If you want to make biogas, and you like things really, really simple—as simple as possible—Then you should move to the tropics.
Why? It's because the rate of biogas production—all else being equal—depends on the temperature of digestion. Within a certain range, the warmer the digester is, the better. By contrast: Sweater weather? No biogas from an unheated digester. So colder is not nearly as good. Bad, bad, bad, in fact, at least as far as biogas is concerned.
Now why should biogas production be so dependent on temperature? Well, the reason is that heat is just a kind of jittering motion of molecules. And the warmer they are, the faster and further they jitter. You can even see evidence of this if you have enough small particles (pollen, for example?) in a jar of water, and you look really closely. You’ll see them move in a sort of random dance, a jitter… bug? (It’s called Brownian motion. Back in 1905, Einstein proved that atoms existed by drawing certain conclusions based on that motion. You could look it up.)
So when these molecules are banging around, the faster and further they bang, the more likely they are to encounter other molecules, and to break apart and recombine to form new molecules, meanwhile (generally speaking) releasing just a bit of heat. Love at first sight happens more often in the tropics, no? (After all, some folks maintain it’s just chemistry.) Love at first sight, and biogas. In the tropics. Add in Tahiti and buy me a ticket, please.
But hey, I assume you’re like me, minus the beard. To be more specific, I assume you live in the U.S. or maybe Europe. For what concerns us here, it’s much the same, because it’s about climate.
For those of us who are living in a place where, at least some of the year, it actually gets cold enough that long pants, socks, and Pendleton shirts make sense, what that means is that we really can’t expect to put a simple, simple, simple biogas digester in the backyard and have it do very much in the winter. You’ll need insulation. You’ll need a heat source. And of course, as we explained in the series about food waste and biogas (part 1, part 2, and part 3), you’ll need enough of the stuff that makes good biogas.
• 95 degrees Fahrenheit/35 degrees Celsius: 100 percent
• 85 degrees Fahrenheit/30 degrees Celsius: 68 percent
• 75 degrees Fahrenheit/24 degrees Celsius: 46 percent
• 65 degrees Fahrenheit/18 degrees Celsius: 32 percent
• 55 degrees Fahrenheit/13 degrees Celsius: 21 percent
• Colder than 55 degrees Fahrenheit: zero percent
Just to keep it simple so as far as temperature is concerned, we’ll call the rate of biogas production at 95 degrees “100 percent,” and compare other (lower) temperatures to that. Every time Mother Nature drops the temperature by as little as 10 degrees, the rate of the production of biogas also drops, pretty steeply, by about a third. (See the table above)
Now, if you have a garden or farm, then you’re familiar with the USDA Plant Hardiness Zone maps, which revolve mostly around how cold it might get where you live. But at least first draft, what we want to know is how warm it might be for how long, and so for the purposes of biogas, the American Horticultural Society (AHS) Plant Heat Zone Map is what we want.
What this map or these maps tell us, according to the AHS website, is “…the average number of days each year that a given region experiences ‘heat days’—temperatures over 86 degrees (30 degrees Celsius)….”
Eighty six degrees ambient… Is that good enough?
Well, how about this: Let’s assume first of all that you carefully studied The Complete Biogas Handbook. That gave you all the tools you need so that you can design your digester to use one of those really good substrates (like food waste) and to be large enough so that when it’s warm and cozy at 95 degrees, it gives you 150 percent of your daily biogas needs: for cooking or whatever it is that you have in mind.
Well, it turns out that if that if you can get 150 percent of what you want at 95 degrees, then at 85 degrees, the rate of production will peg at just about 100 percent of what you want, just by sheer and astonishing coincidence. So if the average daily outdoor (ambient) temperature is 85 degrees or better, then without heating your digester on such days, you can make all the biogas you need, and maybe even a bit more, assuming you keep feeding your digester what it wants, what it’s designed to consume…. Got the picture?
Now I live in Oregon, between Portland and Salem—just above the 45th parallel—and the AHS map for Oregon tells me that, at very best, I should expect only 30 to 45 days a year with “…temperatures over 86 degrees…”. Right? In other words, if I expect to keep getting at least as much biogas as I had planned to get from my digester, I’d have to heat my digester for 335 days a year! (Ouch. That’s a bit discouraging, hey. Now where’s that Tahiti ticket when I need it?)
My digester would be better off in Florida, as you might expect. (I’d have a better tan as well. It’s a win-win, eh?) West and a little south of Miami there’s an area where I would experience better than 210 days a year of biogas weather, but that still means that I would need to heat the digester for in excess of 150 days a year…. The US isn't very “biogas friendly” in terms of climate, is it?
