Free as the wind

By Sean Woods

It’s become fashionable (and perfectly reasonable, in most cases) to castigate Eskom for the occasional failure of our creaky national grid.

Buckling under the ever-increasing demand for electricity, it periodically catapults us into the “dark ages”, prompting pessimists to stock up on canned beans and doomsayers to dust off their worst-case scenarios (the breakdown of society and rampant cannibalism come readily to mind).

But, as Capetonian Peter Becker can attest, there’s a more pro-active option available for those willing to spend some time at their workbenches.

It’s called DIY wind power, and although it’s unlikely to send shockwaves through the power-generating establishment, it could be one of the most satisfying projects you’ll ever tackle.

Fed up with playing victim to the vagaries of grid power, Becker decided to build a modest wind turbine from scratch — and generate his own.

His quest for DIY power began in 2006 when a wayward bolt in the Koeberg nuclear power plant prompted an emergency shutdown of the facility. The consequences were dramatic, to say the least, causing rolling blackouts throughout the Western Cape.

A ‘light bulb’ moment

It was also one of those “light bulb moments” for everyone concerned, showing how easily their lives could be upset — and in some cases, turned upside down — by the simple flick of a switch.

While business leaders cried foul, commuters saw red and householders did their best to save frozen food from spoiling, Becker — along with friend Barry Stott — began searching for solutions to keep Stott’s business afloat (he manufactures customised flight cases for valuable items).

Their first move was to couple an inverter to a car battery. As far as standby power went, it was adequate for Stott’s immediate needs, powering a band saw or drill for a short period — but it was far from perfect.

For starters, the battery still required charging from the mains, and that seemed contrary to everything the two friends were trying to achieve.

Says Becker: “We thought it would be great to be completely independent of Eskom. This was an especially important goal because its power, derived mostly from coal, is extremely dirty and contributes significantly towards global warming.”

As both live in Cape Town, one of the windiest regions of the country, locating a natural resource to charge Stott’s battery was a no-brainer. Solar power wasn’t even considered because of the prohibitive costs involved.

Becker elaborates: “Solar panels are high-tech items priced for first world buyers, and the average guy like us cannot make or fix one. But wind turbines are easy to make from readily available components, and the best thing is, you can teach your buddy how to build one.”

Building a working system

Becker went online in search of answers and was amazed by the size and co-operative nature of the virtual DIY wind turbine community.

He also discovered that the science behind magnetism and the properties of electrons was intimidatingly complex, as were the principles determining the relationship between wind speed, turbine height, generator size and blade diameter (to mention but a few of the relevant issues).

Fortunately, as he says, one doesn’t need an in-depth understanding of the principles involved to construct a perfectly respectable wind turbine. In fact, the strategy adopted by most backyard turbine builders is to aim for a particular output (anything from 250 watts to 500 watts), then rely on old-fashioned trial and error to tweak their designs and improve efficiencies as they go along.

Becker concedes this approach doesn’t guarantee an efficient design, but points out that we’re talking DIY home power generation here, and not commercial installations.

His view: “You’re producing power for your own needs, so as long as you have enough, does it really matter how many inefficiencies are built into your system? Anyway, you can always improve efficiencies over time as you understand more about the mechanics involved.”

Because of the inter-relatedness of all the components involved, Becker recommends would-be wind turbine builders first tackle a small version.

It’s all about learning curves, he explains. For example, the rotors (housing the magnets) can be placed too close to the stator (housing the wire coils) and rub the insulation off the wiring, causing the generator to short out. And the wiring can only take a certain amount of bending before it breaks, so one must have a clear idea of where to place the connection points.

“For any number of reasons, the odds of your first turbine working properly are almost nil.”