A ‘GALATIC VISITOR’S’ ESSAY PART I THE HYDROGEN ECONOMY by Gary Young, retired engineering manager Fort Collins, Colorado It is lamented that far too few of the electorate have any real understanding of the hard sciences. This lack of understanding has given rise to embracing poor (junk) science at even some of the highest levels of academic and political thought. The current concept of most concern is all the political rhetoric about renewables such as solar and wind providing our energy. Unfortunately, to provide all the US energy needs with solar, we would have to cover an area the size of New Mexico. Solving it with wind would insure the “wilderness experience” just about everywhere would have a backdrop of nothing but windmills. Then there is the issue of having energy available at all hours when the wind and solar are absent. Affordable battery technology for utility scale storage just does not exist. There are better solutions. Hydrogen is a viable solution. While a hydrogen economy is possible, it would take a true national priority effort with the need for massive investment to make it happen and even then, it will take time. If the objective is directly powering our transportation fleets with hydrogen, the results will be disappointing. We shall see that gasoline and diesel make more sense to power our transportation fleet than any alternative. The interesting issue is how do we make these liquid hydrocarbon fuels? They contain hydrogen. Imagine that we were an advanced hydrogen based civilization and that we, together with our infrastructure, were suddenly dropped on this planet. Since our civilization is advanced, we soon discovered that this planet had uranium, thorium, petroleum and natural gas in great quantities. This was a situation that did not exist on our old planet, where we only had an abundance of falling water and solid carbon based fuels (coal), which is why we evolved our hydrogen based energy system in the first place. Now that we are here, we soon learned just how versatile, efficient, and relatively safe gasoline and diesel can be for providing the energy for our transportation needs. On our old planet we have great appreciation of facts and logic and so long ago made the decision to invest in power generation yielding the highest Energy Return on Investment, EROI. EROI was originally inspired by a biological concept such as would you starve to death faster in a field of lettuce or in a bare desert. Digesting lettuce takes more energy than the calories contained in the lettuce. We recognized that for our world’s poor to advance to a middle class life style, energy had to be cheap and abundant. What follows is in part why our transplanted society made the decision to base our major transportation needs on page 1
gasoline and diesel while at the same time leaving abundant cheap fuel for the world’s poor to advance. My root source for the calculations that follow is from Donald Anthrop, Ph.D., professor emeritus of environmental studies at San Jose State University as published in a Cato Institute report. Other sources include Marks’ Mechanical Engineers’ Handbook. I call on personal experience because I have also been a member of the Society of Automobile Engineers, a test engineer for fuel cell components as part of the Apollo Space Program, a nuclear trained submarine officer, and as a long time “car guy” which included building a number of alcohol fueled dragsters racing engines. The process I have chosen is to make the case “backwards” from hydrogen to a gasoline based transportation system by first examining how to go from gasoline to hydrogen. This scenario in turn shows why gasoline really is a very reasonable fuel once all the junk science and untenable assumptions are eliminated. Southern California Edison calculated that it takes approximately 0.46 kilowatt hours (KWH) of energy to propel the average automobile 1 mile. This is real data calculated when the utility tried to figure out how to size their capacity to accommodate electric cars. The first impression was that the energy number seemed a little high. Since this entire piece came about because the whole idea of hydrogen based transportation energy system seemed suspect, I wanted to make sure that this KWH per mile number seemed reasonable. That energy works out to about 33 horsepower hours if traveling about 55 miles per hour. The figure of 33 horsepower hour to travel 55 mph also seems to be high for automobile traveling steadily alone on a highway. The number was, however, derived from all the gasoline burning vehicles which include light trucks. It is also based on a real world large percentage of stop and go driving while running air conditioning and other accessories, following the commuter and passenger automobile transportation driving patterns in southern California. The 0.46 number passes the engineers’ “thumb nail reasonableness” calculation. It also recognizes why in-town mileage is a lot less than highway mileage. Professor Anthrop states that in the year 2000, automobile travel in the US amounted to 2.526 