Solar Power isn't Feasible!

Solar Power isn't Feasible!
This cartoon was on the cover of the book "SolarGas" by David Hoye. It echoes the Sharp Solar slogan "Last time I checked nobody owned the sun!"

Monday, July 16, 2012

Analysis of Renewable Energy Potential in the Hinku Valley Part 2

(In our last post we reported on the installed solar electric capacity of the Hinku Valley trail from Lukla to Khare at the base of Mera Peak. In this post we explore solutions to the indoor air pollution and deforestation challenges facing the region.)

The problems:  Deforestation and Indoor Air Pollution

Despite a successful  ban on the collection of the slow growing shrub juniper and its replacement with kerosene and despitee the growing penetration of photovoltaics in the Hinku Valley of Nepal  (roughly 2 kilowatts of installed capacity throughout the valley with an average of  20 Watts per lodge) and the presence of 4 solar cookers (2 in each of two villages), the fate of the forest and general alpine ecosystem is still very uncertain.


 Additionally,  indoor air pollution is still a major health hazard, claiming lives and causing respiratory and eye illnesses as well as cancer, particularly among women and children.

Firewood continues to be the primary fuel used for both cooking, heating bathing and washing water, and for keeping the homes and lodges warm.

 The Hinku doesn't have large yak populations so yak dung for these purposes is in short supply, and even in areas like the Khumbu Valley where there are still substantial yak populations, yak dung, while a sustainable fuel from a production and consumption standpoint, still causes great discomfort and suffering through air pollution when used for combustion.

A yak and a solar cooker - two ways of heating water in the village of Khare at the base of Mera Peak in Nepal.

In summary, as  Balgain and Shakya (BSP report 2005) point out
"The heavy dependence on fuelwood resources has a negative impact on the environment resulting in deforestation around villages and the deterioration of soil stability on the affected hillsides. In addition, the burning  of dung reduces soil fertility.  With deforestation around villages, the daily labour required for collecting  fuelwood increases impacting primarily women and children and leaving little time for education as well as for productive tasks. Additionally the smoke  emitted from the burning of the biomass has adverse health effects on women and children causing widespread eye and respiratory diseases." (p. 6).

The kerosene that has replaced shrub juniper in the highest alpine areas carries with it its own health risks (the hydrocarbon smoke and fumes are both poisonous and carcinogenic) and carries with it substantial economic risks (prices can fluctuate wildly as the supply comes from India and relies not only on price and social stability there but on an entire supply chain that must get the fuel parsed into appropriate containers and transported for many days through the narrow passes up to the mountain villages.)

The Sun as Solution

There is a widespread belief that solar energy can provide the solution to the energy problems faced by people in remote areas, and this is true but only if all forms of solar energy are considered, including organic wastes.  The naive assumption that electricity, whether derived directly from the sun through photovoltaics, or indirectly through wind power or hydro power, can provide the answer  inhibits real solutions from being implemented.

The "energy-ladder" assumption that electricity is considered the apogee of energy development has been called into question when full environmental and cost accounting is done (see "From Linear Fuel Switching to Multiple Cooking Strategies: A Critique and Alternative to the Energy Ladder Model" by Masera  Saatkamp and Kammen, 2000). Instead, as Masera, Saatkamp and Kammen point out, "rural households do not ``switch'' fuels, but more generally follow a multiple fuel
or ``fuel stacking'' strategy by which new cooking technologies and fuels are added, but
even the most traditional systems are rarely abandoned."  To help solve the problems in highland Nepal we need to understand how local people weigh the costs and benefits of any given technology and consider with them what the best mix might be at any given time.

 Westerners accustomed to using electric water heaters, electric space heaters and electric stoves usually do not understand that converting electricity into heat is the least efficient use of this energy medium and that electrical resistance heating uses so much electricity that it is nearly impossible to deliver on a material or cost-effective basis for poverty alleviation.

 Electricity generated in remote areas, whether via fossil-fuel powered gensets, or any of the renewable sources, has been found to be insufficient for sustainable cooking or heating;  its appropriate use is for lighting, communications and computer equipment and power tools.

 For all forms of heating where electricity is in limited supply or costly, people will continue to use wood, charcoal, biomass (like dung and brush) or liquid fuels (like petrol, diesel or kerosene) unless we can supply them with more efficient direct forms of heating.  Even in areas where reliable micro-hydro electricity has been developed, for example  in the Khumbu valley and around Lukla,  there are seasonal outages and rationing and problems with siltation and most lodges must rely on backup generators just to provide lighting. We experienced frequent interruptions in electric service on this expedition when we were staying in Lukla.   Climate change and disruptions of the normal cycles of glacial buildup, thaw and melt will increase the challenge of year-round reliance on hydroelectricity as an answer to all energy needs, even where it is available and well developed.  Thus, other options must be made available to create a diverse portfolio of solutions that is resistant to disruption.

Solar Water Heating (SHW), particularly through the use of highly efficient vacuum tubes which quickly create hot water ranging from 80 C to 110 C, is  a marvelous solution that is easy to implement in the Hinku as we discovered during the 2011 expedition to Dingboche (one must merely be careful to pack glass tubes very carefully and securely for transport and ensure that nothing can fall on them once installed).  SHW is ideal for bathing;  for cooking purposes solar hot water can also be used, usually as preheating solution  to get the water from its ambient temperature in the region (normally between 0 and 15 C) to temperatures well  above 50 C. Using SHW for base energy it then takes very little additional fuel to get it to boil. 


Solar Cookers have also proven themselves popular in the Himalayas, but are still rare in the Hinku, and can not be relied on during cloudy weather.

 Greenhouse heating as an adjunct to space heating is a very plausible answer to mitigating the use of forest resources but  has not been observed despite the presence of two green houses in the Hinku Valley -- these were detached from the lodges so the heat was not utilized for human habitation.  Nonetheless the possibility exists with some awareness training and examples.

 Other forms of solar space heating (passive solar architecture, the construction of solar space heaters using black paint coated aluminum cans in a glass box piped into the house and facing South) have not been observed in Nepal but could be easily implemented; interestingly none of the houses or lodges we observed in the Hinku valley were oriented to use the sun's light or heat; there were no south facing windows to permit solar gain, no thermal masses used to retain solar heat; nothing in the construction of the lodges or homes seemed to be designed to permit heat gain or avoid losses. 

In this overlook of the village of Khare at the base of Mera Peak it is clear that there is no consideration of orientation to the sun used in the building of lodges or dwellings.  Passive solar architecture is not utilized in this region

Our lodge in Thangna (the village before Khare on the trail to Mera Peak) had PV for light and emergency phone, facing south, but thesmall windows were boarded up, had no panes of glass or plastic, and faced west, generally covered in shade.

