Biomimicry: powering the world with lessons from nature

Every year, power companies spend billions on research and development. Yet evolution’s billions of years of trial and error has often meant that many breakthroughs have been found through biomimicry, the idea that says “If you can’t beat them, why not copy them?”. Matt Farmer profiles some recent advances.

Biomimicry is the emulation of the models, systems, and elements of nature for the purpose of solving complex human problems. One of the most recognisable examples of biomimicry is Velcro®, the original hook-and-loop fastener inspired by the hooked seed pods of burdock plants.

When it comes to the energy sector, biomimicry is allowing for the unexpected advancement of efficiency in mechanical designs, particularly around renewables. Often, biomimetic designs come from university research, leading to patented products which could optimise the power environment.

/ The machine mimics the shape of sea plants to allow water to pass through where needed. /

bioWAVE tidal energy

Australia-based tidal power technology company BPS has developed two different tidal energy devices based on sea life, allowing for better hydrodynamics.

Its bioWAVE tidal power device mimics the swaying of undersea plants, using ocean swells to generate power. This would mean more consistent power supply than the more common lunar tide approach.

/ The machine mimics the shape of sea plants to allow water to pass through where needed. /

This technology needs to capture movement from waves, but too much resistance could damage the machine. Because of this, the machine mimics the shape of sea plants to allow water to pass through where needed.

The company has also developed a smaller tidal energy system modelled around fish fins. The bioSTREAM tidal generator is shaped to move through water while moving back and forth with waves. This reduces wear, but also means less of an environmental impact. This slow movement then creates hydraulic pressure and becomes electricity sent to shore via a cable.

The BioWave unit mimics the swaying of underwater plants. Image: BPS

Biome Renewables PowerCone®

In many countries, species of the kingfisher watch over rivers, looking for the perfect time to dive for small fish. When a kingfisher enters the water, it creates almost no disturbance to the surface. The naturally piercing shape of its beak has inspired numerous designs, including the famous Japanese Shinkansen bullet train.

It also gave Biome Renewables the idea for the PowerCone®. This device fits onto the centre of existing turbines and uses its spiral shape to redistribute more air toward the turbine blades. The company says that this makes the turbine more aerodynamic, and more efficient.

This would mean less noise and more power, bringing turbines up to their minimum load sooner. Biome Renewables promises a 13% increase on power generation from their product.

The PowerCone® captures wind which would otherwise have blown over the central turbine. Image: Biome Renewables

/ If we're talking about going to 100% or even 10% renewables, we will need huge areas. /

Fibonacci spirals for concentrated solar arrays

When redesigning concentrated solar arrays to save space, Professor Alexander Mitsos, Rockwell International assistant professor of mechanical engineering at the Massachusetts Institute of Technology, found the layout resembled the spiral of many flower petals.

Many flowers arrange their petals and seeds according to the mathematical series known as the Fibonacci sequence. This pattern comes from adding the two previous numbers: 1, 1, 2, 3, 5, 8, 13, and so on.

For many flowers, the number of seeds in any spiral from the centre of the bloom will be a Fibonacci number. Impressively, this usually works in both directions.

/ If we're talking about going to 100% or even 10% renewables, we will need huge areas. /

Botanists have theorised that this arrangement might help flowers pack in as many seeds as possible. In his study, Professor Mitsos said arranging solar reflectors like this could shrink the area needed for panels by 20% while not affecting the power output.

He told Wired: “Concentrated solar thermal energy needs huge areas. If we're talking about going to 100% or even 10% renewables, we will need huge areas, so we better use them efficiently.”

The centre of sunflowers contain Fibonacci spirals, keeping seeds packed together efficiently.

/ Several companies and universities have aimed to make their panel mounts more like sunflower heads. /

Solar heliotropes and passive sun tracking

Sunflowers have also inspired innovations to photovoltaic panels. When in bloom, sunflower heads naturally follow the sun through the daytime sky. If static solar panels could passively do the same, analyst firm WoodMackenzie estimates that they would generate up to 35% more energy.

Photovoltaic cells operate best when sunlight is directly facing them, but most panels remain static as the sun moves around them. Panels can be made to rotate in one or two directions, each increasing their potential generation.

/ Several companies and universities have aimed to make their panel mounts more like sunflower heads. /

Most systems do this with motors, which means energy and maintenance costs. Furthermore, their weight and expense often rules them out for domestic buyers. Because of these factors, several companies and universities have aimed to make their panel mounts more like sunflower heads, which naturally follow the sun throughout the day.

One team from the Massachusetts Institute of Technology mounted a test solar module on an arch made of two metals. As the sun warmed these, they expanded and deformed to alter the angle of the panel on top.

Elsewhere, engineers worked on systems light enough to be mounted on the roofs of homes. Engineers at SunPoint Technology designed a mechanical system to angle their solar panels, which they said could passively generate 23% more energy.

Sunflowers’ tracking of the sun throughout the day could help model more efficient solar panels.

