Barring grievous errors this is the final release of the Spring 2009 National Renewable Ammonia Architecture, a bi-annual expression of what is happening in the world of renewable ammonia.
What's next? Thanks to the brutal writer's boot camp that is DailyKos I know I can write a quarter million words in a year's time. The question now is whether or not I can write 65,000 well organized words in four months; in an ideal world this work will be expanded into book format in time for the 2009 Ammonia Fuel Network fall conference. Perhaps I'm a little over-eager, but who'd have thought there'd be 224 substantial diaries under this name when I penned the first one on New Year's Eve, 2007?
As always, the tougher you guys are the better the work I produce. Have at it :-)
Ammonia: Food, Fuel, and Carbon Sequestration Catalyst
Thomas Malthus published An Essay On The Principle Of Population in 1798, a stern warning on the dangers of human overpopulation. Growth in biological systems is controlled not by total resources available but instead by the most scare vital resource – a principle known as Liebig's Law. That resource in land based agriculture is often biologically available nitrogen. We avoided this natural population control in the 19th century via the exploitation of the unique, massive nitrate deposits of South America's Atacama desert. As this natural mineral source played out at the beginning of the 20th century fear of impending famine arose again.
A renewable solution was found in electrolysis based synthetic ammonia, but we mastered fossil fuel based hydrogen production not long after that and, ignorant of the consequences of carbon dioxide emissions, set off a quadrupling of our population in just a century's time.
Today we face depletion of some of the natural gas resources that drive our nitrogen production at the same time the industry has withdrawn fully 50% of its drilling rigs from exploration duties due to low prices. Carbon dioxide from our industries is acidifying the seas and has the potential to largely wipe out seafood production, eliminating another major source of human dietary protein.
Ammonia from renewable sources can ensure food production, serve as a liquid fuel directly as well as support biofuel production, and as the critical nutrient in plant growth it should have a future role to play in carbon sequestration strategies as well. We should immediately assess what it will take to place a renewable ammonia foundation underneath our agriculture, energy, and climate change remediation efforts.
Ammonia Production Methods Today
All of the ammonia we have today is made with a century old process first developed in Germany by Fritz Haber. The initial benchtop system, put into operation in 1909, produced a half cup an hour. Four years later BASF chemist Carl Bosch had worked out the particulars of volume production and a large scale plant was built at Oppau, Germany.
The Haber Bosch process requires only pure nitrogen, pure hydrogen, and a high pressure reactor with a catalyst in order to produce ammonia. The nitrogen is relatively free for the taking from the air but hydrogen, no matter what method we use to obtain it, involves the use of energy. The primary sources for the hydrogen used in ammonia manufacture today are natural gas and coal. There are an increasing number of petroleum coke projects in development, and a handful of remaining hydroelectric facilities built forty to sixty years ago.
When a fossil carbon based feedstock such as natural gas, coal, or petroleum coke is used the mechanism for extracting hydrogen is a device called a steam methane reformer, or SMR. Hydrocarbons are mixed with steam under pressure and in the presence of a catalyst, producing hydrogen and carbon monoxide. The carbon monoxide is captured and reused in a lower temperature process called a gas-shift reaction, producing additional hydrogen and carbon dioxide waste.
Nitrogen is extracted from the atmosphere using a cryogenic air separation plant when large volumes are required or pressure swing adsorption systems when smaller amounts are needed. Temperature and pressure are arranged such that the desired nitrogen liquefies while other gasses remain in gaseous form or have already been extracted based on their boiling point. The nitrogen is then cleansed of trace contaminants of the other gases with a variety of methods, yielding an extremely pure feedstock for the ammonia synthesis.
When a renewable source of electricity is available hydrogen may be cracked from water using an electrolysis unit. This was the method of choice for ammonia production until World War II when a variety of developments began to make gasification of coal and the production and use of natural gas lower cost choices.
We studied, as much as one can given the conditions on the ground, the Sable Chemical renewable ammonia production facility in Kwe Kwe, Zimbabwe. The world's largest surviving hydroelectric plant, it originally produced 250,000 tons of ammonia a year using power generated by the Kariba dam, some two hundred miles north of Kwe Kwe. The admittedly sketchy information indicated the plant at full capacity was consuming half of the dam's 1.3 gigawatts of output, which translates into a 35% electrolyzer efficiency. Given the 1969 construction we suspect the efficiency was closer to 55% and that either the report is vague or the dam's generating capacity was later upgraded.