Anrita Sherpa from the Mountain Institute pointed out to many of the lodge owners in the Hinku how his brother in Naamche Bazaar, who uses solar vacuum tube systems, solar cookers, heat exchanging efficient stoves, on-demand propane gas heaters, photovoltaics and large south facing windows, also insulates his lodge by placing hundreds of recycled PET water bottles between the stove walls and the plywood, creating a dead air space that keeps most of the heat in and reduces the need for fuel. 

A sign inside the lodge at the base of Mera Peak reads "Please note: Wood Precious. Heater Charge is Rs 200. Please remember to pay".  There is no insulation other than sporadic thatch coverings on bare stone walls and no glass or plastic paned windows; the few windows that do exist for ventilation in the smoke filled areas are small and face random directions.
A similar sign at Sona Guest House in Thangna reflects the same reality with a "notice for heater charge" apologizing to trekkers with the note: "Please don't feel more expensive because we have wood problem."

Insulation may be the single most important and easy to implement immediate solution for direct reduction of woodfuel in the Hinku.  Besides this, the use of mylar reflective sheet to keep heat inside the lodges would also have a profound effect.  In this case one would be applying the principle used by emergency "silvered" blankets to save people from hypothermia and the principle used by the inside of thermos containers.

 Foodscraps and human and non-human bodywastes: reliable sources of solar energy through biogas

In our opinion, concerning the transition away from burning biomass or fossil fuels, the simplest solution to both the environmental and the health challenges posed by firewood and kerosene is the use of biogas.

 Biogas is an oft neglected form of stored solar energy that nonetheless can be made available 24 hours a day, 7 days a week, 365 days a year, come rain or shine.  If the Cole Porter song "Night and Day, you are the one..." were rewritten to speak about the potential for renewable energy, it would be speaking about biogas.

Rather than falling on solar thermal panels or vacuum tubes  to heat up water which must be stored in a hot water tank, or on photovoltaic panels to create electricity which must be stored in batteries, biogas production depends on sunlight stored in the chemical bonds of organic material -- plants and animals, fungi and microbes, and the waste products they produce.

 In general the cycle is very straightforward: sunlight is absorbed by plants in a farmer's field, humans and animals eat the plants and convert some of the stored solar energy into movement and growth and excrete some as their manures.  A significant portion of the stored solar energy that was converted into chemical bonds through photosynthesis is  contained in plant parts that humans and animals do not eat or is in left over food scraps, and this reliable and easily obtained form of sunshine is simply thrown away in the garbage, paradoxically creating health and hygiene problems.

All of that stored solar energy, whether in the hydro-carbon bonds found in human and animal wastes, plant wastes or left-over food wastes, can be easily converted into methane gas (CH4) by anaerobic bacteria and Archaea that are ubiquitously found in the stomachs and intestines of all animals as well as in lake and pond mud all over the world. The procedure for creating biogas is deceptively simple: one simply creates an "artificial stomach" from any kind of container (plastic, cement, mud, canvas, leather...) fills it with water and any source of the abovementioned bacteria, and fits to it a feeding tube that goes under the water level into which organic waste can be fed, and effluent tube that comes from a spot a little higher than the feeding tube, but still underwater, and a gas outlet tube that comes from the topmost part of the "stomach" where the lightweight biogas will accumulate.  That is it. There is no secret and no special technique that needs to be applied.  The microbes do the rest.

One can always improve the gas production by finding ways to increase the surface area inside the artificial stomach (we use hundreds of small plastic cylinders like the "bioblocks" found in pond filters that permit biofilm growth) and one wants to make sure not to overfeed with food waste lest the stomach get too acid -- the bacteria need a neutral pH.  Similarly, to work properly the bacteria need to be kept between 20 and 40 degrees Celsius, but this are trivial plumbing and insulation and feeding rate concerns, not any kind of rocket science.

In fact biogas production is probably the simplest and most efficient way that any human being, family or community can make good use of solar energy immediately. Everybody has the main ingredients (the bacteria live in our own guts and can be obtained from our feces, and everybody has food wastes of some kind).

Where people are still burning wood and charcoal and suffering from the effects of indoor air pollution and deforestation we must ask ourselves what the reasons are that this easiest of technologies has not yet been implemented in their community.

Biogas in the fight against indoor air pollution in Nepal

Nepal has a long and successful history of biogas training, installation and use and is one of the few countries to have several agencies dedicated to dissemination and improvement of this radically simple and effective technology.

Nepal supports biogas principally in a effort to stop the suffering and mortality caused throughout the country by indoor air pollution.  A secondary priority is the ability for biogas to help curtain deforestation. However, as EPA director Lisa Jackson told a group of us at the Aspen Energy Forum in 2011, if we focus on end-goals that have broad support and appeal (like stopping deaths of women and children from indoor smoke) we will also achieve the other goals (stopping reliance on firewood and charcoal which exacerbate deforestation).

A moving mural on the street in Kathmandu near the river warns the public of the tragic suffering that indoor air pollution created by cooking fires causes in women and children. This depiction of a pregnant Nepalese woman tragically exposing herself and her unborn child to toxic fumes underscores how important it is for us to get clean food-scrap based biogas into common usage as the ideal replacement for firewood and charcoal and not merely "improved cooking stoves" which a recent study reported in Scientific Amercian shows are actually ineffective.

This improved cookstove in Khare uses a 9 Volt computer fan to increase the burn efficiency of the wood fuel. The fan is powered by a battery recharged by a 10 watt solar electric panel.

Some homes have hand powered fans that bolt on to the stoves to increase their effeciency. This one has a handle on the other side that the woman turns as she is cooking to blow air through the stove so that the wood burns cleaner.

 Across from the United States Embassy in Kathmandu on the second floor of a small building complex  is the  office for  "The Partnership for Clean Indoor Air" . Their mandate is

Project 1: Improving Households Energy Management Practices in Sacred Himalayan Landscapes, Langtang National Park-Rasuwa Funded by GEF/UNDP Small Grant Programme
Project 2: Advocacy for Gender Sensitive Energy Policy in Nepal funded by ENERGIA Network

They are partnered with an International Organization, orignally UK based but now with offices in Bangladesh, Kenya, Peru, Sri Lanka, Zimbabwe, Sudan and Nepal called "Practical Action". 



