Could quantum mechanics make energy technology faster, better and more efficient?

In December, Australia will play host to a world-first conference on ‘quantum energy’, the harnessing of quantum mechanics principles to create better, more efficient energy technologies.

The inaugural International Conference on Quantum Energy (ICQE), hosted by CSIRO, reflects a growing belief in the ability of science’s most incomprehensible realm to expedite the global shift to renewables.

“In innovation, we often use S curves to express the performance of a technology which, after some rapid growth, saturates as it comes close to reaching a limit,” explains Dr Florian Metzler to a captive audience of more than 250 faceless webinar participants, a precursor to December’s three-day conference.

In this case, Metzler is talking about typical electrochemical batteries, which he argues are mostly approaching their power density limits. Metzler is a nuclear scientist with a particular interest in quantum mechanics, which means he’s trained in thinking subversively.

“You can bring in new technology and new physical principles and expand these limits,” he says. “That’s what you get when you switch the modus operandi of a particular application – when you change the physics underlying it.”

Quantum mechanics deals with the nature of reality at the atomic and subatomic level – where things behave differently than they do on our scale.

Mathematical waves

At the quantum level, particles are actually waves – not physical waves, but mathematical waves. To find out where a given particle, for example an electron, is going to be at any given moment, it’s possible to perform mathematical operations on the wave function which provides a spread of possibilities as to where you will find the electron.

Once you measure the electron, it pops up somewhere within that area. So, particles like electrons seem to be waves until they are measured. This is encapsulated in the famous double slit experiment.

The infinitesimal quirks of the quantum realm have already enabled technological breakthroughs – quantum mechanics is fundamental to lasers, electron microscopes, and MRI devices.

But James Quach, Science Leader in Quantum Science and Technologies at CSIRO, says that a ‘second generation’ of incoming quantum technologies is particularly exciting, most of which take advantage of two related quantum phenomena – quantum entanglement and quantum coherence.

When two or more particles are created or interact, sometimes their quantum state – perhaps the spin of an electron, or the polarisation of a photon – becomes entangled, so that even if those particles are then separated, the state of one will always reflect the state of the other.

Quantum battery

Much of Quach’s work at CSIRO is focused on creating a ‘quantum battery’, a battery that is functionally enhanced by quantum mechanics.

In typical electrochemical batteries, the energy is stored in electrons. In a quantum battery, the units that store the energy – and they can be molecules, atoms or qubits – are placed in a coherent state, so that they act collectively.

“By being in a quantum coherent state it produces a collective effect where all the units, when put together, are more than the sum of their parts,” he says.

Another way to explain it is that the molecules behave like waves, collectively interfering with each other to increase the energy transition rate.

What that means is that, “the larger or the more capacity your quantum battery has, the less time it takes to charge,” he says.

This fact was a theoretical idea until Quach helped prove it in the lab last year.

Improving solar panels

Other researchers are investigating how solar panels can be improved with quantum mechanics.

Organic solar cells use carbon-based molecules to harvest light, rather than silicon. Much like quantum batteries, these carbon molecules must be quantum coherent.

On an organic solar cell, the molecules are placed in what’s called a microcavity – a device with a mirror on the top and bottom, which allows light to be trapped for an extended period of time.

“The molecules inside this microcavity, because they’re in a quantum coherent state, will act collectively,” Quach explains. “And by acting collectively, instead of each molecule absorbing photons by itself, they work together to more efficiently absorb photons.”

In theory, this could massively improve the efficiency ceiling of solar panels – but there’s a caveat. A prevailing problem with quantum technology is that quantum effects tend to reduce as you scale up: the more molecules, the more likely those molecules are to decohere.

“This is the problem with all quantum technologies, as you scale things up, they tend to lose their quantum-ness,” Quach says.

Another area of research is the use of quantum computing to manage the delivery of energy in complex grids. But those quantum computers that do exist are a currently not all they’re cracked up to be, and the most optimistic estimates place truly powerful quantum computers decades away.

These technologies are in their infancy, and some in the space are concerned about quantum ‘hype’ – the tendency for some researchers working in the quantum space (or the organisations and media discussing them) to overblow the impacts or scalability of quantum tech.

Dr Alexia Auffeves, Director of Research at the Centre National de la Recherce Scientifique (CNRS), has helped establish the Quantum Energy Initiative to ground the nascent space in a methodology that can help it flourish rather than falter thanks to hype and a lack of coherence (excuse the pun).

“Right now, people can claim whatever they want to claim, because there are no objective figures of merit, no objective methodology so you can really estimate properly the energy efficiency of quantum technologies,” she explains.

Big investment

Hype or not, quantum energy is amassing big bucks behind it: China is investing heavily, as is the EU, the US and Japan. Australia is also punching above its weight in terms of contributions to quantum energy research.

CSIRO’s latest foray into coordinating an international conference in the space shows that it recognises the potential for quantum tech to provide solutions to society’s impending energy infrastructure upheaval.

“Our research is across the entire energy value chain,” says Allison Hortle, Science Director for the Energy Business Unit at CSIRO.

“And we’re cognizant of the enormous challenges that raises for us both today and in the future, which is one of the reasons we’re so excited about the possibilities and the potential of quantum to help us address that challenge.”

Hortle says that the exponential growth of demand for electricity as Australia decarbonises – including providing electricity for a growing population, and for the industries that will grow out of decarbonisation like metal processing, long distance transport and the global energy trade – will demand innovative solutions.

“We talk about ‘electrify everything’, that requires an incredible change in our electricity situation, it will need to increase by a factor somewhere around between five to 20 times,” she says. “So we think quantum can play a significant role in the future of this change.”