Friday, February 18, 2011

Scrap metal + Recycled motor oil + Sandbox = Machine parts for sustainable energy technologies in Guatemala

At XelaTeco, an affiliate of the Guatemalan NGO where I'm working on a D-Lab project, an "appropriate technology" process is used for casting metal machine parts. Used motor oil, much cheaper than propane or other potential fuels, flows down a hose to fire up a foundry, where scrap metal is melted. The machine part to be cast is pressed into a box of sand and removed to leave an impression. The molten metal is then poured into the mold, creating an exact replica of the original machine part. Though not the cleanest process, this particular sand casting method makes use of motor oil that would otherwise be discarded. XelaTeco uses the process to make parts for micro-hydroelectric turbines, one of the sustainable energy technologies it's promoting, and for other commissioned machinery.

The whole set-up: the black barrel of motor oil is elevated on the empty green barrel to create pressure for the oil flow. A fan between the barrel and crucible chamber creates a convection effect to increase the heat in the chamber.

The crucible where the aluminum will be melted.

Scrap aluminum is cut with a hacksaw into pieces that will fit into the crucible. Any rubber or plastic is removed.

The machine part to be duplicated is pressed into barely moistened sand in a wooden box. Once the sand is well compressed, the piece is removed and the impression remains.

The process is repeated with the top half of the sandbox, but in this case plastic pieces (sawn off legs of a bed frame!) are used to create holes into which the molten metal will be poured. Due to their conical shape, they are easily tapped out with a hammer, leaving channels in the sand.

The aluminum is heated in the foundry to a temperature of about 1300° F.

The red hot crucible is carefully lifted from the foundry.

Debris and contaminants are skimmed from the surface of the molten metal.

The aluminum is carefully poured into the holes left by the bed frame legs.

Once the metal starts to overflow out of the holes, the pouring is stopped.

15 minutes later, the box and sand are removed, leaving the cast piece, which will need much sawing and grinding.

Pieces for a micro-hydroelectric turbine, cast in bronze using the same process.

 Here's a video of part of the casting process.

-Larisa Jacobson, D-Lab I and II alum, M.S. candidate in International Agricultural Development

Off-Grid Lighting Project in the Niger Delta -- from the field

The Niger Delta is an intense place. We had a short but busy trip to Bayelsa State, where we met with a new local partner, Niger Delta Wetlands Center (NDWC).  NDWC is a long-running local NGO that works on environmental conservation and community development projects in the area. They’re well-managed, and with successful projects under their belt, they have street cred, which seems to be rare in the delta.

The objectives of the trip were to meet with NDWC and other project partners, and be introduced to a community they are working in, called Aduku. The other partners represented were VDI Group and International Institute for Environment and Development, both of whom have long experience in Nigeria.

The format of the visit was an inclusive, 4-day workshop that was attended by all the project partners as well as members of Aduku and other local communities. Miriam, the head of NDWC, organized a great group and the whole proceeding was very participatory in nature—the community members and NGO representatives took turns presenting and discussing various issues around energy, lighting, water, and social development in the community.

Kurt Kornbluth, Director of D-Lab, gave a few different presentations, talking about the D-Lab approach and how we assess project feasibility through the “4 lenses of sustainability.” We also did some hands-on workshops with the groups, walking them through a basic lighting/electricity lab where they learned how to calculate loads, read generators, etc. and also an off-grid lighting demonstration, where we showed different solar lantern products and discussed the various features and costs of each design. We learned a lot about the challenges of working in the delta, and the huge number of (usually nontechnical) barriers NDWC faces in its projects. We trained NDWC staff on some of the concepts of focus groups, and then let them practice running focus groups around the lighting products. Good fun, and lots of mutual learning.