In 2009 Practical Action Nepal published a book called "Inventory of Innovative Indoor Air Pollution Alleviating Technologies in Nepal" which primarily covered improved cookstoves and solar cookers, but which had a chapter on "biogas technology" as disseminated  in Nepal.  I visited the office in Kathmandu and they kindly gave me a copy which is also available in its entirety as a .pdf on the web. I have reproduced the relevant sections here in these photographic scans:





 Nepal has already successfully introduced more than 250,000 domestic biodigestors in their country of some 30 million people and the technology is well known throughout the lowlands. Through awareness campaigns and targeting subsidies the number of digestors is growing daily.  Only in the Himalayan communities is the biogas solution either still unknown or considered "difficult" to implement.

 Nonetheless verybody I met with in Nepal who is involved with biogas seemed to think that high alititude biogas is both  important and doable.  In fact they have been testing several systems in high altitude with good results. The Practical Action report states,

"A research is undertaken to develop appropriate biogas plant designs for altitude higher than 2,100 m.  Two plants were installed during the 3rd Phase in Khumjung and Lukla of Solukhumbu district with greenhouse technology. However,despite the merit of the design and technology, the project cost was very high.  Four years ago, three other simpler new designs were tested in Beni VDC of Solu district with much lower project cost. One of the three designs, a simple addition of heap composting on top of the digestor is found to be the most appropriate and cost-effective design. This design is thus widely promoted between 2,100 and 3,000 m altitude as part of the regular national programme with subsidy. The GGC-2047 design with heap composting  technology was approved for commercial dissemination last year. Till date, some 40 biogas plants with heap composting are constructed in upper part of Rasuwa district and more are under construction. Some 30 plants with such heap composting are installed in Solukhumbu district.  The results are satisfactory. BSP-Nepal is going to undertake more promotional work in remote districts of Karnali and other areas like Manang and Mustang for construction of biogas plants with heap composting  technique.  Further research was initiated in 2007 in Rasuwa district (Langtang area) between 3,000 to 3,850 m using modified GGC-2047 (improved design with provision of multiple feeding , heap composting and warm water feeding."



Since 2003 Nepal has had a robust "Biogas Support Programme" (BSP) which is a "Development Cooperation among AEPC (The Government of Nepal Alternative Energy Promotion Center), SNV (The Government of Netherlands Netherlands Development Organization), the kfw Entwicklungbank (Government of Germany German Development Cooperation) and The World Bank.

The BSP has published a very useful book on the success of Nepal's biogas program, which is available as a .pdf here:  "The Nepal Biogas Support Program: A Successful Model of Pulbic Private Partnership for Rural Household Energy Supply" written by Sundar Bajgain, Indira Sthapit Shakya and editted by Matthew S. Mendis. It is filled with great graphs, facts and figures, including success measurement indicators on a social level, as well as  designs and economic and financial assessements.

As mentioned  Nepal has currently installed more than a quarter million home scale biogas digester systems, most of them directly thanks to the BSP and installed  during the first two phases of their BSP program.

If there is an area that needs to be strengthened in Nepal concerning the provision of low cost clean and renewable energy through biogas it is the adaptation of these systems to the colder high altitude regions of the country, precisely where we are doing our studies.   This is acknowledged in the BSP report.

 Sometimes it is the extra cost associated with building a well insulated digester and maintaining its temperature that is cited, other times it is the difficulty of transporting the building materials to the remote areas through narrow and difficult mountain passes, and sometimes, when people understand that digestors can be built with the same lightweight plastic water tanks or sillage bags available in their communities and that lightweight styrofoam insulation is adequate to keep them warm once heated, and that a combination of solar thermal heating and warm water feeding and compost heating are viable solutions to create that heat,  the usual barriers cited are worries that their isn't enough feedstock to make investment in biogas digesters worthwhile.

The belief that animal manure is necessary for biogas production

All over the world it has been successfully demonstrated that almost all organic material can be made suitable for biogas production.  In  the Mukuru slum of Nairobi we have visited public toilets that produce cooking gas for a neighboring restaurant and in the city of Pune India the Appropriate Rural Technology Institute has appropriated rural biogas digestors, made them smaller and proven that kitchen garbage is actually a simpler and more effective feedstock.  In China Puxin biogas company is showing with its new design that grass and leaves can also be used effectively.  The Culhane household in Germany produces biogas every day for cooking from a porchtop digester that is fed through an Insinkerator brand food waste grinder attached to the kitchen sink and they find that the food scraps produced by a family of 3 alone is enough for daily cooking. The Culhane's have also successfully produced useful biogas from their child's diaper wastes.

Nonetheless, in  many countries including Nepal the criteria for embracing biogas has been based on a belief that one needs a certain number of stable-fed livestock in order to get sufficient feedstock for useful gas production.

The BSP booklet states:
Both Hindu and Buddhist religions have a very positive attitude about cattle. They
attach no stigma or cultural inhibitions to the handling of dung coming from cattle or
buffaloes. The cattle are highly valued and as a result, they are seldom sold. They
are kept close to the farmhouse and in many cases are stable fed during prolonged
periods when land grazing is not practical. 
The conditions in which cattle are raised in Nepal are thus ideal for providing the
animal dung, the feedstock necessary to fuel small farmer based biogas systems,
Permanence of cattle and the family attending the cattle guaranties an adequate and
a continuous source of feed for the biogas systems. 
Only small size (4-10 m3) biogas systems, using cattle and buffalo dung, have been
promoted to date in Nepal. The widespread ownership of cattle provides a good
indicator for the potential of biogas in Nepal. Although some families have only one
cattle, most small farmers have two cattle or buffaloes, which is the minimum
number required for feeding the biogas systems of 4m 3 capacity.

These cultural norms have been key factors in the success of lowland biogas in the country.
But because areas like the Hinku valley have few animals, and in the Khumbu the yaks are free ranging, it has been considered impractical to gather their dung for active biodigestion.  The general design of biodigestors promoted in Nepal (the GCC 2047) and its minimum size (4 m3) discourages the use of this simple technology by families that may have only one cow or yak, even though a single animal could provide enough dung on a daily level for a 2m3 digestor which would yield up to two hours of cooking fuel per day, adequate for many small household.  Meanwhile, though ARTI India has proven that even a 1m3 digestor, made from plastic water tanks, when fed with as little as 2 kg of  kitchen waste or other sugary or starch rich organic waste, can supply a family with anywhere from a half an hour to two hours of cooking fuel per day, this option has not generally  been on the table with development agencies.

 The idea of using food scraps from the lodges has not been considered in the highlands of Nepal until recently and for this reason there has been inadequate attention to urban and high altitude installations of systems.

