Dream Farm II
Dr. Mae-Wan Ho tables a proposal around a zero-emission, zero-waste farm after a highly successful workshop with living legend George Chan, who created dozens such farms to eradicate poverty in third world countries
“Dream Farm is exactly what we need to feed the world, mitigate climate change and let everyone thrive in good health and wealth in a post-fossil fuel economy”
To see the complete version of this proposal, click here.
We featured Professor George Chan’s “zero emission” or “integrated food and waste management system” in an article entitled “Dream Farm” in a recent issue of our magazine [1] (SiS 27). This farm could potentially solve the energy and food crisis that the world is facing (see Box 1), and contribute significantly to mitigating climate change. That is why we are proposing to set up Dream Farm II here in Britain.
Box 1
No more cheap fossil fuels United States food sector uses 17 percent and Canada 11.2 percent energy, not including export-import, food-processing machinery and buildings, waste collection and treatment, and roads for transport
Water running out It takes 1 000 tonnes of water to produce one tonne of grain; aquifers are severely depleted in major breadbaskets of the world
Productivity falling Grain yields fell for four successive years; world reserves are at lowest levels in 30 years
Loss of croplands from unsustainable practices The world loses 20 m ha, or 1.3 percent croplands annually from soil erosion and salination; replacing lost croplands accounts for 60 percent deforestation annually, which greatly accelerates global warming
Urgent need to reduce emissions Food sector in a European country (France) is responsible for more than 30 percent carbon emissions, not including import/export, household use and storage, processing, and imported fertilizers
Global warming threatens food production Yields fall 10 percent for every deg. C rise in night temperature; the latest prediction is an increase in the earth’s average temperature of 1.9 to 11.5 deg. C within this century
We have an energy crisis, and cheap fuel is a thing of the past [2], but our current food system is very energy intensive. The United Nations Environment Programme estimates that the food sector consumes about 10-15 percent of total energy in industrialised countries [3], though only 2-5 percent are on the farm, due to fertilisers, pesticides and machinery. Estimates for the US and Canadian food sector put the figure at 17 percent & 11.2 percent respectively [4, 5], which include total energy consumed on the farm, processing, transport, packaging, and storing farm products, as well as energy used by households to purchase, store and prepare food. The figures do not include energy costs in food-processing machinery and buildings, waste collection and waste treatment, or roads for transport; nor do they include energy consumed in importing/exporting food. The globalised food trade is destroying the livelihood of family farmers all over the world as corporations consolidate control of the commodity market and the food supply chain [6], and subsidized food surpluses are dumped from the rich countries in the North on poor countries in the South [7]. The globalised food trade also wastes huge amounts of fossil fuels and spews extra tonnes of greenhouse gases into the atmosphere.
The depletion of water is perhaps the most serious, as industrial agriculture is extremely thirsty [8]. It takes 1 000 tonnes of water to produce one tonne of grain [9]; aquifers are pumped dry in the world’s major breadbaskets in the United States, China and India [10].
Not only water is depleted but also soil and soil nutrients and fertility, so productivity has been falling. Grain yields fell for four successive years from 2000 to 2003, and the world reserves are still at the lowest levels in 30 odd years.
Unsustainable practices over the past decades have resulted in massive losses of croplands from salination and soil erosion, totalling 20 million ha a year, or 1.3 percent of the world’s croplands [11]. Replacing lost croplands accounts for 60 percent of deforestation, greatly accelerating climate change. That is why catastrophes such as hurricane Katrina, flood, drought and extreme weather are increasingly frequent, impacting further on food production.
There is an urgent need to reduce greenhouse gas emissions to mitigate climate change, and a lot can be done through our food system. An estimate of the French food sector put its carbon emissions at more than 30 percent national total; not including import/export, household use and storage, food processing, and imported fertilizers [12].
Global warming itself threatens food production through the increase in temperature alone. Yields fall by 10 percent for every deg C rise in night temperature [13]; and the latest predicted rise in average global temperature is 1.9 to 11.5 deg. C within this century when carbon dioxide in the atmosphere reaches 560 ppm, double the pre-industrial level [14].