The particulars are in doubt but the principle is clear; a large swath of largely undeveloped territory managed to get their nitrogen fertilizer needs met from a hydropower source and the plant has performed for the last forty years. The plant continues to limp along today at 25% capacity but recent announcements indicate that long overdue electrolysis unit maintenance will be performed and the plant will resume producing at about 60% of its maximum capacity.
Neither Organic Nor Natural Methods Will Suffice
There are a great many fans of organic methods and we believe this is an inescapable trend; our large scale monocultures depend on many fossil fuel based inputs and a tremendous number of food miles are involved. Methods more in tune with the Earth will ease the load our species puts on her. Nevertheless the simple fact exists that protein content in crops depends on biologically available nitrogen; the issue is one of mass balance rather than ideology. Roughly half of all human consumed protein has its roots in synthetic ammonia.
The field corn crops along with rice are probably the most studied nitrogen consumers and the Iowa State University Extension Department's 2006 Regional Nitrogen Rate Guidelines For Corn is most instructive.
High yielding hybrids require up to 275 pounds per acre of available nitrogen. The sources are the five to twenty pounds of naturally occurring nitrates that arrive with precipitation and the remainder is roughly split between nitrogen left in the previous season's corn stover and ammonia based fertilizers. Remove half of the nitrogen expected by the crop and yields will plunge from the current average of 154 bushels per acre to perhaps half of that. Wheat suffers not only a decline in yield but a dramatic decline in protein – an undesirable outcome in places like Egypt where half of the population subsists on $2/day and subsidized bread. Remove 40% of a population's dietary protein and there will be rioting in the streets.
After we hit the planet's unenhanced nitrogen maximum that so concerned Malthus but before we learned how to make synthetic ammonia from fossil fuels we made our way for nearly a century using a fossil resource of the Atacama Desert. More like the surface of Mars than any other place on Earth, this desert held a treasure beyond price: nitrate deposits.
70,000 square miles of land pinned between the Andres and the Chilean Coast Range, the Atacama has been in a twenty million year long rain shadow. Natural nitrates formed in the atmosphere combined with sodium from sea spray blowing off the Pacific and accumulated in the area. The utter lack of water, with precipitation averaging less than a millimeter a year, meant that the normally rapidly moving nitrate compounds accumulated in great drifts up to ten feet thick. Discovered at the beginning of the 19th century the white gold of the Atacama was worked to near exhaustion and only the timely perfection of the Haber Bosch process at the beginning of the 20th century saved us from famine.
Canadian fertilizer producer Potash Corporation of Saskatchewan has begun some operations in the Atacama again, pursuing sodium nitrate and potassium nitrate production using facilities obtained from a Chilean bankruptcy court. It is interesting to see these areas coming back into production but the volume of nitrates available would not broadly support world demand.
Global Ammonia Production Emissions
Global ammonia production is based on about 70% coal or petroleum coke and 30% natural gas. There are three legacy hydroelectric facilities nearing end of life which contribute a tiny fraction of the total annual production of 136 million tons.
The 95 million tons of ammonia produced annually with coal release 361 million tons of carbon dioxide. The 41 million tons of ammonia produced with natural gas release 74 million tons of carbon dioxide. The total 435 million tons of emissions are 1.6% of the global total of 27,250 million tons.
Given that developed natural gas fields are fragmented and depleting quickly in terms of multi-decade ammonia plant operational lifetimes it is reasonable to assume that existing natural gas based ammonia plants could be converted to coal gasification in an emergency. Should this happen across the board ammonia related carbon dioxide emissions would climb to 517 million tons or 1.9% of the total.
Unlike other emission sources there is a fairly linear relationship between ammonia production and food production. We can cut emissions in all other areas by cutting consumption, but cuts in this sector lead to food shortages in a one to two year timeframe. There would be significant changes in this dynamic if a combination of economics and changing ethics made meat a condiment rather than an expected course, but this would be a dramatic shift in western culture and seems unlikely to proceed until it is forced upon us.
