Ken Hickson

Imagine this. Homes and schools of the future could one day be lined with energy-storing wallpaper. Gadget lovers would be able to charge their portable appliances on the go, simply plugging them into an outlet woven into their T-shirts.

Energy textiles could also be used to create moving-display apparel, ideal for students, sales people, sporting types and even soldiers.  This is all be possible thanks to the latest work of Stanford University engineer Yi Cui who has come up with a way to cheaply and efficiently manufacture lightweight paper - yes, paper - batteries and super capacitors, which like batteries, store energy by electrostatic rather than chemical means. Simply and scientifically achieved by dipping ordinary paper or fabric into a special ink infused with nanoparticles. So reported Science Daily recently.

There's a lot to nano - nanoparticles and nanotubes - which can be applied to produce many energy advances. These carbon or correctly graphite related particles are finding their way into applications for medicine, biotechnology, environmental and other technological areas.

Smaller, harder, faster and cleaner is certainly the nano-message from Mr Cui and his team at Stanford, where he announced a couple of year ago a way to use silicon nanowires to reinvent the rechargeable lithium-ion batteries that power laptops, iPods, video cameras, cell phones, and countless other devices.

The new version produces 10 times the amount of electricity of existing lithium-ion, known as Li-ion, batteries. A laptop which now runs on battery for two hours could operate for 20 hours, a boon to ocean-hopping business travellers, computer-transfixed students.

The greatly expanded storage capacity could make Li-ion batteries attractive to electric car manufacturers. Cui suggested that they could also be used in homes or offices to store electricity generated by rooftop solar panels.

Let's consider the development of batteries for electric vehicles. It wasn't long ago that car manufacturers dismissed the ideal of all electric vehicles because there was no way they could see that the batteries could be light enough to carry and with enough power to go beyond a few kilometres.

Now battery technology has advanced so much that more than a dozen automobile makers the world over are currently making electric cars. Some are on the road now in Australia, France, Israel, Japan and Denmark.

The Australian Electric Vehicle Association has these answers - backed up by a number of manufacturers:

• The best battery to use is the Lithium Polymer Battery, at cost more than $20,000.
• For the DIY enthusiast the most cost effective battery is a Lead Deep Cycle Battery.
• A 144volt motor would use 12 batteries. The cost is about $1,500-$3,000 for 7 x 12volt lead deep cycle batteries. If cost is not an issue, you could consider a Nickel Metal Hydride Battery or a high performance Lithium Ion Battery for a longer range or a very high performance Lithium Polymer Battery.
• Electric cars and power plants are less polluting, more efficient, and more reliable. Even if most of our electricity comes from coal fired power stations.

But if we want to go in the direction of totally clean energy for electric vehicles, the answer is in the wind. At last October's first national Electric Vehicle conference in Brisbane, delegates were told that one good sized wind turbine would be sufficient to provide enough energy for 1500 electric battery powered cars every day.

As most (85%) daily car trips in Australia are for less than 100 kilometres, most battery packs could easily keep the car going the distance. While electric definitely appears to be the way forward for cars in the very near future, there has also been a lot of work recently on hydrogen. Honda and BMW have invested millions in hydrogen and fuel cell technology and great progress has been made. But when it comes to size, another US University has come up with the best yet, with applications across the board.

The world's smallest working fuel cell has been created by chemical engineers at the University of Illinois at Urbana-Champaign. It is just 3 millimetres across. Future versions of the tiny hydrogen-fuelled power pack could replace batteries in portable gadgets.

While batteries are used to do that today, fuel cells are able to store more energy in the same space. Even the most advanced batteries have an energy density an order of magnitude smaller than that of a hydrogen fuel tank.

Yet batteries are much easier to make at the small scale than the pumps and control electronics of a fuel cell. And small pumps can use more energy than they generate. But the design for the tiny fuel cell is such that it generates power without consuming it.

The new device has just four components. A thin membrane separates a water reservoir above from a chamber containing metal hydride below. Beneath the metal hydride chamber there is an assembly of electrodes.

Tiny holes in the membrane allow the water molecules to reach the adjacent chamber as vapour. Once there, the vapour reacts with the metal hydride to form hydrogen, which fills the chamber, pushing the membrane upwards and blocking the flow of water.

