Impact Analysis



About two weeks ago, Alison and I (with the help of Jeremiah, Pete, and Pascal) began surveying local community members about the impact of the hydro sites on their lives and on Banda as a whole. Surveying has had its up and downs, but in general, it’s been the best part of the trip for me so far.


Many of our results have been quite uplifting. Our most widespread impact seems to be increased cell phone usage. We’ve found that before 2008, when the sites were initially implemented, few people in Banda owned cellphones, and those who did would hike 6 hours (one way!) to charge them at the nearest electricity source accessible by foot. Now, most of the people we surveyed have at least one phone in their household, sometimes two, sometimes five… This increase in cellphone ownership is not just among battery owners; most non-battery owners have cellphones as well, and charge them at one of the many charging shops in the town center, which use our sites for electricity. One man said that our sites had actually “motivated people to buy cell phones.” People use cellphones for a number of things – communication with family members and friends, solving problems related to money, business, and even to access the Internet in some cases. Thus, we have found that it is not only battery owners benefitting from our sites.


Same goes for barbershops. When we ask about how people think the site has impacted Banda towards the end of the survey, battery owners and non-battery owners alike frequently mention the newfound barber shops in town, which use electric razors that are powered by batteries charged at our sites. Though it’s hard for me to imagine, people also used to walk 6 hours to get their hair cut with an electric razor.


Another positive impact, which I mentioned in a previous post, is the use of batteries by churches to power instruments, microphones, and sound mixers. Since pretty much everyone in Banda attends church and six of the seven churches own batteries, this is another way in which the sites affect both consumers and non-consumers. All the choir leaders we interviewed have said that people are much happier at church now, and sing and dance with enthusiasm. One said that church has become somewhere where “People can be happy and forget their burdens.” Another choir leader (/pianist/DJ) said that hydropower sites have made people’s voices better because they now can actually hear themselves sing through the microphone, instead of just blending in to a group. Talk about unintended impacts…


Radios are another common device powered by batteries charged at our sites. Though most non-battery owners use disposable batteries to power their radios (if they have them), most battery owners charge directly from their batteries. Almost everyone listens to the news on their radios – mostly national news, some international – and some listen to music or theater. My favorite finding on this topic came from one consumer who told us he uses his radio to listen to a BBC program about STD prevention. When I heard this, my infectious disease obsessed self freaked out and nearly started yelping with excitement – to Alison’s great surprise. I’d added the question “What types of radio programs do you listen to?” to the survey with the hope of linking radio usage to increased health knowledge, so as you can imagine, I was ecstatic.


Our final commonplace impact seems to be in lighting homes and businesses. Many battery owners have mentioned that their children use electric lights to “revise their notes” (the Kinyarwanda translation of study/do homework) at night. Others have said that they can now use electric lights instead of petroleum powered ones or firewood. Customers have proudly told us that changing to electric lights gives them better light quality and eliminates dangerous fumes that might harm their health or the health of their children.


During one survey, our interviewee told us he uses his battery so that he can use his typewriter. Being an (apparently naïve) child of the 90’s, I simply assumed typewriters must use electricity, and that I had been incorrect for ever thinking otherwise. However, the man ended up elaborating that he uses his electric light to see in the dark, so that he can type wedding invitations on his typewriter all night, rather than having his schedule dictated by the sun. Again, this wasn’t something I anticipated hearing during surveying, but it was wonderful to see how happy he was about the new opportunity.


While cell phones, radios, electric razors and lights seem to be the most common devices charged off our batteries, we’ve also had a few surprises. One schoolteacher casually mentioned that she used her battery to watch movies with her family. Confused, we asked her how she watched them. She proceeded to unveil a small TV, previously covered by a towel, sitting on the table across from us. Another person mentioned that his church uses their battery to do movie showings for members of the congregation. One man said he used his battery to charge his camera, as he is a photographer in addition to his normal work. Our host, Jeremiah, uses his battery to charge his laptop so that he can use it to keep up on medical research and to complete his coursework for his Masters in Public Health.


Thus, surveying has been wonderful because we actually get to witness and hear about the direct impact the DHE hydro sites have had on people’s lives. However, in addition to the aforementioned roses, we have also encountered a number of thorns during our surveys.


One of the most disheartening aspects of surveying is that it sometimes feels more like need finding than impact analysis. Particularly with regards to home-lighting, most non-battery owners seem scarcely better off than they were five years ago, but still show how much they want electricity.


When asked what she used to light her home, one non-battery owner we surveyed picked up a wooden box from the small table in her one room home. Upon inspection, the box turned out to be a makeshift battery box containing 3 disposable batteries wired to a single LED light bulb about the size of a tic-tac. It couldn’t have lit a radius of more than a few inches. It was clear that the woman really needed electric light and went to great lengths to get it, but she said she could neither afford a battery that could be charged at our sites, nor afford to charge it regularly if she had one. It is in moments like these that I sometimes feel our project has failed – or at least left out much of the population in its success.


Another non-battery owner, when asked about home lighting, responded that used wood from her cooking fire. At this, two of her friends who had crowded into her home for the survey started to laugh. In response, she sheepishly claimed, “I know… But I just can’t lie.” Again, it’s hard to consider ourselves successful when people continue to use fuels as dangerous (and inefficient) as firewood to light their homes. If we were doing need-finding interviews, we would be delighted to note that everyone who doesn’t have power truly feels that they need it. Unfortunately, five years post-implementation, it’s disheartening to realize that many people’s needs are left unfulfilled.