trillion miles. This is another number that at first glance seems high by perhaps a factor of two. However I did another reasonable check from data I already knew. For example, I have read a number of articles about the perils of leasing cars where the leases are written for about 12,000 miles a year. The problem is that leasers are far more often then not getting tagged for several thousand more miles per year when their lease terminates. Further, the lease or buy decision is driven by how many miles are driven and by the time annual mileage reaches about 15,000, buying is generally cheaper. This is one major reason so many people buy instead of lease. Another check is that I remember how many registered vehicles there were in the country. While the data may have been ten years ago, the total was passing 160 million. If each car in the US was driven an average of 15,000 miles, that would total 2.4 trillion miles. Another thumb rule is using the known daily gasoline consumption of 8.5 page 2
million 42 gallon barrels and multiplying by an estimate of 20 miles per gallon. That calculation yields a total annual 2.6 trillion miles driven. In short, the number 2.526 trillion miles driven in a year is very believable and likely very painstakingly derived by Professor Anthrop. In our previous hydrogen fueled planet, we found that the direct conversion of one kilogram of hydrogen gas to electricity in a fuel cell liberated 33.4 kilowatts (KW) of electricity plus 6 kilowatts of energy converted into water vapor. We also found that the reasonably affordable fuel cells used for automobiles were only about 70% efficient. This means that instead of 33.4 kilowatts of energy being available to drive the wheels, and after the electrical resistance loses in the controller and wiring, only about only 23.3 kilowatts are available to drive the motors. The Southern California Edison data on how much electricity it takes to move an automobile seems to be that which is needed at the automobile’s motors. This means that a kilogram of hydrogen gas will move a car about 50.6 miles. That in turn means that the hydrogen generation plants have to produce 50 billion kilograms of hydrogen gas each year to power our automobiles. Perhaps the preferred way to make hydrogen gas is using electricity to separate the bonds between the hydrogen and oxygen in water. It takes 39.4 kilowatts of electricity at 100% efficiency to make a kilogram of hydrogen gas from water by electrolysis as was mentioned above. No energy conversion system operates at 100% efficiency and since this process is also only about 70% efficient (this is higher then it was on Apollo when I worked on the program). So it really requires 56.3 kilowatts of electricity to make a kilogram of hydrogen. Note that it requires really good catalysts to even achieve the 70% efficiency level without losing a large portion of the electricity wasted just heating the water. The 70% efficiency in turn means that it would take 2.815 Trillion kilowatts of generated electricity to make the 50 billion kilograms of hydrogen that would power our cars for a year. Another way to produce hydrogen is using thermal energy to heat water to 1000 degrees C (or perhaps no more than 850 degrees C with the right catalysts). Then there is the problem of having molecular sieves collect only the hot hydrogen gas molecules without allowing the oxygen to pass and re-combine. It is an understatement that the engineering of dealing with anything this hot and under high pressure is challenging. Currently about 95% of hydrogen produced in the US is by the partial oxidation of coal and natural gas. Steam reforming is a well characterized industrial process and currently, less expensive than the electrolysis process. Of course, a great deal of CO2 is produced. The conversion of various measurement units is necessary because the source data for the energy content of most US coal is measured in British Thermal Units (BTUs). The conversion for an electrical kilowatt of energy is page 3
equal to .9478 British Thermal Units per second. A kilowatt hour is equal to 3412 BTUs per hour. To make a kilogram of hydrogen requires 192,100 BTU’s of electrical energy. Coal fired steam generating plants are relatively efficient in the conversion of coal into electrical energy, but that efficiency is still only 60%. This means that it takes 320,000 BTU’s of coal to make a kilogram of hydrogen gas. The newer combined cycle plants that use natural gas to first run gas turbines then the use the turbine exhaust to generate steam for steam turbines can reach efficiencies of greater than 70%. Of course this substitutes one fossil fuel for another. Since in the scenario, our previous society knew all about coal, once we first arrived in the United States, we chose to use the low sulfur Western coal because it only has about 0.5% to 0.7% sulfur content. Unfortunately, Western soft coals are also only about 40% to 50% carbon (verses up to 87% for hard coal) so their heat content per weight is also lower, which means that more tons have to be mined to