Goodbye Stranger

About twenty four hours ago, Julian's flight to Dubai out of Entebbe International Airport took off.  I've got another six weeks or so (until August 6th) on the ground here, so the project is far from over, but we'll miss him loads (bonus points if you get the power pun in there)!

One of his last days this past week, we arrived at work to discover the above beautiful sign sitting in their shop (design courtesy of Obama Jr., whose 22nd birthday is today!).  One of the things when we first spoke about branching with the Lwemodde Youth Group was sort of the question of whether or not they wanted to create a brand for themselves, and we showed them the front of my notebook: our project name with a stick-figure sun. 

At which point Obama was off and away, designing not a name for their shop, but a distinctive sign with which to brand it.  Several iterations of this were drawn, and Julian and I were kind of expecting to have a day on which we painted a sign and generally decorated to advertise the Lwemodde shop as an internet cafe and the Malembo shop as a micro-grid.

However it's obvious that we were beaten to the punch, and showed up on one of Julian's last days to find this super snazzy sign.  It was pretty exciting in a selfish way, seeing their sign with their services and name paired with the name we thought of during our first week in Uganda.  If nothing else, at least Julian can leave Uganda knowing that we have made a mark!  Mission accomplished.

But really: I'll miss Julian; the excitement and proactiveness of the Lwemodde Youth Group never ceases to amaze me, and if you're driving along Ddimo Road, now you know where to stop for some high quality phone repair, hair dressing, agricultural advice, and (crossing our fingers!) internet/computer services.  Here's to another six weeks!

Rome wasn't built in a day, it was built in 4 days!

Today (Friday) we signed the first clients and connected them to our grid.

Alex and this customer signs the first contract ever for the Malembo Micro Grid. She wanted a light in her shop which is across the road from our power house.

Our second client.

Signed contracts!

We ran many wires throughout the day and tried to make them as neat as possible. This usually involved putting them close to house beams under the roof hanging past the building. Each client need their own positive wire because they have a specific fuse on their line but the grounds/return can connect in any way which is convenient. If a client is connected and they already have our wires running past their shop then we attach them to the same negative wire. Considering this means that return current will then build up we have capped a single ground line at 6 lights for now. This was relatively arbitrary but should be well under any sort of maximum current that the wire can hold.

Junior unravels the first reel of wire.

Junior passing wire through roof beams.

Wire going into this clothes shop.

Bulb in place.

Spliced in the switch.

Let there be light!

Ground wire spliced into another ground wire.

Another shop which should be happier tonight.

To create the client contract we discussed the deals that people could sign up for in the days leading up to now. The group decided that 300 shillings ($0.12 USD) per light per day was fair. The wires, sockets, lights and switches are free for people but they will need to pay a 3000 shilling ($1.20 USD) installation fee. The contract was translated using Julie and this made it very easy for people to understand everything. Apart from that Alex does a great job of explain the package to new customers.  The contract in both English and Luganda can be found here.

Some of the clients were challenging to get to; specifically the ones across the street. Putting wires underground would be very difficult because the earth is quite hard and we do not have any easily acquired piping. Our solution was simply to use a pole like any real electricity company. The highest point on our building is the top of this ledge on the roof so we put a nail on the top of that and used that to pivot wire over to another roof where we nailed a pole in the side. This is essentially our first ever power line.

One the left is our roof top and on the right is a client's house.

You may be thinking this is a rough set up. I guarantee that I have seen other real grid lines set up by actual electricians here which look much less legit.

There has been talk of using small step up and step down voltage converters for long distance wires to other parts of Malembo. If we did this we would step up the voltage to 48 V and send then step back down to 12 V in different areas. Doing this we would actually require serious power line poles which I would demand are put in the ground with concrete. We would also need to put small isolators on the poles to hold the wires and potentially even a grounded lightning wire on the top. All of this would be a nice project if we return to see how everything is doing or potentially a second project in another bigger village that the group works on.

On Monday we should be finalizing this grid. Making the wires in the station neater and connecting as many people as possible. As part of the ultimate goal for sustainable development Lydia and I will only give new ideas rather than actually do the building. I am happy with the rate at which Alex and the group members are learning the slithers of electrical engineering necessary to have this grid run safely and with quality. The weekend has just passed and I heard that Alex connected someone one his own which sounds like a great start to this business.