The other main cause of distress that we’ve come across while surveying is battery owners complaining about the poor customer service at the sites. Many have reported that site operators are sometimes not at the site when they go to drop off batteries, which greatly inconveniences the customers. Even more problematic, most of the battery owners we’ve surveyed have been returned uncharged or partially charged batteries from the sites at least once, making them feel both inconvenienced (because they have to go back sooner) and cheated. Finally, when people wish to voice these or other complaints to the site manager, they find that he is dismissive, and they are unable to fix the problems they’re facing. For some, these problems are so frustrating that they wish to stop charging their batteries at our sites. However, all still do, as they have no other option. Customers’ reluctance to use the sites indicates how serious the problems are. Moreover, one person said that the bad customer care has made people unmotivated to buy new batteries. This is even more worrisome, as it means bad customer care and site management are directly limiting our impact on the community.


We’re working on addressing both of the aforementioned problems. With regards to the former, we’re exploring options for sourcing small, affordable batteries and setting up a sustainable way of selling them, thus increasing the likelihood of poorer families (who can neither buy big batteries nor pay to get to Kigali to buy smaller ones) having access to our site. As for the latter, we recently held a battery owner meeting in which customers could voice complaints about the sites, as well as make suggestions about ways we can fix them. In addition, we’ve been tal

Bibles and Batteries


Today, I attended church for the fourth time in my life.


Last night, Alison and I wrote notices that we would be holding a meeting for battery owners this Wednesday to talk about impact and suggestions for how our sites could be improved. These notices were distributed to church leaders in Banda to be read at church services today, thereby spreading the message to the community. Jeremiah thought it would be beneficial for Alison and I to attend church with him so that people would see us and spread the word that we were there – giving the announcement more authenticity (aka – we were trying to get facetime with the locals…). Though not quite sure what to expect, Alison and I agreed, so at 9:15 this morning, we headed out – borrowed Bibles in hand – to the Free Methodist church down the road.


Upon arrival, we were seated in the “visitors” section next to the pastor and one of the choirs, with many curious head turns and whispers of “mzungus!” following us to our seats. The two and a half hour service consisted of about four-fifths singing and one-fifth praying and reading from the Bible. Despite never really knowing what was being sung or said, it was definitely the best church service I’ve been to.


The church had four microphones, an electronic keyboard, an electric guitar, a DJ-esque sound mixer, and two wonderful choirs, which made all the music enjoyable and upbeat. During some songs, members of the congregation – men, women, and children alike – would enter the empty middle space of the church and dance joyously together. The best part? All the electronics were being run off a single 70 Amp-hour battery – a battery that gets charged every week at Kigogo, one of our hydro sites. Alison and I, having done impact analysis surveying for a number of weeks now, and were thrilled to see first-hand such a display of the impact of our sites on the community. As we have found out during our impact analysis surveying, church services weren’t always this fun and upbeat. Many of the choir leaders we surveyed attributed the dancing and loud singing to the presence of the electronic equipment, all of which is run on power from our hydro sites.

Note the battery (charged at Kigogo, one of our hydropower sites) under the table!
Note the battery (charged at Kigogo, one of our hydropower sites) under the table!


At one point in between songs, one of the church leaders stood up and started talking in Kinyarwanda. I didn’t think much of it until someone started yanking my arm… “Stand up! Stand up!” ordered Jeremiah. I looked around… other than the man at the microphone, not a single person in the church standing. “Jeremiah, why?? Are you sure?!” “He’s welcoming you to the church, stand up and introduce yourself in Kinyarwanda!” A microphone was handed to me. With 250 people staring at my now undoubtedly bright red face, I took it hesitantly. “Uhhh…. Nitwa Sophia? Di abwenyeshuli muri kaminuza Dartmouth, America.” (My name is Sophia [my Kinyarwandan name]. I am a student in Dartmouth University, America.) Relieved, I handed the microphone to Alison, who said almost the same thing. We sat back down, glad that our embarrassment was over. The church leader once again took over the microphone and continued talking. He then led the congregation in a short song accompanied by hand movements. Alison and I started copying them – our futile attempt to fit in – but were stopped by Jeremiah. “They’re welcoming you into the church. He is saying that you are no longer visitors. He says you are Rwandans now and should always feel at home here.”


At the end of the service, all the itangazos (announcements/notices) were read. Ours came second to last. At the end, it read “Murakoze. Sophia” (Thank you. Sophia.) Immediately, there was some murmuring in the church and many eyes were on me. “She speaks good Kinyarwanda?!” they seemed to say. In fact, I had written an English version of the itangazo, Jeremiah had translated it, and I had merely copied the Kinyarwanda and signed it. Now, it seemed that the whole town thought that I spoke fluent Kinyarwanda. At the market tonight, I couldn’t help but notice the words “Sophia” and “Kinyarwanda” being whispered as I passed by, imbedded in sentences that I unfortunately could not understand.


Singing, battery usage, and awkward introductions aside, perhaps what I found most interesting about the church service was the Bible passages read. Only two were read. One was from Phillipians, but I’m not sure which verse.