Veteran world watcher Lester Brown summarises the fallout of the “environmental bubble economy” built on decades of unsustainable exploitation of the earth’s resources [10]: “..collapsing fisheries, shrinking forests, expanding deserts, rising CO2 levels, eroding soils, rising temperatures, falling water tables, melting glaciers, deteriorating grasslands, rising seas, rivers that are running dry, and disappearing species.” He warns that the environmental bubble economy is due for collapse, the most vulnerable sector being food; the biggest challenge, therefore, is how to feed the world [15].
He also says we need to restructure the economy at “wartime speed” to one that tells the ecological truth.
What Lester Brown hasn’t quite said is that the old economic model is responsible for much human suffering and poverty. The old model not only lays waste to the earth, it lays waste to people and society, and for the same reasons. It is the mistaken fundamentalist belief in the survival of the fittest; and that competition and exploitation are the laws of the market as much as the laws of nature [16].
What we need above all is a new model, a new paradigm; and that’s what Dream Farm is about. It is a unit of self-sufficiency in energy and food based on reciprocity and synergistic relationships rather than competition, it is a nucleation centre of the sustainable food production and consumption system that we need for a post fossil fuel economy, and a microcosm of the new paradigm working in a very concrete way.
That is why I-SIS is proposing to set up a Dream Farm II for demonstration, education and research purposes; combining the best and most appropriate technologies to showcase the new paradigm and at the same time, to act as an incubator and resource centre for knowledge and technologies that really serve people and planet.
Figure 1 is a very schematic diagram of George Chan’s system, which I shall call Dream Farm I. As is clear from George’s excellent presentation, the farms are very diverse, depending on local resources, ingenuity and imagination.
Figure 1. Dream Farm I according to George Chan
The anaerobic digester takes in livestock manure plus wastewater and generates biogas, which provides all the energy needs for heating, cooking and electricity. The partially cleansed wastewater goes into the algal basin where the algae produce by photosynthesis all the oxygen needed to detoxify the water, making it safe for the fish. The algae are harvested to feed chickens, ducks, geese and other livestock. The fishpond supports a compatible mixture of 5-6 fish species. Water from the fishpond is used to ‘fertigate’ crops growing in the fields or on the raised dykes. Aquaculture of rice, fruits and vegetables can be done in floats on the surface of the fishpond. Water from the fishpond can also be pumped into greenhouses to support aquaculture of fruits and vegetables. The anaerobic digester yields a residue rich in nutrients that is an excellent fertiliser for crops. It could also be mixed with algae and crop residues for culturing mushrooms after steam sterilisation. The residue from mushroom culture can be fed to livestock or composted. Crop residues are fed back to livestock. Crop and food residues are used to grow earthworms to feed fish and fowl. Compost and worm castings go to condition the soil. Livestock manure goes back into the anaerobic digester, thus closing the grand cycle. The result is a highly productive farm that’s more than self-sufficient in food and energy.
What I love most about George’s farms is how happy the animals look [17]. They are organically fed and toilet-trained (!) to deposit their manure directly into a shunt that goes to the digester, so the animals and their living quarter are spotlessly clean, which makes for healthy and contented animals.
I have described Dream Farm [1] as an “abundantly productive farm with zero input and zero emission powered by waste-gobbling bugs and human ingenuity.”
There’s a lot of human ingenuity among scientists and engineers and other professionals who would like nothing better than to use their ingenuity for the good of people and planet and to create a sustainable world for all its inhabitants. But they have so little opportunity under the dominant regime.
I was truly inspired by George’s work, and the idea of setting up Dream Farm II soon occurred to me. Fortunately, the first person I spoke to about Dream Farm II, after making contact with George Chan, was Kenneth Spelman; that was in August 2005. I needed a good engineer, George said, and there were two possibilities. I rang Kenneth first and tried the idea on him, and he got very excited right away.