Setting up the rest of the micro-grid

After making the distribution box the next step was to bolt the solar panels to the roof. We used the same mounting system that we prototyped in Lwemodde since we have had no issues since. Obama Jr., the building king, went back onto the roof with me and there were no damages except for a few dents on the roof. Alex was completely new to all of this and so he had to be taught as well.

Junior explains to Alex how the mounting system will work.

Obama marks where the holes will go.

Alex and Junior were a good team.

Junior is doing something...although I am not sure what.

We got tired on the roof and so we had supplies brought up. Half a pineapple each. (For the record., Ugandan pineapple is extremely tasty.)

We ran out of washers but bottle caps were a great replacement.

On the roof. 

200 W of solar panel now on the roof. Obama was quite happy with the job.

Next we wired up the solar charge controllers. We use one for each panel since they are rated for 6 A each and we expect 5-6 A from a single solar panel at full power. Both of these are connected in parallel to the battery terminals and the load so that we have the same energy flow as in the Lwemodde system but with twice the power.

The two charge controllers and on the right are some sugar cube connectors which will take all the return wires from our grid.

The overall power house at the moment. Distribution box with fuses in top right, load box below that with phone chargers attached, control box on the left.

Our biggest challenge with all of this is to teach Alex, the man in charge of this system, all the things he needs to know to make it run smoothly. The other members have been learning well because we have now had 4 weeks with them but Alex has really just been involved since the start of the week so he is climbing a very steep learning curve. To help with this we got some of the members to teach Alex some skills. Since they can all speak Luganda fluently this is definitely the fastest way to transfer knowledge. The first lesson he got from them was given by Bbaale who taught him good soldering technique.

Bbaale teaches Alex good soldering technique.

Alex takes notes.

As we started wiring the system we also realized that there were going to be a jungle of wires coming out from our station. The best thing to keep this ordered should be a map of the village with the clients and wires marked accurately. Hopefully this keeps things in order.

Lydia and Junior walk around Malembo to draw a map.

By the end of the day we were wired up as a power station and all we needed were the fuses to connect people, the lights and light sockets. We had to choose between which LED lamps to use. There was a discussion to decide if we go with the 10,000 UGX dimmer light which draws only 135 mA or the 16,000 UGX brighter light which takes 200 mA. We ended up going with the cheaper light. In terms of our available funds this makes more sense especially since we can load more lights onto this system with their lower current consumption. Although this light was dimmer it was decided that it was still bright enough for most people. If people want they can get two lights.

The light we chose. It is an array of many LEDs.

Tomorrow we will get the first clients signing the contracts we have been drafting and then connect them. It is an exciting time.

The Malembo Micro Grid

The overall project has become clearer in our minds. Essentially we are going to set up a 12 V DC micro grid in Malembo that people can use for lights at night time. Perhaps we will expand this to general purpose items in the future. Phone charging can be done through the same power source at the station (power plant) itself and if you wanted to use 12 V DC for something else, like perhaps to run a radio, then it would require no infrastructural change.

For now the system will follow the diagram below but everyone is very keen for expansion as soon as possible.

The Malembo Micro Grid

The micro grid will use two 100 W solar panels to charge a 100 AH deep cycle battery and then power the loads that are connected. There are two ways in which the energy in this system is used. Firstly there is a load box just like the other system we set up in Lwemodde. This is used to hook up arbitrary loads directly to the 12 V DC lines. Most of the loads connected are likely to be phone chargers but there may be one or two other things such as a radio or even an inverter. When this branch is upgraded to an internet café the computers will connect directly to the load box.

The second way in which energy is distributed is via the distribution box which is essentially a bunch of electrical connectors and fuses. This is where electricity is taken from the battery and sent to individual houses via a fuse.

The uses of fuses comes about because of a very clever system that Lydia thought of. As mentioned in the first post about Malembo, the problem with the last attempt to supply people with lights at night was that they would attach other devices to the lines given to their house. These were 240 V AC lines that he connected to a generator he used at night. While they were only paying for one light a client would hook up other devices in parallel with their light and therefore take more watt-hours of energy than they should be.