The community Aduku was interesting in a few ways. Situated far from the electricity grid and alongside a creek near the River Forcados, the whole village is strung along the waterway in a thin row of houses. Almost all houses are stick and mud with corrugated metal roofs. Most residents are subsistence farmers and fishermen, with some timber and gari (cassava meal) processing as well. One unexpected finding was that a large number of households own and run small (<1kW) generators, which they use to power TVs, fans, fridges, and lights. Even though fuel is subsidized and costs only US$0.50/liter at the pump, some of these households end up paying more than N2000/week in fuel, or about US$13.   

Obviously these households are not in the lowest income group, but the amount spent on fuel and generators was still surprising if you compare it to someplace like Zambia. Of course, culture is a big driver, and apparently there are some strong social status implications with owning and running a generator—witness the colloquial name for these small generators: “Pass My Neighbor.” So you can imagine that in an area where a fossil-fuel based generator is a primary symbol of a household’s movement up the socioeconomic ladder, there will be some challenges introducing a solar-powered alternative.

Bryan Pon, D-Lab Graduate Student Researcher, PhD Candidate, Geography

In the Field: Flaming gas or a lot of hot air? Complications of deforestation, firewood, and household biodigesters in rural Guatemala

Larisa here, in the field for D-Lab in Guatemala (see this earlier post for background on the project). A month of long days, sweat, and pig manure has meant few blog posts! Though by now we´ve completed the biodigester installations (more on that in a bit), we first visited La Felicidad to meet with the five families purchasing the pilot biodigesters, and to learn more about their household energy use, cooking habits, farming and animal raising practices, and more before the installations.

Setting off in a pickup truck from Xela, our ears popped as we wound down more than 7,000 feet into the coastal region, past potato, onion, and cabbage farms, the land powdered white with the lime so commonly used here for its effects on soil nutrients and acidity. Once we reached sea level, we sped by endless coffee fincas and rubber plantations, their slashed trees dripping milky sap into black plastic cups.

Along the way, Guatemala’s struggle with deforestation, and the resulting erosion of already steep slopes, was evident.

Population growth, clearing of land largely for subsistence agriculture, and cutting of trees for firewood have all played a part: in the past twenty years, Guatemala has lost 23% of its forest cover, or nearly 134,800 acres (that’s 102,121 football fields, including the end zones), according to the Food and Agriculture Organization of the United Nations. A Zeno’s Paradox of farmable land—precarious land tenure, the land distribution legacies of colonialism, discrimination against indigenous peoples, and high birth rates force parents to divide up the little property they have among multiple children—means that cleared land, however depleted the soil, is a valuable commodity.
Land to be planted next season

Factor into this that 95% of tree-felling in Guatemala is carried out illegally by those in need of fuel and/or income, and that unstable eroded soils not only make farming more difficult but can lead to life and home threatening mudslides (the UN ranks Guatemala fourth in the world for risk of death from mudslides), and you have a very complicated problem knit tight into daily life by a web of constraints and trade-offs.

As in much of the world, the simple acts of cooking and getting food on the table each day require large amounts of fuel, labor, and time. Worldwide, two-thirds of people in developing countries cook or heat their homes with biomass fuel—wood, dung, crop residues, or charcoal. In Guatemala, estimates vary, but it’s believed that 60 to 80% of families cook with firewood.

In addition to the environmental effects, there are the health risks associated with burning so much solid fuel. According to the World Health organization, indoor air pollution contributes to more deaths worldwide—an estimated 1.6 million from cases of pneumonia, chronic respiratory disease, and lung cancer considered “strongly associated” with the pollution—than malaria each year. Women and children are most affected, and the lower a family´s income, the more likely it is to depend on such energy intensive practices on a daily basis.

And finally, buying large quantities of firewood can strain families’ limited resources. In La Felicidad, a typical family spends 2000-5000 Quetzales (around $250 to $650) on firewood per year—a lot for those who depend largely on subsistence farming and whose little income may come from selling a few animals each year and working seasonally on the nearby coffee and rubber fincas. To reduce costs, some families spend hours each week gathering wood.