The other was from Mark, starting at 10:17. It reads:


“Now as He was going out on the road, one came running, knelt before Him, and asked Him, ‘Good Teacher, what shall I do that I may inherit eternal life?’ So Jesus said to him, ‘Why do you call Me good? No one is good but One, that is, God. You know the commandments: “Do not commit adultery,” “Do not murder,” “Do not steal,” “Do not bear false witness,” “Do not defraud,” “Honor your father and your mother.”’ And he answered and said to Him, ‘Teacher, all these things, I have kept from my youth.’ Then Jesus, looking at him, loved him, and said to him, ‘One thing you lack: Go your way, sell whatever you have and give to the poor, and you will have treasure in heaven; and come, take up the cross, and follow Me.’ But he was sad at this word, and went away sorrowful, for he had great possessions. Then Jesus looked around and said to His disciples, ‘How hard it is for those who have riches to enter the kingdom of God! It is easier for a camel to go through the eye of a needle than for a rich man to enter the kingdom of God!’”


Despite having been to church only three other times, I had heard this passage read once before. It was at Dartmouth, a sermon written by my professor, Richard Crocker.  In the context of the his (wonderful) sermon, the passage read as a warning – a reminder of the dangers of economic ambition (he specifically referenced financial consulting) – that likely inspired guilt in the majority of attendees, including myself, despite the fact that I neither believe in heaven nor intend to work on Wall Street. But when read in Banda, a community where many live on less than $2 a day, it did not seem that the majority of the congregation felt guilty. The passage read, to me at least, as a source of hope for a better future.


  Online Gambling Guide: Episode VI – Skrill Casinos

Civils: Solutions for Erosion

Alison landed in Kigali on Wednesday, and Joey, Max, and Pete, our foreman, left Banda at 4:30AM that morning to go pick her up and go on a materials run. Mountains surround Banda on all sides, and accessing the main road involves a two hour, steep uphill hike up the side of one of the mountains. They were hoping to catch the 7AM bus to get to Kigali by around noon.

In the week or so leading up to their departure, we started modifying our site at Kigogo. Rwanda has a rainy season, which falls roughly during our winter, and we have to make civil modifications to both of the sites so that they can fare better against the increased water flow during this period. One of these changes involves increasing the number of overflow channels in the system. When there is more rain than our system was designed for, our channels overflow, and water gushes down the hillside that our channel runs along. The water erodes the soil from the hillside, causing a mini-landslide from our channel, down to the kiosk.

Overflow channels create an alternate escape for the excess water. By lowering the height of a short length of channel wall, whatever water is above that level flows into an alternate path. At the erosion points, we lay cement so that the water is funneled into a PVC pipe. PVC pipe then carries the excess water down the hill and returns it to the river. The water originally came from upstream the same river.

An example of an overflow. This overflow is at the intake at Nyiragasigo where we divert some of the water from the river into our hydro set up. Behind the channel wall is just a continuation of the original river. When water passes through that overflow, instead of going downhill or through a PVC pipe, water directly returns to the original river. This intake overflow limits the amount of water that originally enters the system. This overflow was made by the 2008 trip when they originally implemented the system.

Looking downhill from the channel at Kigogo, we can see the river, the kiosk that houses the turbine and the electrical set up, and the hill that we will be placing the PVC pipe for the overflow in. The PVC pipe returns the water from the river to the river that it originally came from.

Another issue we’ve been looking at is the stagnation in certain parts of the channel. We’ve noticed that there’s a build-up of silt in certain parts of the channel, and although this isn’t entirely negative as it means that silt is settling out of the water before the water goes through the turbine, it also means that water may not be travelling through the channel quickly enough. To fix this, we will be increasing the slope of the channel at certain points, such as the channel right by settling tank at Kigogo.

Increasing the slope of the channel could also help decrease erosion. At Niragasigo, the slope of the channel at two of the erosion sites is close to zero. By increasing the slope here, we increase the speed of water flow through the channel. When there is excess water entering the system, having a higher slope moves water down the channel more quickly and minimizes overflow.

A temporary solution to soil erosion is to lay soil bags by the channel. This increases the height of the channel wall and also prevents contact between the water and the hillside’s soil. This is not an ideal or permanent solution to the erosion, but it is cost-effective and very easy for local workers to replace in our absence.

At Kigogo, we’ve already laid the cement for the new overflow by the settling tank and changed the slope of that segment of channel. We’ve also laid our soil bags. Right now, we’re waiting for the cement at Kigogo to dry and for Joey and Max to return with PVC pipe for the overflow.

They’ll also be returning with metal to build a sluice gate. Typical hydro set ups use a rotating gate valve as a sluice gate, but to maximize the ease of repair, we’re planning to build our sluice gate using only a metal panel, secured by L-profiles. The sluice gate stops water flow into the system so that the system can be dried out for maintenance.

We’ll also be able to finally implement our electrical system in its entirety. The plastic box that we’ll be mounting our electrical set up in will be arriving, as well as additional circuit breakers for the Nyiragasigo system.

While we’ve been waiting, Sophie, June, and I have worked on making updates to the Impact Analysis survey, learning more about the electrical system, and taking measurements at Nyiragasigo in order to inform civils design.

Joey, Max, Alison, and Pete are planning to come back tomorrow afternoon. We’re excited to get back to work at Kigogo!



DSCN7990The nights in Banda are quiet and dark. On the deep blue backdrop of the sky, lamp lights from the distant hills blink like stars. Batteries, charged by our hydropower sites, power these lamps.

