could begin in any number of ways, but let’s start with what the world needs – an inexhaustible, renewable source of clean fuel, food, fertilizer and electricity, that actually pulls carbon out of the atmosphere, can be “scaled up” to the industrial level, “scaled down” for remote villagers with very limited means, and is completely open source… belonging unconditionally to everyone. Do you want to improve on it and put those modifications into open source as well? Do you want to develop a proprietary technology that builds on this one? Go for it!
Later we can discuss why the above features are important, but for now let’s lay out the invention in question. Rest assured what follows uses several very simple long-established techniques, that just happen, in this case, to be working together to give us what we need.
The tools in question boil down to gravity, photosynthesis, air pressure, bacterial action, and sunlight. There’s a solar-concentration option for larger operations, and some charcoal burning if you want to lock up more carbon in the soil. But those first five resources are widely available.
Let us address some of the key objections experienced renewable-energy hands may instinctively have to the system we are about to discuss. They are important – in particular, because each one is a strength of this design, as opposed to a weakness.
First let’s list, and then we’ll go over each in turn as we describe the invention proper.
Is the real EROEI – the Energy Return On Energy Invested – positive? In other words, is the energy gained after the process of finding, extracting or manufacturing, refining and transporting it to market a net positive, especially if you count the energy required to make all the machinery and infrastructure in your system, and everything required to replace its parts and keep it in good repair?
Yes, and dramatically so. That’s one of the advantages of getting the natural elements of the system to do virtually all the work. And of having a system that can be built on the small to moderate scale with little more than scrap.
If there’s biomass involved, isn’t your system inherently limited by the amount you can find and transport to it?
Technically yes, but not if you’re creating even more biomass on site.
Aha! But how much can you realistically produce on site, or right around it?
Absolutely ludicrous amounts, especially at the industrial scale. Any biomass that doubles itself even once in a day, much less multiple times, is growing at a rate adequate for your needs. The theoretical, exponential daily increase in the feedstock in question is naturally limited by the inputs fundamental to its production – which is why our ability to supply those, essentially for free, at a phenomenal scale is so critical. That factor is why this particular innovation is a turning point with regards to the production of food, fuel and organic fertilizer, and a primary reason why it can absorb so much carbon out of our ecosystem.
Does this solution render everyone else’s work in, say, conservation or renewable energy pointless?
Not at all. In fact, quite a few techniques become even more powerful when joined to this open-source method. We’ll get to those as they come up, but having experience in anything from concentrated solar to waste treatment to algae harvesting to aquaponics would not only be useful in using this system but also in developing your own open-source or proprietary applications. If you are running a business, such advantages may give you a considerable edge in what has just become a vastly larger market for your skills.
Will this push conventional farmers out of business?
The kind of food produced directly, while eaten extensively in some parts of the world, will more likely be used as feed, feedstock or fertilizer and thus contribute to our food chain slightly less directly than if we ate all of it ourselves. Then again, given how much food, fuel and fertilizer are consumed by virtually all forms of agriculture, that isn't much of a drawback. Rather, it's something we need. And for farmers, this will reduce the cost of key resources needed for their work.
Will a few large corporations simply move in and dominate this field, pushing out smaller competitors?
While large organizations could easily set up major operations producing methane, fertilizer and other products, suppliers are apt to be much more of a patchwork presence, even in instances where intrepid companies carve multiple, highly profitable niches. Why? Two reasons. Natural gas has many benefits, but its greatest “drawback” is that it is both hard and dangerous to transport. As a gas, it can be moved around within a city or other locality, but liquefied natural gas is both tricky to process and very perilous if detonated, and pipelines have a distressing tendency to leak, if they even exist in a region in the first place. Further, large organizations with the greatest reason to generate huge quantities of extremely cheap methane are those who have a guaranteed market that directly benefits from very low costs, themselves. Power plants, some foundries, and other manufacturers are obvious candidates. These groups may produce some excess methane for the local market, and other associated products, particularly fertilizer. But for the most part, it will be other, higher-value products they ship to distant markets, if anything. Closer to home, electricity will be a more mobile resource, within the limits of the regional or national grid.