Solar CITIES Egypt's Hanna Fathy and I found the same situation in Rwanda and discussed this with SNV, who support the project there as well as in Nepal.  We were told that SNV had tried  food waste based systems but had a poor experience when families believed they could increase the amount of gas they were getting from a small fixed sized system by simply putting in more food waste; the systems went acid and stopped producing gas and there wasn't sufficient followup to teach them that the systems will often recover if left to sit without feeding and can be put back into service by neutralizing the pH with calcium carbonate or sodium bicarbonate or some other alkaline solution (wood ash would also work) or by simply adding more manure or human toilet wastes and waiting for several weeks. It was considered simpler to restrict the program to people who had animals since animal wastes are pH neutral, contain the bacteria necessary for the reaction and can be added in unlimited amounts and so are ideal for families with livestock as a feedstock, even though the energy content is tens to hundreds of times lower than food wastes.

The last two days of our expedition while in Kathmandu I had meetings with the professors and students at Tribhuvan university (who remembered me from last year), the head of the Nepal Biogas Support Program (BSP) and the head of Practical Action Nepal. They kindly supplied me with lots of publications to read on the airplane and we had long discussions. 

With BSP and Practical Action  engineers and outreach specialists  I had productive  discussions about specific techniques we should be pursuing to keep the digesters warm.

The use of the compost toilets for heat is one they recommend, and this is something Solar CITIES also  recommended in the first Moutain Institute/Blackstone Ranch/National Geographic Expedition to Nepal in 2011 so we are on the same page there. They also recommend the use of vacuum tube solar for the "warm water feeding" of the digestors. This is something we started in Dingboche with the installation of a 15 vacuum tube SHW system on the roof of the Mountain Institute Information Center in the village and a workshop we conducted on how we could use the 80 C hot water it produced each day, through the In-Sink  Food Waste Grinder that Insinkerator corporation kindly donated, to warm water feed the digestor and keep it at temperature.

In Dingboche we were able to prove that even over 5000 meters the less expensive vacuum tube solar hot water systems performed well and could supply reliable heat for a digester; the only bad experience with the system we had was when a strong wind blew the cold water tank down from above the system and smashed some of the tubes.  Because the cheaper systems lose all of their water if a single tube breaks the system must wait for replacement tubes before continuing to operate.  The more expensive "heat tube" vacuum systems, like the Culhane's have on their roof in northern Germany and like the systems on the Italian funded Solar Pyramid en route to Everest Base Camp, continues working even with several broken tubes, and would increase reliability if the budget permitted, but the inexpensive systems are perfectly adequate (this is in contradistinction with the flat pate solar hot water systems which reflect much of the sun's heat early and late in the day and tend to experience burst copper pipes at extreme altitudes due to thermal expansion and contraction).

 With good insulation (easily achieved with light weight styrofoam) the temperature in a digestor fed by a small vacuum tube solar hot water system like the one we installed in Dingboche over 5000 meters  (costing no more than $200) should stay between the required parameters (20 to 40 C) to produce reliable biogas. These digestors can be built from 1000 or 2000 liter plastic water tanks and insulated with styrofoam.

Besides small plastic digestors, another option is the one time investment in a large cement community digester like the GCC 1047 that the BSP supports, or the Puxin digestor cited in the Practical Action manual, which Solar CITIES recently built in the Philippines in a remote jungle village. Once the fixed costs of materials and transportation for cement (35 sacks, 40 pounds each), sand (obtained lcoally) and gravel (obtained regionally) styrofoam and the Puxin steel molds is paid for, the systems have a lifetime of over 30 years. These can be built underneath the compost toilets and can be connected to solar hot water systems; the technical challenge is actually simpler than transporting rock and cement and timber to build the typical sherpa homes and lodges and toilet and sheds.

Another option for keeping high altitude biodigesters at the appropriate temperature and making good use of the nutrient rich fertilizer they create is to build them inside a greenhouse structure. In Khote we found two operating greenhouses uses a simple plastic sheet for its greenhouse effect. One greenhouse was next to the Mera Lodge for convenience sake but the heated air was not being used to assist with space heating in the lodge; the other was down near the river.  When Culhane poked his head inside the greenhouse during sunlit hours the temperature was sweltering and uncomfortably hot; well over 40 C.  It was clear that a simple greenhouse structure like those already existing in the Hinku valley could provide much of the thermal gain necessary to keep the digester at the proper operating temperature if the digester were well insulated and the heat was supplemented by hot water feeding (A note to the thermodynamicists in the audience: a well insulated digester wouldn't experience much heat loss or heat gain due to the ambient temperature of the air in the surrounding greenhouse; the function of the greenhouse would be to prevent heat losses by maintaining a temperature greater than that of the digester above the digester. This would inhibit heat from flowing up into the greenhouse. Hot water feeding would do the main heating of the slurry in the digester).

Families in the Hinku Valley and elsewhere in Nepal's highlands could replicate what is being done in China where the fertilizer produced by the biodigester flows into the greenhouse soil, radically improving its productive capacity. As this is occuring, CO2 is expected to build up at the bottom of the greenhouse through bacterial action in the soil, helping to buffer the temperature; one can also burn a portion of the biogas produced directly into the greenhouse  to not only keep it warm at night and during cloudy times but to increase the CO2 levels in the entire greenhouse therebye causing an additional "greenhouse effect" -- the same one now threatening our global climate whereby carbon dioxide acts as a heat trapping gas.  The elevated CO2 levels would also accelerate plant growth.  In all of these ways a combination of biodigester and greenhouse makes a very powerful solution set for improving the quality of life and the quality of food for people in the highlands of Nepal.

I visited the labs at Tribhuvan university  and saw not only the same  Puxin biogas system that we had installed in a girls school on the island of Palawan in the Philippines the previous month,  but a bunch of improved cookstove designs and gasification designs.  I also met students working on biogas and home made wind power solutions.  They are now part of our Solar CITIES biogas innoventors and practioners group on facebook and I have been corresponding with them since getting back to Germany.  The consensus from our conversations has been that high altitude biogas will be fairly simple to achieve, but it needs targeted investment and a dedication to proving the model.

Culhane spent the morning with students at Tribhuvan University who were working on their own windmill blade designs as well as projects to get biogas from tobacco residues.

The Tribhuvan University students also showed Culhane simple gasifiers that can be used to turn waste biomass (leaves, grass, wood chips, branches, dung, dried food waste) into a gaseous fuel through pyrolysis and gasification. These devices also can create biochar which can be agglomerated using starch or mud and the resultant biochar briquettes can be used for cleaner cooking. Gasifiers like this thus yield two products -- direct gaseous fuel and char.

