical and productive as some people believe is possible. This is an intriguing possibility and something that should be closely monitored and nurtured.

Natural gas vehicles (NGVs) eliminate the need for gasoline; they are clean, and they are already successful. However, domestic supplies of natural gas are limited, and extensive conversion to NGVs would deplete our reserves faster. The United States would soon be as dependent on foreign natural gas as it now is dependent on foreign oil. In addition, the natural gas pipeline infrastructure is inadequate for widespread use of natural gas vehicles, and we would have to expand it at great effort and expense. Moreover, on-vehicle storage of natural gas requires larger and heavier fuel tanks than gasoline, resulting in conflict between the need for smaller, lighter cars and the public’s demand for good driving range. For these reasons, I believer that the appropriate role for natural gas is in fleets of larger vehicles like buses, delivery vans, service vans, and the like that are fueled at depots. Fueling at central depots minimizes the need for expanded infrastructure, and deployment on large vehicles minimizes the storage tank size/weight penalty. Using natural gas in large vehicles is the most efficient application of this resource in vehicles.

Gasoline hybrid electric vehicles (HEVs) are getting very good fuel economy, around 50 mpg. Most current HEVs burn gasoline, though there is no reason they could not be powered by diesel or flex-fuel engines. If all cars on the road achieved 50 mpg, gasoline consumption would drop more than 50%, just about matching current imports of foreign oil. However, having two almost independent drive systems makes hybrids overly complex and expensive for their benefit. They are transitional between internal combustion engine vehicles and electric-drive vehicles. Switching to pure electric cars would be beneficial. Their complexity and cost would be less than HEVs’, pollution would be less, consumption of oil would be less, and the cost of fuel per mile would be less.

Following the HEV as a second transitional step is the series electric vehicle (SEV), a pure electric-propulsion vehicle with electricity coming from an onboard genset—a motor/generator combination—burning fuel. The SEV would provide all the benefits of electric drive and would get maximum benefit from all of the alternative fuels such as natural gas, diesel, and biofuel. This vehicle could be the entire solution to eliminating gasoline should a nonpetroleum fuel such as algal biodiesel or coal-derived synthetic fuel become available. Especially important, we could deploy large numbers of SEVs immediately, as no new infrastructure or technology is required.

The next step would be the elimination of fossil fuel entirely by removing the SEV’s fossil-fuel genset. Electric-drive vehicles are more efficient than internal combustion engine vehicles, produce no pollution themselves, and eliminate demand for oil and natural gas. That is not to say that the two leading contenders, the pure plug-in electric vehicle (P-PEV) and the hydrogen fuel-cell vehicle (HFCV), do not present challenges.

The P-PEV is similar to the gasoline-electric vehicle, but it does not generate electricity onboard. It has a large battery charged from the power grid. It is impractical now because there is no convenient charging infrastructure. Moreover, the size/weight penalty of the large battery limits driving range too much. The Chevrolet Volt is advertised at 40 miles per charge, the Nissan Leaf 100, and the Tesla Roadster 200. All have shorter range than the 320 to 400 miles per fueling stop we have come to expect. Achieving sufficient improvement in range through battery R&D is unlikely.

An alternative to storing electric energy in large batteries charged from the grid is storing hydrogen onboard and generating electricity in a fuel cell. The HFCV is impractical now, but it looks like we are on track for a practical model in a decade or so. We will then need to provide hydrogen at filling stations. Building a network of hydrogen pipelines is grossly expensive and unnecessary. One alternative would be to tap into the expanded network of natural gas pipelines that would be developed to support NGVs and convert natural gas to hydrogen at each filling station. However, it would be much more efficient to burn the natural gas in an NGV than to convert it to hydrogen for use in fuel cells. It would make more sense to manufacture hydrogen at each filling station by electrolysis. The same expanded electric grid that would support P-PEVs could support HFCVs.

Neither the P-PEV nor the HFCV is ideal. The energy storage size/weight penalty is more severe for the P-PEV, limiting range. While range is better, overall fuel efficiency of the HFCV is poor because of the losses incurred by the circular process of consuming electricity to generate hydrogen to generate electricity. We will most likely see large numbers of each type of electric vehicle. The P-PEV could provide local transportation when range is not crucial, and the HFCV could provide long-distance travel. We would just have to accept poorer fuel economy in exchange for better range, and even then the driving range of HFCVs would be less than what we expect from gasoline cars.

Deployment of electric cars will require a network of fast, very-high-power charging stations. The backbone of this network is already in place; electricity is available at all gasoline filling stations. However, electric cars will almost double demand for electricity. If increased demand from growth in population and usage of electronic devices is considered, overall demand for electricity will soon triple. We would have to increase the capacity for electric current at filling stations and feeder grids, and we would have to double generating capacity. Doubling generator capacity presents its own set of challenges. Moreover, batteries cannot accept the large charging currents required for really fast charging without damage, so charging a P-PEVs will probably always take much longer than fueling a gasoline vehicle.