The technique for doing all this is simple, though it involves several elements, which we shall overview before going into greater detail on each one.
Biogas digesters are a method for reducing organic waste into methane, and can be used to turn animal manure into natural gas, or as a productive part of a city’s sewage-treatment system. Various types of digesters exist, but this book is primarily concerned with a version that combines organic waste, usually manure, with water in a slurry in which materials break down as they slowly flow through the system. In theory, up to 75% of organic waste being treated can be reduced to gas, roughly 40% of which is carbon dioxide while 60% becomes methane. Now, while this would yield up 45% of an organic mass as methane (and another 30% as CO2), getting close to the theoretical limits in a reasonable period of time is a bit more complicated, and most industrial efforts go through considerable effort to keep the slurry at the ideal temperature for the bacterial action involved, and to keep it periodically stirred up so that organisms can feed and break down organics more efficiently. Ironically, given the degree to which this system recycles all of its elements, maximizing gas production each time your organics pass through this digester will probably be one of your lowest priorities, for reasons discussed below.
As they stand, biogas digesters have many virtues, especially when you have large quantities of relatively safe organic waste that is easily reduced to gas and a remnant mass of fertilizer. But they are limited by the amount of usable biomass available.
Yet there are obvious ways to improve algae’s growth rates. Other land-based crops have been grown very successfully and at greatly enhanced rates in water, using aquaponics. Certain plants thrive under the aquaponic technique of suffusing the water around their roots with nutrients, while keeping them under light of greater-than-normal intensity for a period exceeding normal daylight hours, if not continuously. Ironically, while sustained lighting will prove helpful, determining ideal light intensity may actually be counter-intuitive. Research by Sorokin and Krauss
on five varieties of algae found that lighting less than that of full, direct sunlight was most productive on their samples growing in a medium which was set in a water bath – with chlorella pyrenoidosa doubling just over 8 times in a day at 39 degrees Centigrade with illuminations ranging from roughly 1,000 to 4,000 foot-candles. Whether or not this full rate of growth can be achieved in normal water, or even water treated with our byproduct nitrates as described further on, the information that some varieties may in fact do much better in less than direct sunlight is very promising for operations taking place in less sunny parts of the world, and for any location dealing with inevitable cloud cover and so forth. Ultimately, you will want to test whatever varieties you have available to see which ones operate best under local conditions. Someone in a desert may want algae which makes fuller use of very intense sunlight, but an operation in temperate zones or under normally cloudy weather may be very happy with a species which favors dimmer conditions. Whatever your chosen crop, you will want an energy-efficient means to expose great masses of algae to roughly their ideal illumination.
The solutions here seem to present themselves. First, simply increase the time in which your algae is exposed to its ideal illumination, and the volume of algae thus exposed. Remember, normal algae in a pond or pool, for all its productivity, is limited not only to its daily allotment of sunlight, but by how much of the algae mass can be fully exposed to it. But what would happen if your algae were in a tank with at least two transparent walls on the sides facing the east-west daily path of the Sun? And what would happen if you used inexpensive mirrors, such as reflective mylar, to shine that light not only into the top of your tank but, by way of these walls, throughout it? Or if you “backscattered” direct or reflected sunlight using a bright white or moderately reflective surface, such the bottom of your tank or sheets of material (such as aluminum flashing) beside it? This backscatter can let you direct lesser or greater intensities of light onto that “lesser,” “imperfect” reflective surface, giving you a greater ability to control the exact luminosity. You can therefore shade a tank from harsh, direct sunlight while leaving your incoherent reflectors partially or fully unshaded, thus providing adjustable lighting. Reflectors around the tank could kick in, either manually or automatically, during substantially dimmer daylight conditions.