 The conclusion of the first chapter of the BSP report gives an idea not only of the importance of biogas for Nepal, but of the huge potential once we can improve the digestors for cold climate and urban operation, which is something Solar CITIES has been successfully working on and is committed to:

The biogas systems installed by the BSP ore of the fixed dome type. The capacities
of the systems presently promoted are of 4, 6, 8 and 10 m3, using cow and buffalo
dung and water as the main feed materials. The popular sizes are 4 and 6 m3 sizes.
A 6 m3 system requires 36 kg of dung and an equal amount of water per day in the
hilly areas to burn a stove for 3.5 hours.
Biogas can be used for cooking, lighting, refrigeration as well as operating machines.
However, to date biogas is popularly used in Nepal for cooking. Used for cooking,
biogas has to a large extent helped in reducing the use of fuelwood and hence
conserve the forests, In replacing kerosene for cooking and lighting, biogas has
helped reduce expenses on imported fuel. The slurry from the digester is also used
as fertiliser in the fields. This has enhanced agricultural production and replaced the
use of chemical fertiliser. This technology has social implications such as health
benefits from reduced indoor pollutions and livelihood enhancement from income
generation opportunities such as masonry available in this sector. In recent years
this technology has also indicated potentials as a source of national income through
carbon trading under the Clean Development Mechanism (CDM).
1.5. Potentials of biogas in Nepal
Livestock plays an important role in the Nepalese farming system. According to the
Agriculture Sector Census of 2001/02, the total cattle population in Nepal was
estimated to be 2.2 million heads, while 1.6 million heads of buffaloes were
registered. Based upon a study of the technical and geographic feasibility, it is
estimated that a total of 1.9 million biogas systems can be installed in Nepal: 57
percent in Tarai, 37 percent in Hills and 6 percent In Mountain regions (BSP, 2004).
When taking economic factors into consideration, the potential of the smaller fixed
dome design (4 and 6 m3) in Nepal is estimated at about half a million units. With
innovative financing (subsidy structures, co-operatives) and delivery structures (self
help building), the potential can be doubled to one million units
. Besides the above
small domestic biogas systems, there is huge potential of cold climate, industrial as
well as municipality systems.

The current small fixed dome design works well at altitudes up to 1500m. However,
during the winter months the gas production decreases, especially above the 1500m.
When the fixed dome design is built at altitudes of 2000m or higher, special
adjustments to the design are required such as thermal insulation and warm water
feeding to maintain gas production during the winter.
 The "huge potential" described above can be realized in a very short period of time.  Part of what was called for by the BSP to make this happen are "innovative financing and delivery structures (self help building)".   Part of the two missions we have made to the Himalayas on these Mountain Institute/Blackstone Ranch Foundation/National Geographic expeditions these past two years have been to explore the concept of "last mile technology, something that National Geographic Fellow Chris Rainier joined Alton Byers and Thomas Culhane on this expedition to investigate.   The training workshops that Byers and Rainier and Culhane and Sherpa gave were explorations of these kinds of 'innovative delivery structures'.  In this context the annual visits of scientific teams from the Mountain Institute and the National Geographic, partially funded by generous grants from the Blackstone Ranch Foundation, enable us bring and share ideas and expertise on a continuing basis with the requisite follow up.  The ability to come together at symposia and conferences like the National Geographic Explorer's symposium each June gives us the chance to refine and improve upon those structures.  Solar CITIES, meanwhile, applies the lessons learned in their home laboratory, testing and improving on insights gained in the field.

Heat and Hydrogen from Scrap Aluminum and cookstove ashes:

 One of the lessons learned on the past two expeditions to areas of Nepal over 4000 meters is that there are substantial garbage depots filled with aluminum cans and other waste from the trekking industry and local populations. Because wood fuel is so heavily relied upon, there is also a substantial source of wood ash.  Most of this wood ash is from the burning of rhododendron wood which is a hardwood, and it turns out that hardwoods (along with fruit tree wood, palm fronds and banana peels among other plants) are potassium rich and easily yield a strong pottasium hydroxide solution (lye) when hot water is passed through them.

Culhane found that by collecting hot ashes from the cook fires in the Sherpa lodges and simply pouring dirty water on them in a steel container yielded him a powerful concentrated lye solution the next day.  He then found that if he placed scrap aluminum, recovered from the trail where it is easy to find aluminum cans and can tabs, he could generate rather large quantities of flammable hydrogen and that the chemical reaction created heat up to 64 C.  He also discovered, in 2011, that if he used a less concentrated lye solution and connected the aluminum to a Joule Thief Circuit, he could generate enough electricity (by creating an aluminum-air battery reaction) to run several bright LED lights. 

Culhane used these reactions to his benefit in the field, lighting his tent for example, and keeping his hands warm, and shared the knowledge he discovered with members of the Sherpa community.  Upon his return to Germany he further refined his techniques, demonstrating, for example, that a dinner plate's worth of dirty waste aluminum foil could yield up to 50 liters of H2 gas and heat a small bucket of water to 30 C, then he shared those explorations with the other members of the team at the Explorers conference.

The refinements and new knowledge will be shared during the next trips to Nepal but they are also being shared actively with our Sherpa colleagues using social media, primarily facebook, youtube and Google Plus.  In a similar vein the Sherpa community is sharing its knowledge and innovations with us using the same media and this was one of the rationales for Chris Rainier's last mile technology workshops.  Innovative knowledge delivery systems are now available for empowering cross talk across cultures and beyond borders.

Some of the solutions, like biogas, wind, solar heat, composting toilets and photovoltaics, are ready for immediate scale up. Some, like aluminum-lye reactions for heat, electricity and hydrogen, are still experimental, but through these innovative information transmission mechanisms, can achieve practical results in an accelerated timeline.

A vision for how to use waste aluminum and wood ash in the highlands of Nepal

Sources of potential hydrogen fuel abound.

Learning about the wood-ash/aluminum/waste water hydrogen reaction, many people have asked "what is the cost efficiency of buying/making the hydroxide per return in hydrogen gas BTUs? And how much KOH can practically be made from ashes where draino is not available? "

The economics do need to be made explicit but when working in remote villages trying to apply "last mile" technologies we can operate along different assumptions. I ask, "besides making heat and hydrogen with it, what would you do with the scrap aluminum up in the Hinku valley or the Khumbu Valley  or out in the Okavanga Delta where there is no economic incentive to cart the aluminum cans and tabs and foil  all the way down to Kathmandu or to Maun for recycling and it sits in trash dumps and is currently burned?" 