supply the power plants. That in turn also means that there is more ash that has to be disposed of later. Fortunately, western coals are easy to mine, which more than offsets their lower energy content. These coals have energy values from 7800 BTUs per pound to somewhat more than 12,000 BTUs per pound. Power plants of course prefer the higher energy coals because they have relatively less problem with ash disposal and such. If we use a conversion factor of 10,500 BTU’s per pound of coal (about 23,000 BTU’s per kilogram), we would be near the low end of what the utility industry uses. This means that it takes about 14 kilograms of coal to make one kilogram of hydrogen gas which moves our cars about 50.6 miles. Another major problem with hydrogen gas is that —well, it is a gas. At a standard atmospheric pressure and temperature, it takes up 3107 times the volume of the same energy stored as gasoline. Professor Anthorp says to be a really useful fuel; hydrogen must be compressed to at least 4000 pounds per square inch. For example, the goal at GM is creating systems that use hydrogen compressed to 10,000 psi. That much pressure is required to keep the storage tank volume small enough so that the range between fill-up is on par with gas powered vehicles. Automobile manufacturers are making progress. Honda is now using up to 5,000 psi in their Clarity to be introduced in 2017. The fuel cell generates about 80 horsepower and the EPA estimates 240 miles between fill-ups. Of interest is that Toyoda has found a material they can put in a high pressure tank which apparently absorbs hydrogen at high pressure. This technology allows the storage of about twice as much hydrogen in the same size and at the same pressure as would be contained in a tank without this material. The energy to compress hydrogen is in the range of 10% to 20% in addition to the energy required to make it in the first place. BMW is studying liquefying hydrogen because a greater range between fill-ups is possible and the page 4
fuel tanks are smaller. The problem with the liquefying solution is that it currently takes approximately another 40 % more energy to liquefy hydrogen as it would take the electrolysis process to make it in the first place. Perhaps this efficiency can be improved with massive scale plants. The distribution infrastructure is also a great deal more complex than the distribution for gasoline. Pipelines have to be substantially larger because hydrogen gas at pressures that are reasonable for pipeline transfer is very much less dense than gasoline. Because hydrogen is a small molecule, at high pressures it can leak right through steel pipes! Hydrogen can cause steel to become very brittle as molecules ‘wedge’ between crystals of steel. Local distribution is a major problem because it would take several truck loads of compressed hydrogen gas to equal the energy content of one truck load of gasoline. This is because the pressure vessels required to hold compressed hydrogen are very heavy and account for the majority of the load capacity of the trucks. Liquefied hydrogen is not much more difficult to transport than gasoline, but because it is so very cold and no insulation is perfect, it constantly vents away. In time, it ALL vents away. For the purposes of the scenario, I am going to state that our home planet’s advanced technology solved all these distribution problems by having to provide only another additional 20% of the energy contained in the hydrogen to get it to where it was needed and in a form safe enough to use by consumers. Thus, it means that including distribution, it takes about 16.7 kilograms of coal to move our cars about 50.6 miles. In terms of pounds, it takes 3/4 pounds of coal per mile traveled. That is also translates into 3.1 TRILLION pounds of coal per year to drive our cars on hydrogen. In terms of tons, that is 1.6 BILLION tons. When measured in total British Thermal Units, the total is 32.5 Quadrillion BTUs. When discussing massive amounts of energy, a “Quad” is one quadrillion BTU’s, so the short analysis is that our old hydrogen based society used more than 32 quads of energy to drive in the year 2000. Generating hydrogen from burning fossil fuels: The only way the US could quickly go to a hydrogen based system over the short term is to use energy from converting coal and natural gas. With the partial exception for hydroelectric generation, wind turbines, wave generators, and massive solar direct conversion, most of the energy will simply have to come from coal and natural gas. Natural gas while now abundant, has better uses, fast reaction electrical generation, heating our homes, making petrochemicals etc. Since the average carbon content for western coals is about 47%, it means that we had to burn 750 million tons of carbon which resulted in 3 Billion tons of carbon dioxide gas that went into the atmosphere. Oh by the way, we also had to deal with about 190 MILLION tons of sulfur dioxide per year. These amounts are just for transportation and over and above that which was required to supply the electrical grid.