Energy-efficient LED bulbs, especially red and blue bulbs such as are produced cheaply for Christmas trees, would enable even a modest operation to sustain this light during the darkest days or nighttime hours, if it were so inclined. Some aquaponics practitioners have found that artificial red and blue light seems to be more effective than normal full-spectrum light. If this proves to be the case with algae, filtering sunlight into those wavelengths might an efficient way to blunt the full intensity of the Sun while allowing only the most useful light through. But there is no data on whether a normal filtering material could do this properly or how the algae would respond. Either way, the energy efficiency of simply using existing sunlight, especially in sunny regions, is hard to beat. Still, more than a few large operations are apt to have excess electricity, especially at night, a problem still endemic to most grid-supplying power plants. Hence, LEDs, at least, will be a viable option for many, if not all producers.
Some will argue about just how efficient algae are in terms of the percentage of sunlight they convert to useful energy in photosynthesis. This question is interesting, but for our purposes, somewhat beside the point. Our real concern is how much of the solar energy that falls in a particular area we can use in this process. When dealing not with a single cell or single layer of cells, but an entire, three-dimensional mass of algae more or less floating in a tank of water, you have to realize that a beam of light passing through one thin layer of organisms travels on only slightly occluded to the next. Which is why we are more concerned about not overloading exposed algae with too much light, and surrounding any mass we are nurturing with a more ambient light at an intensity it can make the most use of. In most brightly lit regions, the full light of day will actually be more energy than this process can really make use of, except in exceptionally optimized and high-density operations.
Now, you might reason that, even if you could fully illumine all the algae in your tank, for as long as possible, there is only so much CO2 available in the air to convert, much less in the water, and if you are not adding nitrates, the richest source of nitrogen will be the air as well. Even if you were effectively growing algae in three dimensions, would effective limits to these inputs limit growth in the depths of your tank as well?
They would, if we were only working with the CO2 present in the atmosphere, and only the gases available at the top of the tank. But we aren’t.
Remember that your biogas digester has two primary gaseous products – CO2, and methane, which we burn, and which converts to water vapor and CO2 in turn. I suspect that in many less advanced biogas systems, the methane and CO2 often mingle significantly despite their different density. For our purposes, it does not matter if there is some dilution of the methane we burn on site, as we will be “sequestering” all the carbon produced by turning it into our feedstock – whether for the digester, as actual food, or as fertilizer. Algae, you see, is eaten in many parts of the world, though more heavily in the Far East, and most commonly in forms such as kelp. Direct production of food is one option for this system, but many algae varieties best able to absorb CO2 may work best as the feedstock for our biogas digester and as organic fertilizer (either as a dead mass or as the solid remnant left after being processed the digester). In all likelihood, biogas methane and fertilizer will be the dominant, basic products of this system.
For sequestration, we can bubble carbon dioxide and some ordinary air into water as very small bubbles, as can be created through air pressure in submerged “leaky hoses” and other, more advanced methods. Ideally we will dissolve some of this CO2 into the water going into the algae tanks ahead of time, without reaching a concentration that becomes acidic. As with many aspects of this system, the larger your production becomes, the more effort you will have to make to keep everything in balance. A huge, rapidly growing algae biomass may require more and more carbon, but you can only pre-load so much, and you can only bubble in so much at a time to be sure that you do not overwhelm the algae’s capacity and risk acidifying the water.
But the best form algae can take for the sake of raw production is probably a loose mass, essentially a slimy cloud of floating, photosynthesizing life, preferably made of many very small, discrete units, if not individual cells. Micro-bubbles caught in this mass can slowly filter up through it, being used by each algae in turn, which being small and semi-independent will have that much greater surface area to be exposed to the carbon dioxide, nitrogen, water and sunlight. Similarly, you can make sure the tiny bubbles entering your water encounter a barrier that forces them to move a great deal as they rise, such as a slightly tilted sheet along which they slide to the highest edge, from which they spill over and rise to… the next sheet, tilted in the opposite direction. You could have several of these, folded together a bit like a deck of cards frozen in mid-shuffle. Alternatively, you could pass your bubbles through a mesh such as a screen or mass of fibers which helps to break them up further as well. Or you could possibly do both. And of course, considerable CO2 will already be dissolved into the water flowing into the algae tanks of operations burning significant methane on site, as we will discuss further below.