When people find out that we can make hydrogen from ashes and aluminum scrap they often ask, "but where are you going to get aluminum in these remote areas?  You can't make it can you?". The answer is lying on every trail and in the garbage pits.
 The hydrogen principally comes from the 80% H20 in the lye solution (which is generally 20% KOH or NaOH); the Al turns into AlO2 (alum)  or NaAlO2 (sodium aluminate) which precipitates out of solution as  a kind of gritty powder which can indeed  be recycled back into aluminum and is actually easier to transport that cans or dirty  crumpled foil because it has turned into an amorphous powder.  

There are also "dead" batteries lying along the trails and in the trash heaps which can still be used to run LED flashlights through the Joule Theif circuit.
If people  still  didn't want to cart the oxidized aluminum to a city recycling center it can be easily thrown back in the garbage pit without bulking it up, because it is now a powder,  or it can be scattered on the ground  (one has to see how much AlO2 the soil can handle if one places it in the garden, it can almost certainly be placed in areas where food is not being grown; there should be no worries  of any toxicity due to  the small quantities one would be creating in these areas (alum is a component of many fertilizer treatments,   though not of direct use to plants,  sodium aluminate is actually used in wastewater treatment plants as an effective way to remove phosphorous; excess aluminum ions can be rendered inert with the addition of lime and in any case aluminum is the most abundant element in soil; issues with aluminum in excess come from free Al +++ ions which can be controlled with pH).
 The BTUs that reacting waste aluminum with wood-ash lye creates are, in a sense, "free" BTUs".  About 50% of the value comes from the exothermic reaction which can reach up to 80 C   while hydrogen is being generated (although I have only observed 64 C in my experiments)  while approximately 50%  is in the form of H2 bonds. 
 The hydrogen in my scenario can be bubbled into the biodigestor to help feed the microbes in there (the methanogens metabolize H2 and acetate at the end of the chain of reactions that invovle many species of bacteria) while the heat can help keep the temperature of the digester warm. 
Since the H2 production is more or less instant (i.e. it occurs within 30 seconds or so of combining the reactants but can take up to a half hour or more to finish the reaction and accumulate useful quantities of hydrogen; heat production rises within the first few minutes and falls off within a half hour or so) it is also a great emergency source of fuel and heat in cold areas such as we find in Nepal.
Once a biogas reactor has been comissioned it can take 3 weeks or longer to build up the right bacterial populations and densities to start turning waste into energy.  Biogas production from food ground up food scraps then  takes 24 hours.  The key to keeping the biogas system working effectively in the high altitude area  is maintaining the right temperature and the right feeding; aluminum-lye reactions can help here by turning two common waste materials found in every Sherpa or Rai home and trekking lodge (aluminum cans and wood ashes) and turning them easily into heat and hydrogen.  Hydrogen is one of the principle feedstocks of the methanogenic bacteria in the biogas digester; they are the last species in the bacterial consortia to metabolize and they wait for the hydrolytic and acidogenic and acetogenic species to turn food waste or other organic material into the acetate and hydrogen which they feed on. It seems reasonable to assume that if hydrogen that bubbles out of the aluminum-lye reaction is fed to the digester it will improve its performance; any hydrogen not metabolized by the bacteria into methane (CH4), hydrogen sulfide (H2S) or water (H2O) would be collected in the gas collector with the methane and carbon dioxide and hydrogen normally present in biogas.
Aluminum-lye reactions are also useful  for emergencies and for extreme cold weather conditions.  Just as trekkers often bring chemical hand-warmers with them for emergencies (usually made from calcium chloride or sodium acetate), wood ash, water and aluminum can also be used for emergency heating.  
Because the raw materials are present in the region and are generally considered a nuisance, cost efficiency for these hydrogen and heat generating reactions  isn't really an issue.    In the communities where we are working we can think "what can I do with these ashes that have been thrown out and this aluminum that has been thrown out, and this dirty water that has been thrown away?" The answer can be "mix them together in a plastic container and get heat and hydrogen!"
 The net cost is ZERO if one is willing to donate one's labor, and it may turn out to be easier at these altitudes to do the chemical reaction each time enough aluminum and ash accumulate rather  than expending the energy to haul it to the trash heap. 
A side benefit to collecting waste aluminum and cookstove ashes from the lodges in the area rather than throwing them in the trash heaps is that the same chemical reaction can be used to provide enough electric current for LED lights.  Culhane discovered after the Khumbu trip of 2011 that a weak solution of lye (made from wood ashes over which hot water has been poured) can be combined with aluminum foil or tabs and hooked up to several parallel wired bright white LED lights through a Joule Thief circuit.  Using stainless steel as the positive electrode and aluminum as the negative, the stripping of the oxidation layer from the aluminum by the lye enables it to recombine with oxygen from the air which liberates electrons.  What you have is an "aluminum-air battery". This chemical reaction normally yields no more than .5 volts but the Joule Thief circuit, Culhane discovered, enables one to do useful things with this low voltage.  

Throughout Nepal's highlands Culhane used his "Solar CITIES aluminum tab torch" to light his tent and to navigate paths on dark nights.  Culhane lit up 5 LEDs at a time and they provided enough light to read by in the tent if one held the book close and certainly enough to be a reliable night light.  

Culhane demonstrated to his Sherpa colleagues how to create such a lighting solution using the local ashes and aluminum tabs and sees improvements to the technology playing an important role in offsetting the current uses of firewood for lighting in homes that do not have the money to purchase solar electric panels or wind generators.  It is also surmised that the reaction can eventually be scaled up and improved through parallel and series configurations  to provide lighting for fluorescent bulbs and electric current to charge mobile phones.

It is to be noted that if and when highland Nepal switches to biogas made from human, animal and food and agricultural wastes (including wilted flowers) and wood burning is the exception rather than the norm, the source of potassium hydroxide (lye) from wood ash will diminish and this will make it harder to maintain a "hydrogen from waste aluminum" solution if it ever gets started.  Culhane is not concerned about this for several reasons.

The first is that it doesn't take very much ash to make the required amounts of KOH solution and for cultural reasons there will always be some wood burning done.  Ritual burning of shrubs for incense, cremation and cooking fires created for flavor or aesthetic reasons should provide enough KOH to consume the available aluminum; principally the idea is to make use of aluminum that is simply becoming a garbage problem and exploit its potential for heat and hydrogen while rendering it into an easy to manage or recycle powder. 