(Hey. Don’t lose hope now. It will be all right. We’ll get there. Together, if you keep reading.)
In any case, of course, all that AHS Plant Heat Zone stuff is far from the whole story, because you may not have to heat the digester very much even on colder days, particularly with proper insulation and the proper approach.
In fact (spoiler alert), on a day that is 55 degrees, the new digester I am working on (see the picture?) can be heated to 85 degrees using less energy in an hour than you generate as heat just by sitting down and watching internet videos for an hour… Even if you’re not laughing!
Want to learn more? Then keep reading… Part 2 will come along real soon now!
Photo:October first, 2014: Jeffrey Ironwood-Hunt tightens the main bolt on “The Compressor” a tool developed by David William House so that his new, low-cost, kittable & shippable, well-insulated biogas digester could utilize very low cost ‘bungs’ (holes in the wall of a container). These bungs David has developed cost less than a dollar apiece, and replace purpose-made bungs costing $20 or $30 each. The digester being built as shown here is larger than 2 m3, and the materials cost is less than $350.
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One of my clients, Sun Light & Power, a Berkeley green business just sealed a deal with San Rafael-based solar electric finance specialist SolED to do Power Purchase Agreements (PPA) in the State of California. In addition, this partnership enables both companies to be stronger California Benefit Corporations for the State and taxpayers.
As we all know, this means:
• schools municipal buildings
• village halls
• fire departments
• city halls
• other halls of government in the State.
This well needed energy savings or tax monies will enhance the educational budgets of schools; setting that great example needed while reducing government’s overall carbon footprint. Gary Gerber, founder and president of Sun Light & Power also announced that the deal will give both his public sector and his private sector customers better access to a full range of financing options. ; which can now include the PPA contracts to "pay as you go". This also gives the owner of the system (SolEd and/or Sun Light & Power) the tax advantages of the renewable energy tax credits and accelerated depreciation.
“We wanted to enhance our ability to help our clients navigate the complexities of solar energy financing and incentives,” Gerber says. “A strategic partnership was clearly the best way to achieve that goal, but we took our time finding the right match, with people who truly share our customer-centered values.”
“Our mission is to provide host customers with the lowest lifetime cost of energy,” said David Kunhardt, CEO of SolEd. “Sun Light & Power has been delivering quality for repeat customers for decades, and is also a B Corporation, the perfect partner for SolEd.”
Again, this is news worth noting.
Sources: Sun Light and Power for schools; Sun Light and Power for homeowners
All MOTHER EARTH NEWS community bloggers have agreed to follow our Blogging Guidelines, and they are responsible for the accuracy of their posts. To learn more about the author of this post, click on their byline link at the top of the page.
How much biogas from how much food waste? In general, that’s the question we left unanswered in that last blog, part 2 in this series. (Here… And part one is here, in case you missed it.)
Well, the rule of thumb is that a biogas digester kept at the proper temperature — body heat, which is 105 degrees Fahrenheit … or at least it is for a cow — will produce its own volume in biogas every day. According to this rule, if your digester is a cubic meter, and you keep it properly warm, you will get a cubic meter of biogas from it, every day. (That’s about 35 cubic feet, and comfortably more than most families will need to cook their lunch and dinner, but not a lot more.)
But that rule of thumb comes from experience with manure-fed digesters. That is, if you have a digester and you’re just putting manure in it, then the rule of thumb applies. But the fact is that different substrates produce different amounts of biogas. Remember when we said that food waste makes great biogas? (No? Well, we did….) You can see the difference by looking at the following chart which I produced, using data published by the Bavarian Association for the Promotion of Solar Energy:
Click on the graph to see a larger version. Source data derived from Solarenergiefoerderverein Bayern e. V., “Biogas– Strom und Wärme aus der Natur”, pg. 9 (here)
Freshly cut grass clippings can ultimately produce better than 1½ cubic feet of biogas per dried pound. By contrast, the same dry weight of cow manure, under the same conditions, will produce less than a quarter of that. If you’re lucky enough to have enough of what the Bavarians call “residual fats,” then the comparable pound will produce 24 times the amount of biogas as the cow manure. So like I said: different substrates produce different amounts of biogas. In spades.
