Clean energy for Australia: the elegant solution

Long ago, in high school maths, I was taught about the value of "elegant solutions". A correct answer might be good; an elegant correct one is better.

What is "elegant"? In common usage – graceful, stylish, sophisticated, attractive. In technical innovation – a simple, neat, clever, efficient, way of solving a problem, of making an improvement.

"Elegant" is important for successful innovation, as two recent energy examples show. In one an elegant advance appeared out of the blue, surprisingly, unexpectedly, rapidly dominating the competition. In the other, a solution began with popular support, involved some elegant science, looked good initially, but then turned into an inelegant clumsy mess. Now it's stumbling towards failure. A new more elegant solution is desperately needed.

The first example involves batteries and electric vehicles. There's a long background story. Battery-powered electric cars were on the roads as early as the late 1800s. Then, around 1900 the first cars with internal combustion engines fuelled by refined oil arrived. Before long electric cars couldn't compete. By about 1930 they had disappeared.

Now, after a century-long gap, the electric car has made a big comeback. Battery powered EVs attractive to the modern market suddenly became a commercial reality. What happened? It's a great innovation story.

First came a long anticipated scientific breakthrough. A practical rechargeable storage battery based on lithium chemistry finally arrived. Electrochemists (like me) had realised that lithium should offer the best prospects for high specific-energy EV batteries (that is, with a high energy-to-weight ratio) simply because lithium is the lightest metallic element in the periodic table. However, devising a working lithium-based battery presented an exceptional scientific challenge. It took intense electrochemical research efforts on electrodes, electrolytes and cell design over 20 years, beginning around 1970.

Three researchers, John B. Goodenough, M. Stanley Whittingham, and Akira Yoshino, earned the 2019 Nobel Prize in Chemistry for the work that led to that cell.

The first rechargeable lithium-ion battery cells became commercially available around 1991. Within another 15 years the "18650" lithium cell (18 mm in diameter, 65 mm long), similar in size to the everyday AA battery, was in mass production. Lithium batteries rapidly penetrated the market for small portable cordless electric devices, like tools for the building trades. But a lithium battery big and powerful enough to meet the greater demands of automobiles for useful periods or distances was yet to come.

There was an intermediate stage when fuel cells seemed to be the solution for electric vehicle electric propulsion. These are similar to batteries, with one big difference; they can use gaseous or liquid electrochemically active ingredients that can be fed to the cell continuously, so generating current for an unlimited period. In the decade from around 2010 a few models of mass-produced fuel-cell cars appeared. But they all ran on hydrogen gas, not liquid fuels, hence requiring thick-walled high-pressure hydrogen tanks, heavy and awkward for refuelling. Not a particularly elegant solution.

Then came a second major lithium battery advance, delivering a knockout blow to the fuel cell car. The Tesla Roadster was a battery electric sports car produced by Tesla Motors from 2008 to 2012. Based on the Lotus Elise chassis it was the first highway-legal all-electric car to use lithium-ion cells. Its battery comprised 6,800 of the AA-sized 18650 lithium cells! Weighing 450 kg the novel battery gave the Roadster a range of about 250 miles per charge, outperforming all its competitors.

That Tesla battery boasted the second elegant advance needed for EV success. It was a marvel of innovation in battery design, unheralded and unexpected. What did the battery look like? Where could a driver find it? Under the hood? In the boot/trunk? In a trailer? Or did it take up all the passenger space, as with some early experimental EVs?

None of the above. The battery was in the floor. In fact the battery WAS the EV floor. And that innovation almost immediately became the basis for all modern EV design. Today's EV batteries comprise huge numbers of individual small cells much like those in the mouse I'm now clicking, all in the floor of the car.