Ammonia In Domestic Agriculture
Fully half of all human protein comes from man made ammonia. Plants require nitrogen to produce protein and ammonia is the only viable source for large scale nitrogen applications. The United States uses about 18.5 million tons of ammonia annually from the global production of 136 million tons. 90% of this is used in agriculture. Over the last forty four years of statistics corn has averaged nearly 44% of the total, wheat almost 14%, and the remaining 42% of agricultural use is spread among all other crops. Historically ammonia use has hovered around that 15 to 16 million ton mark for at least the last two decades but the import percentage has climbed from 18% to 48%.
year | prod | total | imp% |
1991 | 12800 | 15540 | 18% |
1992 | 13400 | 16090 | 17% |
1993 | 12600 | 15260 | 17% |
1994 | 13400 | 16850 | 20% |
1995 | 13200 | 16800 | 21% |
1996 | 13400 | 16790 | 20% |
1997 | 13300 | 16830 | 21% |
1998 | 14700 | 18160 | 19% |
1999 | 11000 | 15800 | 30% |
2000 | 11800 | 15680 | 25% |
2001 | 9120 | 13670 | 33% |
2002 | 10100 | 14770 | 32% |
2003 | 8770 | 14490 | 39% |
2004 | 8900 | 14700 | 39% |
2005 | 8340 | 14860 | 44% |
2006 | 8190 | 14110 | 42% |
2007 | 8840 | 15370 | 42% |
2008 | 8240 | 15960 | 48% |
American farmers planted 86 million acres of corn and 65 million acres of wheat in 2008.Corn fertilization averaged 170 pounds of ammonia per acre and wheat received 72 pounds per acre. Yields averaged 154 bushels per acre for corn and 36 bushels per acre for wheat.
Fertilization rates are given in ammonia equivalents. Depending on the crop, producer preference and availability, ammonia can be applied in various compounds. Actual usage by volume of nitrogen was anhydrous ammonia (59%), urea (27%), a mixture of urea and ammonium nitrate known as UAN (9%), and the remainder were various specialty forms of fixed nitrogen such as ammonium phosphate and ammonium sulfate compounds.
Properly fertilized wheat will yield fifty to sixty bushels an acre while alternating fallow cultivation methods will struggle to produce just a little more than half that amount. Protein content is also a concern – hard red spring wheat will have up to 17% protein when fertilized and as little as 9% if not. Many farmers didn't fertilize in the fall of 2008 due to the difference between grain price and ammonia price which may mean a 50% reduction in total yield and a a 40% reduction in protein in what is harvested. If this has happened to farmers in all of the large wheat exporting nations, and we believe it has, it's a recipe for collapsing governments all over the developing world.
The corn crop is raised primarily for its starch content and protein is not closely tracked. A sudden reduction in ammonia based fertilizer input here will have the same yield effect as is seen with wheat – a sudden plunge to about 60% of the current average.
Domestic Ammonia Production Facilities
These 29 locations are ammonia plants either operating or, in the case of the recently idled Agrium Kenai facility, in good enough condition to be returned to service. Many of these plants are not purely ammonia production but instead operate in conjunction with follow on fertilizer manufacturing or are involved in the production of derivative industrial products such as nitric acid. All capacity figures are in thousands of tons of ammonia per year.
Owner | Location | Capacity |
Agrium | Borger-TX | 490 |
Agrium | Kenai-AK | 280 |
Agrium | Kennewick-WA | 545 |
CF Industries | Donaldsonville-LA | 2040 |
Coffeyville Resources | Coffeyville-KS | 375 |
Dakota Gasification | Beulah-ND | 363 |
Dyno Nobel | Cheyenne-WY | 174 |
Dyno Nobel | St. Helens-OR | 101 |
Green Valley | Creston-IA | 32 |
Honeywell International | Hopewell-VA | 530 |
Koch Nitrogen | Beatrice-NE | 265 |
Koch Nitrogen | Dodge City-KS | 280 |
Koch Nitrogen | Enid-OK | 930 |
Koch Nitrogen | Fort Dodge-IA | 350 |
Koch Nitrogen | Sterlington-LA | 1110 |
LSB Industries | Cherokee-AL | 159 |
LSB Industries | Pryor-OK | 300 |
Mosaic Company | Donaldsonville-LA | 508 |
PCS Nitrogen | Augusta-GA | 688 |
PCS Nitrogen | Geismar-LA | 483 |
PCS Nitrogen | Lima-OH | 542 |
PCS Nitrogen | Memphis-TN | 371 |
Rentech Energy | East Dubuque-IA | 278 |
Terra Industries | Beaumont-TX | 231 |
Terra Industries | Donaldsonville-LA | 360 |
Terra Industries | Port Neal-IA | 336 |
Terra Industries | Verdigris-OK | 953 |
Terra Industries | Woodward-OK | 399 |
Terra Industries | Yazoo City-MS | 454 |
Total | | 13945 |
U.S. Ammonia Facilities Excluding Alaska
Domestically the year 2007 saw the closure of the 280,000 ton per year Agrium facility in Kenai, Alaska due to natural gas depletion, the impending conversion of Rentech's 278,000 ton per year East Dubuque facility to coal from natural gas, and the Farmland Chemicals plant from Lawrence, Kansas resuming operation after being dismantled and reconstructed in its new location in the natural gas rich Persian Gulf state of Oman.
