DC-only Solar PV Deployment at Haitian School to Charge 500 Laptops

Laura Hosman
August 18, 2011 | 6 Comments

On roof

In a whirlwind eight-day trip to Lascahobas, Haiti, following nearly a year's worth of planning, designing and hard work, a partnered team from IIT, Green WiFi, and OLPC-Haiti successfully carried out their first solar powering deployment on August 3-11, 2011. They provided the EFACAP school in Lascahobas with the capability to charge 500 One Laptop Per Child (OLPC) XO laptops with a direct current (DC)-only solar system. According to research by the team and OLPC, the installation is the largest single-school solar laptop-charging deployment in the world.

The DC-only solar powering solution simplifies the system, increases efficiency, and saves on costs. Since solar panels generate DC power and laptops charge with DC power, avoiding the unnecessary conversion saves about 30 percent of energy normally lost in the DC-AC-DC conversion process,. It also saves on the cost of a converter, and helps prevent repurposing of electricity generated, ensuring that the energy is used for its intended purpose — charging the laptops.

The team consisted of Prof. Laura Hosman from Illinois Institute of Technology, Bruce Baikie from Green Wifi, seven students from IIT (Dhara Shah, Jacob Ernst, Mario Berrones, Regine Antenor, Ryan Tillman, Simon Brauer, & Stevie Brummer), Fabrice Urrizalqui from the French-American School in San Francisco, and Guy Serge Pompilus, Director of OLPC-Haiti. Adam Holt from OLPC HQ, Carl Friedrich Lacrete, an engineering student at the State University of Haiti, and four members of the NGO Haiti Outreach joined the team on-site to execute the deployment.

team working

The IIT-based team, with Baikie’s assistance, has worked since August 2010 on the design, drawings, fundraising, lesson plans, and all the various parts of the project. Starting in January 2011, they raised $27,000 to buy all of the equipment and make the travel and deployment possible. The flexibility and replicability of their design was put to the test in multiple ways, as the team improvised and overcame a last-minute change in the school receiving the deployment, a customs problem with some equipment, and the threat of a tropical storm.

training staff The team also set up a new library at the school, filled with books in French and Creole, and created an inventory, catalog and system for checking out the books. The team also talked with the teachers at the school about using the library, about lesson plans on solar power that the team will continue to develop over the coming semester, and carried out a baseline survey on electricity, technology, and laptop usage in the home and classrooms. The team also provided training to the local maintenance staff in solar system upkeep.

The team hopes to make another trip to Haiti in just four months to complete a second installation at a school in the Lascahobas area and return to the EFACAP school with improvements and a system check-up. This group’s work to bring solar solutions to Haiti is entirely reliant on the generosity of donors who have contributed to funding their project.

The information and views expressed in this blog post are solely those of the author and not necessarily those of RenewableEnergyWorld.com or the companies that advertise on this Web site and other publications. This blog was posted directly by the author and was not reviewed for accuracy, spelling or grammar.

6 Comments

Stan. SWAN
August 24, 2011

Orangehouse: An interesting project indeed. Since that time (assumed 2006?)solar PV cost have fallen, fuel costs have risen and LEDs have become brighter AND cheaper. Off grid solar lighting projects hence have become even more viable.

FWIW observers have noted LED developments tend to follow the so called "Haitz's Law" (a LED equivalent of Moores Law) -see =>http://en.wikipedia.org/wiki/Haitz%27s_Law.

Brian Thomas
August 23, 2011

Interesting work. I worked on a simlar 12V system in Kenya once using white LED lights. Here is a paper I wrote about it, if you are interested: http://library.queensu.ca/ojs/index.php/ijsle/article/view/2089/2189

Also, I recently wrote about a biogas/biomas system I toured in Honduras. It was fascinating: http://lifeobservationsfromorangehouse.blogspot.com/2011/08/african-palm-trees-real-power-plant.html

Stan. SWAN
August 23, 2011

Aircon. is a power hog, so forget it in such skinflint setups. But-argh-you mean there's now NO ELECTRIC LIGHTING in the classrooms?! Surely this is a TOP priority, especially given the wonderful efficiency of today's LED systems! I consider suitable lighting essential in education, especially in the tropics where building interiors are often very dark. The ability to use the rooms after sunset will also then be beneficial.

FWIW,for just a few hundred $US,high efficiency pure sine wave inverters (running off perhaps a couple of 12 V automotive batteries)could provide mains voltages for conveniently powering low drain devices. There's always a demand for running printers, small TVs and (yes!) cell phones in schools. If the grid has failed for the school then it's probably down for neighvours as well,& such a charging availability could be a welcome community service- especially at weekends.

I repeat that heavy duty copper cabling is valuable,& hence may be stolen.This alone is often reason enough to use an inverter - "silicon is cheaper than copper".

Bruce Baikie
August 23, 2011

For this project, the grid electric network has failed and recharging the "existing" laptops became impossible. To keep system cost affordable (no expensive inverters) and to prevent energy diversion (plugging in any AC powered device), the system was designed DC only. The focused project goal was to recharge laptops only, not lighting, cell phone charging, air conditioning, etc. Since laptops run on DC why convert from DC to AC then convert from AC to DC again? So this was a very purpose built solution, not a general school electrification project. The laptops are charged in one room then taken to the class rooms each day and returned for charging. Keeping the solution DC reduced project costs and kept the system straight forward and simple.

Stan. SWAN
August 23, 2011

Electrotech 101-let's not forget the voltage drops that'll curse low voltage DC supplies unless thick & costly copper wiring is used! This naturally was a major reason behind the adoption of AC back in the 1890s. Higher voltages mean lower currents & thus less line loss for the same power. Given the high global cost of copper,thinner supply wires are often being used, and even a few 10s of metres/yards at 12V may suffer significant losses.

Silicon is often now cheaper than copper - & less likely to be stolen! Sine wave inverters are highly efficient & increasingly cost effective. In such applications it's often better to invert to mains voltage very early on.

IMHO using PV energy just to charge laptops is very short sighted, especially given the usually more pressing need to run LED night lighting & charge cell phones. The rapid rise of smart phones means today's laptops may soon be quaint items as well!

Anumakonda Jagadeesh
August 20, 2011

DC-only Solar PV to power Laptops in Haiti - very interesting. Yes. DC PV can be a boon in developing countries.

Dr.A.jagadeesh Nellore(AP),India
Wind Energy Expert
E-mail: anumakonda.jagadeesh@gmail.com

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Laura Hosman

Laura Hosman is Assistant Professor of Political Science in the Department of Social Sciences at Illinois Institute of Technology. Prior to IIT, Professor Hosman held postdoctoral research fellow positions at the University of California,...