Now, of course, all energy, but most especially small-scale (they call it) alternative energy, biogas included, is situational. It doesn’t matter how fancy/cool some to-be-purchased wind electric system is if you don’t have wind where you are. And you’ll never heat your water with the sun… at night. In the same way, it shouldn’t matter to you how great corn silage is for making biogas if you don’t have any corn silage. And as for “residual fats”— like used cooking oil, maybe?— the biodiesel folks probably have all that stuff snatched up before the fast food places have time to even think about pulling the last dripping French fry out of it.
But these days, almost any of us can get access to wasted food, stuff that gets tossed from places out all over town, restaurants, and cafeterias and grocery stores. Mark my words: A day will come when food waste will be as hard to get as used cooking oil is now. But for the time being, almost any of us can get just about as much as we want.
So again (since I still haven’t told you, right?) how much biogas can you get from your food waste digester?
Well, maybe I did give you the answer: about 4 (or more) times as much per dry pound as you could if you were using cow manure. In general, in other words, take the rule of thumb and multiply by 4.
And how much will you need? Well, what you really need to get detailed answers about your specific situation is more information. For example, to figure out how much biogas you need to heat your house, you need to know a lot about the weather outside, how large the house is, how well insulated, and things like that. That whole process is described in The Complete Biogas Handbook, chapter 28. The book will also tell you how to convert the burners on your stove to run on biogas, the practical details of designing your own digester, how to figure out things like how much hot water you need, how much biogas it will take to heat it, and all the cool stuff you need to know to really make practical use of biogas. Besides, when you visit the site you can find the best free information on the web about how to build any of the four most common home-scale digesters (on the “build” page).
Now, at this juncture, most explanations that I have seen about biogas get a bit coy, and they don’t give you really practical information in a clear form. We’re not going to do that. The chart below is like no other that I have seen in all my years of involvement with this subject.
The chart asumes two critical things: first, that you are digesting food waste, and second, that the digester is at body temp. Given just those two assumptions, it shows you how many 1-gallon buckets of food waste you need to be able to get the outcome you want— and what size of digester you’ll need too. Simple. Clear. Ready? Here it is:
Food waste power!
(Click here to see a larger version)
req’d, 1 gal
|Lights, 100 w equiv.
||2 lights, 3 hours in the evening
|Cooking, per burner
||2 burners, 2 hours, 2 meals
|Hot water, per gal
||Assume 30 gal/da for shower, dish washing, etc.
|Engine, 100 HP
||Small engine (genset?), 4 hours/day
(For hot water, we figured we would need to raise the temperature from
50° to 130°F, @40% efficiency, using biogas @60% methane.)
If you've been reading along with these blog posts, you'll know that in part 2, we mentioned that we were going to answer what is, for biogas, the ‘holy grail’ question: “Can I run my car on biogas?” Well, look at the chart. The answer seems pretty obvious: sure you can; but you need to get a hold of a couple of hundred one gallon buckets of food waste… every day. (That’s based on the thought that most cars have engines that are larger than 100 HP.)
What? Did you think I'd tell you some fairy tale? Cars are Big, Lumbering, Inefficient Energy Hogs. Does it really make sense that you could power one with three or four buckets of food waste?
If you do the math, you'll see that a standard engine requires about 16 ft3 per HP per hour. And that 100 HP engine? The digester needed to provide 4 daily hours of fuel for it (if kept at body temps) would be the size of an above-ground swimming pool: 20 feet across and 4 feet high. And keep looking. The chart can give you a lot more information like that ... And along those lines, notice that except for running your Range Rover, the biogas you need to provide light, cooking and hot water for an averagefamily can be produced if you can find 6 gallons of food waste a day. Is that a lot or a little?
So I think that's good, yeah? Biogas and food waste. And the folks who end up making food waste into biogas will be doing the rest of us a great big favor, because when that food waste gets put into the landfill, it produces methane there too. The difference is that the methane from the landfill goes into the atmosphere, and there…, well, it’s a very powerful greenhouse gas: it has 38 times the negative impact of carbon dioxide. But when we make biogas (and burn the biogas), all that methane is turned into carbon dioxide… and the impact of the food waste is dramatically reduced. Talk about a powerful way to reduce your carbon footprint: Think biogas.
Be a good guy. Make some food waste into biogas, and then burn the biogas, joyfully. (The first time you see that pale, almost invisble blue flame, you’ll be hooked, for sure.)
I think maybe in the next blog series we’ll say a few things about temperature, a really important parameter in biogas production. And, hey, just because I like you, I’m going to give you an Excel spreadsheet to calculate the effect of temperature on the digestion process. Keep reading...
David William House is the author of The Complete Biogas Handbook.
