World Stove

FOUR QUICK ANSWERS TO THE QUESTION:

Better stoves can…

1. reduce indoor- and outdoor air pollution.
2. reduce the amount of biomass burned for fuel.
3. reduce emission of Greenhouse gases and particles.
4. produce biochar by which carbon can be removed, for centuries, from the air.

NOT SO QUICK ANSWERS TO THE QUESTION:

1. Indoor air pollution results in 1.6 million premature deaths per year, mainly in women and children. Many of these deaths occur in the half world which cooks with open fires or inefficient biomass stoves. Efficient, clean burning stoves can reduce this mortality. As one example, women cooking over solid fuel fires in unventilated areas have twice the risk of developing cataracts than do those using gas stoves. (International Journal of Epidemiology 2005;34:702–708).Burning of non-fossil fuel (wood, dung, and trash) is the source of a vast brown cloud that hovers over much of South Asia and the Indian Ocean every winter. (Örjan Gustafsson, et al, 2009. Brown Clouds over South Asia: Biomass or Fossil Fuel Combustion? Science 323: 495–498). More efficient stoves would improve the health for billions of people.
2. An open fire applies about 7-12% of the combustion energy to cooking; other small stoves achieve 43%. LuciaStoves reach 93% (calculated on the basis of fuel available in pyrolyzation mode). This means that the LuciaStove releases more energy than do other small stoves, and it does it with just over half (55%) of the fuel, sequestering the rest in char. With open fires, much of the fuel escapes as smoke and flammable gas, and that’s why they are inefficient and smoky. In fact, when open fire cooking is regularly employed, it consumes about one cubic meter of wood (or equivalent) per person per year. Worse yet , collecting this fuel takes a lot of time and effort, often in dangerous circumstances. Efficient, clean burning stoves can reduce fuel needed, smoke released, and time lost.
3. The high efficiency of the LuciaStove allows cooking and heating with less fuel than would other stoves. Less fuel consumed means reduced emissions of Greenhouse gases. Also, the emissions are filtered through the developing char, where particles can be trapped.
4. The LuciaStove converts about 30% of the fuel weight to biochar. Biochar is up to 80% carbon and very resistant to decay. If collected and buried (for good ecological and economic reasons discussed in FAQ #3 and FAQ #4), this actually reduces the carbon dioxide in the atmosphere.

QUICK ANSWER TO THE QUESTION:
James Lovelock recently suggested that, “There is one way we could save ourselves and that is through the massive burial of charcoal. It would mean farmers turning all their agricultural waste – which contains carbon that the plants have spent the summer sequestering – into non-biodegradable charcoal and burying it in the soil. Then you can start shifting really hefty quantities of carbon out of the system and pull the CO2 down quite fast.” (See Vince, G. 2009. Interview with James Lovelock. New Scientist, 201(No 2692), pp. 30-31)

NOT SO QUICK ANSWER TO THE QUESTION:

According to Strand and Benford (2009), atmospheric CO2 carbon is accumulating at the rate of about 4?6 Pg per year. (Pg, petagram = 1015 g, = 1 gigaton) To have a significant impact on that rate of increase of CO2, the technology must remove and sequester at least 0.5 Pg per year. Those authors report that the above-ground crop residues produced globally in 2006 were about 5 Pg. Since dry crop residue biomass contains on average 40% carbon, up to 2 Pg crop residue carbon is produced annually. (See Strand, S.; Benford, G. 2009. Ocean Sequestration of Crop Residue Carbon: Recycling Fossil Fuel Carbon Back to Deep Sediments. Environmental Science and Technology, 2009, 43, 1000-1007). In other words, there is more than enough agricultural waste to fulfill Lovelock’s suggestion. In fact, agricultural waste, now viewed as a disposal problem, is actually a valuable energy source and it presents us with four times what we need to have a significant carbon negative effect with char. (See Pacala,S.; Socolow,R., 2004. Stabilization Wedges: Solving the Climate Problem for the Next 50 Years with Current Technologies: Science 305 (5686) 968-972.)

QUICK ANSWER TO THE QUESTION:

When added to many soils, biochar reduces the loss of water and nutrients to drainage and runoff. The cost of fertilizer has risen 45.8% recently and reducing its loss can benefit both growers and the environment. Biochar may increase the activities of beneficial microbes, and many studies indicate that yields of crops are increased.

