Green up: Microgeneration with a big payoff

June 16th, 2009 Print Print Email Email

This month, we take a look at alternative energy on a much different scale, embarking on a journey to change lives for the better. (more…)

This month, we take a look at alternative energy on a much different scale, embarking on a journey to change lives for the better.

Let me paint a picture of a life that is hard for most of us to imagine. There’s a place where the land is so dry, water is trucked in and people stand in line for hours and hours waiting to fill a 5 gallon can day after day after day. Electricity is only available one out of every five days. School work is done by candlelight, when the children aren’t dodging hyenas. Medical and dental care is rudimentary at best, given the lack of electricity and water.

The place I’m describing is Ethiopia. I’m lucky enough to be involved with a nonprofit organization, Hope Arising, that is trying to change this state of affairs by assisting vulnerable children and their caregivers in the region.

One of the pressing problems faced in most of Ethiopia is electricity. Electricity drives today’s global economy; without it, even simple things like reading and caring for the ill are difficult to accomplish in less-developed countries. Alternative energy sources such as solar panels are relatively expensive to install and maintain, and there is also the challenge of needing to create jobs in the local community.

A start-up company called Pedal Power Generators, LLC (PPG) is working with Hope Arising to create human-powered charging stations that can inexpensively create jobs and power. The concept is simple – a bike can easily power a small motor (motors running backward are generators, after all) and charge a power pack, which can then supply AC or DC power for several hours (see Figure 1). PPG has done things such as cell phone-charging kiosks at events in the United States, and offers plans and components for purchase via its website.

Brad Whaley of PPG recently gave us a demonstration of the device. There are three key components: a patent-pending mounting structure that supports the motor driven by an adjustable v-belt from the rear wheel of a stationary-mounted bike, a charge controller that limits the transfer to the powerpack so superhumans can’t provide more energy than the powerpack can take, and the powerpack itself.

Brad said there are two major challenges for a motor in these units: mounting and cooling. While almost any motor will do – he mentioned that windshield wiper motors scavenged from vehicles could do the job – there are considerations of cost, reliability, and efficiency. He has located what he hopes is a low-cost motor (pictured in Figure 2, target price $19 in volume) that mounts securely, but needs a bit of modification to cool effectively during operation. It takes anywhere from 2 to 4 hours of pedaling to fully charge a 28 Ah powerpack, which we’ll talk more about shortly. His team is working on holes and fins to keep the motors cool during extended operation, and is hoping they can use these models since the cost is so low.

The charge controller PPG is using is the NC25A, available in 12 V and 24 V models from SES Flexcharge, based in Charlevoix, Michigan. The company claims that the unit has 99.5 percent charging efficiency, and it provides features such as charge divert and an advanced charging algorithm to handle a variety of battery technologies, including deep-cycle batteries.

Figure 3: SES Flexcharge NC25A

The powerpack can vary, but one of the units PPG works with is the Duracell Powerpack 600 designed and built by Xantrex Technology Inc., based in Burnaby, British Columbia, Canada. These units contain absorbed glass mat batteries, which provide advantages in that they don’t spill if ruptured, they can be shipped as nonhazardous material, and they don’t freeze in most conditions. The Powerpack 600 supplies either 12 VDC output or 120 VAC via an internal 600 W inverter, and the total package weighs just 32 lbs.

Figure 4: Xantrex Technology Duracell Powerpack 600

This idea creates several interesting possibilities. Creative Ethiopian entrepreneurs could produce units from locally available components, and villagers could provide labor to supply the pedaling energy. Charging stations could be permanently located in medical or dental facilities to provide on-demand power as needed for lighting or tools. Or, in a more demand-driven setting, consumers could pay to have their powerpacks charged and take them back to their homes for a variety of uses.

In a part of the world where jobs are scarce and AC power doesn’t automatically emanate from the plug on the wall when it’s needed, this idea combines technology and innovation into something truly green – microgeneration.

[Editor’s note: If you’d like to learn more about Hope Arising, Pedal Power Generators, or the components described, just follow the links we’ve provided.]

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