2008 saw the closure of two additional U.S. plants and the percentage of imported ammonia rose from 42% to 48%. The world added five million tons of capacity, with total production rising to 136 million tons. Half of that capacity increase was built in China and it appears that coal gasification is being used as the hydrogen source. Also reported was the delay of the Rentech plant's conversion to coal.
Dakota Gasification's facility deserves mention for being more environmentally friendly than any other coal operation – they've got carbon capture in place. Unfortunately the final resting place for it is oil field pressurization, but recycling carbon dioxide is a step in the right direction and their capture facility will work as well for sequestration as any other purpose. None of the others are capable of carbon capture at this time.
Domestic Ammonia Distribution
The United States has a roughly 3,100 mile ammonia pipeline network owned primarily by two separate carriers. The pipeline network begins in the Gulf Coast region where 60% of domestic manufacturing capacity is, proceeds to Iowa in the geographic center of corn country, and then branches out from there to service the corn growing region.
National non-agricultural ammonia usage is about two million tons a year evenly distributed in time across the manufacturers of plastics, fabric, and explosives. There is a great fall and spring rush in which the other sixteen million tons are dispensed in the window after crops come out in the fall and again before they are planted during the spring.
The pipeline network can store roughly a one and a half million tons and it transfers around three million tons a year or only 15% of the total usage. There is a national network 2,975 miles long serviced by 31 barges, primarily on the Mississippi, each with a capacity of roughly 2,500 tons. 6,000 rail tank cars each holding roughly a hundred tons each are also in use.
The system already strains each spring and fall when fertilizer demand is at its peak. Expanded use, whether from the fertilization of other regions with an eye on biological carbon sequestration of the direct use of ammonia as a fuel need to be considered carefully so as to not interrupt vital agricultural production.
Domestic Ammonia Economics
Domestic ammonia production was 8.84 million tons in 2007 and the USGS states that plants were running at 84% capacity Production figures are not exact and we attribute this to overall market instability – plants were on and off based on the prices of both inputs and outputs.
2007 imported ammonia totaled 6.5 million tons. Major suppliers were Trinidad (55%), Russia/Ukraine (21%), and Canada (12%). The price at port is stated to be $339/ton indicating a transfer of $2.7 billion overseas.
2008 domestic ammonia production was 8.24 million tons and plants were running at 78% of capacity. USGS sources do not agree entirely as some numbers are beginning of season projections and others are end of season statistics.
2008 imported ammonia totaled 7.7 million tons. Major suppliers were Trinidad (56%), Canada (15%), and Russia Ukraine (22%). The price at port is estimated to be in excess of $500ton indicating a transfer of $3.9 billion overseas.
Ammonia prices crashed to as low as $125/ton at the Tampa Bay terminal late in 2008 but inland stocks remained high in available quantity and price, having been purchased during the price spike in the spring and summer of 2008. The cooperatives holding stocks and the farmers needing them played a mutual waiting game, with 2008 fall nitrogen fertilizer application being about 10% of the norm.
Natural Gas Supply Issues
Natural gas is, like all fossil fuels, on a trajectory towards depletion both outright and in terms of energy return on input and there are the potential for attendant above ground issues in already unstable places. We examine the three largest sources of supply: Trinidad, Russia/Ukraine, and Canada, each of which reveals a facet of the various failure modes.