NOT AT ALL QUICK ANSWER TO THE QUESTION:

The effects of adding char to soils are many: improvements in water and nutrient holding capacities have been clearly demonstrated, especially for sandy soils. (See references 1 and 2, just below). The dramatic increases in yield reported in some soils and circumstances point to broader effects, certainly involving profound changes in soil microbial- and mycorrhizal activities. These too have been well documented, and we can only say that this is an area of extremely active research, one we don’t pretend to summarize here.
To learn more, see the following:

1. Glaser, Bruno, Johannes Lehmann, and Wolfgang Zech (2002) Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal – a review, Biology and Fertility Soils 219, 223
2. Steiner, Christoph, Wenceslau G. Teixeira, Johannes Lehmann, Thomas Nehls, Jeferson Luis, Vasconcelos de Macêdo, Winfried E. H. Blum, Wolfgang Zech (2006) Long term effects of manure, charcoal and mineral fertilization on crop production and fertility on a highly weathered Central Amazonian upland soil. Plant & Soil 291: 275-290. “The application of charcoal significantly reduced leaching of applied mineral fertilizer. The increased ratio of uptake to leaching due to charcoal application indicates a high efficiency of nutrients applied with charcoal.”

With these highly efficient stoves, less fuel is consumed and, if biochar produced is collected, it can actually be sold on the open market or used to improve your garden soil.

TWO QUICK ANSWERS TO THE QUESTION:

1. All WorldStove products have been designed for mass production. (with the exception of some fireplace inserts which must be custom made).
2. And not all of our stoves are small. A large biomass converter is the equivalent of hundred of little stoves. At present, the largest burner we have built, good for converting agricultural waste to thermal energy and char, takes in about 500 kg of biomass per hour, generating 1.2 mega kW of thermal energy and about 150 to 200 kg of biochar (depending on the biomass). The LuciaStove, for example, consumes about 200 grams per hour, so our large unit, is equal to more than 2500 LuciaStoves!]

NOT SO QUICK ANSWER TO THE QUESTION:

Mass production of critical components has several benefits: it allows consistently high quality at a minimum of cost. Produced in our facilities, these critical pieces can be shipped fully assembled or disassembled. Assembly at point of use not only saves shipping costs but it also creates employment opportunities in different parts of the world.

Obviously there is more to this story, and you can read more in other FAQ on this site. Or, if you prefer, don’t hesitate to contact us through the “Contact us” tab in our webpage.

For the moment, let’s ignore what we read for and against climate changing and look at some facts nobody really denies:

GREENHOUSE WARMING, HOW IT WORKS.

QUICK EXPLANATION

If you park a closed car in the bright sunlight, the interior will soon become much hotter than the outside air. This is because the energy of sunlight gets in through the windows but cannot escape as easily as it entered. The temperature goes up. When sunlight reaches the earth, the air has the same effect as the windows in the car. Heat gets in more easily than it gets out so our earth gets warmed. Increasing gases in the atmosphere, such as carbon dioxide and methane, will increase the greenhouse effect by keeping more heat in.

NOT SO QUICK EXPLANATION

Sunlight reaches the outer atmosphere in many different forms: The colors of a rainbow are just the part which we can see. But there are also powerful ultraviolets (which give sunburns and skin cancer) and also low energy light forms, such as infrared, which we feel as heat, but cannot see. Each of these forms of light contains energy and, if they are absorbed by a rock, or an ocean, or a person, the rock, ocean, or person will be warmed up a bit. But no matter if the light reaching this rock etc was 100% green, or blue, or whatever, it will be given back to the environment as heat, that is, invisible infra red light. What happens then? Gases such as carbon dioxide (CO2) and methane (CH4), tend to block the easy passage of infrared, that is, heat! More carbon dioxide means more blockage of escaping heat and thus a warmer earth.

How significant is this energy trap, that is, the greenhouse effect? We can measure it by comparing the average temperature on earth with that on the moon. This is a fair comparison since the moon and the earth are both about the same distance from the sun, which heats them both. Any difference in temperature on earth and on the moon arises because, unlike the earth, the moon has virtually no atmosphere, and thus no greenhouse effect. The average temperature on the surface of the moon is -9F, that is -23C, while earth averages +59F (+15C). http://www.asi.org/adb/02/05/01/surface-temperature.html

Some details for inquiring persons:

Does carbon dioxide really impede the passage of heat (also known as infrared light = IR)? In laboratories, we measure the amount of CO2 in a gas with an instrument called, naturally enough, an Infrared Gas Analyzer. A beam of IR light is passed through a sample of the gas to be analyzed. The amount of IR light that gets through diminishes with increasing CO2. In other words, more CO2, more IR blocking, and more greenhouse effect.