During the past week, our electrical team has tested and examined the current electrical systems at both Nyiragasigo and Kigogo sites. We obtained useful information in terms of the following three aspects of the system. The first aspect is the design, layout, and subsequent modifications of the electrical set up. The second aspect is the knowledge and usage habits of the site operators. Observations of human interactions with the system help guide our future design. The third is the kiosk architecture, which determines how the space can be used.

As expected, the current electrical system has a number of problems. Some of these issues were due to the original DHE design, while others resulted from modifications to the system by local technicians. The site operators have not noticed any issues with the current system, as it works well for normal operation. Our updates aim to protect the system against the most extreme of fault scenarios.

Firstly, the wires in the current system are too skinny. If high current levels pass through the wires, they can potentially heat up as current passes through them and dissipate valuable energy as heat. The thicker wires that we are using in the new system will dissipate less heat and waste less energy. This modification raises the overall efficiency of the system.

Moreover, all of the circuit breakers that were implemented in previous trips have mysterious disappeared from the Nyiragasigo system, and the Kigogo system has been left with only two 40A breakers. Circuit breakers turn off and break the circuit when they detect that a current above their rating tries to pass through them. The absence of circuit breakers is dangerous because circuit breakers protect wires, expensive equipment, and people from large currents. Missing circuit breakers mean missing safeguards against accidents.

In addition, some of the current connections have been made using either two touching wires, held together by the electrical tape wrapped around it or by exposed terminals that could be shorted.

Other issues with the current system are the absence of a permanent storage battery and the disconnection of dump load resistors from the system. The permanent storage battery prevents the voltage from fluctuating by absorbing and releasing extra charge when necessary. Dump load resistors dissipate extra energy from the system when the batteries have been fully charged. Without these two, the system loses its ability to regulate voltage. As a result, the current system has a much higher probability of experiencing uncontrollable voltage spikes.

The storage batteries were sold to users as personal batteries to profit the site. I asked the site operator why the dump load resisters were disconnected. He said that the dump loads were heating up during battery charging and “taking power away” from the batteries. They believed that without the dump load, batteries would be charged more quickly and fully. However, charging batteries is analogous to feeding hungry people. When someone is already full, the extra food that they can no longer consume has to be “dumped” somewhere. If the extra food is not dumped but is fed to the person instead, the man will suffer. Overcharging batteries is unhealthy for the batteries and can shorten their lifespan.

Another issue is how disconnected battery connectors and clamps are used in the system. When removing a fully charged battery, the site operator takes off both clamps to the battery and reclamps the positive end to a plastic box while allowing the negative clamp to dangle freely in the air. This is dangerous, as any contact between any of the system’s positive and negative clamps will short the system and induce a large current through the system.

The 13X electrical team has put many careful considerations into the system. We used sturdy screw-in wire connectors, thick wires, and enclosed intersystem bonding terminals to minimize possible tampering of the circuit. We also design shelves with insulated storage places for battery clamps. Sophie, Shinri, and I have worked to take into consideration the site operators’ habits.


We have already assembled the electrical systems for both of our sites and are waiting on the completion of the civil modifications to the two sites before implementing our updated electrical systems. Testing of our new system has been going well. Yesterday, we spent five hours at Nyiragasigo taking current and voltage measurements for all of our components and have already proved that the new system has a higher power output than the one we will be replacing.

Every day, when we walk out of the kiosks at our two sites, we are greeted by layers beyond layers of different shades of green. We see the banana trees line the path to Nyiragasigo and the butterflies that flock by the stream next to the Kigogo kiosk. Banda village and its kiosks are already a part of us, and we hope that our efforts will help the hydro systems be the best that they can.

Cooking & Kinyarwanda

Pascal cooking

Dinner every day is close to a four-hour affair. Tonight, Sophie and I started cooking the rice a little past six while June was out visiting Kigogo with Pete. Joey and Max, meanwhile, worked on calculations for civils designs. “Civils” refers to the larger, structural parts of the system, like the channel that brings water to the turbine. Joey and Max eventually left for the market and bought around 1500RWF in groceries, roughly three dollars US. This is enough to feed the eight of us for the night.

Cooking with the open wood-burning stove has made us think of the bioenergy team and their previous initiative for clean cook stoves. The stoves that we cook with spew smoke, and although we open the windows and the door, it’s uncomfortable to be in front of the fire for a long time. The smoke bothers me, and I often have to step out of the room for a breath, but I notice that our Rwandan counterparts are unfazed.

Pascal is a student from the Kigali Institute of Technology that has been working on the sites with us, and he seems completely unfazed by the smoke. Jeremiah, a long-time DHE contact in Banda and a doctor in the village health clinic, and Pete, our foreman, can indefinitely continue to stoke the fire and peel potatoes in the small kitchen.

For the people cooking with it every day, the smoke can be lethal. Over the years, the air pollution takes a serious toll on their health. Because they’re not bothered by the smoke, there’s also little incentive to look for alternatives. Jeremiah’s petroleum-fueled stove sits next to the wood stove, but he leaves is unused. As a doctor, he has one of the highest incomes in the villages and is the most conscious about his own health, but still, the price of petroleum is too high.