In mid-2012, we avid do-it-yourselfers cast a lustful eye on photovoltaic solar for our home. We reasoned that the sun was there every day – why not capture its free, clean and renewable energy? The thought enticed us not unlike Ralphie in A Christmas Story.
Just like Ralphie, was enticed by the Red Rider BB gun, but held at bay by the threats of shooting his eye out, we were enticed by shiny solar possibilities with the threats of failing and being made a laughing stock (at best) or becoming a pile of incinerated ash (at worst). Danger does lurk around every corner for the novice and/or the careless, and extreme caution should be the rule. Being aware of this, we still decided the take the plunge and build the system ourselves. We began the build in January 2013. Six months later, we completed the project successfully and were up and running.
Here is a picture of our finished system in front our home. We built an on-ground system for ease of maintenance and the ability to rotate the frames and capture more solar energy at different times of the year.
Advantages of DIY Home Solar Power
By taking on the project ourselves we were able to:
- Capture more electricity by designing (manually-driven) automated rotated frames, which incorporate full tilt angle variation to track the sun all year.
- Have on-grid/off-grid capability with the flip of a switch.
- Capture free renewable energy and help keep the Earth clean.
By designing and building the system ourselves, we estimate we saved over 70 percent. Our payback (with incentives included) is a mere 6.2 years. We realized that almost anyone, anywhere will benefit from photovoltaic solar energy. (See NASA charts at this link.)
We are delighted with our photovoltaic system and have written a book entitled DIY Photovoltaic Solar Power for Homeowners. In our book, we’ve included our detailed charts, wiring diagrams, parts lists, and energy analysis. We’re looking forward to sharing details of our system build and design in future blog posts.
One of the worst traits of humankind is our reliance on fossil fuels and the incessant depletion of non renewable resources. There are many alternatives and yet the majority of the world still acquires energy using practices which are causing irreversible damage to the earth, the people, the land, the air and the water. The exploitation of natural resources and reliance on coal powered plants and nuclear energy plants will lead to a dismal future if solution based renewable energy systems are not replaced as the norm.
Introducing Aur Beck
Luckily, individuals like Aur Beck are shedding light on the easy transition to choosing renewable energy. My dear friend, Aur 'da energy mon' Beck, has been immersed in the growing field of renewable energy since he was a teenager. In 1990 at age 15, after independently researching solar energy, Aur moved into a 12 volt, battery operated camper in his parents’ driveway.
Aur translates as "light" or "to enlighten" in both Hebrew and Latin, a perfect name for a solar energy expert. According to Aur, “reading profusely and consistently tinkering with Renewable Energy (RE) has been a continuous constant throughout my life. Never officially attending school left me time to do in depth study, intern, view, and install renewable energy projects. Of course, working in one of the first United States passive solar schools helped.”
The Power of One
Aur is the president, chief tech, and coordinator of the Renewable Energy Install Network (Green Geek Squad) for Advanced Energy Solutions. Since 1999, he has been putting his knowledge to great use promoting, installing, & educating about renewable energy.
Aur has made significant contributions to Solar Energy in recent years. Aur sheds his light in many ways:
Founder and on the board for both the Illinois Renewable Energy Association and the Southern Illinois Center for a Sustainable Future
Started Oil Addicts Anonymous International
Hosts a weekly radio talk show called Your Community Spirit
AESsolar won the “Missouri Schools Going Solar” contract in 2005 and assisted with the sale and installation of 17 school systems
January 2007, trained presenter for Al Gore’s Climate Project
Based on the vast knowledge base Aur has in the field of renewable energy, he was invited to join the Midwest Solar Training Network (a DOE program) and to become an adjunct professor at Hocking Energy Institute in Logan, Ohio
Aur grew up on the family farm in the heart of the Shawnee National Forest, in an off-the-grid, solar-electric-powered home which makes it very easy to advocate for a life of simpler living, energy efficiency and renewable energy. Aur came up with and definitely lives by Advanced Energy Solutions slogan: We Empower YOU to Get Energized!
Dedication to Sustainable Living
I have been impressed with Aurs dedication to sustainable living and renewable energy since I first met him in 2000. One of Aurs most notable accomplishments in the last few years was being hand selected and invited to teach a semester of Solar PV Design and Installation by Neil Hinton, the Dean of the School of Engineering and Information Technology of the Hocking College Energy Institute in Nelsonville Ohio. This is impressive in light of the fact that Aur hasn’t been through any formal schooling whatsoever. He has no degree but he is a living breathing encyclopedia of all things solar. Aurs ability to confidently teach at a college level with no formal training is very inspiring. Not only does it encourage others to follow their dreams but it also offers a bit of insight into just how powerful it is to be passionate about what you do in life sans a degree.