The second is that once a biogas economy has been created it should be self sustaining.  A portion of the biogas produced  can be used to maintain temperatures in insulated tanks, particularly when compost heat is added to the equation.

Compost heat is already well known in the Khumbu where potato growing families have built above ground composting toilets next to the houses and lodges that use rhododendron leaves with the human fecal material to create high temperatures that turn both aerobically into high quality fertilizer.  In some cases the heat is also exploited to heat animal sheds or the homes themselves. This practice is unknown to most people in the Hinku valley where potatoes are not grown and where toilets are generally pit latrines located far from the home (usually next to rivers, which creates the possibility of unsanitary conditions and ground water contamination).  

Anrita Sherpa and Culhane spent time in Khote and Khare discussing the advantages of compost toilets and shared their experiences in the Khumbu and around the world with composting toilets.  Since compost heat has already been demonstrated to be effective for biogas systems by the BSP in high altitude situations it is just a matter of integrating the various systems that are already found in the region into a best practice model that will replicate.  

Once compost systems and cooking systems and greenhouses are all connected there should be plenty of heat for a robust biogas solution.  Aluminum-lye reactions can still play a role but they will become less and less necessary.  Ultimately the chief use for aluminum may be for low-grade lighting and peripheral electronics charging until it becomes profitable to take the aluminum to an actual recycling center.

Culhane has discovered that it is worth carrying small bottles of crystalized Sodium Hydroxide (NaOH) salts, purchased as drain cleaner, wherever he goes to power his "Solar CITIES tab torch" and suspects that once people catch on to how easy it is to get some light from aluminum, they will keep on hand bottles of NaOH crystals or liquid drain cleaning preparations, much as we do under most kitchen sinks in developed countries, or will prepare enough KOH so that they can get instant light when there are no batteries or instant heat and hydrogen when needed.  Since both NaOH and KOH are used in soap making they are hardly rare or exotic chemicals, no matter what their origin, and most societies will  have some around or know how to make them so that they can be used for other purposes like heat, light and electricity and hydrogen formation.

Summing it up on the way to the summit

Our trip to the Hinku valley, like the one to the Khumbu the year before, gives us great confidence that we can solve the energy and health and ecological problems currently plaguing the high altitude communities of Nepal.

When I visited Prof. Dr. Tri Ratna Bajracharya at Tribhuvan University at the end of this expedition he was kind enough to give me the "Proceedings of the Third International Conference on Addressing Climate Change for Sustainable Development through Up-Scaling  Renewable Energy Technologies" of which he was one of the editors.

This conference, held from October 12-14, 2011 in Kathmandu, covered the following topics:

Of relevance to our expedition are serveral articles in the proceedings. I have high-lighted in bold those most germane to our work:

5. Assessement of Current Energy Consumption Pattern and Green House Gaseous Emission Trend: A Case Study of Helambu VDC of Sinhupalchok, District Nepal

6. Energy Conservation through Thermal Insulation Building for Minimizing the Greenhouse Gas Emission at Local Level

8.  Information Dissemination on Effectivness of Alternative Energy Use and Biodiversity Conservation in Buffer Zones of Shuklaphanta Wildlife Reserve, Nepal

9. Perception on Climate Change and Its Impact and Adaptation Practices in Energy Resource in Chepang Community in Chitwan District, Nepal

10. Restocking Traditional Rural Energy Sources Through Rehabilitation of Dryland Ecosystem in Southern Pakistan

21. Household Energy Generation and Consumption Pattern: A Case Study from Syafrubesi VDC, Rasuwa

22.  Issues Relating to Energy Efficiency and Renewable Energy in Bangladesh

24.  Mini-grid: A Project for Empowering Rural Nepal

25.  Prospect of Integration of Energy Resources for Reliable Rural Electrification in Nepal

27.  Bio-Hydrogen Production:  Present Problems and Future Possibilities

28.  Biomass Bamboo Knot Furnace for Replacement to Heavy Oil in Joss Paper Mill

29.  Bimethanantion of Organic Waste under Psychrophilic Conditions

30.  Clustering Plan:  Micro-scale CHP from biogamss (dn10kW) for Decentralized Steam Turbine Power System

31.  Design and Fabrication of Stoves Using Jatropha curcas as the Cooking Fuel and its Prospects for Clean Development Mechanism

32.  Energy and Environmental Benefits of Liquid Biofuel Switching from the Traditional Solid Fuel in the Rural Community of Palpa District

33.  Innovation of Jeeban's Amrit-Irving Model Bio-Reactor for Organic Municipal Waste Management

34.  Performance Assessment of Biomass Cookstoves in Rural Bhutan

35.  Performance Evaluation and Emission Characteristics of AIT Model Biomass Gasifier

36.  Role of Biogas in Easing Ecological Stress: A Case Study from Buffer Zone of Shuklaphanta Wildlife Reserve

37. Study on the Temperature Variation Inside the Biodigester of Modified 2m3 GGC 2047 Biogas Plant

39. Fabrication of Dye-Densitized Solar Cells (DSSCs) with Zinc Oxide (ZnO) Nanorod Electrodes

41:  Off-grid Sustainable Small-scale Photovoltaic Project in High-Altitude Region of Nepal

42.  Performance Comparison of Funnel Type and Bernard Type Solar Cooker

43.  Solar Thermal Power Plant in Thailand:  Potential, Opportunity and Barriers

44.  Thermosyphon Heat Exchanger for Cleaning System of Community Power Generation

46. Locally Manufactured Wind Turbine Blade Mold Pattern

47. Reliability Analysis of Hybrid PV/Wind Energy  System at Remote Telecom Station

49.  Energy Recovery from Munipial Solid Waste as Refuse Derived Fuel

50. The Spread of Rice Stoves in Nepal

53.  A comparative analysis of the Solar Energy Programs for Rural Electrification: Experiences and Lessons from South Asia

Note that

27.  Bio-Hydrogen Production:  Present Problems and Future Possibilities


29.  Bimethanantion of Organic Waste under Psychrophilic Conditions

support our summary of opportunities for the Hinku Valley.

