Sparks

A turbine the size of a penny

 By Robin Wylie

When you think of wind turbines, you’ll probably imagine a white, building-sized structure in a field somewhere. But a new generation of micro turbines could be about to change the way humans draw power from the wind. In a new study, researchers from the USA and Brazil investigated the performance of a new micro wind turbine, approximately the size of a penny, which is designed to power small devices using low wind speeds. The researchers found that the micro turbines – which resemble tiny jet engines – were more efficient, and generated a higher power density than previously tested micro turbines, over a broad range of wind speeds. The results suggest that such micro wind turbines could soon be used as a carbon-neutral way to power micro wireless environmental sensors such as smoke and gas sensors or temperature controllers, which would otherwise require batteries or external power sources…

(Cover photo by www.uta.edu)

At this stage in the climate game, few would argue against wind power. But it does has a slight image problem. To some people the herds of sky-scraping turbines that have started appearing on our hillsides have a certain stark beauty to them; to others, however, they’re alien eye sores.

Opponents of wind farms are going to have to learn to accept them — the need to wean ourselves off fossil fuels is just too pressing to waste such a plentiful source of green energy. But its detractors may be happy to learn that wind power also comes in smaller packages.

In engineering speak, a “micro-wind turbine” is any with a blade diameter of less than 1.5 m (5 ft). But recently, researchers have been shrinking wind turbines to such a degree they had to invent a new term: Say hello to “centimeter-scale micro-wind turbines” (CSMWT).

Clunky as their name may be, CSMWT are worth knowing about. In contrast to their large white counterparts, these turbines can be as little as 2 cm (0.8 in), small enough to hide behind a dime or British five pence. Naturally, their diminutive size means that CSMWT generate far less power than conventional wind turbines. But they have a host of potential uses.

One of the most promising roles for these microturbines is in the field of environmental sensing. Measuring the properties of the air is necessary for a wide range of purposes, from pollution monitoring to fire safety to temperature control. Today, such measurements are usually made using battery-operated devices. But scientists hope that soon, discreet microturbines could be powering the next generation of environmental sensors.

Micro-wind turbine model LED power generator (imagine by www.aliexpress.com)

Relying on wind to power a sensor might seem restrictive, but CSMWT have the potential to operate in a wide range of locations. They can generate electricity at wind speeds as low as around 7 miles per hour (about the strength of a light breeze), which means that these microturbines could be used to power environmental sensors in all but the calmest outdoor locations — and even certain indoor ones, such as ventilation or air conditioning ducts.

Using wind to power environmental sensors is clearly good from a green perspective. But it may also change the way these sensors are used.

In theory, battery powered sensors can be placed anywhere, but in reality, their power source places constraints on their use. For example, the need to revisit each device every few years to replace the battery significantly limits the number of sensors you can place — beyond a certain number of sensors, the job of switching each battery becomes unfeasible. Wind-powered sensors, on the other hand, can potentially run for much longer without needing to be serviced, which would allow more sensors to be installed at a given location, for longer.

And it’s this increased coverage where the main advantage of wind-powered sensors seems to lie. By ditching batteries in these devices, the effect on humanity’s carbon footprint would be negligible. But by giving us more detailed information about the state of our air, turbine-driven sensors could still do their part for the climate.

about the author
Robin Wylie
Freelance earth/space science journalist. Currently finishing off a PhD in volcanology at University College London.