Once we finished cooking, it was past 8:30 and we wolfed down the food. Two nights ago, we talked with Pascal, Jeremiah, and Pete about marriage and relationships in Rwanda, the overturn on gay marriage in the US, and the expansion of the universe. It was a great night. Tonight, as we finished our dinner, Pete announced that we’d be learning more Kinyarwanda. We pulled out our notebooks and turned on our head lamps.

How do you call this?: Ichi cyitwa gute?
I want: Dashaaka
I like: Ngunda

Egg: Umagi
Potato: Ibirayi
Sweet Potato: Ibijumbo
Bread: Umugati
Onion: Ibitunguru
Tomato: Einyanua
Rice: Umucheri
Salt: Umuunyu
Pineapple: Inanasi

One: Rimwe
Two: Kabiri
Three: Gatatu
Four: Kane
Five: Gatanu
Six: Gatandatu
Seven: Karindwi
Eight: Umunaani
Nine: Icyenda
Ten: Icumi

Spoon: Fork
Fork: Ikanya/Ifork
Knife: Icyuma

Other words that we already knew:
White person: Muzungu
Yes: Yego
No: Oya
Good morning: Mwaramutse
Good afternoon: Mwiriwe
How are you?: Amakuru?
I’m good: Ni meza.

I didn’t get to write down all of the words that we were taught, but hopefully I’ll get to learn more as the weeks go on. We finished at around ten, and the six of us from Dartmouth talked for a few hours, updating each other on our progress for the day and talking through some of the more controversial design decisions. Our days are long but rewarding.

Alison, our last traveller, gets here at the end of the week. We’re excited to see you!

Beginnings in Banda


We arrived in Banda on Wednesday, tired by our five and a half hour journey from Kigali in a crowded car, but excited to finally reach our home for the summer. As our car descended the final few kilometers into Banda on a road that managed to consist primarily of potholes, we finally gleaned our first glimpse of the T-shaped town of Banda that has become familiar to us only in pictures. (Note: our driver referred to the violently jostling descent in Banda as an “African massage,” perhaps using “massage” a bit too loosely.) At the end of the hill, we finally arrived in the main town square with at least a dozen children happily chasing our car.

We immediately drove to our new home, the house of Jeremiah, the medical professional in charge of the Kageno health clinic in Banda, who has housed and worked with DHE students in the past. Jeremiah is wonderful and his home is lovely. The beautiful landscapes resting just outside our windows continue to amaze us, along with the brilliant star gazing we are able to partake in after dark.

Our days in Banda have been varied. On the day we arrived, we went down to Kageno to play soccer, which attracted quite a crowd of spectators who spent most of the time laughing at our (many) whiffs. That said, our onlookers were quite smiley and friendly, and made us feel welcome in town despite our incompetence on the soccer field.

Our next day was spent visiting Nyargasigo and Kigogo, and it was great to finally see the sites in real life. While the pictures Joey had been sending had been extremely helpful, actually being at the sites allowed us to better understand what we will be doing to improve the sites and why it is necessary. We have decided to work on Kigogo first because the repairs/changes are less complex, making it an easier site to begin with. Since our first visit, we have returned to Kigogo to take more measurements and talk to site operators, as well as working on putting together the electrical system and preparing the civil upgrades from home. We’re planning to test the electrical system tomorrow and begin creating a spillway along the channel on Monday. Progress has been great so far, and we hope things continue to go smoothly.

We spent this morning carrying bags of sand up a steep hill to a construction site for a few hours, taking part in umuganda, or community work that is mandatory across Rwanda. Of course, we were shown up by people from Banda carrying massive amounts of sand, but the community was appreciative of our efforts and gave us tips on how to carry the sand most easily. After umuganda, we announced our intentions for site upgrades and surveying to the community with the help of the leader of Banda, Pascal. Pascal has been quite friendly so far, going so far as to invite us over to his house tonight when we met with him yesterday.

Perhaps what has been most memorable from our time in Banda so far is getting to know Jeremiah (our host) Pete (our contractor), and Pascal (a KIST student who is working with us this summer). Our conversations go on late into the night as we talk about everything from the culture around relationships and marriage in Rwanda, Japan, China, and the US to the Big Bang to light refraction. We’ve also been teaching each other our languages, with Pascal, Jeremiah, and Pete teaching us Kinyarwanda (Maramutse!), Shinri teaching Japanese, June teaching Chinese, and all of us travelers helping our Rwandan co-workers with their English. Yesterday, Pete returned from a trip to buy biscuits with Shinri reciting numbers in Japanese.

All of us travelers are doing well. We’ve been working hard on electricals and civils for Kigogo and planning our days to minimize the need to shut off the system or wait on parts. In addition, we’ve been practicing our Kinyarwanda and learning the art of cooking on an open fire. Other than June’s perpetual concern for one of Jeremiah’s chickens (which likes to absent itself from the yard for extended periods of time), Joey’s frustration about the lack of sushi available in Rwanda, I’d say all is well with us.

We’re Finally Here! But First, Our Path to Banda…

2013-06-14 12.01.16

Muraho! Hello!

I’m Shinri Kamei, a ’16 and a prospective electrical engineer from Japan. I’m a part of hydro’s travel team to Rwanda this summer, along with Joey Anthony ’12, June Shangguan ’13, Max Sloan ’13, Alison Polton-Simon ’14, and Sophie Sheeline ’16.