And so over the next months, we assembled a team of potential partners for a proposal to the UK Carbon Trust, which seemed like the ideal funding agency for the project. The Carbon Trust required 50 percent of the funding to come from industry. The companies we approached mostly liked the idea; it was a heady time. We managed to submit the proposal just before the November deadline.
Unfortunately, the proposal failed to get through even the first round. We have since learned that the Blair government’s idea of reducing carbon emissions is to build more nuclear power plants [18], which are widely known to be ecologically disastrous simply in terms of the radioactive wastes generated, also highly uneconomical; and provides little, if any savings on greenhouse gas emissions compared to a gas-fired electricity generating plant (SiS 27) [19, 20]. The Blair government’s “energy from waste” programme is limited to burning wastes in incinerators that spew toxic fumes for miles around [21].
But we are not giving up, and I hope you will see why. I take this opportunity to thank George Chan for his encouragement and answering numerous questions over the e-mail, Kenneth Spelman, likewise, and undertaking to donate practically all the building works involved for the Carbon Trust proposal. Thanks are also due to our intended partners, Biogas Technology Limited, CHP Services Ltd., and ElmFarm Research Centre; and to David McGrath of SiGen, James Bakos of SHEC, Peter Saunders, Peter Rae, and others who gave valuable comments and suggestions. The Carbon Trust proposal [22] was put together with great enthusiasm from everyone concerned and at “wartime speed”.
For the Carbon Trust proposal, we had to call Dream Farm something boring: Integrated Reduced Emissions Food and Energy Farm, IREFE, for short. Kenneth’s advice was never mention waste, or else the waste bureaucracy will descend on us like a tonne of bricks.
The aims of IREFE are: to maximize productivity and balanced growth; to minimise environmental impact, hence “zero emission”, “zero waste”, and even “zero input” are the ideals; and most important of all, to achieve self-sufficiency in food and energy.
These aims are also the basis of the new economic model [23] (see “Sustainable food systems for sustainable development SiS 27), described in the complete version of the present proposal.
What really excites me about George’s dream farm is that it demonstrates concretely a theory of the organism I first presented in the second edition of my book The Rainbow and the Worm, the Physics of Organisms, published in 1998 [24].
At around the same time, I proposed that we could look at sustainable systems as organisms. This idea has been developed more completely in a paper published with theoretical ecologist Robert Ulanowicz at the University or Maryland [25].
The important features of zero-emission systems are the same as those of the zero-waste or ‘zero-entropy’ model of organisms and sustainable systems. Entropy is made of dissipated energy, or waste energy that is useless for doing work, and simply clogs up the system, like ordinary waste.
The zero-entropy model predicts balanced development and growth as opposed to the dominant economic model of infinite, unsustainable growth. This disposes of the myth that the alternative to the dominant model is to have no development or growth at all.
Back to the practicalities: how are the aims of Dream Farm achieved?
First, we harvest greenhouse gas (biogas methane) not just from livestock manure and used water, but also crop residues and certain food wastes, which constitute feedstock for the anaerobic digester to produce fuel for on-farm energy needs and mobile uses for transport and farm machinery, substituting for fossil fuels. Notice how this reduces carbon emissions twice over, first by preventing methane and nitrous oxide from the farm wastes going into the atmosphere, and second from the fossil fuels saved by burning methane instead. But that’s not the only benefit of our approach, as distinct from the UK government’s approach of burning the wastes.
As a result of confining the farm ‘wastes’ in the anaerobic digester, nutrients, especially nitrogen, are conserved, instead of being lost as ammonia and nitrous oxide, a powerful greenhouse gas; or else leached into ground and surface waters as pollutants. These nutrients can now support the growth of algae, fish, livestock etc. for maximum farm productivity.