But remember, this system can be optimized in terms of photosynthesis by doing more than extending the length of its daily exposure to sunlight. Now, of course, there is no chart of how much light all your various, local varieties of algae can use at various temperatures, especially when given full access to all of the CO2, nitrogen and water they may need to use with it. Obviously, you will eventually want to test these properties, especially if you are moving beyond those varieties about which there is
some established information (such as those tested by Sorokin and Krauss
). The simple technique would be to begin by using the best known, optimal luminosity for extended periods if not all day long, and then to slowly vary each critical input – light, CO2 and any nitrates you choose to add (the system can produce and recycle these in excess) – and to note at what point you seem to have maximized your productivity. As you appear to reach practical limits, be sure to keep track of how much CO2 and even air (mostly nitrogen) that you are using, and then vary those amounts to see if your algae mass needs more (or less) of those resources rather than having reached the limit of how much light it can employ. Also be aware that other factors can affect a mass’ ability to process sunlight, such as becoming so heavy and thick that the central core is more heavily shaded, and so forth. Regular harvesting of excessive growth should limit such problems.
Some who have noticed algae blooms of chlorella in the presence of fertilizer may wonder if, say, nitrates should be added as an accelerant in the process and, if so, whether truly rapid increases in your supply of algae are sustainable without correspondingly significant supplies of fertilizers. We should remember, therefore, that the biogas digester digesting the algae produced will only convert a maximum of 75% of the organic mass fed in into gas. The “solid” remainder is, in fact, a fertilizer. Again, if you add any of this mass to your algae tanks, you will want to be very judicious in how much you add, and in confirming this digester fertilizer is sufficiently safe in whatever form you use it. Ideally, you will want professionals who can vouch for either the safety of any fertilizer going into your algae tanks – even if only into tanks used exclusively for digester feedstock – or who can vouch for the system you consistently use to treat that material. (A standard feature of these systems, as we shall see, is the ability to reduce this remnant to charcoal, even in most technologically-limited environments, so a reasonable degree of sterilization should be readily available.) You should also watch each variety of algae you are working with to see how it responds. As chlorella is apparently apt to create a bloom in the presence of only small amounts of fertilizer, excessive use may prove counterproductive, more so with some algae than others.
But we should also remember that the “normal” pace of algae growth can be extremely impressive. The earlier cited figure, that chlorella can double within eight hours or less given proper conditions, is no small detail. Three doublings in a 24-hour period is in fact a tremendous expansion. Remember that a mere two doublings per day will, in five days, give you ten doublings. How much is that? 2, 4, 8, 16, 32, 64, 128, 256, 512, 1,024. In other words, if you have “the room” in terms of space and resources, ten doublings means slightly more than a 1,000-fold increase in, say, five days. In ten, at that pace, you would have an over 1,000,000-fold increase. Obviously you will reach limits on all of this, but your key inputs are mainly water and sunlight, with CO2 and nitrogen being easily added and easily recycled from the most obvious uses of the algae you are producing. And the water will, to a degree, be recycling as well. You will reach limits on space, but depending on your situation – particularly in the case of certain large organizations and governments – there are some very impressive options available to you, even if you want to ramp up a massive operation quickly. As we shall see. But maintaining balance in all of this will, of course, be a key concern the faster you put these forces into motion.
Now you might ask, given water’s capacity to store heat and to convert light into heat, how hot your water will get if you are both concentrating sunlight and venting the exhaust of burning methane into your tanks. Clearly this would be an issue, but there are several factors that will help keep your tanks viable, even in warmer climates, though obviously environmental conditions may complicate the situation.
