Portable Power Stations Go On Trial in Rural Nicaragua

IEEE humanitarian group installs two units

19 August 2011

A medical clinic and a group that treats HIV patients, both in remote parts of Nicaragua, each now have a source of reliable electricity and other services, thanks to portable stations designed by IEEE volunteers. Powered primarily by photovoltaic panels, the stations include a refrigerator, a ceiling fan, a cellphone charger, an AM/FM radio, three powerful lighting zones, and an optional electric water pump. The stations also include data-gathering technology to track performance, environmental conditions, and user behavior.

The stations are the first of five proof-of-concept deployments of small power sources built by members of the Reliable Electricity team that evolved out of the three-year IEEE Humanitarian Technology Challenge. Earlier this year, the IEEE Community Solutions Initiatives group, part of the HTC, delivered solar photovoltaic power stations to Haiti as sources of reliable electricity for entire villages.

The HTC, launched in 2008, asked IEEE members and others to work on three technical problems facing poor countries: providing reliable sources of electricity, electronically identifying patients and storing their health records, and developing a data-transmission system for exchanging health information between remote and central medical offices.

The Nicaraguan electric power stations were installed in May at two sites, one run by Catholic missionaries in Waslala, and the other on a remote farm in San Juan Yaro run by volunteers who treat villagers infected with HIV. The units, composed of two large photovoltaic panels, a control module, and a collection of peripherals, were delivered to the farm on horseback.

“We identified problems that we thought we could alleviate with electrical energy, such as providing clean water, lighting, maybe a little bit of cooling, and food preservation,” says Butch Shadwell, who chairs the Reliable Electricity team. “We decided to design a system for rural clinics that have no electrical service of any kind. Doctors there typically end up operating on patients by candlelight or by light from oil lamps.”

The Reliable Electricity team includes Shadwell, a senior IEEE member; Graduate Student Member David Williams, Shadwell’s nephew; Senior Member Pritpal Singh, and Singh’s students from Villanova University, in Pennsylvania. Shadwell is the principal of Shadwell Technical Services, which provides consulting in applied physics and electronics, in Jacksonville, Fla. Singh, chair of Villanova’s electrical engineering department, volunteered the university’s lab space to develop, design, and build the units.

Singh and Villanova have been working on humanitarian projects in Nicaragua for several years, so it was the logical place for them to deploy their prototypes. Funding is being provided by the IEEE New Initiative Committee. Each station cost about US $2000 to build. Shadwell expects to deploy the three remaining stations to medical clinics in sub-Saharan Africa and other parts of the world by the end of the year. 

human_2 PHOTO: Butch Shadwell


Each station can deliver up to 270 watts at 24 volts buffered by two 70-ampere-hour batteries, which are charged by current from the photovoltaic panels. Keyed connectors send current to as many as five external loads at a time, each one rated for 4 amperes of continuous power and a peak of 8A. Optional loads include a ceiling fan, a 1.8-cubic-foot refrigerator, and a 7-gallon-per-minute water pump. There’s also an AM/FM radio and a 12V-switching regulator for charging cellphones, which Shadwell says have become “ubiquitous” in rural areas.

Among the external loads are three LED fixtures, each providing about 650 lumens. “That’s quite a bit of light—enough to use during an operation,” Shadwell says.

Anticipating that users might be illiterate, and perhaps have never seen LEDS/a light bulb or photovoltaic panels, the designers made putting the system together intuitively obvious, Shadwell says. It is intended that someone with no instructions can assemble the system without damaging anything and have it produce useful energy. To that end, most system functions are automated; when user actions are required, instructions are given by pictograms. For example, when the panels need cleaning, a pictogram of someone cleaning the panels is illuminated.


To be in a position to improve their design, the team decided it had to gather data from the systems to understand how they were being used. 

“We included services in this first design that we thought would be appropriate for the sites in Nicaragua,” says Shadwell, who explains that the team’s information on what was needed came second- and third-hand from representatives of nongovernmental organizations. “We included data-gathering technology so we could learn more from the actual users about their needs.”

Shadwell designed load-management boards inside the control systems that include data logging. The system records when loads are turned on and off, which loads are used most frequently, and how much current each device draws. The device tracks the efficiency of the photovoltaics and how much energy they generate at any time. Information about weather in the area is logged as well. All the data is stored in a nonvolatile memory chip and can be downloaded to a computer with a USB port. Carlos Ruiz, a student at the National Engineering University of Managua, and individuals from the places where the stations are installed, periodically collect the information and e-mail it to Shadwell and Singh.

The system monitors all the loads and internal functions continuously. If it detects that something is malfunctioning, it can disconnect it automatically. If anything short-circuits, redundant circuit protection detects the short and resets the system after the short is cleared.

“One of the reasons we did so much design work is that this type of technology—load management and data logging—would normally pull a lot of current and reduce the useful load capacity of the batteries,” he says. “To extend the life, we designed the technology so it would have the least possible load on the battery’s capacity.”


Eventually, the intellectual property associated with the projects being developed as part of the HTC will be given to commercial entities to build and sell to NGOs who can introduce them to user communities, Shadwell says, adding that the portable power stations would be ideal for groups that respond to earthquakes, tsunamis, and other natural disasters.

“They might have to quickly set up a medical clinic in a remote place, so they could take our system and immediately provide essential services,” he says.

“IEEE might license the intellectual property but not charge for it,” he continues. “Any agreements should include caveats that ensure the project ultimately be used for humanitarian purposes.”

Check out pictures of the Nicaragua installations on Facebook. To learn more about the stations, e-mail Shadwell.

If you would like to get involved in a humanitarian project, check out the Engineering for Change project a partnership among IEEE, the American Society of Mechanical Engineers and Engineers Without Borders-USA. The partnership is charged with developing technical, locally appropriate, and sustainable solutions to humanitarian challenges.

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