How do we know what pre-industrial greenhouse gas levels were in the air?
The most informative measurements have come from air bubbles trapped in Antarctic ice. These show that, for at least 400,000 years, CO2 levels in the atmosphere have closely followed the global temperatures as recorded in ice cores, tree rings and elsewhere. http://www.oursouthwest.com/climate/faqs.htm#p

What was CO2 content of the atmosphere in 1850, before we started burning coal? And what is it now?
In 1850, it was about 285 parts per million. Today, it is 385 parts per million. To learn what this means, see FAQ#7.

QUICK EXPLANATION

The first thing to realize that climate change does not mean everybody will get a little bit warmer. If climate were just a matter of incoming solar radiation the mild climate of Milan, Italy (45° North latitude) would equal that of frigid Montreal, Canada, also 45° North). Local climates are modified by mountains and currents of wind and water, not just latitude. Climate changes will modify wind and ocean currents. Some areas will be warmer, others cooler, some wetter, others less so. Furthermore, as we say in FAQ#8, change, almost by definition, is likely to be stressful for those adapted to the present.

Instead of prolonging a not very quick answer, we ask you to think about implications of 385 ppm CO2. These are well expressed by Greg Craven. He suggests that if the many scientists that say climate change is real, are correct, and we do nothing, we put the world, as we know it, in danger. If they are wrong, that is, it’s just “cyclical”, we will have spent wasted a lot of money and effort for no great need. (See What’s the Worst That Could Happen? A rational response to the climate change debate by Greg Craven Perigee Press.)

However, to this we add that, even if climate change were not happening, would reducing air pollution, saving fuel, and improving agriculture, be such a bad idea?

NOT SO QUICK EXPLANATION

Two references would get you started on learning what is currently believed about short- and long term climate changes.

The first discusses short term global cycles, for example, those due to oscillations in the Atlantic Ocean. World will ‘cool for the next decade’ by Fred Pearce, . New Scientist, 2009, 203, 12 September 2009, p. 10.

The second reference, Six Degrees – Our future on a hotter planet by Mark Lynas (2008) National Geographic Press, uses long term geological records to estimate how our planet will change if climate change continues into the future. See also FAQ #8.

QUICK EXPLANATION

It has happened before, but that does not mean it’s trivial. When a plant or animal is well adapted to its environment, a change in that environment will very often make the organism less well adapted. Highly adaptable organisms with short generation times: cockroaches, mice and crabgrass, etc. would probably not notice climate cange. Highly specialized organisms with long life cycles would suffer the most. Sequoias are adapted to foggy climates, polar bears to ice floes, rice farmers to abundant water supplies. All these would suffer. There will be other foggy climates developing, and increased rainfall elsewhere, but will the Sequoias get there? Will the newly wet areas be right for rice cultivation? Eventually, there will be new adaptations, new species. It has happened before, but, remember, meantime, we have a lot of people to feed.

NOT SO QUICK EXPLANATION

See the book Six Degrees – Our future on a hotter planet by Mark Lynas (2008) National Geographic Press. Here’s a sample of Lynas’ insight: Before we started using fossil fuel in the 1860’s, the CO2 concentration in the air was 285 parts per million. Now it is about 385 ppm. The last time the CO2 level was this high was 3 million years ago, a time geologists call the Pliocene. What was the climate like then? The world was about three degrees C warmer than it is today. There were no continental glaciers in the northern hemisphere, and today, glacier fed rivers sustain half the world’s population. And sea level was much higher than it is now. Three degrees will make a difference!

QUICK EXPLANATION

Carbon positive activities include anything which adds CO2 to the atmosphere.
Carbon neutral activities do not change the CO2 in the atmosphere.
Carbon negative activities reduce the CO2 in the atmosphere

NOT SO QUICK EXPLANATION

Consuming fossil fuels, such as oil, coal or gas is carbon positive since these add carbon dioxide to today’s atmosphere. Harvesting trees for firewood or for extending agricultural fields is similarly carbon positive.

In contrast, the consumption of biomass such as agricultural waste, sawdust, scrap wood from forests or yards, etc. is carbon neutral since, with or without our intervention, this biomass, would soon be released to the atmosphere by decay.