Convincing arguments for cooking with biogas, right? Beside the initial cost of the biodigester (offset in a year or two in saved firewood costs) and the 15 or so minutes of labor required each day to gather manure and feed the digester, there are few to no costs, the methane gas burns cleanly without smoke, and the process produces an organic fertilizer that can be used in the fields, in some cases replacing costly chemical fertilizers.

I’ve emphasized statistics in this post for a reason. But I can tell you that in rural Guatemala, many of these don’t mean bunk. Life here, as in many places in the world, is rarely decided in response to compelling statistics, or even promises of financial savings on the scale of a year or health benefits over a lifetime. What is compelling is the day-by-day of getting by, and doing things in a way that makes sense to the people doing them.

Take Doña Gloria, who we visited in La Felicidad. Her outdoor cooking area, or polletón, is essentially an open fire—a few iron slats laid across burning wood. Though not as smoky as enclosed kitchens (where it’s estimated that cooking with an open fire is the equivalent of smoking two to five packs of cigarettes a day) polletóns are often in semi-enclosed wood shelters, and the woman stands directly over the fire as she cooks.
A typical outdoor kitchen

A polletón

Cooking a pot of beans takes 3 hours and lots of wood and smoke

In recent years, NGOs and government institutions such as Guatemala’s Social Investment Fund (FIS) have promoted the installation of planchas, improved stoves with a metal surface into which different sized pots can fit, chimneys to decrease smoke in the kitchen, and in some cases specially modified combustion chambers to increase fuel use efficiency and reduce firewood consumption by 50 to 70%.
A plancha with chimney and cooking surface with removable concentric circles for pots

But… Doña Gloria already has one of the improved stoves. She only uses it during the rainy season, when the wet and wind make her outdoor wood fire impractical. In the dry season, the plancha makes the kitchen too hot and stuffy, so she prefers to cook outside and use her indoor kitchen for organizing the items she sells in her small tienda (store). In other homes, the plancha is used more like a highly accessible shelf for pots and pans than a highly efficient stove. From the colorful plastic containers littering the surface, you can see the planchas aren’t used regularly.

As for the toll that deforestation takes, with a few exceptions, trees are prized not for carbon credits and “ecosystem services,” but are appreciated for the fuel and the shade they provide, especially in this region of blazing sun. Likewise, the smoke from the open fires is valued as a powerful mosquito repellent. And besides—as I can attest from the lunches of stew and tortillas that have been generously given to us when we work in La Felicidad—cooking the food over a fire gives it a lovely, smoky taste, one that people are fond of and used to.

Another issue is the task of collecting manure to feed the biodigester daily: here, most families’ pigs are not enclosed, but run free in the streets during the day, pooping where it pleases them, only returning at night to their corralito. Often, as we left La Felicidad in the evening, we would see the pigs dutifully trotting home for dinner. There's plenty of manure around, but would people want to take the time to collect it?

So, in her outdoor kitchen in La Felicidad, Doña Gloria wasn’t buying it. Without consulting her, her husband had agreed with the community leader (who wants the biodigesters in the community for the financial savings they should bring and for their possible draw as a ecological demonstration site) that their family would be buying a biodigester that cost more than a month’s income. This was Doña Gloria’s first time hearing about making cooking gas from manure, and for all she knew, we were selling snake oil. She was also worried about whether the biodigester would bring odors and flies, and about the surface of her tile counter (she was assured that it would not be harmed). She shot her husband a sideways look much like my grandmother used to give my grandfather when he was trying to make himself “useful” in the kitchen, conveying without words a dubious combination of “Give me a break…” “What have you done?,” and a resigned “Ay, Dios mio…” As we asked her and her husband the questions for the baseline survey, her doubt was palpable.