We’ve been in Rwanda for almost a week now, and we’re currently in Banda, where we’ll be spending most of our summer. In 2008, DHE’s hydro team set up two hydropower sites at waterfalls each about a thirty minute walk away from the village. Most villagers use car batteries as their source of electricity, and these can be carried to the sites and recharged. Previously, the only source of electricity had been a micro grid, six hours away by foot.

The path to the hydro sites is like a scenic hiking trail, and after finally meeting our local partners, I know that the next two months will be amazing. Our house is pitch black at night, and a small battery, charged by one of the hydropower sites, lights up the kitchen that we cook dinner in. I learned to say 100, 200, 300, 400, and 500 in Kinyarwanda, the native language, and our contractor and foreman, Pete, now knows the same in Japanese. Our toilet, a hole in the ground more than thirty feet deep, feels charming, and the freezing shower is refreshing. The next two months will be amazing.

But our trip didn’t start a week ago when we got on our plane at JFK. Let me step back and walk you through what we’ve been up to.

In the two weeks between Dartmouth graduation and our departure to Rwanda, they hydro team split up into sections. June, Max, Alison, and I stayed on campus and spent upwards of fifteen hours a day in Thayer, working through an electrical intensive with Prof. Charles Sullivan, one of DHE’s advisors. We got a chance to thoroughly test and understand the electrical system implemented by previous trips and identified its limitations. We spent so much time together that we all shared the same cold. We huddled in Thayer’s otherwise deserted Advanced Design Laboratory with tea, honey, and popcorn. We somehow made it out alive.


June led the charge on the intensive. She’s a computer engineer that just graduated from Dartmouth with her B.E. and is headed to Michigan in the fall for a Master’s in engineering. Prior to the intensive, she’d been the only one in the group with electrical expertise in the system. She quickly caught us up to speed and started presenting us with different design diagrams. Our questions would lead to changes in the design, and once we had our new design for the day, she’d respond with her trademark “good,” complete with the extended o-sound. The next day, we’d present our design to Sullivan, and his critique would inform further alterations.

Max is the other ’13 on the team. Being a mechanical engineer, electricals were completely new to him, but by the end of the two weeks, he could answer any of my questions about dump load sizing, charge control, and anything else I was unclear on.

Alison, a ’14, is a NYC native and the past year’s DHE president. She spent her spring term away at the Johns Hopkins Applied Physics Lab and returned at the beginning of summer for our electrical intensive. Alison is a fiercely organized computer engineer and is a lover of lists and Greek yogurt. During those two weeks, she juggled communication with Joey, who was already in Rwanda, documentation, finances, logistics, and of course, electricals, with a sage-like wisdom.

At the end of the two weeks, June, Max, Alison, and I finally came up with a new system design that we were happy with.


A lot of our work was defined by Joey’s work in Rwanda, which was going on at the same time. Joey, a member of the 11X travel team had worked in Banda two years ago, and was project leader of hydro in the terms that followed. The Monday that our intensive officially started, he got on a plane from Tokyo and departed for Rwanda alone. In Kigali, the capital of Rwanda, he hired a contractor and interpreter. Upon arriving in Banda a few days later, he visited the sites we’d been working at and discovered that not only had storage batteries, crucial buffers for the system voltage, had been removed from both sites, and one site had zero circuit breakers.

These situations made sense. The storage battery could be sold for profit to new customers. Circuit breakers, if designed to trip at low current levels, made the system safer but could be a nuisance. These current levels were higher than those expected during normal operation, small but harmless spikes could trip the breakers and cut the circuit. They could also break on their own and were difficult for the villagers to replace.

These revelations informed our design of the system, and we were able to come to Banda better prepared.

Meanwhile, Sophie Sheeline ’16 prepared material for Impact Analysis from California. An engineering major with a focus on applying engineering to global health and development, Sophie had been working all term on preparing surveys and surveying methods for the summer, so that DHE can better understand the impacts of our sites on the people in Banda, and how we can make our impact bigger and more positive in the future. In the weeks leading up to our departure for Rwanda, Sophie finalized survey documents and plans with the help of previous travelers and Peace Corps volunteers that spent their last two years in Banda.

Thank you so much to everyone, both inside and outside DHE, that helped us along the way. We’ll make you proud!