Thus, stoves which consume otherwise waste biomass are largely carbon neutral, (not totally neutral since harvesting these takes some energy as does converting sawdust to pellets.) Stoves that produce char, if they burn biomass in the process, are only partially carbon neutral, but, the resulting char is a carbon negative product. Because this char contains carbon recently drawn from the atmosphere, and it will resist decay for centuries

NOT SO QUICK EXPLANATION

Carbon Neutral:
We (meaning, the whole world, now, and for millions of years of years past) have depended on photosynthesis in green plants to produce ALL biomass. ) In photosynthesis, carbon dioxide and water and energy are combined to produce
energy rich biomass and oxygen. (Tiny exceptions are found in sulfur springs in ocean depths but these are irrelevant here.)

In the reverse of photosynthesis, biomass and oxygen are combined, in fires, or in respiration within ourselves or other living creatures, to release carbon dioxide and energy (which keeps us going!) So…. If today’s photosynthesis is balanced by today’s respiration, or fires, nothing is really changed. This is Carbon Neutrality. Burning wood, for example, is carbon neutral. However, Eric Johnson (Environmental Impact Assessment Review 29 (2009) 165–168) rightly points out that forests are enormous reservoirs of biomass so, when they are burned for fuel or charcoal, vast quantities of CO2 are released to the atmosphere and this is certainly carbon positive. Burning waste wood such as fallen trees, branches, sawdust, agricultural waste, etc., all of which would decay anyway, is nearly completely neutral. We say “nearly” since some energy consumed in gathering and processing. For example, converting sawdust to pellets takes some energy.

Carbon Positive:
Hundreds of millions of years ago, green plants produced great masses of biomass which were eventually buried and converted into gas, coal and oil as fossil fuels, rich in both carbon and energy. Until about, 1860, with the development of coal and oil as energy sources, this carbon was locked safely away, underground. Now it is being released and many studies indicate that it is an important source of the carbon dioxide increase in our atmosphere. Burning fossil fuels is Carbon Positive.

Carbon Negative:
If today’s waste biomass is converted to biochar and buried, it will remain there for hundreds of years. The carbon it contains (about 80% by weight) is thus removed from the atmosphere. This is a Carbon Negative product. According to James Lovelock, burying char is the one effective thing we can do to pull down atmospheric carbon dioxide. (See FAQ #2. Is there enough biomass around that converting this to biochar would make a difference in climate change?)

QUICK ANSWERS TO THE QUESTION:

WorldStove are different in that…

1. They are designed for mass production.
2. Guaranteed for five years.
3. Can be adapted to local fuels.
4. Can be adapted to local cooking customs.
5. Emissions of flammable gases and particles are greatly reduced.
6. Char is produced automatically.
7. Fuel can be added during cooking or heating.
8. Critical components can be shipped disassembled.
9. Individual components can be replaced at low cost without use of tools, extending life.
10. Most components of LuciaStoves are made from recycled materials and, in the end, can be recycled themselves.

NOT SO QUICK ANSWERS TO THE QUESTION:

1. The efficiency of WorldStove products depends on complex geometries of critical components. Individual machining of these would be prohibitively expensive and also require extensive quality control.
2. These critical components are guaranteed for five years.
3. Although WorldStove products consume a wide variety of fuels, they can be tuned to
   locally abundant materials. For example, rice husks and wheat straw do not have the same fuel characteristics, but we can adjust for such differences.
4. WorldStove products are already in service in institutions where cooking involves batches of 70 liters of material but the same burner can simmer a pot of tea.
5. Flammable gases such as methane, carbon monoxide and hydrogen are reduced by passing through the flames, and particles are trapped in the char.
6. Pyrolyzation occurs when biomass is heated in the absence of oxygen. With the LuciaStove stove, pyrolyzation begins almost immediately, goes to completion and then stops automatically. In some other small stoves, char is obtained only if the process is stopped by closing the burn chamber or, more difficult still, by dumping the burning fuel into water. In either method, some fuel may not be completely pyrolyzed, thus reducing the value of the char. Furthermore, when the burning fuel if plunged into water, an unhealthy, not to say dangerous, burst of steam and carbon monoxide occurs. This quenching in water also modifies char quality still more. Finally, also the pH of the resulting char can be controlled.
7. Unlike some other small stoves, fuel can be added as needed to prolong cooking or heating.
8. Critical components can be shipped disassembled and then assembled at point of use. This saves shipping costs and assembly at point of use creates local employment.