To guard against this each client will have a fuse assigned to them which will only allow the current necessary for their number of lights to pass. If the lights are taking ~200 mA each and someone wants three lights we would give them a 700 mA fuse. This fuse will sit in the power station and be the critical link between their positive wire and the grid. If a client was to attach an unpaid load to the grid, such as a phone charger, then they would suddenly draw more current than was allotted to them and their fuse would break immediately.

For this to work we need racks of fuses with individual lines connected to each. Now the biggest issue here is getting the correct fuses. Specific fuses are extremely hard to get even in Kampala. The Ugandan way is to simply replace a blown fuse with an arbitrary/bigger fuse or simply hot wire the fuse. I found a shop in Masaka which had a few fuses but got them to order in 40 fuses of different types from Kamapla. What came in two days later was roughly half the order because the others were impossible to find.

What is even harder to find are fuse clips or holders. So we had to be innovative and make our own. After some prototyping we came up with this:

Our fuse holder design.

Mapping our the array of fuses. We staggered them in height and gave each  fuse enough horizontal space so that no shorts would occur.

The middle fuse in place on the distribution board.

The team from Lwemodde and Alex (our man in Malembo) all helping out to make these fuse holders.

Took a while but we got 12 connectors done. Will probably have to make a second rack before long...

The terms of the contract that each client will sign will state that to be reconnected upon blowing their fuse they will need to buy a replacement fuse from the Malembo Micro Grid. We get each fuse for 1,300 shillings and the grid will charge 2000 for a replacement. This system should keep clients in line and also, if they do attempt to take more electricity than they paid for then the grid will gain a small profit from selling the replacement fuse.

The fuse system is almost perfect however there is one major restriction. We must only use lights which have an extremely constant current usage. With LED lamps (which are the most expensive and efficient) this is not an issue however we cannot use fluorescent lights. Due to the surge of solar power in Uganda there are many fluorescence lights which run on 12 V DC and they are actually the cheapest 12 V lights you can get. The issues with a fluorescent light is that it requires a very high voltage to start the light which is usually achieved via a very large inductor giving a voltage spike. This requires a large amount of current in the first millisecond of operation and then the light settles to a current usage roughly half the initial demand.

This property means that if we wanted fuses which did not break after a light is simply turned on we would need to use fuses which are so large that they will accommodate clandestine loads attached to the client’s outlet. Our solution to this problem is to simply use LED lamps. They have an extremely constant current because usually they are a purely resistive load. They are also more efficient and last longer.

Other concerns with this micro grid are too many loads causing the battery terminal voltage drop to be too large and also the loss of power in long distance electricity transport at low voltages. Operating a 12 V means that for any significant power we need to draw hundreds of milliamps and considering that the power loss in wires follows a squared law proportional to the resistance of the wires we should be doing everything possible to lower the current consumption.

The answer to this very classical problem is elegantly demonstrated in Julian Ilett’s video. After we set up this first system we will have to access its performance and look into small step up and step down circuits.

When in Rome...

Yesterday we bought two 100 AH deep cycle batteries. We got both for 800,000 Ugandan shillings which is roughly $320 USD. Just 1 hour previous to buying these I was given my FSD seed grant which is designed to fund a portion of the project each intern is working on. It didn’t take me long to blow the whole lot since the grant was 750,000 shillings. The extra 50k came from the youth group.

One of the deep-cycle batteries. German technology but definitely manufactured in China.

Today we brought the batteries out to the field. One will go to Lwemodde and the other will head to Malembo. Each day we take a boda-boda (motorcycle) to work but today we need another one to just carry the batteries. Each one weighed an estimated 30 kg. 

When in Rome, use Boda to carry your deep-cycle batteries.

First thing we did when arriving in Lwemodde was install their new battery. This was twice the capacity of the their 50 AH car batteries and will last much much longer since it is not a vehicle battery. Finally the solar charge controller will actually do something because the vehicle batteries, which were sitting siting at a comfortable 8-10 V, were not really charging at all. The group now has a really cute set up with the charge controller outside of the box (because the last one melted from overheating inside), the control box all wired up and sending power to the load box which is just a set of connectors to phone chargers, their inverter and anything else they want.