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Then there was the problem of RADON gas. While not a problem on our old planet, Radon is a radioactive gas which is produced by the decomposition of uranium. Over the millions of years it takes for nature to make coal, the gas has been seeping up from the heavy dense rock below and saturating the coal beds. Burning an extra 1.6 Billion tons of the coal released thousands if not tens of thousands of curies of this radioactive gas. So how much radioactivity is released by burning this much coal? I have found no definitive and reliable data, but it is on the order of at lease one Chernobyl every ten years. The good news is that Radon is chemically inert so it doesn’t combine with other elements that could directly poison our bodies. However, and as a bench mark, hundreds of thousands of our houses have radon remediation systems because breathing it is thought to be a strong carcinogen under the theory of ‘linear-no threshold” which is a highly suspect junk science theory! Fortunately, radon is also a very heavy gas and likely eventually sinks to the bottom of the oceans, I have not found any definitive studies on just what does happen to the radon. The Argument for Gasoline: Gasoline has 120,600 BTUs per gallon. This works out to 5.065 million BTUs of energy content per barrel. This BTU number per gallon is 2000 lower than the number used by Professor Anthrops’ and has much to do with the fact that there are more than 50 special formulations mandated for use in various geographic areas which are purposely designed in the hope that these formulations would reduce air pollution. Most of these formulations are before alcohol is added in many areas of the country. The rational to add alcohol was to lower the energy content of the gasoline in order to “lean out” the running engine fuel air mixture to reduce smog. (This by the way is more junk science.) Anthrop’s number is more reflective of the really good gasoline that is mandated for use by the government in the published mileage numbers for new cars. That is a major reason why actual mileage is less than that printed on the window sticker. Back to the scenario: It was in our societies’ interest on planet earth to switch to a gasoline based transportation system. We figured out that in the year 2000, it would only take 8.47 million 42 gallon barrels per day. (Actual numbers) The 5.065 million BTUs per barrel per day means that it takes only (!) 15.66 QUADRILLION BTU’s, or only 15.7 quads of gasoline energy to drive our cars. In short, we switched to gasoline because we could save more than half the energy over what was required by burning coal to get hydrogen! Gasoline has a lot of hydrogen in it and available for producing energy. Burning hydrogen produces over 60,000 BTU’s of energy per pound. Gasoline also has about 84% by weight of carbon which of course contributes to the carbon dioxide problem. In the process of making as many gallons of gasoline as possible from each barrel of crude, gasoline has become less dense then it used to be, which is mostly why the BTU content described above has become less. The page 6
average density of gasoline is now 5.935 pounds per gallon. Alcohol is heavier than gasoline so adding 10% raises he density to just about 6.0 pounds per gallon. The carbon content of alcohol is 52% and therefore, a blended 10% alcohol gasoline mixture is 80.8% carbon. In turn it means that for each gallon of gasohol, there is 4.848 pounds of carbon. Using 8.47 million barrels times 42 gallons per barrel times 365 day in a year times 4.848 pounds of carbon in a gallon means that we burn only (!) 314.7 million tons of carbon yields 1.154 billion tons of carbon dioxide. The bonus from switching from hydrogen produced by burning coal to using gasoline for our transportation needs is that only 38% of the carbon dioxide is released! Real world political problems: It seems that this planet has the affect of giving a general lobotomy to political decision makers. It is also unfortunate that we discovered that the majority of the petroleum most easily extracted is located in areas under the control of some of the least stable political entities. One outcome of this has been the drive in our country to meet energy demand by producing alcohol. Worse, is the “selling� of alcohol/gasoline mixtures as a way to save the environment. Alcohol is not a good solution: Alcohol for fuel is primarily ethanol and is produced by first converting the starches in plant matter into sugars and then fermenting. The majority of plant matter used in this task is corn. The use of corn was primarily the very political desire to subsidize farmers to buy their votes. Sugar cane and sugar beets would make for a better solution because the need for, and the energy required to malt the corn into fermentable sugars would be eliminated. However the politicians have since about 1803 (Louisiana Purchase to protect sugar cane growers from the potential loss of France as their primary market.) used your tax dollars to reward the sugar lobby into driving the cost of domestic sugars so far above the world market prices that it makes sugar less attractive for making alcohol, but I digress. For now, I will leave it that for every dollar the consumer directly pays for the alcohol in our gas, the consumer also nearly matched it in taxes paid that were given to farmers and distillers as incentives. The production of alcohol from corn starts with using quite a lot of energy to grow the corn, transport it, and malt it, all of which generates carbon dioxide which is released into the atmosphere. In another study, I have calculated that it requires 7% more fossil fuel energy to make corn ethanol than the energy contained in the ethanol. Our own experience with the family corn farm would lead me to speculate that picking 7% is a very conservative number. Safety problems: Remember the Hindenburg? Hydrogen gas is lighter than air as well as being very flammable. The BMW approach to liquefying hydrogen as an automobile fuel is very dangerous because the gas will constantly vent as it boils page 7