Trinidad, supplier of over half of our total imports, had reserves of 30.7 trillion cubic feet (~17 Tcf proven, 7.8 Tcf probable, 5.9 Tcf possible) of natural gas in 2004 and usage was just under a trillion cubic feet a year. Many additional industrial plants meant to use the inexpensive gas and labor in this Caribbean country were planned to come online between 2008 and 2010. A 2004 IMF study indicates that Trinidad would exhaust its reserves within ten years of these plants becoming active. The global economic recession should slow domestic industrial consumption but liquid natural gas exports will ensure an ongoing drawdown of reserves.
Russian exports are subject to periodic geopolitical tensions and these are never going to be resolved. Two thirds of Gazprom's exports flow through Ukrainian pipelines. The Ukraine has natural gas production but only covers 25% of domestic need with their own resources. The Russians would prefer that NATO not expand to include the Ukraine and they wield natural gas as a stick at times. Three months ago the International Energy Agency declared that Russia had "lost its status as a reliable gas supplier to Europe" due to the frequent disputes resulting in lowered gas flows.
Canada, source of 15% of U.S. ammonia and 18% of imported natural gas, faces a decline in energy return on input (EROI) for its production. Much like the situation we face with all large oil fields having been discovered and worked, the Canadian natural gas production depends on continual exploration of smaller and smaller pools as the larger, more profitable ones decline. There will come a day within the next decade where Canadian natural gas production stops, not because there isn't any gas left in the ground, but because the creation of the wells to get to them require more energy than the pools contain.
The three largest ammonia import sources are all under different stresses and will all decline or fail precipitously within at most a decade, cutting the United States off from 88% of current imports. This alone will amount to a reduction in ammonia supplies in the continental United States of about 36%.
National Ammonia Independence
Given the dangers we face the United States can and must achieve national ammonia independence by a mix of refurbishing existing plants and construction of new renewable production facilities.
Existing facilities operated at capacity could produce about 14 million tons of ammonia annually and would require 2.5 million tons of hydrogen to do this. This hydrogen, current produced from a mix of natural gas and coal gasification could be replaced with electrolytic production.
Using current technology 6,300 two megawatt electrolysis units would be required and assuming 8,760 hours of operation annually 12,600 megawatts of continuous power would be needed to fully replace hydrogen derived from fossil fuels. A scheme to store renewably produced hydrogen would enhance the flexibility of such a configuration but at this time the best method seems to be just getting on with the process of making ammonia. Even so, the Louisiana ammonia plants may have access to nearby salt domes which would allow the creation of solution mined caverns capable of storing large volumes of hydrogen, a configuration that would naturally complement the large but variable wind resources available on the Texas plains.
The 7.9 million tons of imports could be replaced with distributed renewable production. This volume of production could be covered by 7,900 megawatts of continuous power and a $25 billion investment in Haber Bosch style plants. Assuming $0.04/kwh electricity resulting in an annual cost of $2.8 billion the physical plant costs could be recouped in ten to fifteen years given the Gulf Coast ammonia pricing we saw in 2008.
Hydroelectric or nuclear are the only clean power sources steady enough to drive this process today. We believe there is a simple route to a system that would work with a hybrid wind and base load power source but this likely uneconomical; why would anyone build a wind driven plant to run 85% of the time and only achieve 40% of capacity when the same equipment could be installed near a hydroelectric or nuclear facility and produce 100% of the time? Carbon credits may change that dynamic but more work is needed in this area before definitive statements can be made.
Renewable Electric Sources
Ammonia can be produced by a completely carbon free process that releases no greenhouse gases. What is needed to do this is renewably generated electricity at a relatively low cost, air and water.
Hydroelectric power for ammonia.
The United States Department of the Interior maintains a national inventory of dams – a database of over 8,800 locations in the United States with information regarding their purpose. Giving a nod to Bill McKibben's consciousness raising work regarding the need to not just limit carbon exhumation but actively reverse its effects we chose the 350 largest facilities for our hydropower map. This map and associated Google Earth file show locations with either an impoundment in excess of eight square miles or a run of river installation. There is a negative correlation between good cropland and the elevation changes needed for good hydroelectric power. Hydroelectric power in the $0.02/kwh to $0.04/kwh range will yield ammonia in the $450 to $600/ton range.
