Copenhagen’s solar duck and other renewable energy fairytales
Activists on either side of the climate fight may argue whether wind turbines are eyesores or majestic beauties. Meanwhile, designers have drawn up plans for a massive solar duck for the waters around Copenhagen.
A bit like a bath toy, but instead of yellow rubber, its skin would be made of solar PV cells, and rather than bathtub-sized, it’s scaled up for a cityscape. The inspiration isn’t just the rubber duckie, but the Common Eider Duck; currently a familiar sight in Copenhagen, it’s a species at risk from climate change.
The idea – part of the Land Art Generator Competition – is just an idea at the moment. It’s art. Rooted in the belief that aesthetics and social interaction matter when it comes to renewable energy, it aims to push visionary thinking over renewable energy beyond just technical details.
All the Land Art Generator ideas are site-specific. Part of the point is that innovation in energy will only work if we work in harmony with the culture, society and the environment (built and natural). In 2012, they considered Freshkills Park, New York City. In 2010, it was Dubai and Abu Dhabi, UAE. 2012 ideas have included a NASA-inspired field of red solar balloons, a kinetic playground, solar baths and a collection of swaying leaves designed to reflect the Manhattan skyline and harvest both wind and solar energy, depending on the variable weather. The Copenhagen-inspired ideas also include a Viking-inspired series of giant horns built from decommissioned ships; wind turbines and sound-art at once, inviting us to consider Danish pasts and futures.
But back to the duck, which is much more than a renewable energy generator, it’s also an energy storage device and a tourist destination, a celebration of local wildlife and a piece of public art. The duck is designed not only to create and store energy, but help us see that energy in practice. Solar radiation is converted to electricity using reasonably simple, and cheap, off-the-shelf PV panels. The floating nature of the duck also offers some degree of energy storage. The nod to the Eider invites us to think about the impacts of global warming, and what we might save by responding to it. The floating height of the piece is also designed to indicate city-wide energy use: As demand peaks, it sinks. Visitors can climb inside the duck, letting them see the back of the solar PV panels’ mesh, as well as the seawater rising and falling within storage tanks.
Copenhagen is known for fairytales. The bronze Little Mermaid (Den lille havfrue) statue sits at the side of the Langelinie Promenade where many of the Land Art Generator ideas have imagined themselves. Maybe one day the Solar Duck and its ilk will be more than just stories told by designers. Or at least, maybe this bit of design-storytelling will help us imagine new, brighter, cleaner and more sustainable futures. Four years on from the first Land Art Generator, we might ask when we’re likely to see these sorts of ideas realised. I for one would like a chance to play with my renewable energy.
I think Betteridge’s law of headlines prevails on this one: “Could a giant solar duck in the waters by Copenhagen be the key to unlocking the energy debate?” – No
Where to start? Further schematics of the scheme can be found in the following link: http://www.designboom.com/technology/solar-energy-duck-concept-generate-renewable-power-copenhagen-08-03-2014/. According to the illustration they generate electricity by admitting seawater to the base through a turbine. This arrangement would fall under the category of “low head turbines” renowned for low efficiency! There is a reason hydroelectric stations operate with reservoirs up mountains (e.g 396m of head for Cruachan dam in Scotland) – one is that high head turbines operate at a much greater efficiency with smaller rotating components for an equivalent amount of power extraction. The bigger reason of course is energy storage capability. My back of the fag packet calculation based on the scale of the duck in the above link suggests that the base can be flooded with around 64,000 metric tonnes of water with a centroid height of roughly 10 meters. That would represent approximately 1.7MWh of energy storage. Now the average electricity consumption for a UK household works out to be around 11kWh/day (https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/338662/ecuk_chapter_3_domestic_factsheet.pdf)- therefore the storage within the device would equate to the total daily demand of about 155 houses – hardly a town (as the designers claim) – the designers also claim a 4 meter tall duck would service a house… well if we scale everything by 4/40 we get 0.0875kWh! (that’s a 3kW kettle for a couple of minutes!) – these figures are actually pretty optimistic because I haven’t considered the round trip efficiency penalty associated with the turbines, generators, power electronics… I’d be surprised if you’d get half of that! And don’t get me started on the suboptimal arrangement of panels – let’s hope this remains as the author says – just an idea!