in the automobile fuel tanks. The next time you are in a parking garage, or even in your garage at home, notice all the “pockets” in the ceiling where hydrogen can gather. Hydrogen will start to burn at a volume concentration of about 4.2% in air and becomes progressively more explosive up to about 8%. In the submarine force, we were very careful about the hydrogen generated from charging batteries because of past disasters. I have seen the diesel engine that ventilates the batteries run without diesel fuel when the concentration of hydrogen reached a little over 3.6%! I also went through a couple of static electricity triggered “huffs” while standing in an Apollo fuel cell test facility designed to withstand explosions. Interesting, but it wasn’t fun being blown out of the test cell and rolled across the facility like a giant pill bug. The BMW approach to liquefying hydrogen has merit in the case of collision. This is because the hydrogen is not under much pressure and is very cold, which makes it less susceptible to ignition. It should be possible to make some collision survivable tanks that would not be overly heavy for inclusion in automobiles. Still on our old planet, we discouraged liquefied hydrogen because of building codes. We simply could not risk venting hydrogen into parking structures and our homes. It gives me nightmares thinking of car wrecks with fuel tanks full of hydrogen under pressure of thousands of pounds per square inch. Only in Hollywood, with their stick-of- dynamite-in-the-gas-tank special affects, do gasoline powered cars routinely explode. Gasoline powered cars of course do burn, but without a way to first atomize the gasoline in air, it burns from the vapors that come off the surface of the liquid. Rupturing a gas tank in an accident only infrequently results is a fire and when there is a fire, it burns for a relatively long time before the gasoline is all used up. Rupture a highly pressurized hydrogen tank and the potential energy from the compression of the gas is more than sufficient to ignite the gas as well as mix it with a large volume of air in a few tenths of a second. Think of a million BTU’s of energy released in a few tenths of a second. That is a big explosion! Can compressed hydrogen fuel tanks be made safe? The answer is that nothing can be absolutely safe because an absolutely safe system would cost nearly an infinite amount of money. Tanks could be engineered so that consumers could be still be able to afford them and only blow up in perhaps one accident in a hundred thousand. Of course, US trial lawyers will be all over that like stink on limburger. On our old planet, we fortunately had ‘loser pays’ in our legal code. A possible hydrogen breakthrough? There was an announcement in 2008 that some scientists at the Technical University of Denmark have found a way to store a great deal of hydrogen in “tablet” form. The mechanism is the use of ammonia which is a gaseous chemical compound of hydrogen and nitrogen. Ammonia has a great affinity for water and page 8
various salts. The result is the relatively safe storage at moderately low pressure. Before use in a fuel cell, the tablet has to be heated to separate the ammonia from the strontium chloride salt carrier agent and then a catalyst separates the ammonia back into hydrogen and nitrogen. The researchers have founded a company, AMMINEX that now makes the tablets where ammonia is used to reduce oxides of nitrogen in diesel engine exhaust. Apparently the technology is well advanced with working devices and catalyst system to achieve the release of fuel cell grade hydrogen from ammonia. Vehicle fuel tanks would be primarily containers of salt tablets that would be recharged by ammonia at filling stations. One reason why this approach has great promise is that throughout farming communities, ammonia has for a long time been transported, stored and used in liquid form for fertilizer. (Liquid ammonia gasifies as it is injected into the ground where most of it is quickly absorbed by the moisture in the soil. Bacteria in the soil break down the ammonia releasing the nitrogen for use by plants). Of course, most agriculture ammonia is made from natural gas, so efficient ways would have to be found to make it from hydrogen and air. Making ammonia from hydrogen gas and air will take enormous amounts of energy. Other fuels: There are other scenarios that should be looked at and these include the other ways to obtain liquid fuels that would not necessarily come from petroleum or alcohols. The problem with using coal to make liquid fuels is that the liquids must be combined with more hydrogen to form hydrocarbons like heptane, octane and other liquid components of gasoline. Coal has very little hydrogen. Heavy dense oils that come from tar sands and oil shale don’t have enough hydrogen in them to utilize all the carbon to make the petroleum like fuels without either adding more hydrogen or stripping out some of the carbon. Natural gas, a rich source of hydrogen could be used to process these carbon sources to produce liquid fuels. As was previously seen using natural gas would be counterproductive over the short term. Once again, a good interim step would be to construct hydrogen generation plants that separate water in order to make liquid hydrocarbon fuels.