Waste heat output from a renewable ammonia plants is a concern; 90% of the plant's electric budget will go to electrolysis and 20% of that will become low quality waste heat in the 160F range.. Our estimates indicate that a continuously operated plant will produce half a million BTUs of waste heat per hour for each 1,000 tons of annual production capacity. Production near large impoundments or large volume rivers ensures that cooling needs will be met.
Run Of River Or Impoundments Greater Than 5,120 Acres
Wind power for ammonia.
There is excellent correlation between national wind resources and the wheat growing states of North Dakota, South Dakota, and Kansas. The corn growing states of Iowa, Illinois, Kansas, Nebraska, and Minnesota have good wind resources in their own right and usable rail links to the wind rich Dakotas. Assuming the wind intermittency problem can be remedied, either by the mastery of the solid state ammonia synthesis process or the creation of a grid footprint large enough to ensure continuous production, a wind energy based ammonia production industry can be envisioned. 7,900 2.5 megawatt turbines each with a 40% capacity factor would produce the electricity needed to cover the anticipated import deficit.
Cooling requirements would be as described above and water use is an increasingly sensitive issue even in the riparian rule areas where corn and wheat are grown. Water use for electrolysis is relatively small at only 420 gallons per ton of ammonia. This works out to 42 gallons per acre at the heaviest level of corn fertilization – and annual rainfall per acre in Iowa is about a million pounds or three acre feet.
National Wind Energy Map
Solar power for ammonia.
Solar PV costs are too high for ammonia production based on current technology, but solar ammonia has potential.. A clever concentrated solar storage process using ammonia is in the pilot phase at the Australian National University but at this time there is no commercially deployable ammonia synthesis solution tuned for the sunny, relatively windless American southwest. A concentrated effort to develop such a thing would permit ammonia manufacture in that region, creating a domestic bilateral energy/food circuit in place of a similar trade arrangement with less friendly parts of the world such as Russia and the Persian Gulf states.
National Solar Energy Map
Second Generation Ammonia Production Methods
The century old Haber Bosch process has received many incremental upgrades but its fundamental nature remains constant: large in terms of capital and space, high temperature, and high pressure. Second generation ammonia synthesis methods must address these concerns and solve other problems, too.
Most promising and furthest along of the new methods is solid state ammonia synthesis. The basic idea is that an ammonia fuel cell can be run in reverse, consuming electricity and producing ammonia. This method shares the need for pure nitrogen with the Haber Bosch but takes water directly as a hydrogen source. The modules themselves are similar in shape and construction to a fluorescent tube style bulb and promise plants costing half of the older method since they don't need the expensive precious metal based electrolysis units. Besides the roughly 50% capital savings the electricity input will be 25% less than the electrolyzer based production.
University of Minnesota graduate student Mark Huberty and his advisor Dr. Ed Cussler have designed a Haber Bosch derived system meant for small to medium scale batch production. The system requires both a hydrogen and nitrogen source. The gases are mixed, the process runs to completion, and instead of gaseous or liquid ammonia an ammonia salt is the result. The ammonia can be extracted from the salt for use as fertilizer or fuel and the recovered salt is reused for the next batch.
The solid state ammonia synthesis and batch salt ammonia synthesis methods are important because they address the two biggest failings of the Haber Bosch process. Today the minimum plant size for a renewable Haber Bosch systems seems to be about 50,000 tons a year. Solid state ammonia synthesis can begin with a single tube, it will still scale up to as large a plant as is needed, and it will tolerate the variable nature of wind generated renewable electricity. The batch salt system will fit into the context of a farm in wind country with one utility scale turbine.
It should be noted that these production methods will form a continuum even after solid state ammonia synthesis and the batch salt method are off the bench and into production. Small and variable sources of electricity will need the new methods, but business plans that make sensible use of the waste heat and oxygen from the older method will lead to plants being built and operated profitably.
An Urban Plant Scenario
We completed a study of renewable ammonia production in the Niagara Falls area at the beginning of 2009. The area that drew our attention was in the largely abandoned south Buffalo industrial zone. We found a rail siding, an essentially idle industrial scale water tower, a nitrogen pipeline, an abandoned 115 kilovolt electrical feed, a nearby industrial user of ammonia, and all of these were neatly arrayed around an area that had formerly hosted greenhouses.