At the Energy Institute, Aur inspired students by his minds on/ hands on teaching methods. He tested their knowledge initially to try and fill in the knowledge gaps throughout the semester. He gave them useful and practical knowledge which can actually be related to real world applications.
The reason he was selected to teach is due, in part, to him being double NABCEP certified. Helping students in the program taking The NABCEP, (North American Board of Certified Energy Practitioners) Entry Level knowledge test was his primary goal.
Inspiration is cyclical. Renewable energy can reshape the future.
Advanced Energy Solutions
To learn more about Aur and his company, please visit his website. Advanced Energy Solutions offers:
Solar and Wind Generated Electricity
Utility-Tied/Net Metered or Off-Grid Systems
System and Component Sales
On-site Consulting and Electric Load Analysis
Follow-up on Technical Assistance and Service
Training from Basic to Advanced hands installation
Training Programs-designing & installing hands on training labs
Aur also manages a living off-grid Facebook group.
Cliff hanger, right? We told you there was a gold mine in back of your local restaurant in part one of this subject series (here), and we waved somewhere toward the direction of using the “found energy” tied up in the carbon bonds of that wasted food for this and that. (We mentioned cooking with that energy, for example.)
So the question is: How? How can we make the energy which is potentially available in food waste into usable energy? Let’s see….
In the developing world, many things happen at the village or household scale. If we cook our own meals using wood that we’ve gone into the forest and gathered, that is a system that has a household scale. (And it would please Thoreau, eh? Wood fire warms you twice, he said.)
But virtually all our systems in the US are industrial scale (that is, Big), including our energy systems (consider those long electric lines on towers marching along the freeway) and this includes the scale at which we waste food. Studies (such as this NRDC study) show that not quite half the food we produce in the US is thrown away.
From the NRDC study:
“Getting food from the farm to our fork eats up 10 percent of the total U.S. energy budget, uses 50 percent of U.S. land, and swallows 80 percent of all freshwater consumed in the United States. Yet 40 percent of food in the United States today goes uneaten. This not only means that Americans are throwing out the equivalent of $165 billion each year, but also that the uneaten food ends up rotting in landfills as the single largest component of U.S. municipal solid waste where it accounts for a large portion of U.S. methane emissions. Reducing food losses by just 15 percent would be enough food to feed more than 25 million Americans every year at a time when one in six Americans lack a secure supply of food….”
[Given the population of the US, ‘one in six Americans’ is about 50 million people.]
Now even given that almost all of our energy systems exist at an industrial scale, there are some circumstances where smaller scale energy production makes sense: a farm, a homestead; the kind of place you have now, or (since you are reading this) the kind of place you may want to have, someday soon. For those situations, a local energy system providing all or some of your energy may make sense.
And in planning for that local situation, your situation, one of the first things you need to consider is matching needs to energy sources. Wind can be a great source of (intermittent) electricity. Direct solar is also good for electricity (PV), for space heating and hot water. But cooking presents a modest challenge for those two common local energy sources. You can make a solar oven— it’s pretty easy, really— but (begging the forgiveness of the solar gods) most solar ovens are kind of bulky and clumsy, don’t you think?
So here’s a twist: how about using wasted food to supply all of your cooking needs, and to supplement your space heating, or even hot water supply?
And how can you do that? (Gee. Somehow biogas comes to mind….)
The short story is:
Start with a container. It doesn’t have to be strong, but it has to hold liquid, and gas at very modest pressures. The container can be steel, concrete, plastic or made of any other suitable material, with few exceptions. (Toxic stuff is not good; the biogas biology is sensitive.)
Get some organic material, of the kind we might use in making a compost pile. (Not woody stuff, but almost anything else. Food waste makes great biogas.)
Keep it wet, keep it warm, keep it pH-balanced, and very shortly, by a process that is natural, very ancient, and which may seem a bit magical (hey presto!) a burnable gas— biogas, made almost entirely from methane and carbon dioxide— will bubble out. (And just to clarify: methane is the main molecule in natural gas, the fossil fuel that is getting so much press nowadays because of fracking. Biogas gives you methane without the fracking. And it can even shrink your carbon footprint.)