The Hydrogen based energy solution and how to make it work for the US. The political reality is that the sources for petroleum are dominated by unstable countries and where petroleum products are consumed are primarily in the most industrialized countries who don’t have matching reserves of petroleum. That happenstance means that there really is a need for the use of hydrogen in one form or another for transportation in the industrialized countries. The first page 9
issue in using hydrogen gas is the major safety problems that come with broad public access to the distribution and use of hydrogen. The second issue is that non-polluting ways have to be found to manufacture the hydrogen that does not use coal and natural gas and on a massive scale. Third, the logistics and infrastructure for the hydrogen and all the supporting activities have to be established. It is not expected that hydrogen will replace products like jet fuel or even much of the diesel fuel and heating oil market. However, making a serious dent in making synthetic guels from hydrogen would do wonders in driving down the market price of petroleum products which would in turn, greatly reduce the costs of fuels for which there would be no substitute. A reasonable goal would be to replace three quarters of petroleum based gasoline consumption. However, by the time we are able to achieve that 75% level of market penetration, total need then would probably be 30% to 40% more total energy than the total energy from gasoline consumption s in the year 2000. This means that we probably need to generate four TRILLION kilowatt hours of electrical energy per year just to make hydrogen. This number comes from the need to produce about 50 billion Kilograms of hydrogen requiring the 56.3 kilowatts of electricity per kilogram and adding a margin for the additional growth in demand. We would need to build 460,000 megawatts in additional power plant capacity. Power plants are measured in megawatt capacity and for example, Dominion Virginia is a utility that serves 3.8 million people using 89 power plants producing 18,600 megawatts of power. This is an average of 209 megawatts for each plant. The size power plant complexes I propose in Part II are each 183 times greater capacity than the average Dominion Virginia plant! For example, this means that we should target for building a dozen 38 mega kilowatt (38,000 megawatt) power plant complexes and those will be very much bigger than any in existence today. The problems with the electrical utility grid: The original concept behind distributing electrical energy was to generate it close to where it was used. A lot of energy is lost transmitting large amounts of power over wires because of the electrical resistance of the wire. The gird becomes less and less efficient the longer the distance. The most reliable design for the grid requires generation plants close to points of consumption which are in turn interconnected by greatly over-designed high voltage transmission lines connecting the “nodes” of the grid. By greatly over designed, I mean transmission lines capable of supplying the entire demand if the local generation plants go off line. When the grid is operating “normally,” there would be very little actual power being transmitted over the grid between “nodes.” Of course it is not economic to build transmission lines and NOT actually transmit power over them and indeed, there are few places in the grid operating with little load. Further, the politics of power generation and transmission lines page 10
is that of “not in my backyard.” Political considerations have led to not having required power generation close to users, and for the most part, causing the grid to operate at near capacity in many geographical areas. This of course all means that our vulnerability to serious power outages has increased. The use of wind and photovoltaic power generation to supplement the present utility grid suffers variability of output. The variability includes the wind dying down and the sun setting. Naturally, you have to place wind generators where the wind blows and that is generally places that were avoided when our forefathers built cities. Demand is where people choose to live and work and is driven by lifestyle norms which cause such things as the peak demand for power coming in the early evening. Peak demand usually occurs when power is needed to turn up the heat or air conditioning, cook dinner, turn-on lights at dusk, fire up the TV and other uses. About the only present practical way to quickly match supply when demand fluctuates is with gas turbine generating units. Because of economic considerations, law suits, environmental concerns, overloaded grid sections and such, most of the gas turbine generating units are located closer to cities and are fired with natural gas. Natural gas is also the most efficient fuel to heat our homes so when vast quantities are diverted to making electricity, it drives up the cost of for heating