The envisioned plant would require a fifty megawatt continuous feed which is easily accomplished with the abandoned 115k circuit. No nitrogen separation facility need be constructed thanks to the existing pipeline in the area. Cooling would not be problematic given the massive heat sink of Lake Erie but power rates in the area can be extremely attractive when job creation is an effect of the operation. We examined current greenhouse design and operations as a component of the study with an eye on accessing the inexpensive power.
A 50,000 ton per year ammonia plant will churn out $25 million a year in ammonia at today's prices and require roughly $100 million in investment to construct. The plant itself will employ between thirty and forty in managerial, professional, and operations roles. The twenty five million BTUs an hour of low quality waste heat will support twenty acres of greenhouse space in the depths of a Buffalo winter. During this process we also determined there were some strong synergies between wholesale produce greenhouse operations and fish/shrimp farming, but we did not delve into this in detail.
Estimates of employment in the greenhouse operation vary wildly depending on which crops are selected and which cultivation methods are used – somewhere between at least fifty to as many as two hundred fifty could be employed by such an operation. The operation would be hydroponic, requiring no herbicide, and with industrial scale carbon dioxide production in the area the houses would be kept at 1,500ppm CO2 which renders insect reproduction impossible. Ultraviolet sterilization methods can eliminate root fungus problems. The produce would not be organic due to its hydroponic nature but it would be largely chemical free if the operation is well run. A facility of this size would produce approximately eight million heads of lettuce annually.
Similar synergies will be found applying waste heat and excess oxygen to the needs of rural markets. We have several opportunities in this area but they are unformed and we suspect that there will be additional patents to be had beyond our existing work on methanol synthesis.
Ammonia As A Liquid Fuel
The Ammonia Fuel Network, formed in 2004, has met annually and the conference now draws several hundred attendees. Manufacturers currently build both compression and spark ignition engines in demonstration quantities that use ammonia. Ammonia is difficult to ignite so some sort of hydrocarbon is used as an accelerant. Schemes include diesel/ammonia mixtures, gasoline/ammonia, and propane/ammonia. The long term solution would seem to be a pure ammonia system with onboard reformation of hydrogen to provide the accelerant.
There are current field tests of 100kw systems in fixed generation applications and a gasoline/ammonia hybrid truck was driven from Detroit to San Francisco in a 2007 feasibility demonstration. Not yet tested but entirely feasible is the conversion of a high efficiency natural gas turbine to a methane/ammonia mixture, or a reformed hydrogen/ammonia mixture.
Concerns regarding emissions of the various nitrogen/oxygen compounds are frequently raised by those not familiar with ammonia's combustion properties. Bearing only 40% of the energy of comparable volumes of petroleum products and burning at a much cooler temperature the nitrogen compound emissions associated with ammonia are lower than that of a gasoline engine. Nitric oxide (NO) emissions are comparable to those found in fossil fuel combustion engine exhaust and are easily handled with a standard catalytic converter. More problematic is the nitrous oxide (NO2) found in concentrations up to 25 ppm. This gas is 310x as potent a greenhouse gas as carbon dioxide, but its resident time in the atmosphere is much shorter.
The natural progression for the adoption of ammonia as a fuel would seem to be first in fixed generation situations where safety concerns are easily addressed. Natural gas turbines at peaker electric plants can be refitted for ammonia combustion and diesel generators need only a little manifold and control work to begin using an ammonia/biodiesel mixture. The first choice mobile users will be farmers, as their use coincides with the existing national ammonia distribution network, they are already largely trained to handle ammonia safely, and the horsepower required over long durations makes their tractors and combines unlikely candidates for any sort of hybrid power scheme.
Ammonia is indeed an inhalation hazard but it has been pressed into service before when carbon based liquid fuels were scarce; Dutch school buses ran on ammonia during World War II without any serious incident. The litigious United States will obviously proceed extremely carefully with regard to the use of ammonia as a general transportation fuel, but the delays are more political in nature than due to operational concerns.
Ammonia: The Other Hydrogen
There has been much work done in the last decade regarding the use of hydrogen as a fuel. The primary troubles are that most hydrogen production schemes involved fossil fuels somewhere in the process as their energy source and that hydrogen presents challenges in its transportation.