The first and most obvious step is to keep your water from getting too hot in the first place. One step with clear benefits is to sequester your CO2/water vapor exhaust from methane combustion in a separate tank where it can cool – preferably by bubbling the gas as often as practical through water waiting to enter your main algae tanks, where it can dissolve. As with your algae tanks, you can break these CO2 bubbles up as they enter the water so that they hopefully dissolve a bit more efficiently. Remember, within limits, carbon saturated water will actually transfer the CO2 more effectively to your algae. As with many inputs in this system, you simply have to avoid overdoing it – the water will eventually turn acidic if carbon is constantly added and rarely removed. Keep an eye on the situation. If you can not measure the presence of carbon (as most remote villagers can not) practice moderation, spread out your distributed carbon, and see how your algae does as you change each factor in turn. If you can measure this input, then – as with sunlight, nitrates and phosphates – we will shortly discuss methods for automating these sensors and your system’s reaction to them.
The second most obvious method is to circulate and refresh your water – removing excessively hot liquid and replacing it using a much cooler source. You could simply include an overflow pipe at the top of your tank at roughly the water level you want to maintain. Warm water will spill out on this side to be stored or used in other parts of your system as you choose. Meanwhile, on the other side of the tank, allow cool water to flow in, for example from just above the water level. Obviously, in very large tanks, you may have more than one inflow pipe and more than one overflow pipe. A “caveat” to the overflow pipe method is that some forms of free-floating algae will rise to the surface of your tank water and then want to flow out through your pipe. But as you will discover as we discuss conventional biogas digesters, the normal “slurry” is a 4-to-1 water-to-manure mix. If you are using an algae easily “skimmed” off the top, you may not want to filter it out, but rather position a long, flat opening to take in a high algae-to-water concentration, and use this liquid as your slurry water, thus minimizing labor, complexity and processing. (Setting this overflow pipe at 45 degrees and in a corner, or anywhere else that might serve as a crude funnel may prove useful with masses apt to get tangled upon the edges of a normal opening, especially if your algae is slowly drifting out of the tank. Apertures that are large as well as flat may prove advisable as well.) If you find you still have too much water, you can simply flow that water/algae mix into a flat, shallow evaporation “tank,” covered by glass, and use sunlight, concentrated or not, to vaporize as much water as necessary. A dark bottom to this segment will help, but if you have decent sunlight and a lot of reflective material around for concentrated solar, reducing the water content should be simple. If you have a lot of excess water and a great deal of algae production going on at night, you may want to evaporate an extra measure of liquid during the day to offset what you are not doing at night. Alternatively, you may have other sources of heat on site, such as any natural gas being burned, which may even be able to handle this process as a side-effect of the excess heat they are generating. Fortunately the digester will probably prove more adaptable to changes in temperature, both because most biogas systems will be dug into the ground (which naturally stabilizes the temperature at a lower level), and because there are other means of regulating their internal heat, to be discussed further on.
Now, to keep water cool as efficiently as possible, the best method for both industrial scale operations and smaller, village-level projects is to simply have an underground water tank, using the ambient temperature of the Earth to cool your water (a bit over 50 degrees Fahrenheit in most of America, as an example). If you can arrange it, putting a shaded, underground tank in a nearby hill and then flowing water down using gravity is particularly efficient for this aspect of the operation. Further, methane is notably lighter than air, so you could conceivably allow your biogas to flow up to an uphill tank, an advantage if you are planning to burn the gas beside that water and then filter your CO2 and water-vapor exhaust through it. On the other hand, in terms of collecting water for your overall system, other locations may prove more practical, even if you have a hillside handy.
Fortunately, there are other options. For the village-level operation, we will discuss various alternative water pumping options shortly. But in terms of water cooling, remember that not only can you shade your tank and bury your tank, but you can reduce ambient temperature around your site by a number of means, the most obvious of which is to alter the amount of sunlight absorbed everywhere other than your algae tanks and any other key, solar-driven processes. Aside from any convenient shade you may have which does not interfere with your algae’s lighting or the operation of your mirrors, you also have the very simple option of painting rooftops, asphalt roads and other dark inanimate infrastructure white, thereby reflecting considerable sunlight and helping to break down your local “heat-island effect.” This may seem trivial, but remember that simply using passive means to reduce your site’s temperature by several degrees during hot months of the year will help considerably in keeping everything cool, while using much less energy.