our homes. In short, the unintended consequence of the increase in wind and other green technology in making electricity is to increase the costs to consumers for heating their homes. The utility grid itself is another way to “smooth” demand to match supply. A really large grid transcends time zones which has the effect of “stretching out and smoothing” peaks and valleys of demand. The larger the piece of generation equipment, the more efficient it is likely to be, but as mentioned above, it also generally takes longer to change output to match fluctuations in demand. The desirable feature of large grids for electrical generation is that remote and large steam driven generation plants can operate most efficiently. A large grid also combines many generation sources which could include a lot of wind, solar, tide and other power sources. For example, wind which picks up in some geographical area, can off-set the wind dying down in other areas. There is however, some limitation ratio of how many fast changing “green” variable output generation devices can be incorporated in a grid before the slow changing generation plants cannot change output fast enough to keep the line voltage from dropping to unacceptable levels. Once again, the partial solution is gas turbines “idling” along (called hot standby) and producing little output, burning precious natural gas, but able to pick up the load very quickly because they are already rotating. Of course, idling along is a very inefficient use of natural gas. However, the larger the grid, the more time the utility has to bring up output from all generation sources including steam plants and gas turbines that are started from cold.
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A major problem with large grids is that they become progressively more vulnerable to failure. And in a world of terrorism, they have become unacceptably vulnerable. Further, once power is lost, the larger the grid, the longer it takes to get power back on line. Revisiting Energy Return on Investment (EROI). On our old planet EROI was the core of energy decision making and how we became ‘rich’ enough for galactic travel. On earth, M.J. Kelly, at the University of Cambridge in the UK, wrote a review called ‘Lessons from Technology Development for Energy and Sustainability. It was published in MRS Energy & Sustainability: A Review Journal. (Materials Research Society, doi:10.1557/mre.2016.3) Figure 2 is an interesting chart showing EROI of many energy technologies. More interesting is the choice of the Economical Threshold of seven (7). A seven times return on investment is about what is happening in the industrialized world and results in a growth in living standards of only 1 to 3 % per year! It should be noted that in terms of constant dollars, the US living standards has been declining by 1 to 3 % for most of the last decade. The decline is directly related to reduced productivity. In the scenario of choosing the highest EROI on our old planet, a reasonable goal for earth so that the poorest can advance in life style is in the EROI range of 15 to 20 to higher. President Obama recently announced that US employment numbers in renewable energy production recently exceeded that in all fossil fuel based energy production. That is NOT a good thing because it represents a massive reversal of productivity since the beginning of the Industrial Revolution! Worldwide, fossil fuels still account for 86% of energy output. Wind, Solar, and biological account for about 9%. Nuclear and Hydroelectric account for the remaining 5%. Nuclear could in one fell swoop reverse the loss in productivity and enrichen mankind. Kelly summarized meta-studies of how well solar photovoltaic power generation worked for Germany. The answer was an EROI of 3.9 and that does not include provision for buffering power delivery when the sun does not shine! Including the cost of backup such as batteries and hot standby gas turbines, the EROI drops to 1.6. Clearly, the use of solar PV reduces living standards. Next up is biomass, namely corn ethanol. I have previously published about how bad a deal is corn ethanol and not surprisingly, the EROI is only 3.5. Nothing better conveys disdain for the world’s poor than using food to provide energy. Worse, high starch corn is better for ethanol than high food quality corn which is more expensive. Naturally, the world’s poor are ‘nudged’ by price into eating low quality corn. Wind turbines coming in at an EROI of 16 at least exceeds the present economical threshold. The buffered EROI of 3.9 means that wind power alone will reduce current living standards. A little wind power that does not exceed what base station generation can handle in buffering does make a contribution, page 12