Harvesting sunlight is what crops do naturally, as do the algae in the aerobic digestion basin that produce all the oxygen needed to purify the partially cleansed water coming out of the anaerobic digester, and the phytoplankton in the fishpond that feed one or more of the several species of fish co-existing happily in poly-culture. Solar panels are incorporated, especially as the new generations of solar panels are much more affordable, durable and easy to install [26].
Conserving and regenerating potable water free of pollutants is a very important aspect of this farm, as water shortage and deprivation are affecting many parts of the world. After being cleansed by the algae, the water goes into the fishpond. From there it can be further polished by various species of aquatic plants before it is returned to the aquifers. Water from the fishpond also returns to the aquifers by being used to ‘fertigate’ the crops, and filtered through the layers of soil and subsoil.
Dream Farm is run strictly on organic principles, because pesticides and other chemicals will kill the bacteria in the biogas digester. There is now substantial evidence that organic foods are healthier; not only free from harmful pesticide residues, but also enriched in antioxidants, vitamins and minerals [27].
Energy is used at the point of generation. This micro-generation is gaining favour all over the world. It doesn’t depend on a grid and is therefore most suitable for developing countries. In developed countries, local micro-generation protects against power failures and black outs, not to mention terrorist attacks on the grid. A study in the UK estimated that up to 69 percent of the energy is lost through generating electricity at power stations and piping it over the grid [28].
What better way to reduce food miles and all the associated environmental impacts of food import/export than consuming locally produced food fresh and full of goodness, instead of goodness knows what?
A recently released report on Food Miles commissioned by UK’s DEFRA (Department of the Environment Food and Rural Affairs) put the direct social, environmental and economic costs of food transport at more than £9 billion each year [29]; with congestion accounting for £5 billion, accidents for £2 billion, and the remaining £2 billion due to greenhouse gas emissions, air pollution, noise and infrastructure damage. The gross value of the agricultural section was £6.4 billion and the food and drink manufacturing sector £19.8 billion. In other words, the £26.2 billion worth of agriculture and the food and drink industry involves externalising £9 billion, or 34 percent of the costs to the taxpayer [30].
The anaerobic biogas digester is the key technology in Dream Farm.
Digesters can be any size, ranging from small ones made of plastic material, disused petrol drum, moulded fibre-glass to big ones made of reinforced concrete as George has shown us [17]. I have seen small ones buried in the ground serving a single family, which are simple and easy to maintain [31] and mammoth constructions serving the manufacturing or waste-treatment industry.
I found one that treated wastes from a school toilet in Addis Ababa, also buried underground with two covered potholes. Animal manure could be added through one of the holes, and stirred with a wooden stick. The second pothole revealed a pipe and valve, presumably for controlling the flow of biogas.
Another I spotted recently in Kasisi Agricultural Training Centre near Lusaka, Zambia, was no longer in use; it was built next to a pig house, now empty.
Two big ones – 2 500 m3 each – were installed on a 1 000 acre farm in Wisconsin with more than 1 000 dairy cows [32]. They are fully automated, heated, monitored, with alarm fitted, valves, whistles, what have you. The farmer is reported to be happy with his investment.
But as George has warned, the more automated, the more parts there are to go wrong. So the challenge is to design something affordable, easy to use and maintain, on a more human scale.
Pierre Labyrie [33], who works for Eden (énergié, dévelopment, environment) Toulouse, France, an organisation helping farmers install biogas digesters, tells me that the typical digester installed is 2 000 m3, even for small farmers with only 100 cows. The reason seems absurd. Farmers in Europe are by law required to store four-months worth of manure in slurry lagoons, which have to be that big. Rather than getting the law changed now that fresh manure is being treated and there is no need to store the slurry, they find it simpler to construct big digesters. But that means extra capital and maintenance expenses for the farmer. I have posed this question to the UK Department of Trade and Industry, and am awaiting a reply.
These digesters are not very good to look at. We need landscape architects and engineers to work together to design a beautiful and perfectly functional farm. What can be done besides the main crops and livestock, with trellised fishponds, algae shallows, grazing fields, woodlands, orchards, vegetable, herb and flower gardens, some floating on water….
