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Publication Date: 09/1/2010
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Solar Energy Powers Remote African School
Orkeeswa School students with solar panels for new 1,080-watt solar energy system to power their classrooms, staff offices, and newly constructed science lab.
Lashaine, Northern Tanzania — It's an ongoing project, bringing the benefits of today's technology to a school in this remote village. The prime movers behind it are Engineers Without Borders Portland Professionals Chapter (EWB), and they traveled to Lashaine Village, Tanzania in June to oversee the expansion of a rainwater harvesting system and the installation of an expanded solar energy system at Orkeeswa Secondary School. The school was built and is operated by the Indigenous Education Foundation of Tanzania (IEFT). Addition of a second water tank and expansion of the energy system ensures there will be sufficient resources at the site to accommodate the growing student population.

"It was great to see how all of our efforts over the past year have come to fruition," said Brad Ostapkowicz, EWB travel team member. "You gain a lot of perspective when you are in direct contact with the students who the EWB's projects are helping. It also gives us incentive to keep working through the coming year; knowing the students will be progressing in their studies, in part, due to the sustainable sources of water and electricity we helped to provide." The 60,000 liter rainwater harvesting system, installed by EWB last year, was increased with the addition of another 60,000 liter ferrocement tank. The tanks will soon be supplemented with a bio sand filter to treat collected rain water, and a pipeline to deliver water directly to the school's kitchen.

Maximizing Solar Power
EWB partnered with Chloride Exide, Ltd. to expand the 160-Watt solar power system that Chloride Exide had donated the year before. The school now has a new 1,080-watt solar energy system to power classrooms, staff offices, and a newly constructed science lab. There is now enough energy available to power the entire school, as well as the future library and computer lab. Orkeeswa students are also anxiously awaiting the arrival of new energy efficient computers that they will be able to use on a daily basis.

The design included an assessment of the power needs of the school for both the current number of students and the planned future expansion. This particular project had the good fortune to start with a substantial budget that included a generous grant from Boeing. Because of the school's equatorial location, Orkeeswa Secondary School enjoys a fairly consistent length of daylight throughout the year. Seasonal weather changes are what impacts the number of hours of sun, as dark rain clouds block the sun mostly during the months of May through August. The peak sun hours (PSH) vary from 6.5 during the dry season to just above 4.0 PSH during the wet season. Data for insolation — a measure of the solar radiation per unit area available for transformation into energy — was obtained from an online NASA database.

Peak Sun Hours
An annual average of 5 PSH was used in making the analysis. The Boeing grant was used to purchase eight 135-Watt (W) PV panels, ten 200ampere-hours (AH) batteries, a 2024-W inverter and a 60Amp charge controller for this totally off-grid system. The system will supply the school with 2.5 kilowatt-hours per day, even during the rainy season.

The battery bank size was determined so that there could be three days of autonomy — three days with no sun — during which the classrooms would have to conserve power, but would nevertheless be able to use electricity. The battery bank uses ten 12-volt 200 amp-hour flooded lead acid deep cycle batteries wired in series, providing a 24V, 2000 ampere-hour system for the school.

To maximize the amount of usable direct sun, photovoltaic modules are pointed toward the equator and tilted at an angle that matches the latitude. Since the school is located three degrees south of the equator, the panels were mounted at 10 degrees from horizontal to maximize exposure to the sun, while still allowing rain water to run off the panels without ponding. The solar energy system is able to provide sufficient power to light three classroom buildings and staff offices, an energy-efficient computer lab, projectors and other miscellaneous appliances.

Affordable Education
IEFT is dedicated to providing affordable secondary education to underprivileged indigenous children in rural Tanzania. They have made it a priority to create a reliable and sustainable

infrastructure at Orkeeswa School; understanding that students' ability to attend school depends on the availability of a reliable and safe source of potable water and a renewable source of energy. Rainwater is the only source of water available to the Lashaine Village, prior to the installation of the new tanks the school was collecting rainwater in small plastic tanks positioned under the roof downspouts. The volume of the plastic tanks, however, was insufficient to last through the entire dry season and the school was forced to truck in water from neighboring areas, diverting funds from the school's budget.

IEFT opened Orkeeswa Secondary School in April of 2008. The first 40 students that were enrolled in English-immersion classes have nearly completed their Form II (sophomore) courses and 40 more students are added each year, beginning with the English-immersion classes. IEFT plans to expand school facilities and accept additional classes until the school has reached its full projected size in 2013. The Indigenous Education Foundation of Tanzania (IEFT) is a 501(c)3 nonprofit community-collaborative organization that provides quality, affordable secondary education to underserved indigenous children in rural Tanzania. IEFT empowers children to positively transform their lives, improve their communities and break the cycle of extreme poverty, while working to preserve their culture and traditions. Through the development of Orkeeswa Secondary School in Lashaine Village, IEFT provides secondary education to children who have no hope of continuing their education past primary school. The opportunity to receive further education is the key to escaping extreme poverty for students and their families.

"The most amazing part of the trip was driving around the villages, meeting the students' families and seeing their home life," said Ada Banasik, programs coordinator for IEFT and EWB travel team member. "As engineers, we of course enjoy seeing our designs implemented, but the hospitality and warm smiles of the Orkeeswa students, their families and literally thousands of village children that seem to spill out of the bush wherever we show up is unforgettable and makes the countless hours of design work, report writing and fundraising that made this project possible so rewarding."

Contact: The Portland Chapter of Engineers Without Borders-USA (EWB-USA) Web: or Indigenous Education Foundation of Tanzania (IEFT) Web:

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