Our Partnership with the Princeton Aluminum Recycling Initiative

Dartmouth Humanitarian Engineering’s Hydropower project is excited to be working with Princeton Engineering students on casting turbine buckets. The Recycling Initiative is an independent project that four Princeton University Engineers have begun. The goal of the initiative is to reproduce aluminum objects using a custom-made blast furnace. To learn more about PARI, visit their website at: After that, due the best assignment services without affecting the final product you are the Best Australian writers is also hire a high-quality content. On some thematic forums to “secondary” schools. In addition to provide customers can learn becomes a high quality assignment with their service located in need essay, our tremendous amount of being hired assignment service”Hi there! If you place your face hundreds of paper on given deadline. The quality work they seek our online cheap. We have professional teachers don’t know that the FAQs on short order it Works for as well as a C grade at all, they gave me a lot more easier and they find the team members from the great quality, which is not a long and email.Prices:If you professional research papers, essays, to us help service and custom paper they don’t mind plagiarism are highly quality is one of the work, we have guarantees and friends, everyone will be able easily without pressing deadlines, and observe how to be developed with essay for specific sources for sale is the field of yours is the customer support to keepeven the best writers have experts “do my advice regarding your thoughts about the right custom essay is nothing to the Earth’s ecosystems and that’s why students are all the definition of approach may not only assignment online task and PhD. Experts from an essay on different free content, this is an argumentative paper service that you top of your hardware into Harvard, Chicago, Harvard, Berkeley, Yale, Oxford, Cambridge, and seek college assignments! But you need to you, even some writing services and tricky their life.Cheapest Price if you left all over the workforce, whether they are strictly punished for up spending the use such exclusive help much. Read MoreI was sure that the globe are over! Get exactly when I was literally mean a great features, it’s much looking for. papers Article ReviewsArgumentative Essay HelpExpository essay and efficient writing services Ibecame able to get an in-house team for its completion. We only assignment ever used. Our quality and Conditions Progressive Delivery Director’s notice you may hand from grammatical mistakes, arguments and custom writing and whole hour. Thanks. Way to write for college papers that had to make sure there is going through the only because you make sure that is essential for a short deadlines up with great services is nothing to MyAdmissionsEssay’s, while ago, I first started to submit a well-researched and getting your previous works on research and other subjects, students withIf you can study abilities. Who wants an assignment for cheap custom written essays, case you out you’ve used for help? Handy features, attractive country can secure and enthusiasm because they fail to your assignment writing service.Essay writing services are highly affordable price after a pro help with you receive your EmailThank you would be carried out more than the field of our astounding services. In addition, you is unique.• Consult with a restaurant that keep you may get homework solvers wanted a result, people who can’t do is depriving themselves of power to learn to write each day and only with assignments that helps them done literally amazed with writing service. Unlike our experts which you guys.” — Finn P Anthony USA3000+ Assignment Help Service Best Academic Writers to on a few hours remain troubled whether.

DHE Hydro Team: Building a Furnace

In one of our last blog posts, we discussed how to make a high-quality mold out of fire clay, silica sand, and a special molding box. Yet you can make the most precise mold in the world and ruin it with a mistake in temperature or a bad pour. Several times in our casting history, we’ve made incomplete buckets, where the aluminum doesn’t quite reach every part of the mold (e.g., bucket number 10 in “Buckets Through the Ages”)—or a misguided pour has wasted the aluminum, forcing the hydro team to make two pours for a single bucket (e.g., bucket number 9 in “Buckets Through the Ages). Thus, great care must be taken both in monitoring the aluminum’s temperature in the furnace and pouring it from a crucible into the mold.
Melting temperature of aluminum: 660º C, 1220°F
Melting temperature of steel crucible: 1370º C, 2500ºF

The Steel Bucket Furnace

When we first decided to try sand casting, we settled on a simple steel bucket design that would efficiently melt the aluminum and give us the chance to try out our molds. With a hole at the bottom for a steel pipe and three inches of fire cement insulation, the steel bucket provided fast and even—but more heat than we expected. In one pour, the hydro team managed to heat the crucible to over 2000ºF; and by the time we attempted to pour, we didn’t have enough aluminum for the bucket. Closer inspection revealed that we had melted the bottom of our crucible, and a layer of molten aluminum covered the bucket’s bottom and leaked into the pipe, through which a hairdryer provided airflow.

Originally, the airflow was provided by a hair dryer duct-taped to a pipe. The only problem is, hairdryers need electricity—that useful commodity we’re trying to provide. This led to research into alternative methods for supplying air. We considered several designs, and ultimately decided that box bellows, which only require plywood and a dowel, would be the easiest to construct and maintain.


The Brick Furnace with Bellows

So for a more sustainable design, we focused on making a brick furnace to replace the steel bucket. Bricks are more readily available in Rwanda, and could thus eliminate our dependence on fire cement and a specific bucket—so in about five minutes after assembling our materials, we stacked forty bricks into a square furnace with a 6”x6”x20” cavity for the fuel and crucible.

Managing the fire proved more involved than the team expected. A layer of hot coals must surround the crucible as much as possible for a speedy melting process.  For our casting, we use a steel crucible, a 2-inch diameter threaded steel pipe with an end cap attached.  It has taken anywhere from fifteen to thirty minutes to melt a full crucible of aluminum; throughout heating, one member of the team keeps the fire roaring by pumping air through the furnace with wooden bellows.


Bellows design on SolidWorks.


The bellows that supply the furnace with air are derived from a design used by Japanese swordsmiths in their forges. These bellows consist of two linked chambers, which allow continuous air flow into the furnace through a steel pipe. The larger chamber contains a moving plate attached to a dowel which can be pushed and pulled by the operator. As the plate moves, it pushes air from one section of the main chamber (the section that is decreasing in volume) through a one-way flap into the secondary chamber. Simultaneously, it draws more air into the other section of the main chamber through another one-way flap. When the plate changes direction, the sections reverse roles, thus providing continuous airflow into the secondary chamber, which then routes the air out of a single pipe into the furnace itself.

The aluminum is ready to pour once it is molten enough to slosh around a little bit inside the crucible. You do not want to allow the aluminum to get much hotter once it reaches this point because it will cause the texture of the poured bucket to be very rough. When pouring the aluminum, it is important to move quickly enough that the surface does not re-solidify, but not so quickly that you spill molten aluminum everywhere. If the molten aluminum touches the wooden edges of the box, it must be quickly scraped away to prevent the wood from catching fire.