The PWM5 solar charge controller, control box (left) and load box (right). Excuse the tape, we still have something to tweak in that box.

The final task for today was to discuss the logistics of our set up in Malembo which will occur this week. This is the first real branch for the Lwemodde youth group. It should be a great service to that town and a very large income generating asset to the youth group. Hopefully local people from the town latch on to this enterprise and from a similar community of people enthusiastic about technology. We decided that to send both solar panels and so more mounting wood had to be cut, drilled and varnished.

Sawing wood was apparently so interesting that everyone had to see it.

The week's plan is to spend Tuesday explaining the system and building the power distribution box, Wednesday will be spent mounting the solar panels, Thursday will be connecting and explaining the system and Friday will be signing up our first clients. This week is going to be entrepreneurship on steroids. Possibly the fastest electricity grid ever built…

Malembo: The Real Site of of the Second Branch

Two days ago, we received a surprise visit from the FSD Masaka site team that supervises all of the interns working for the Foundation for Sustainable Development based out of Masaka (lucky for us, they arrived shortly after our hour long tea break instead of during!). With the site team and their four wheel drive, we got the opportunity check out Malembo, a local fishing village.

On Monday we discovered that Ddimo is on the verge of closure.  The fishing village, home to 2,000 or so people, is being shut down in 3 months and individuals currently working out of there will have to relocate.  Overfishing and unsustainable practices have led to a serious depletion of available fish, and so the local government has imposed a no-fishing period.  To us, this means that Ddimo is a significantly less than ideal place to branch into.  It doesn’t seem too wise to open a business in an area where it will soon be basically illegal to earn a living. 

However, this hiccup has been a blessing in disguise.  Malembo, a fishing village that is further away, is in no such situation.  The population, and most relevantly, the population of fishermen, is smaller, although still apparently larger than Lwemodde.  The area is thriving, and has potential for growth in the near future given that there will be local fishermen looking for jobs.  On top of this, Malembo is actually off-grid.  The grid is a relatively new phenomenon in this sub-county in general; the grid only came to Lwemodde (and in fact Ddimo via Lwemodde) within the past two years, and Junior estimated that it would take another 15 years of advocacy and work before the grid might reach Malembo. 

Fishing boats on Lake Victoria

View from the roof tops of Malembo. Sea is in the background.

California-esque with that palm tree.

Random cows with large horns do patrol the streets!

At the moment, this means that all of the phone charging business belongs to a certain Alex Mukiga and his 50 amp-hour car battery.  Alex used to live in Lwemodde, and is a member of the Lwemodde youth group, but has since branched out to Malembo where he owns a video hall, a small shop that sells sodas, beers, and random bits of clothing, a phone charging shop, and what is essentially a small scale utility company.  His car battery (not deep cycle: see Julian’s post) lasts for about four days of phone charging (charging 15 phones a day for 500 shillings or so each) before he pays 3,000 shillings in transport and 1,000 shillings in charging fees to have it recharged.  At night, he turns on a generator from 7 PM until 11 PM, and for 500 shillings a day, he will install a single 12 volt light in someone’s home and use his generator to turn on their light for those four hours.  He currently has four customers for whom he provides this service, and he used to have more but they tried to siphon off more electricity than they paid for by hooking up phone chargers and other devices to the lines he ran into their homes.  For those who did this, and those who failed to pay bills on time, Alex cut them off and his customers have dwindled to these remaining four.  That’s still a 60,000 shilling income each month, and he’s the only person in town who provides this service.

The last thing Alex offers is a screening of 1-2 movies each night to people who may a humble fee to watch. He also runs this mini theater from this generator.

Julian and I imagine a million opportunities in this shop that Alex owns.  First and foremost, he already passes a portion of his profits onto the Lwemodde Youth Group as part of being a member, so the group is well prepared to work with him.  Secondly, the marginal benefit of installing a panel where there is no grid access is larger, and for a town in need of a simple utilities company (someone to power a few lights in their homes), solar power can be a safe, inexpensive and environmentally friendly option.  In fact, in considering options for dealing with people who try and steal extra power from the company, we are hoping that a simple system of master fuses will do the trick.  People wishing to gain access to power “get” their first fuse free, meaning that Alex could install their lights for free, with a fuse in his shop that is rated for the maximum ampage they can draw with those lights.  If their fuse is blown by attempting to draw more current for more electric purposes, then to re-enter the service they must pay for a new fuse.  This eliminates the complete loss of customers with electricity theft without putting a cost of regulation on Alex and others working in the shop.