Once we have converted the transportation fleet from gasoline to electricity, we will have to focus on increasing range. Battery improvement is one obvious path. Another path is making vehicles smaller, lighter, and more streamlined. Once the internal combustion engine gives way to electric propulsion, aerodynamic drag, tire rolling resistance, and inertia become the main sources of energy loss. Making the car smaller, lighter, and more streamlined provides much more benefit for an electric car than doing the same for an internal combustion engine vehicle. What we cannot achieve with battery improvement we may achieve with body design. However, making the city streets and highways safe for small cars will then become an important challenge.

Green Energy Sources

I expect demand for electricity will increase markedly because of population growth, increasing demand for electronic gadgets, and electric cars. Transmission lines and generating capacity will both have to double or triple within two or three decades. Expanding the transmission line network will face strong public resistance. Coal-fired power plants could provide the electricity, but with unacceptable increases in greenhouse gases, pollution, and environmental damage. Clean coal technology might overcome the greenhouse gas and pollution problems, but I believe clean coal has a low probability of success. I am not ready to abandon it now, but I think we should put more effort into other projects.

Expanding nuclear power is a viable option. Nuclear power is the cleanest mined-energy resource; it does not produce greenhouse gases or other pollution. World reserves should last a hundred years at current rates of consumption. Nuclear power does present some dangers: environmental issues associated with radioactive waste material, accidents, natural disasters, and terrorist activity. While these dangers are real and we have to address them, countries around the world have been using nuclear power for decades with no natural disasters or terrorist actions and remarkably few serious accidents. I believe the fears are overstated. Even so, while uranium will last a lot longer than oil or natural gas, it will not last forever. One of the potential benefits of nuclear power is the possibility of perfecting fast breeder reactors, which produce almost as much nuclear fuel as they consume, making fuel for nuclear power plants virtually inexhaustible. Some technical issues have to be resolved, but we have a hundred years to work them out before we run out of uranium. It seems to me that nuclear power will be the dominant source of electricity in the future.

Renewable sources of electricity—hydroelectric, geothermal, wind, and solar power—can help meet overall demand, but the role they can play is limited. The renewables have several features in common: though their technologies are initially high in cost, they become self-sufficient once established; they will not run out; they do not produce greenhouse gases or pollution; they can only be located where conditions are correct; and they have a large physical footprint.

Geothermal power plants require geologic reservoirs of high temperature within a couple miles of the surface. Estimates indicate that geothermal power plants might eventually provide 2% to 3% of current national demand for electricity. Hydroelectric power requires rivers with sufficient flow of water and suitable surrounding geology to make a dam and large reservoir practical. Estimates of potential hydroelectric sites indicate that fully developed hydroelectric potential in the United States could provide about 10% of total current demand.

Wind power is a definite option. Unfortunately, very few areas on land are capable of providing useful amounts of wind energy. There is public resistance to wind farms near population centers because of the hazardous noise levels produced by wind turbines. The logical choice is to put wind farms offshore, where the wind is much stronger and the noise will not bother anyone. Even so, the huge footprint of a wind farm is a major limitation. One would need offshore wind farms covering a band 9 miles wide from Maine to South Carolina and from the Canadian border to San Francisco to provide 22% of the current US demand. I doubt that much more than a quarter of this offshore swath is available for wind farms. There simply is not enough sufficiently strong wind in the United States to provide much more than 5% of our energy demand.

Unlike conventional, hydroelectric, and geothermal power plants, wind power is intermittent. Wind dies unpredictably, and power generation drops to zero. This is not good for the consumer, and it is very bad for the power grid. Power dropouts are serious problems for grid stability and can bring large segments of the grid down, causing widespread power outages. This has happened several times already and it will happen again. The solution to intermittent wind power is to ensure that output from each wind farm is steady and continuous. That is, each wind farm has to have a backup energy storage system similar to the uninterruptible power supply many computer users depend on. Uninterruptible power systems using sodium-sulfur batteries are in place at several wind farms and will probably become standard. Unfortunately, this is expensive.

One might expect hydropower and geothermal and wind power to provide as much as 20% of our current demand for electricity. This percentage would require almost maximum utilization of these resources. That is, should demand for electricity double or triple as expected, the contribution of these three renewables would decrease to less than 10% of total demand.

Solar power could supply much more electric power than these three sources combined. I estimate that to meet all of our current demand for electricity would require 36,000 square miles of solar farms and transmission lines. That is an area the size of Ohio, 1% of the country. To meet three times the current demand would require 100,000 square miles of solar farms and transmission lines, an area the size of Nevada. While technically feasible, this seems rather impractical.

Solar power has several features in common with wind power. Solar farms have to be located where the insolation is good, and they take up a large area. The footprint issue is not as severe as with wind farms because solar farms get about three times more power from an acre than offshore wind farms do. The location issue is not as critical because the best locations for solar farms are in the Southwest, where much of the land is barren and sparsely inhabited. The downside to putting huge solar farms in the Southwest is the long transmission lines that would be required, with the resulting demand for real estate for the lines and power loss in the long lines.