And, of course, there are various refrigeration, air-conditioning and water-cooling systems powered by natural gas available – a power source you will obviously have in considerable supply, though one which you should make a point of conserving for practical reasons, as well as on principle.
For the water used in your system, collected rainwater and, for the biogas digester in particular, greywater should prove adequate. Care in recycling usable water will always be useful, for numerous reasons. Ironically, collecting water in urban areas, given the number of rooftops available and the greywater accessible, may prove easier than anywhere other than major freshwater sources such as lakes and large rivers. Rainwater collected from rooftops and stored in rain barrels can also be stored up at higher stories and use gravity to help pump that water supply. But large reservoirs and natural bodies of water may be the most realistic alternative for remote, low-tech rural systems, though we will eventually discuss some passive desalination techniques for seaside operations and ways of moving large quantities of water without pumps in case your operation is far away from your nearest large freshwater source. And, obviously, we will be recycling water as well as creating it in the exhaust of any methane burned on site.
Now finally, your biogas digester will be producing two main components – gas, and the solid remnant of the organics broken down within it. The gas mainly consists of CO2 and methane. Nitrous oxide, another common greenhouse gas produce by organic decay, is volatile and unless separated out deliberately for sale, will likely burn up with the methane or break down when dissolved when cycled back into the algae tanks with the CO2.
The solid remnant, however, is normally used as a kind of fertilizer. Of course, you may recycle some of this material back into your system to spur algae growth, but in all likelihood you will at some point have an excess supply you want to deal with. Could you use the raw remnant directly as fertilizer? Well, so long as you abide by any regulations and there is nothing of health concern in the material, yes. But as there is presently a serious concern regarding the impact of human-released carbon on the climate, let us consider a form less apt to break down into greenhouse gases once put in the ground or spread over it.
Dr. James Lovelock, originator of the Gaia hypothesis, has suggested reducing agricultural waste to charcoal before using it as fertilizer. The operation described above, given its capacity to produce huge amounts of fertilizer as a by-product of its main work, is an obvious candidate for such a procedure. Charcoal making has been around for a very long time, and amounts to a low-oxygen burn which slowly reduces the material in question. The temperatures do not have to be terribly hot, and if you have a lot of unused solar-concentration material on site during bright, sunny days, you can concentrate light on the steel barrel or tank you are using for charcoal making. Anyone using concentrated solar to squeeze out more free energy from the Sun in very dim conditions will probably have at least some unused reflectors during full sunlight, given that you will not be using all the light available for your algae production anyway.
Operations that are burning methane on site may also be able to tap that excess heat as well, but if you can not do so in an absolutely safe fashion, do not bother. You will have plenty of energy available in most climates if you plan your charcoal burning carefully and make full use of the free energy on hand and, failing that, you can use your spare methane directly as a fuel. Still, technically adept and creative operations will want to make use of all of their resources rather than wasting them, especially since raw heat is one factor you will want to contain in any industrial-scale project.
We will discuss a number of unusual ways the above system could be brought online, especially in areas with very limited resources. But governments and companies dealing economic crises and other challenges might wonder how they could ramp up this kind of production on short notice, given the time it would take to build even this relatively simple system on a very large scale. They should remember that many elements of this design may already be in place and near at hand.
A Brief Disclaimer
The material in this book is for informational purposes only. Please seek appropriate technical, legal, financial and/or medical advice as appropriate before attempting to use any of the concepts discussed herein. Future Imperative
is about sharing ideas and possibilities rather than prescribing any specific plan of action. The author expressly disclaims responsibility for any adverse effects that may result from the use or application of the information contained in this book.
The above piece is the partial introduction to Future Imperative: Power to the People
that you can also read for free on Amazon, as well as the disclaimer. This part of the book is here only because many readers may not have the free program to read Kindle ebooks on their Mac or PC, and because you can get a good sense of the invention from this section, even if you don't get or can't afford the book.