Lastly, if this branch reaches the point that we’re considering installing computers and internet access, it will give a huge number of people a service that would be at least fifteen or twenty years off if reliance for power was placed on the grid.   

The way that Alex’s roof is configured as well is much preferable to the Lwemodde roof as well for solar panels.  It’s higher and has no nearby roofs tall enough to risk casting a shadow, and the roof appears from rough glances to be at a good angle for a panel on it to track the sun.  There is even a solar panel mounted on the roof already, belonging to a man who lives about 100 meters away but in a temporary shelter that can’t support a panel.

Bouncing Ideas on Reflection

There are many features in our solar node which are designed to conserve every millivolt and milliampere from the solar panel. This is something which Julian Ilett, designer of our solar charge controller, has incorporated into the PWM5. For example the diode he uses to ensure current is not going towards the solar panel is a Schottky diode. As I understand this diode is not pure semi-conductor but also has some metal incorporated somehow. The purpose of this is to have a lower forward voltage than a normal diode. The Schottky diode has a forward voltage of approximately 0.3 V. Not the usual 0.7-0.8 V. This means at peak solar panel output of 5 A we only lose 1.5 W, not 3.75 W. Great!

Somethings we have done to minimise power loss is have our measuring circuits only engage upon pushing a push switch and having enough control to turn on and off the loads even if all they do, when not used, is power a single LED.

Recently we have had another idea which may be of benefit to our maximization of solar output. We know quite well now that the angle of the solar panel towards the sun makes a large difference. We had an entire less about this with the youth center. If you have the panel perpendicular to the sun's rays then you will have maximum current from the panel and the more angled the more that output drops off. (Of course, due to the photoelectric effect, the impact of angle on the voltage of the panel is not really observable.)

Now we cannot pivot the panel multiple times throughout the day. A mechanism which would be strong enough to do this and still be secure from theft seems very ambitious especially on a thin tin roof. But we are thinking of doing something else. Instead of moving the solar panel we could move some lighter mirror in the morning and afternoon which would reflect light onto the panel. In the morning you raise one mirror to capture and direct the sunlight when it is quite low. Around 11 am you would lower this mirror, wait until 2 pm and then raise another mirror on the opposite side. This would require moving 2 ropes to be moved per day and since there are people always at the center this is a very minor piece of work.

We tested what a single mirror would give us if perfectly directed for the solar panel at around 4:30 pm.

Junior sets up.

Junior focuses the mirror to be exactly on the solar panel.

Checking the current output increase.

From this testing we got a rough 800 mA increase from that mirror. The mirror is not the full width of the panel and it is a bit dirty but this was a notable increase. The main issue to a flat mirror however is that it is perfect for only a very short time during the day. After that time the mirror's reflected light will spread over the panel unless redirected.

We are thinking of creating a very light curved mirror from aluminimum foil. This will not be as reflective as a mirror but with a large surface area and curved surface we may get up to an amp. Luckily we have a way to easily test curved shapes.

We have not done the actual mathematical derivation yet but we have tested arbitrary curves so far using a piece of software called GeoGebra. This is a terrible name for a piece of software and it is essentially a more annoying version of Geometer's Sketchpad, but its free! So this software allows you to define lines which are tangent to surfaces or points which are the reflection of other points about lines etc.

We take the sun's rays to be parallel to each other and not radiating from a point since the sun is so far away and then we just construct all the necessary lines from first principles. We can then move certain points, still keeping the integrity of all of the lines, so that we can test different mirror angles, sun positions etc.

Screen shot from our GeoGebra model. The curve through B represents the reflective surface  and the sun is opposite.

We still have plenty of practical and theoretical testing to do before we begin even thinking of constructing a real mechanism. Hopefully this will be worth the effort.

Shortsightedness

Today we visited another fishing community. This one is not on the grid so we are most interested about putting solar panels here. This town is called Malembo and Lydia is going to write a post about it but I will write a short note about a parable that Junior told us.

