I love windmills. Whenever I go to the Karoo I spend hours watching and photographing them, from every angle and at different times of the day, seeing how they capture the light.

A Karoo windmill. Photo by Helen Lockhart

I even have a miniature windmill sitting on my office windowsill (which whirrs noisily in the wind) and several handcrafted wire windmills dotted around my garden.

Lewis Levin's kinetic sculpture in Joburg. 'The metal structure can be interpreted in several ways: it has a nautical shape, similar to a large sail; it can be seen as a Zulu shield; or as a giant Aids ribbon.' Image courtesy Google Maps

And there’s a windmill museum – in Loeriesfontein in the Northern Cape. The museum, one of only three of its kind in the world, boasts 27 windmills.

I think this is why I love our wind turbine here at the Aquarium. I am filled with pride every time I see it, especially when it is whirling effortlessly in the wind. Not only is it functional, capturing the energy of the wind and turning it into electricity, it’s also very beautiful, a kinetic sculpture of sorts.

About 10 years ago we were approached by an architect, Lewis Levin, who is also a kinetic sculptor. Lewis dreams big – he had a vision for a kinetic sculpture, in the shape of a whale outside the Aquarium, which could harness the wind and provide energy to the Aquarium. Back in those days this just seemed like an incredible idea to me.

While the wind turbine at the entrance to the Aquarium doesn’t represent a whale, its blades are almost whale-bone like – I realised the other day that the turbine’s structure reminded me of Noel Ashton’s Sacred Ocean whale sculpture, which can be seen in the foyer of the Aquarium.

I then got to thinking about a story I had heard during our first biomimicry workshop back in 2010: that the shape of the flippers of humpback whales is being applied in the design of wind turbines, industrial fans and aeroplane wings to make them more efficient and aerodynamic.

According to Ask Nature: “Flippers on humpback whales (Megaptera novaeangliae) have non-smooth leading edges, yet demonstrate superior fluid dynamics to the characteristically smooth leading edges of our wings, turbines and other kinds of blades … Wind tunnel tests of model humpback flippers with and without leading-edge tubercules have demonstrated the fluid dynamic improvements tubercules make, such as a staggering 32% reduction in drag, 8% improvement in lift, and a 40% increase in angle of attack over smooth flippers before stalling”.

A company called WhalePower, co-founded by Dr Frank Fish, Dr Phil Watts and Stephen Dewar (I kid you not!), is now using this knowledge in the design and development of wind turbines and even computer fans.

The presence of the wind turbine at the Aquarium is thanks to the local NGO Project 90 by 2030, which chose the Aquarium as one of six renewable energy demonstration sites in South Africa. With funding from Misereor Germany, we were able to install the wind turbine and solar panels. This renewable energy is being used to supplement the power requirements of our admin offices on the east side of the Aquarium building.

The windmill on the roof. Photo by Two Oceans Aquarium

Technical specifications:

• The wind turbine is a Urban Green Energy (UGE) 1kW vertical-axis wind turbine (VAWT) which is rated 1kW at 12m/s. UGE claims the unit can withstand gusts of up to 55m/s, far in excess of the strongest gusts measured at Cape Town International Airport. The VAWT also complies with all IEC61400 certifications
• Wind turbines work pretty much the same way as windmills. As the wind causes the blades to turn, the blades collect the wind’s energy. The blades are connected to a driveshaft that turns an electric generator to produce electricity
• The wind turbine generates wild AC, which needs to be converted to DC. The DC power is fed into a grid inverter where it is converted to compatible AC grid voltage and frequency. In order to regulate the unit when there is a power failure, a regulator, connected to a dump load, is required
• All the required equipment was supplied and installed by Power Solutions (www.powersolutions.co.za)
• The wind turbine is a vertical turbine as opposed to a horizontal one. The rationale for this choice is that vertical turbines are less noisy and they are also more visible to birds, thereby reducing the potential of bird fatalities

My windowsill windmill. Photo by Helen Lockhart

Windmills, whales and wind turbines are all icons in their own right. Windmills are iconic features on the open plains of our country, especially in the Karoo, reminding us of the power of renewable energy and the existence of precious underground water which so many people in that arid region rely on for their livelihoods and livestock.

Whales are icons of the blue planet, which is our only home. They remind us of our ancient connection with the ocean, and our interconnectedness with all life on the planet.

Wind turbines demonstrate that there are alternatives to fossil fuels and that it is possible for us to live sustainably within the carrying capacity of our planet – if only we dare to apply our minds creatively, using nature as our guide and mentor.

Find out more about the Two Oceans Aquarium sustainability efforts here.

Stay in touch: For daily Aquarium updates, follow us on Twitter (@2OceansAquarium) and become a fan on Facebook.