If we wish to use hydrogen in the place where gasoline goes now it is a simple fact that using coal or petroleum coke to drive a steam methane reformer is a net loser in terms of reducing climate impact. Emissions relocated are emissions nevertheless. We have to come clean here and renewable ammonia does just that.
Hydrogen, touted as the next wave of energy for our economy, is more properly described as an energy carrier rather than an energy source, and it has many vices.
The hydrogen atom, formed from just one proton and one electron, will automatically pair with another of its kind. This tiny molecule, atomic weight two, behaves dramatically differently from the next lightest flammable gas, methane, with an atomic weight of sixteen. Methane, which we better know as natural gas, can be easily and safely be herded into our homes via plain iron pipe with simple sealing compound at its joints.
Pressurize hydrogen in an iron pipeline and that pair of protons might dissociate when they hit the wall , tunnel through the metal, and then form hydrogen molecules again on the other side. That is unless they're somehow bound to the metal during transit causing what is known as hydrogen embrittlement. This is true of all metals except a few expensive alloys purposely made for hydrogen pipeline construction. Polymer pipelines don't degrade like metals when bearing hydrogen but they're porous enough that the hydrogen molecules leak straight through.
If you make a sandwich of metals and polymers the dissimilar methods by which hydrogen moves through them means the diffusion rate will be dramatically lower, but even so the pipeline will require a water jacket so an explosive air/hydrogen mixture does not form and collection points where the leaking hydrogen can be reintroduced. This is dramatically cheaper than the high cost alloy pipelines but the easy refit of existing petroleum and natural gas pipelines stands in stark contrast to the installation and maintenance issues associated with hauling hydrogen long distances.
It is fairly easy to envision an expansion of the existing 3,100 mile ammonia pipeline network delivering this hydrogen rich gas across the nation to reformation stations where ammonia is broken down into its constituent hydrogen and nitrogen again. The resulting hydrogen could charge vehicles, fuel cells, or enter short haul distribution networks of the metal/polymer sandwich pipeline for delivery to larger volume users that aren't quite big enough for a reformation station.
Conclusion
The more we explore ammonia's role in agriculture, biofuels, energy storage, and carbon sequestration the more excited we become.
The upgrade of current plants to renewable hydrogen sources coupled with a building program to replace import sources that will soon fade is a fine form of economic stimulus. The perfection of a synthesis method that is more capital and energy efficient as well as being tolerant of wind's variability will facilitate the firming of wind energy sources and the replacement of peaker natural gas systems with ammonia driven generation. Increasingly stringent diesel particulate emission standards for farm vehicles may be met using hybrid diesel/ammonia engines and as supplies become larger a full scale conversion to ammonia/reformed hydrogen will be a natural next step. Readily available nitrogen applied to the fertilization of long term tree crops coupled with a biochar program could lead to greatly enhanced carbon sequestration.
These things will not happen without an application of funds as well as the talent and will of those involved in the ammonia fuel and renewable ammonia communities.
The Haber Bosch method is a well understood process that takes on a new air of environmental protection when driven with renewably produced hydrogen and carefully integrated into other systems so as to make good use of its waste and byproducts. Progress here depends on access to capital and a willingness to envision the twin disasters of fossil fuel depletion and climate change as hazardous opportunities rather than hopeless outcomes for our species.
Too long we have watched exciting developments in ammonia production twisting in the wind for lack of research dollars. The arrival of the Obama administration and in particular Steven Chu at the Department of Energy has unleashed a torrent of funding and it seems very likely that a portion of it will be secured for solid state ammonia synthesis and other similar developments. Given the gravity of the situation we face this ought not be left to chance, but renewable ammonia has not yet found its champion despite its many benefits.
The carbon emission avoidance associated with renewable ammonia production is easily calculated but the carbon sequestration potential is wide open territory for researchers. Human agriculture has always had the boundary concern of biologically available nitrogen; freedom from that particular Liebig minimum may yet permit us to avoid some of the grimmer consequences of climate change by judicious plant based carbon sequestration.
There is room in this plan for everyone – the third shift plant operator, the organic food activist, the farmer, the manufacturing plant owner, and the banker. But the horizon recedes a little more each day we continue burning through our remaining oil endowment without putting in place the things we'll need when that energy source inevitably runs dry.