In another family, the father, who surprisingly had heard of biodigesters before, was fascinated by the technology but also concerned about the cost and whether the investment would pay off. Again, his wife was skeptical. Since it’s the women who will cook with the gas, it’s crucial that they be on board and included, and they obviously hadn’t been in the decision-making process to date. All of which has interesting implications for future efforts to create a Guatemalan biodigester company.

In the end, Doña Gloria and husband decided to wait a few weeks for their installation, while the other family decided to go ahead right away. Would the first biogas produced calm the families’ doubts, or would they continue to fear that we ourselves were full of cow manure? More about the installations in posts to come.
-Larisa Jacobson, D-Lab I and II alum, M.S. candidate in International Agricultural Development

Monday, February 7, 2011

In the Lab: Drip Irrigation Systems Analysis

The morning of February 3, D-lab students met once again at the UC Davis Student Farm under clear skies to learn about drip irrigation and its role in agricultural development. As a student in D-Lab and practitioner in irrigation, I introduced students to the intricacies of working with drip irrigation. The class compared two different drip systems in order to evaluate the range of quality and effectiveness available in the global market. Students gained a basic understanding of water pressure, flow rate, and the complexities of assembling a drip irrigation system.

The first system we looked at was one manufactured by the company NetaFim. This system is designed for large-scale farm operations and is quite expensive to install. This system ran off of the Davis city water supply and was quite effective. The key advantage of this system is that its emitters are designed to regulate flow and ensure that an even amount of water is distributed throughout the system.

The company Drip Tech manufactured the second system that we looked at. This system is designed for smaller farms in developing countries. It can operate off of a gravity fed water source and is much cheaper to install than the NetaFim system. However, our test demonstrated the advantages that the NetaFim system held over the Drip Tech system. Although the system was not that effective, the 55-gallon drum supplying the system was only half the height of what Drip Tech recommends. Nevertheless, the system did not have a continuous flow rate and had a more unreliable distribution of water.

The differences between the two systems clearly demonstrated the range of drip irrigation available and the important things to consider when selecting a system. Students also gained a good understanding of why drip irrigation is only appropriate in particular situations with specific crops.

Curran Hughes, D-Lab Student

Thursday, February 3, 2011

Making Charcoal from Agricultural "Wastes"

On a very cold and foggy morning last week we went out to the UC Davis Student Farm (an operational farm since 1977, which emphasizes hands-on, real-world application and courses in sustainable agriculture)...and apparently space for us to learn how to make charcoal.

The goal for the day was to learn how to produce charcoal from agricultural "wastes". Why? Because charcoal and wood are still used throughout the world for cooking indoors, thus adversely impacting indoor air quality and health as well as resulting in significant CO2 emissions world wide.

The UC Davis D-Lab class has over 25 students in it and we all set to work on various tasks. The process sounds simple, but actually is rather complicated and really more of an art form.

We were super lucky to have Ephrem Rukundo (he's the guy in the red hat --photo left-- with the shovel) in the class as he has worked throughout the world perfecting this process. THANKS Ephrem for showing us how to get the job done!

The process consists of burning the "waste"-- in this case we used corn cobs (you could also use coconut husks)-- pounding the carbonized corn cobs into powder, mixing the powder with a binder (we used tapioca, but in developing countries the more likely binder would be casava), and then pounding the mixture solid in a press. 

It's actually rather time consuming with multiple steps and really an art form. Key points along the way included determining when the fire was stocked properly; when to seal the drum; recognizing when the cobs were properly carbonized and thus time to open the drum; how much binder to use--the first batch we tried was a disaster because we mixed it in hot water rather then cold and couldn't get it to dissolve; and learning precision welding to build a functional press. The benefit/cost question remains, particularly if wood is abundant. However, if there is NO wood for miles and charcoal is not within purchasing distance AND you do have ag wastes...well, then perhaps the added time factor is worth the issue to further explore.

Well, we produced a short video to show you the process. We will attempt to barbeque (veggies, of course) with it and let you know how that goes.