There’s nothing else that’s essential, although lot’s more can be said about it. It really does not get any simpler for any kind of renewable energy use, except maybe standing in the sun to get warm, or burning wood. (Or eating. Definitely eating.)
It really is simple. Honestly. In fact, would you like some free plans for building any of four of the most common kinds of digesters? Then visit the free plans for biogas digesters page on the Complete Biogas website….
Of course, what you get out of your digester will be determined by what you put in. It has to be sized properly— and again, again, again, kept warm— but all else being equal, the more you feed it, the more gas will be produced.
Realizing this, you may well want to ask: How much food waste should I put in the digester? And what size should that digester be so that I can cook my meals, and get light in the evening?
And booyah, while we’re at it: How about the holy grail of biogas? Can I run my car on biogas?
Well, friends…. That’s all going to be discussed in the next blog… Keep reading.
“A biogas plant installed at a house in Coimbatore, Tamil Nadu. Photo: S. Siva Saravanan” Or one might say: Feeding an ARTI-style digester with a floating gas holder.
Source: The Hindu (newspaper), “Cost effective green fuel for the kitchen”
There’s a gold mine out back of your local restaurant.
…Or at least that’s one way of looking at it. Of course, what I’m talking about is wasted food — the stuff you don’t eat from your plastic tray of super-sized this and that, the French fries that got a little too brown in the fryer, the stale burger buns. That stuff. It’s gold, really.
As my good friend Bob Hamburg of Dragon Husbandry once said:
“As for ‘waste disposal,’ we’ve got two mis-defined terms mashed together, resulting in an abominable oxymoron. In nature there is no such thing as waste. All residues serve as resources for further growth — there is nothing to be disposed of. Nothing is thrown away. Indeed, there is no ‘away.’ Everything must go somewhere. The misconception of ‘waste disposal’ must be superseded by a better understanding of ‘residue management.’”
Right on, Bob.
But hey, look at the stuff in that trash bin: It’s gooey. It’s gross, right? Who really wants that stuff, anyway? Well, maybe you will, when you see the whole picture.
Waking Up to Nature’s ‘Waste’ Management
It all grows out of standard ecology, the way the planet deals with energy and information (and the way we will, too, once our species gets past adolescence). Sunlight enters the atmosphere and makes green things grow: The largest usable bank account of stored solar energy on the whole planet is the set of green growing things, all the way from algae to giant sequoia. And a small fraction of that green riot is harvested to feed us and our animals.
Now in our (present, soon to be superceded; have faith) way of doing it, plant resources all go into factory-type buildings and come out as packages. Then, the packages are opened, we prepare food and eat it, and all that packaging trash is thrown away along with the food we don’t eat: more wasted food. We send it all to landfills or incinerators, go to sleep, wake up (sort of) and do it all again.
In nature’s way of doing it, just like Bob said, there is no “waste.” Ecological scientists talk about “trophic levels,” which in part is a way of saying that whatever one living thing leaves behind, another living thing uses as a source of energy. Plants consume sunlight, air and soil to produce green matter to feed vegetarians, such as cows or caterpillars. Vegetarians consume green matter to produce flesh to feed carnivores, such as wolves or people (or birds that eat caterpillars). And when anything once alive dies, then (if there is enough moisture available) the remains feed arthropods (little bugs), fungi, and a seething mass of microscopic life: nature’s compost pile.
This is the picture of the energy of life being shared among all living things, in a kind of sacred dance, happening all around us and unseen by most. The threads of the complex web of life are each connected to each — except where they are broken by the ignorant actions of man.
Stored Solar Energy
But hey. Too serious, right? Sure. But even still, that’s what we should maybe see when we look at that food behind the restaurant. Gooey? Well, that’s one way of seeing what’s there.
Yet maybe one of the wisest ways of seeing what’s there is to think about all that energy tied up in the carbon bonds of that food: the stored solar energy that can help you cook your own food, make great compost for your garden, and even heat your house, if you have enough of it.
How can this energy be put to use? Well that’s a story for part two.
Photo: Matt Steiman’s hand (Matt is Assistant Manager, Dickinson College Farm and Project Support, Dickinson College Biodiesel) pointing out a feature of the 3-year old EDPM plug-flow digester inside a greenhouse at the Dickinson College Organic Farm. Matt says: “We are making plenty of gas for cooking at the intern kitchen…. Currently we transfer gas from storage near the biogas digester to our kitchen using inner tubes that we fill from a manifold attached to our gas measuring drum. The 100-liter tubes are weighted at the kitchen and provide enough gas to cook a meal or two on our single Chinese burner.”