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Lindsay Brooke

23.03.2018, Lindsay Brooke

Who wants Afreecar?

One billion people globally survive on less than $2/day but desperately need personal mobility and electric power. One of the auto industry’s most creative minds offers what could be a unique and sustainable solution.


Game-changing ideas come to engineers in countless places and circumstances. For Dr. Chris Borroni-Bird, it was in a tiny village in Mali. The year was 2009, and Dr. Borroni-Bird, then director of GM’s EN-V program for the 2010 Shanghai World Expo, was on a typical vacation: working on clean-power and clean-cooking initiatives in sub-Saharan Africa.

“I noticed some solar panels donated by BP which were being used by the village’s resident entrepreneur to charge lead-acid batteries, the type used in cars,” he recalled. “The guy would then lease the fully-charged batteries out to villagers who needed electricity.”

During his ten days working in the village, Dr. Borroni-Bird witnessed three use cases for the batteries. One provided cheap LED lighting, enabling the local work day to be extended without using kerosene lamps. Another battery application was for grinding corn. A third use was to pump water from deep in the ground; the village’s fetid-gray well water was undrinkable.

Another piece of the idea came while Dr. Borroni-Bird was walking 10 miles to the next village—a typical trip for millions who cannot afford powered vehicles. “Then it hit me—what might work here is a simple and cheap battery-powered vehicle that could be charged with solar panels, which are increasingly inexpensive. Such a vehicle could provide both transport and elec-tric power to Africa’s poor. Transport, no matter how humble, enables economic development,” he said.


Personal mobility, mobile power

The incumbent means of personal mobility in sub-Saharan Africa are costly and inefficient. Walking is limited to distances of under 10 miles and a payload of about 10 kg. Oxen and other typical beasts of burden have greater capacity but can cost $200—and require food. Small motorcycles offer greater range and payload capability but can cost $2,000 to purchase and require regular fueling. So what sort of ‘new’ vehicle would work best?

A small electric 3- or 4-wheeled ‘golf cart’ might be too large, heavy and costly, he calculated. And it might lack the 5-to-10 miles (8 to 16 km) range needed for a typical rural African duty cycle. But a small, lightweight trailer coupled to a bicycle, would combine the rider’s pedal power with a battery and electric motor. This ‘e-trailer’ would have a roof covered with solar panels to charge the battery. The battery would power a small electric motor which would in turn drive the trailer wheels through a chain and sprockets.

The 3 kW·h of energy that 100 kg (220 lb) of lead-acid batteries can store on a solar-powered electric trailer can deliver a minimum 30 km (almost 19 mi) daily range to allow inter-village travel, Dr. Borroni-Bird calculates. He realizes that heavy lead-acid batteries will be most widely available and affordable until secondary use of lithi-um battery pack modules from EVs become a viable approach.

The solar e-trailer could be built from a kit that utilizes some ‘repur-posed’ items—bicycle or scooter wheels, for example—and locally-harvested materials for the frame, axle and roof that supports the small solar-cell array. It would provide supplemental motive power to the bike rider when traveling up hills, and serve as a mobile elec-tric-power unit for charging phones, pumping water, milling grain, running small refrigerators—and hauling.

During Africa’s planting season, people can’t easily access fertilizer. Villagers often walk up to 15 miles (24 km) per day to buy a 50-kg (110-lb) bag of fertilizer and carry it back home.

“Entrepreneurs with the bike-trailer system which I’ve dubbed ‘Afreecar’—a play on the word Africa— could ride to the distribution center, pick up three bags of fertilizer,” he envisioned. “They’d haul it back to their villages and get paid by the farmers. More food could thus be grown and it could be transported to market much, much easier.”

Researchers at the University of Michigan who did early work with Dr. Borroni-Bird have modeled a typical rural-Africa duty cycle in which bike-and-solar-trailer rigs could deliver reasonable 50-100-mile (80-160 km) daily operation. He sees similar multi-use opportunities for the mobile power system in the cities of Africa and those of other continents.

With support from the university and automotive prototype special-ists Pratt & Miller, he helped finance a proof-of-concept trailer devel-oped and built by Pratt & Miller, as shown in the photo above. But a mar-ketable unit needs to be lighter, less costly and more robust.


Locally sourced components

To achieve favorable economics that stimulate local manufacture, the solar e-trailer solution must be very low cost and robust to generate profit. When integrated with a cellphone, which are ubiquitous in Africa, the Afreecar concept becomes “a low-cost, locally made ‘hub’ that can transform lives and create a vibrant manufacturing and ser-vice economy,” he said.

The vehicle or hub might be owned and operated by the same company that makes or distributes it, or by an entrepreneur who buys or leases the vehicle from the company. In either case, the operator generates revenue by providing mobility, electric power and wireless communications - and perhaps by monetizing data gener-ated by the service.

“The cell phone is an important tool in the solar e-trailer concept,” Dr. Borroni-Bird explained. “Besides providing direct operator communica-tions, the phone’s GPS map would provide route information, battery monitoring, and even inform the rider of the optimum angle to set the solar-panel roof in relation to the sun at any given time of day. It could offer predictive maintenance and data analytics.”

Readers who admire Dr. Borroni-Bird’s idea will ask, “What’s to keep this idea from being co-opted by oth-ers?” He concedes that “there is no competitive advantage in the hardware—it has to become a com-modity if the vision is to be realized.”

More detailed analysis and planning is required for creating a sustainable business model. “Local communities around the world could take the standardized elec-trical kit, produced in scale perhaps in Taiwan or China, and provided by company or foundation for integration into whatever version of the vehicle is developed locally. Let those communities figure that out, using a reference design and specifications,” he said.

Dr. Borroni-Bird also believes “it would be a good idea to provide complete vehicles, but the foundation is the elec-tric system. Some [local operators] may make the solar trailer for bikes; others may cut up a motorbike and make a 3-wheeler or golf cart,” he surmised.

Versions of the solar e-trailer for developed markets might also include a low speed autonomy kit, such as for MIT Media Lab’s Persuasive Electric Vehicle.

What are the next steps? Dr. Borroni-Bird now has a half-time appointment at MIT Media Lab in the City Science Group, directed by Kent Larson.

At MIT, Chris is keen to study community needs and to develop a rugged “solar e-trailer” prototype that pulls all these ideas together. He hopes to secure sup-port to build the electric kit consisting of the battery, motor, controller and solar panel.

Those interested in collaborating can contact Dr. Borroni-Bird at MIT Media Lab.


Lindsay Brooke is Editor in Chief, Automotive Engineering International (SAE International).


Source: SAE’s Automotive Engineering magazine