Pradhan, Sharma et al.  (27)  say "Hydrogen is an important intermediate product in anaerobic digestion. Therefore, if the final step of methnogenesis were blocked by inhibiting methanogens, only acidogens would be left to produce hydrogen, carbon dioxide and volatile acids...(p. 143) Hawkes et. al (2007) has reported on two stage hydrogen-methane process and found most of the two stage process has a higher total efficiency in terms of waste retreatment and energy recovery than a traditional one stage process."   While their work seeks to inhibit methane production to harvest the hydrogen, our proposal is to use hydrogen produced through ash-lye and scrap aluminum reactions to enhance methane production while liberating significant quantities of heat ( 31 kilojoules per gram of aluminum released as heat during the reaction

Jha, Bhattari and Liu  (29) point out the potential for using bacteria acclimatized to psychrophilic conditions; in our expedition in 2011 to Mt. Everest Base Camp Culhane brought back active psychrophilic methanogens that were making methane under the ice in mud wallows and ponds along the Khumbu trail and, by feeding them organic waste, proved that they were capable of making good yields of biogas.  These bacteria are available all over the high Himalaya regions. 

They write, "Most of the psychrophilic studies relate to biomethanantion by low temperature acclimatized mesophiles (psychrotrophs; not true psychrophiles) (Kashyap et al. 2003).  As a result the majority of remedies proposed in the literature to enchance biogas production are aimed at  increasing  the digestor temperature to mesophilc range such as the use of the gas produced for preparation of feed slurry, integration of a green house, construction of a system below buildings (heat transfer from the barn) and use of excess gas to heat up the digester to maintain higher digesester temperature (Sutter et al. 1987; Zeeman et al, 1988). However, these techniques suffer from techno-economical constraints (Kashyap et al. 2003). The energy required to heat the process makes it uneconomical in temperate climates".

Nonetheless, Culhane and Katey Walter Anthony, on the first Blackstone Ranch/National Geographic Innovation Challenge grants in 2010, demonstrated the effectiveness of biodigestors inoculated with true psychrophilic bacteria obtained from thermokarst lakes in Alaska. Their research further suggested that greater efficiencies could be obtained from a mix of true psychrophiles and psychrotrophic mesophiles, taking advantage of the fact that the water in the digester tends to settle into distinct thermoclines so that slurry between 10 and 20 C is found at the bottom of the digester while slurry between 20 and 40 C can be found at the top of the digestor.  With proper design (the use of vertical surface in the tank for biofilm formation) psychrophiles can coexist with mesophiles. The psychrophiles inhabit the bottom regions of the tank and the mesophiles the upper regions.  The data of Walter Anthony and her group showed greater production of biogas from a mixed tank kept in a room of ambient temperature 25 C than either population considered alone.

Jha, Bhattari and Liu corroborate these observations in their papaer stating "with the extension of retention time and diminishing loading rate psychrophilic anaerobic digesters can successfully degrade organic matter for reasonable biogas production (Lettings et al., 2000; Lettomaga et al, 2001; Sutter and Wellinger, 1985)... Yu and Gu (1996( reported that psychrophilic anaerobic digestion is stable and is as mesophilic or thermophilic digestion processes. A reduction in pathrogenic micro organisms by psychrophilic anaerobic digestion was also observed (cote et al, 2006)." 

These data have fit nicely with the proposal Culhane has made for Hinku and Khumbu development, suggesting that psychrophilic bacteria be obtained from the Khumbu and Hinku Valley glacial lakes, combined in a modified digester with yak dung and human fecal material derived mesophiles and the system be used to degrade all organic wastes, from food scraps and toilets, to produce  energy for heating water and space that can replace firewood and fossil fuels while creating a valuable fertilizer and reducing pathogens as the preferred solution for waste water treatment.  With the addition of hydrogen thermal energy generation and hydrogen feeding of the digesters taking advantage of the aluminum and ash waste in the region, supplemented by compost and greenhouse and solar heat, 
the challenge of stopping both indoor air pollution and deforestation as well as greenhouse gas emission should be solved.


Miscellaneous photos from the trip:


Solar NJ said...

The beginning cartoon made me really laugh my ass off.

Back on topic, you guys really put to use the basics of electricity, loving the use of LED lights for just about everything. More pictures though next time (I know you guys took alot already)

Awesome stuff,

-Sharone Tal

pvc windows said...

Solar heaters have a plate that collects the heat from sun consisting of tubes and water is transfer to the tank where it will be used in as insulated hot water tank.

brian oliver said...

Hi T.H.,

I saw your demonstration on the National Geographic Hangout Tuesday. I was intrigued by the joule thief and the Al-air battery that you created to run the lights. I spend a good deal of time yesterday watching your YouTube videos and reading your blog I am planning on doing some of the experiments with my kids for their science lessons.
I also spent a couple of weeks in Mozambique last year in areas that don’t have running water, sanitation, or electricity, so I’ve seen firsthand how your work is beneficial to many people if only they knew about it.

I had a couple of questions about both of the demonstrations you presented.

1. In the first experiment with the spinning magnet. Is it an Axially Magnetized or Diametrically Magnetized? Does it matter. I’m going to order some from a supplier, and want to buy the correct ones. It seemed to me that I would want a diametric magnet, but I am very new to this area of science.
2. On the Al-air battery. How long does the coke tab last, I saw on your blog that it turns into a powder.
3. How often did you need to add more KOH?
4. How often do you have to replace the steel wool?

You might look into a gopro camera with a head strap for your video needs.

Thanks for the work you are doing and sharing.

brian oliver said...

Hi T.H.,

I saw your demonstration on the National Geographic Hangout Tuesday. I was intrigued by the joule thief and the Al-air battery that you created to run the lights. I spend a good deal of time yesterday watching your YouTube videos and reading your blog I am planning on doing some of the experiments with my kids for their science lessons.
I also spent a couple of weeks in Mozambique last year in areas that don’t have running water, sanitation, or electricity, so I’ve seen firsthand how your work is beneficial to many people if only they knew about it.

I had a couple of questions about both of the demonstrations you presented.

1. In the first experiment with the spinning magnet. Is it an Axially Magnetized or Diametrically Magnetized? Does it matter. I’m going to order some from a supplier, and want to buy the correct ones. It seemed to me that I would want a diametric magnet, but I am very new to this area of science.
2. On the Al-air battery. How long does the coke tab last, I saw on your blog that it turns into a powder.
3. How often did you need to add more KOH?
4. How often do you have to replace the steel wool?

You might look into a gopro camera with a head strap for your video needs.

Thanks for the work you are doing and sharing.

Solar Power Solutions said...

Bravo for such a well-written article with an interesting topic and discussion.

Josh Lobley said...

Looks like an awesome trip and great progress was made. I'm very interested in "alternative" energy sources & love your real world use of the joule thief circuit. I wanted to let you know I have linked to solar cities on my joule thief circuit website, on the links page here -
Will enjoy reading the rest of your blog in time, you guys are doing great work.