but once dispatchable generation is involved (i.e. hot standby gas turbines), the EROI plummets to 3.9. Spain has found that Concentrated Solar Power (CSP) where mirrors concentrate solar on a tower containing a molten salt medium that in turn is used for steam generation has an EROI of 19. While molten salt can carry over energy when the sun doesn’t shine, the buffered EROI is only 9. While 9 is above the current ‘muddle on’ threshold, a lot of the advantage is lost in the grid because the facilities have to be located in deserts a long way from where the electricity is needed. Combined Cycle Gas Turbine (CCGT) plants have the highest thermodynamic efficiency and don’t need to be buffered, but are complex and expensive which yields an EROI of 28. This is close to the EROI of 30 for conventional well characterized coal fired steam generation. The down side is they both use fossil fuels. Hydroelectric generation has an EROI of 49 which is really attractive. Buffering schemes such as pump storage reduces the EROI to 35 which is still very attractive. Unfortunately, the best sites have already been taken so more hydroelectric does not look promising. In fact, many hydroelectric dams are being torn down for ecology reasons. NUCLEAR IS THE EROI CHAMPION: NUCLLEAR SCORES 75! There is only one well understood technology at the present time that could produce such vast amounts of power and that is nuclear power. The good news is because the generation of hydrogen can occur at any time of the day, significant supplemental power from wind, tide, photovoltaic and other means could also be well utilized. For comparison with the issues that we now experience, generating electricity to make hydrogen from these “green” means is a far better solution than using these generating sources for supplementing the present utility grid. We are held back from the nuclear solution by unfounded fear. The root of the fear is the very wrong doctrine of “liner no threshold” concerning the biological effects of radiation. In truth, there are thresholds and almost nothing in science is linear. More in Part II. THE BOTTOM LINE on THE HYDROGEN ECONOMY: The world has a serious energy problem because we depend on petroleum of which we will in a few decades not have enough. The US part of the problem will not go away using various schemes to mitigate the problem by marginally greater vehicle mileage standards, making blending alcohols, drilling in Anwar, horizontal page 13
drilling, fracking, Deep Ocean drilling and the recent availability of abundant natural gas. These schemes will at best only buy much needed time for a more elegant solution. Petroleum distillate fuels have a lot of energy per liter, second in energy density only to nuclear, and can be safely transported to where used at less cost than any other energy source. There is the significant moral hazard of the developed countries restricting the use of hydrocarbon fuels upon which the world’s poor are so dependent. For the world’s poor to have any prospect of better lives, they must have easy and low cost access to fuels like diesel and gasoline. Corn ethanol is another example of a moral hazard where developed countries convert food crops to fuel which drives up the world cost of food. Perhaps worse, ethanol production does not require high quality food grade corn and when the price of all corn rises, the lower cost fuel grade corn end up in the food chain of the world’s poor. The nature of the more elegant solution is the separation of lots of hydrogen from water using a core group of massive nuclear generating plants, the primary purpose of which is to generate electricity. These plants could be supplemented by a variety of “green” electrical generating methods. The nuclear approach is a reasonable core solution that could be done with technology we now understand. The hydrogen generated could be used in part to create liquid fuels from coal, heavy tars and shale that we possess in North America. Hydrogen used this way free the US of dependence on foreign oil and still utilizes the well characterized and already existing distribution and use of gasoline and diesel. The hydrogen could also be used to directly power fuel cells in our transportation fleet except that the overall efficiency is a lot less than generally understood. The distribution problems for both gaseous and liquid hydrogen require solutions that do not exist and have significant risks and safety problems. Experience with liquefied and compressed natural gas shows we presently have the technologies to solve the distribution problem but because these fuels are not very energy dense, they will be at a cost far beyond the distribution of petroleum products. The scale of the enterprise is so enormous that it would require significant government financial backing and the national resolve to not choke the development in red tape, regulations and legal actions. The dependency on petroleum has reached the point where EROI
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smart action must be instigated in the next few years or we will face real freedom crushing and economic crises in not many more years.
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