Like wind power, solar power is intermittent, because of clouds and bad weather, and each solar farm needs an uninterruptible power system. Solar power is unique in that it provides electricity only during daylight, around six to eight hours a day, and nothing at night. The United States uses almost as much power at night as it does during the day. This constant power demand is problematic for solar power because it means that nighttime power-generating capacity has to be as large as daytime capacity. Taking care of nighttime demand with conventional power plants and daytime demand with solar power is a massive power management problem. Solar plants would go offline in the evening and come online in the morning, while conventional plants would come online in the evening and go offline in the morning. This would be an impractical approach. An alternative is to ensure steady output from solar farms by increasing the size of the power backup to handle dropouts lasting eighteen hours. This is a simple solution, but extremely expensive. A possible solution to this problem may be found in concentrating solar power (CSP) technology, which uses sunlight to heat a fluid that drives electricity-generating turbines. The advantage of CSP over photovoltaic cells is that the heated fluid may store energy overnight.

The intermittent renewables, wind and solar power, present a quandary. We want to place solar and wind farms in areas of good conditions. That is, wind farms would be concentrated along the coast, and solar farms would be concentrated in the Southwest. But with concentration comes vulnerability. A single tropical storm or hurricane going up the east coast could shut down most of the coastal wind farms for days. A single blizzard in the Southwest could cause most of the solar farms to stop producing for days. Heavy reliance on power sources dependent on the vagaries of nature would be a serious mistake. We need to maintain conventional power-generating capacity, idle most of the time but ready to take over on short notice for wind and solar plants forced to shut down by severe weather.

Renewables may be able to provide substantial capacity, but they cannot provide the major portion of our current electricity needs. The role renewables play will only decrease in the future as growing demand outstrips geographically limited supply. It seems to me that there is no alternative to increased nuclear power.

Strategy

What is the overall strategy I am suggesting? First, we should do the following to prolong our oil supply:

• Increase domestic production and exploration, put fuel-efficient conventional and hybrid cars on the road, and convert fleets of large vehicles to natural gas.

• Explore possible nonpetroleum liquid fuel by investing in R&D on algae as a potential source of ethanol and biodiesel.

• Develop Fischer-Tropsch processes for producing gasoline, diesel, and other fuel oils from coal, while limiting emissions.

• Start phasing in electric-propulsion SEVs, thereby increasing fuel efficiency beyond that of HEVs and NGVs.

• Take advantage of the power flow in electric propulsion systems by developing lighter, smaller, more efficient road vehicles while addressing making the highways safe for smaller vehicles.

• Prepare for increased demand for electricity from P-PEVs, population growth, and increasing demand from electronic devices by developing renewable sources of electricity, expanding nuclear power capacity, expanding the transmission line network, installing a fast charging station infrastructure, continuing battery R&D, and addressing power grid stability.

• Work on developing nonpetroleum sources for the nongasoline products we currently get from petroleum.

• Work on developing algae as a source of biodiesel fuel and other hydrocarbon products.

• Adjust to a two-fuel system in which gasoline remains available for small power devices and off-road operations and biofuel and electricity are available for highway vehicles.

• Continue to research clean coal technology, but take a hard look at its feasibility and the safety of sequestering large quantities of CO₂.

Second, we should do the following to expand our non-fossil-fuel sources of electricity to meet growing general demand and prepare for the switch to electric vehicles:

• Develop hydroelectric and geothermal power plants and solar and wind farms where appropriate and economical, expand the transmission line network, and develop widespread fast charging stations for electric vehicles.

• Ensure power grid stability by requiring an uninterruptible power system at each solar farm and wind farm.

• Improve power grid stability to accommodate intermittent power from solar and wind farms, thereby lessening the required capacity of uninterruptible power systems and facilitating the connection of community-level or individual solar and wind systems to the grid.

• Increase conventional electric power generator capacity by constructing nuclear power plants.

• Deal with concerns about nuclear plant safety, security against terrorist activity, and storage of waste materials and rescind the prohibition against reprocessing spent fuel rods.

• Continue investment in fast breeder reactor technology, which could provide almost inexhaustible nuclear energy.

This plan should markedly reduce our dependence on oil and markedly reduce noxious vehicle emissions. Unfortunately, it will not eliminate demand for gasoline, as we will probably still need it for the small engines in power tools and so on. Perhaps biofuel could replace gasoline in small engines, but even that will not eliminate demand for oil, as we will still need fuel oils, lubricating oils, and all the other products we get from oil. We may eventually learn how to do without or extract these products from coal, but we will need oil for a long time.

I believe the actions listed above provide a logical general strategy that accounts for all the nuances of green vehicles and eliminating dependence on oil. I make no claim that I have answered all the questions. Oil will run out. Natural gas will run out. Uranium will run out. With the uncertainty in estimates of reserves of natural resources, we do not know exactly when. Nevertheless, it looks as if our grandchildren or great-grandchildren will be living in a very different world. I hope you now have a better grasp of the issues and the facts behind the sound-bite headlines and are better prepared to address the very important energy issues that the future has in store for us all.