When we visited Malembo we went to a phone charging station run by one man, Alex Mukiga, who was running a number of shops simultaneously. He had been working there for 1 year and actually used to live in Lwemodde where we work now. He told us that it took him only 9 months to take a new battery to completely useless with all the charging and discharging. Every 4 days he has to do go to Kalisizo (1 hour of Bodda/motorcycle riding) to get to his battery charged. Over the four days he charges 15-20 phones and provides lighting to 4 shops from 7 pm to 11 pm. His battery is a 50 AH battery.

It was obvious why his battery only lasted 9 months. It is a car battery, not a deep-cycle battery. He bought this new for 165,000 shillings which is roughly, $66 USD. I reminded Junior about the talk we had on deep-cycle batteries and how a car battery is not designed for full charge and discharge. It has thin lead plates designed for giving large bursts of current. The deep-cycle has thinker lead plates and some other minor differences which make them very good at going through phases of full charge and discharge. That 165,000 shillings should have been invested in a deep-cycle battery.

Junior's answer to this was very simple. "Here in Uganda,"  as he typically says, "people don't look too deeply into things." He went on to explain that because car batteries would have been used in the dawn of mobile power sources and are known for powering 12 V systems it is very unlikely that people would get something that looks different. A deep-cycle looks very similar to a car battery but they are usually sealed which means you don't see the very distinctive cell valves which you do on vehicle batteries. Junior said that people would see a deep-cycle in a shop, not know that it was better and then get a vehicle battery because it is what they have always been using. 

This makes complete sense. This is why we put a chapter in the manual about batteries so that hopefully this simple but valuable knowledge can spread. We are looking into buying some deep-cycles soon because both this new site will need one but Lwemodde also needs one since both its vehicle batteries are pretty dead. In fact, the voltage measuring circuit we built to test the state-of-charge of a battery doesn't show any sign of life since the voltage on the battery is lower than the bottom threshold of the measuring range. Today we measured their battery to be between 8-9 volts.

Our Translator, Julie!

Julie Nabiryo has been a prime discovery in our efforts to get the manual translated.  Julian and I actually met her on the first day we were in Kalisizo when we bought Cokes from her mom’s shop, but it was just this past week when we realized that (a) her English is great (b) she’s only in Kalisizo for a few months before she starts at Makere University in the fall and (c) she’s planning on studying Electrical Engineering and has completed A levels in physics, biology and chemistry.  A.K.A.: she’s perfect to translate our manual for us. 

Over the weekend, we left Julie with one page of the manual, a very unedited version of page 3.  We were planning on printing out a longer chunk of a more recent version, but at the moment we reached the printers the power went out and we had to settle for a page that I had been taking notes on while we were teaching circuitry.  We took the translation to the youth center during work today, and it was kind of confusing what they felt about it.  It was clear that Julie translated incredibly intelligently, and had the appropriate way to designate things that aren’t in a Lugandan vocab (i.e.: photon, electron, etc.), and in fact the versions were basically identical translations of each other.

The complaint that the youth had was that the Lugandan version was more confusing and that it seemed pointless to have a version like that.  However, I think ultimately their point was that it was confusing to just get the Lugandan version and start reading, that it should be coupled with someone who knows what is going on to explain it.  To them, that person is us, so you need a translator anyways to explain it.  But several of them have said they would like copies to be able to read and remember all of the material (because there is a lot to remember!) outside of the classes, and only two members really read English.  Also, once they start teaching others themselves, then it will most likely be incredibly helpful to teach a class from a manual in that language.  Ultimately the point we ended on was that the translation should be provided, as well as an English copy.  Which is what we were planning on anyways.

The first person we asked about translation had been Anita, the program director for the Foundation for Sustainable Development interns in Masaka, and she said the translator that she knew charged 15,000 shillings ($6 USD) per page.  Our book is currently 30 pages, but with about fifty percent of those pages being diagrams and pictures.  Julie is translating this section (which follows basic electronics through the node and its construction) for 150,000 shillings ($60 USD) and based on the length of the second section (which will address the specifics of establishing an internet/computer café) we’ll probably add on top of that, maybe 50,000 shillings or so ($20 USD).