/A lot of insects take their colours from nanostructures. /

Scattering light like a butterfly’s wings

While solar heliotropes aim to fix the problem of decreased generation, another biomimicry design simply aims to remove the problem.

Researchers from the California Institute of Technology in the US and Karlsruhe Institute of Technology (KIT) in Germany were looking to improve the efficiency of thin-film solar photovoltaic cells. KIT researcher Radnawul Siddique told Popular Mechanics: “I was in a conference and somebody was presenting about butterflies and their nanostructures, and I was intrigued. A lot of insects take their colours from nanostructures.”

In the case of the rose butterfly, the black colour of their wings helps them efficiently absorb light for warmth. To find this light-absorbing structure, the researchers then looked at the butterfly under an electron microscope.

/ A lot of insects take their colours from nanostructures. /

The research teams found the wings to be full of microscopic holes, which scattered the light hitting them. This in turn meant the butterfly could absorb more heat, and that solar panels could use this structure to absorb more energy.

The teams published their findings in the Science Advances journal. Their study produced a photovoltaic panel design based on this structure, which captured approximately twice as much light when directly under the light source. At angles of up to 50°, similar to evening sun, the panels caught up to three times as much light. In July, further research at the University of Oulu studied more butterflies, and managed to increase short-circuit current by 66%.

A butterfly’s wings have many holes to scatter light, which could be used to increase photovoltaic efficiency. Image: Siddique et al/Science Advances

Tubercle wind turbine blade designs

Another turbine innovation took inspiration from the pectoral fins of humpback whales. The shape of these front “flippers” has evolved to include small bumps on their leading edge, known as tubercles.

The shape of the tubercles pushes oncoming water into more compressed, faster-flowing streams between the bumps. This reduces the drag of the fin, allowing the whales to move faster through the water.

The same effect applies to wind turbine blades, which can use tubercles to turn faster with less drag, generating more energy. The concept also applies to helicopter rotors and fan blades, meaning less energy used. Toronto-based company Whalepower has tested one design, generating power from 10 mph winds that would usually need 17 mph.

The tubercle wind turbine blade design takes inspiration from the pectoral fins of humpback whales.

/ The design took inspiration from the fluttering of leaves in the breeze, and how plants treat that energy. /

Vibro-wind oscillators

While many natural sources have influenced innovation in wind turbines, one university team found a way to get rid of the turbine entirely.

The Vibro-Wind Research Group at Cornell University in the US designed a machine to convert vibrations from wind energy into electricity. The design took inspiration from the fluttering of leaves in the breeze, and how plants treat that energy. Where natural designs disperse the energy, the university team would aim to capture it.

/ The design took inspiration from the fluttering of leaves in the breeze, and how plants treat that energy. /

The design uses piezoelectric elements to create an estimated 54W/m². Comparatively, standard photovoltaic solar panels generate approximately 60-100W/m². The prototype also starts generating electricity with wind speeds of 2m/s, significantly lower than the 9m/s usually required for wind generation.

The team hopes the design will appeal to urban residents, because of its small size, small footprint and appealing design.

Playing catch-up in the US

“In Europe, offshore wind has been there for a number of years, but I think in the United States we're a little bit behind that,” said Karustis.

Should it be successful, Halo’s approach could lead to a surge in US onshore wind, which has historically lagged behind other regions in terms of wind installation and production. Since 2016, according to the International Energy Agency, the US has installed just 22.6GW of new onshore wind capacity, compared to 30.7GW in the EU, and 50.3GW in China, struggles that Karustis hopes to address.

Last December, the Chinese Government approved a number of new offshore wind projects, totalling 13GW of production and costing around $13.3bn, as the country continues to invest in utility-scale power. Karustis hopes projects like Halo’s distributed turbine can contribute to a more balanced wind sector in the US, with both large- and small-scale operations expanding renewable power.

“The large-scale wind turbines wouldn't be phased out, it's kind of an ‘all of the above’ thing,” he said. “The large wind farms play a very important role for us in reducing the carbon footprint globally, and hopefully the micro wind market is going to augment that by producing energy where energy is being used. It's a good two-pronged approach.”

This two-pronged approach also includes other renewable power sources, including solar and utility-scale wind; Halo is not trying to replace all clean energy with its turbines, but offer another option for people eager to engage in renewable power, who may have been historically sidelined due to the high costs of building utility-scale facilities or the unsuitable geographical characteristics of the places they live.

“When you look at that market we're very excited because just as megawatt-scale wind is a large market, I think distributed wind can be as big of a market or bigger over time,” said Karustis.

“When you have incentives and improvements in the technology, the costs go down, so you can be more competitive and compete, and that's certainly the case with megawatt-scale wind,” he continued. “Just 15/20 years ago, it wasn't competitive with natural gas [and] coal, but it is now. So those government policies have helped and they've driven the technology improvements, so it's all bundled together.”