The company that made the big digesters [32] also provided a combined heat and power generation unit based on an internal combustion engine, which burns the biogas and generates electricity and heat. These heat and power generation units can now produce electricity at about 30 percent efficiency, with 50 percent recovery of power as heat, giving an overall power conversion efficiency as high as 85 percent [34].
At an initial stocking rate of 0.8 cow/acre on a 1 000 acre Minnesota farm, 2 063 kWh/cow was produced per year from biogas. I did a little calculation on the energy yield and carbon emissions saved per cow per year. The amount of methane required to generate that amount of electricity is 620 m3 or 0.4464 tonnes, assuming 30 percent efficiency in converting to electricity. This is equivalent to 9.828 tonnes CO2 equivalent, using global warming potential of 22 for methane. The amount of oil saved per cow by using the methane as fuel is 0.553 tonne, which represents an additional 1.715 t CO2 equivalent saved (1 tonne oil = 3.1 tonne CO2). Hence the total savings by processing manure produced from a single cow per year, counting only methane is 11.543 t CO2 equivalent.
A 100-acre farm with 80 cows - a nice size for a demonstration farm, with plenty of room for woodlands, an on-site gourmet restaurant to take advantage of all that lovely fresh organic food plus an analytical research laboratory - would yield more than 160 000 kWh per year in energy and save 923.4 t CO2 equivalent in emissions.
If all the farm manure produced in the UK – estimated at 200 m tonnes - were to be treated in biogas digesters and the biogas harvested for fuel use, the carbon emissions saved would be more than 14 percent of the national emissions.
But we can do much better than that. When other farm and food residues are included, the yield of biogas can be far higher (see later). A 1 000 t CO2 equivalent saving a year is quite realistic. The market price (16 Jan 2006) was €23.35 per tonne CO2 equivalent. So 1 000 tonnes is worth more than 23 000 euros in carbon credits.
(I was informed by UK’s Department of Trade and Industry that one would be unable to gain carbon credits in Britain through the Kyoto route, i.e., Clean Development Mechanism (CDM) or Joint Implementation (JL) [35]. CDM projects are in developing countries only, and while JL projects are eligible in developed countries, the UK has not yet signed up to it. One option may be voluntary emission reduction (VERs) credits, which are sold to the retail market for offsetting companies and individual emissions on a voluntary basis. Watch this space)
Livestock manure is in fact rather low down in the league of biogas yield [36]. Fats and grease are way up there with 961 m3 per tonne. Bakery waste not far behind at 714 m3 (see Fig. 2). Waste paper, not included in this chart, is also a good substrate for generating biogas.
Figure 2. Yield of biogas with different feedstock
As you can see, it is possible to produce an excess of biogas, if that is needed.
The incentive for producing more biogas is that methane can be used directly as fuel for cars and farm machinery after being cleaned up and compressed.
Biogas digestion is certainly a far better way of getting energy from wastes than just burning wastes. It also makes nonsense of the ‘biofuels’ that the UK and other governments are supporting, which involves burning biomass or making ethanol out of maize and soybean [37], especially the glut of GM maize and GM soybean that Monsanto can’t sell. Even ethanol from agricultural wastes is not sustainable, because you lose irreplaceable soil nutrients and generates pollutants. Similarly, burning crops will involve mining irreplaceable nutrients from the soil.
A schematic diagram of Dream Farm II (Integrated Reduced Emissions Food and Energy Farm, IREFE) is presented in Fig. 3. This is an improved version of the one submitted to the Carbon Trust, mainly in the addition of solar power.
Figure 3. Dream Farm II
As mentioned, new generations of solar panels are cheaper and easier to install and maintain, and there is no reason not to include them as a core technology for generating energy alongside the biogas digester. (We shall definitely need extra energy for the on-site gourmet restaurant and the analytical lab.)
Our approach is to get the farm up and running on core technologies while newer technologies are integrated or substituted at the periphery as time goes on. As said, we want the farm to serve research/education purposes and as an incubator and resource centre for new technologies, new designs, new ideas.
