Modified diesel engines power electrical grids and tools in Uganda

Engineers from Columbia University are working with communities in Uganda to install Lister diesel engines like this one. Photo credit: Alison Ferris

Rain has invigorated cassava crops (and mosquitoes) this year in the Teso region of northern Uganda. The fields are greener, but the weather hasn’t erased the memory of last year's drought, or the threat of hunger to come. Fortunately, student engineers from the prestigious Makerere University in Kampala and Columbia University are developing a tool that could help irrigate crops and perform a variety of other tasks.

Last year, the Columbia's student chapter of Engineers Without Borders helped install two engines for local cooperatives. The versatile engines power attachments for chores that currently include grain milling and electricity generation. The list is growing, however, as designers develop new attachments. In the queue: water pumps for crop irrigation.

The Swiss Army knife of machines
The engines are called Multifunction Platforms (abbreviated as MFP). Their name is clunkier than the noise they make – they are quiet, 6 hp, 750-lb. stationary, Listeroid diesel engines. These engines are durable, easily maintained, and proven – the design dates to the 1920’s. They have a main rotating shaft connected to a flywheel. A pulley system links them to their attachments. The attachments could be anything that rotates, and the engine can drive two attachments at once.

The setup in Uganda costs nearly $9,000 for each engine and attachments, plus $3,350 to train people to use them. Pilgrim, the NGO that established the cooperatives, offers eight-week training programs that meet twice weekly in the evenings.

Pilgrim plans to install as many as 50 machines throughout the region. The first two were donated, part of the EWB program, and the others may be, also. To pay for the rest, Pilgrim is looking at other options, such as loaning the cooperatives the start-up cost and collecting gradual repayment.

This is a multi-function platform engine with a mill and an electricity generator attached. Photo by Alison Ferris

Vegetables, not fossils
A design tweak makes the engines sustainable without the need to import fuel: they can run on vegetable oil. Matthew Basinger, a post-grad at Columbia, developed the trick. The factory-issue engines are fitted with a steel plug next to the combustion chamber. Basinger took a drill to it to allow vegetable oil to circulate through.

Now, with modified plugs, heat from the combustion chamber warms the vegetable oil, reducing its viscosity so it does not clog the injector. Basinger tested his design to make sure that Ugandans could manufacture the plugs.

The problem is where to get the oil. To avoid using food crops as fuel, Pilgrim urges its cooperatives to plant hedges of jatropha. Jatropha is hardy plant that grows throughout Uganda. Its seeds are inedible with a high oil content. With the right attachment, the MFPs themselves can press it into oil.

Putting them to work
Micro economies have sprung up around the engines in Teso. Cooperatives mill corn for consumption and sale. People from neighboring villages bring raw goods to the MFP mills and pay a fee to the cooperatives to process them.

The engines charge 12-volt batteries and energize micro-grid electrical connections. Light bulbs flickered on this summer for the first time in homes that only knew candlelight before.

A crash course in electrical wiring
The Columbia engineers worked with Calvin Esabu, an electrician from the Ugandan city of Soroti, to hook up the electrical generators and lay the grid. The students had trained in electrical work before leaving New York, but Esabu gave them some hands-on instruction in his trade.

One lesson was the grounding rod. To install it, Alison Ferris, a Columbia engineer, helped Esabu dig a three-foot pit in the ground. Then they hammered in a rod connected to a copper wire and poured a layer of coal dust into the hole to improve electrical conductivity. They emptied four jerrycans of water into the pit, waited for it to drain off, then filled the pit with coal and soil.

That was the start of a two-week apprenticeship in practical rural village wiring. “We dug trenches for the copper grounding wire, we helped chisel bricks to allow for the wiring conduit, we nailed and cemented the conduit in place, we clipped wiring to the beams and walls in the MFP structures, we put in switches, circuit breaker boxes, outlets, and light sockets. All done without power tools,” Ferris wrote E4C in an email.

Evram Dawd and Alex Lopez pour coal into a pit dug to bury the grounding rod for the electrical system. (Photo by Alison Ferris)

Lessons learned
The Columbia engineers took stock of the program this year and rediscovered the adage about location and a successful business. MFP mills need to strike a geographic balance. They can’t be too close to competing mills or too far from the communities that would use them.

The Columbia team also discovered that each cooperative should develop its own management strategy, rather than try to adopt a one-size-fits all plan.

On the drawing board
Students at Columbia and Makerere plan to collaborate on new attachment designs. Besides a water pump, some of the projects in the pipeline include mill improvements, better 12-volt lead-acid battery chargers, a biodiesel reactor and a better mechanism for switching between attachments. Both teams plan to compare and contrast their ideas throughout the next year.

For more information

The EWB team members wrote blog entries on their chapter’s web site. Check their site’s main page for updates and general information. Pilgrim posts updates on its site. The organization also accepts donations (click the "Give" button in the upper right corner of the main page).

We posted more photos of the MFP project in our Flickr photostream.