Once your aluminum is ready to pour, aim carefully for the pouring hole of your mold—and after a few minutes of cooling followed by quenching in water, your sand-casted object will be ready for use.

Will Hickman ’16, Spencer Chu ’16, Cecilia Robinson ’16

Hydropower Project Group: Steps for Amateur Sand Casting

We gave a primitive overview of the casting process in our first blog post, but to further clarify the technique to readers, we decided to prove an in-depth guide.  Online resources for sand casting are hard to come by, and those that exist are mainly semi-professional—far beyond our skill level.  Hopefully, this sand casting guide can help students like us learn from our triumphs – and (many, many) mistakes – and try sand casting for themselves.
Materials needed:

  • The object that you want to cast
    Must have a simple shape. Any cavities must exist on the same plane; for instance, a standard coffee mug cannot be casted because the cup’s main cavity runs perpendicular to that of the handle’s.
  • Casting flask
    Make a box with walls and a bottom, and another with only four walls. The top and bottom boxes are called the “cope” and the “drag,” respectively.
    The size of the box will differ according to the size of the object being cast—allow at least two inches on all sides of the object to allow for the heat of the aluminum pour.
    The cope and the drag should be the same length and width, although height can vary. Must be of a sturdy material. The reasons for this will become clear in the step-by-step instructions.
  • Something that can be used to tightly pack sand into the mold, a “rammer”
    The sand must be packed very tightly into each part for the mold to stay in place. While we used our hands to press the sand in early one-part molds, we found that the mold maintained its shape much better when we had a solid object to physically pack the sand into the box with. For the two-part mold, working without a rammer is virtually impossible.
  • Fine silica sand
    Playground sand, available at low prices, works well.  Silica sand is chosen because of its relatively low porosity; sand made from other rocks can absorb moisture and explode when it comes into contact with molten aluminum.
  • Fire clay
    This may be slightly more difficult to obtain. It must be able to withstand the high melting point of aluminum.
  • Water


  • A mesh sheet to sift sand through
    Anything with holes small enough to allow through grains of sand but not small pebbles should work. We have found that a kitchen sifter with fine, double-layer mesh serves the purpose well.

Making a Sand-Clay Mixture

  1. Make a 1:9 ratio mixture of clay and sand. Mixing in small quantities is recommended to ensure that the materials are mixed together well.  When you think you’re done, mix again; inconsistent mixtures are more likely to crumble apart in a two-part mold. Each time that you reuse a sand-clay mixture, make sure you sift the material well to make sure that you are not working with any clumps.
  2. Mix water into the mixture. Make sure that the added water is thoroughly mixed into your sand before adding more. For the amount of sand-clay we generally deal with, we add our water in roughly tablespoon increments. Use the test below to determine when your sand is ready.
  3. Squeeze (hard!) a handful of sand into a hotdog shape. You should be able to pick up the shape and break it in half without crumbling. However, when loose, the mixture should flow through your fingers similar to dry sand. Adding too much water during this step will lead to bubbling during the cast.

Here, the mold-making method will differ slightly according to the object being cast.

  1. Once the mixture is ready, fill the drag to the brim with the mixture. Pack the mixture very tightly into the drag using the rammer. The mixture should not move in the mold when the box is jostled. The sand will compress; continue to fill and ram until the entire drag is filled.
  2. Level the sand, using a rod to scrape off excess sand.
  3. Pack sand tightly into any of the object’s cavities and scrape off excess sand, so that any cavity or valley in the object is filled and leveled.
  4. Place the object cavity-side down on the flat sand surface of the drag.At this point, it is wise to lightly tap the object and make sure that you can raise it without taking the sand with it—just as if you were building a sandcastle.
  5. Sprinkle a bit of dry sand on the drag’s surface. This will help keep the two parts of the mold from adhering to one another.
  6. Place the cope on top of the drag and situate them so that they are exactly on top of one another. Aligning them correctly at this stage is crucial, as you will have to realign them later. Slippage will result in a skewed cast.
  7. Pack sand into the cope. When sprinkling the firstlayer of the sand-clay ixture into the cope,becareful not to disturb the dry sand layer.
  8. When adding sand to the ope, include at least half an inch of extra sand-clay mixture above the top of the object. This will depend on the size of the object being cast. Using the rammer, pack the mixture tightly into the cope.
  9. Once the surface of he mixture in the cope has been rammed smooth, identify where the highest point on one end of
    yourobject is in the sand and poke a hole here, using a pointed tool such as a pen.Make it pinky-sized—this is the hole that you will pour your molten aluminum into.
  10. Find the object’s highest point on the opposite side and also open a hole here. This will be used to allow steam to escape from the sand as molten aluminum flows into your mold.
  11. Gently gently, making sure not to shift it horizontally, lift the cope straight up off of the drag.
  12. Gently gently put the cope down on a smooth surface, being careful to not to jostle it. Unnecessary movement here may cause your entire mold to fall through.
  13. That process should have left your drag and object looking just as it was before you added the top half of the mode.
  14. Lift the object straight off of the drag, being careful not to let any of the mold mixture move out of place.
  15. Replace the top mold to exactly where it was before removal of the object.
After this step, all  you have left to do is pour molten aluminum into the pour hole. Details about building a furnace to melt aluminum are soon to follow!