For example, combined heat and power generation is currently done using an internal combustion engine, which is noisy, and produces some noxious fumes. The ideal is to have heat and power generation with a fuel cell.
Fuel cells are theoretically highly efficient and emission-free. A fuel cell generates electricity, operating on pure hydrogen, and produces nothing but water as by-product.
In a proton-exchange membrane fuel cell (PEMFC) most suitable for on-farm use, a proton-conducting polymer membrane separates the two electrodes, typically made of carbon paper coated with platinum catalyst [38].
On the anode (negative electrode) side, hydrogen splits into protons and electrons. The protons are conducted through the membrane to the cathode (positive electrode), but the electrons travel to an external circuit to supply electrical power before returning to the fuel cell via the cathode.
At the cathode catalyst, oxygen reacts with the electrons and combines with the protons to form water. A fuel cell typically converts the chemical energy of its fuel into electricity with an efficiency of about 50 percent. (The rest of the energy is converted into heat.)
New generations of fuel cells are under development that can take methane and reform it into hydrogen inside. The farm in Wisconsin tried out a prototype, but it did not perform as well as the internal combustion engine [39]. A major problem was that the biogas had to be substantially cleaned up before it could be fed to the fuel cell, leading to great losses of methane [40].
Methane can be purified to less stringency and compressed as fuel for mobile use: to run cars and farm machinery. Cars run on biogas methane are available in some countries and gaining in popularity, especially in Sweden [33], which already has biogas methane refuelling stations dotted around the country.
Another route to go is to convert the methane to hydrogen at high efficiency using a new solar-assisted thermocatalytic process [41], and then use the hydrogen to run vehicles. Yet another route is to have a two-staged anaerobic digestion, the first stage at slightly acidic conditions, which optimises the production of hydrogen, with a second stage under neutral pH for methane production [42].
Hydrogen storage is still a problem, though it is a very active area of research at the moment. Tanked hydrogen is now used to run buses on an experimental basis all over the world including the UK; but for smaller vehicles in particular, the ideal is to store hydrogen in a lightweight solid absorbent and use that with a fuel cell. There are promising developments in those areas also [43].
Benefits of Dream Farm II
It is clear that as far as energy is concerned, IREFE is not only self-sufficient, but can also export electricity to the grid. Some of the energy can be used to heat the biogas digester, to make it work more efficiently. Surplus electricity can also be used to recharge hybrid gas-electric cars.
As far as food is concerned, there is a complete menu, limited only by the imagination and industry, rich enough to supply an on-site organic gourmet restaurant, all for free. I am thinking of the fishpond possibilities: fresh water oysters and other bivalves, crayfish, prawns, silver carp, grass carp, what else? Specialty mushrooms, rocket, mange tous peas, salad greens, orange beetroot, blue potatoes… plenty of room for research and innovation there.
There’s certainly enough food to spill over to local villages, schools, old people’s homes, nearby cities, delivered fresh everyday.
In short,
Dream Farm is exactly what we need to feed the world, mitigate climate change to let everyone thrive in good health and wealth in all senses of the word in a post-fossil fuel economy.
Unfortunately, our government prefers other solutions to the energy crisis. It doesn’t realise there is a food crisis yet, and is emphatically against UK being self-sufficient in food.
When asked about UK’s food policy, a DEFRA spokesperson wrote on behalf of the Minister for the Environment Elliot Morley [44]:
“Supporting greater UK self-sufficiency in food is incompatible with the concept of the European single market, in which different countries specialise according to comparative advantage. In an increasingly globalised world the pursuit of self-sufficiency for its own sake is no longer necessary nor desirable.”
We need something like Dream Farm not only to feed the world, or to mitigate climate change, or to avert the energy crisis. Yes, it is all of those and more. Most important of all, we need to mobilise human ingenuity and creativity, to make us go on dreaming and working for a better world.
Article first published 30/01/06
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