The hydrogen is gradually depleted, though, as it reacts at the electrodes beneath the chamber to create a flow of electricity. And when the hydrogen pressure drops, more water can enter to keep the reaction going.

Why didn't you or I think of that?

When it comes to batteries, energy storage and fuel cells, there is some good news coming from places other than the US - even from within Australia.

Steve Hollis, CEO of Lloyd Energy Systems, an Australian company that has created a large scale, low cost, energy storage system based on high purity graphite. There's that ever-useful carbon again - literally the same thing as the "lead" in your pencil.

How does it work? Very simple, says Mr Hollis. "We are using high purity graphite. High purity graphite has a unique combination of properties, so it's an ideal thermal storage medium.

He explains that the system simply collects solar energy via tracking heliostats, which are mirrors that track the passage of the sun across the sky, and focus the sun's energy in a very sharp image and project that image into our ‘storage block', which does three things.
It collects the energy into a receiver which is concentrated and focused into it be the tracking heliostats. Once it is in the block it is absorbed by the high purity graphite and it just sits there until you want to retrieve the energy in the form of electricity.

The graphite has conventional heat exchangers embedded in the graphite and when electricity generation is required, it simply passes water through the tubes which is like a normal steam blower that makes steam, and that steam drives a conventional steam turbine to create electricity. There are very few moving parts and it's quite a simple system.

So says Mr Hollis of Lloyd Energy Systems and its storage blocks are already being used to turn the Queensland town of Cloncurry into a totally solar dependent place.

Our very own CSIRO has something of an obsession with batteries, and have come up with the UltraBattery. This innovative advancement on conventional battery design delivers low cost, long life, high performance power and provides a solution for future energy storage needs.

The UltraBattery is a hybrid energy storage device that integrates a supercapacitor with a lead acid battery in one unit cell.
Developed by CSIRO Energy Technology as part of the Energy Transformed Flagship research program, the UltraBattery has applications for use in hybrid electric vehicles (HEVs) with further research aimed at resolving issues of intermittency in capturing energy produced from renewable sources.

Honda is well advanced with its hydrogen fuel cell technology - its experimental FCX Clarity car is regularly seen running around California - but it is also doing some interesting work with an outfit called Plug Power to produce energy for the home and the car.

They have together developed a Home Energy Station (HES), designed to provide fuel for a hydrogen-powered fuel cell vehicle as well as heat and electricity for the home. It is like having your own power station and petrol station all in one alongside your garage.

There's an Australian company, Ceramic Fuel Cells, which is doing something similar. Its BlueGen units generate electricity in the home far more efficiently than the power grid, cutting energy bills and significantly reducing carbon emissions.

Connecting to existing gas pipes and about the size of a dishwasher, BlueGen uses fuel cell technology to convert mains gas into electricity. Over a year, each BlueGen can produce twice the electricity needed to power an average home. Surplus electricity can be sold back to the local power grid. BlueGen also produces enough heat to satisfy the average home's daily needs for hot water.

Ceramic Fuel Cells has achieved electrical efficiency of 60 percent, far higher than any other technology in the rapidly expanding market for small scale power and heating generators. When heat is recovered from the electricity production process, total efficiency is up to 85 percent - twice as efficient as the average among current European power stations.

But the last word goes to something far from small. If fact it's big and it's as potentially fiery as an aluminium smelter.
In fact, engineers led by Donald Sadoway at the Massachusetts Institute of Technology were inspired by the way aluminium is smelted using electricity. They created a similar but reversible process that can either consume or release energy.

Their batteries are simply tanks filled with three separate layers of liquid at 700 °C that float on top of one another: the top one is molten magnesium, the bottom antimony and the one in between a salt containing magnesium antimonide, a dissolved compound of the two metals.

When the battery is being charged, magnesium antimonide in the middle layer breaks down into the pure elements and so the upper and lower layers deepen. Discharging the battery reverses the process and releases electrons to provide power. Once heated up to its operating temperature, the battery generates enough heat on its own to keep the liquids molten.

A small prototype provided up to 20 times as much current as a lithium-ion battery - the kind used in portable devices and electric cars - from the same area of electrode. And the materials used are much cheaper than lithium, making scaling to up to grid scale feasible, he says.

The MIT team calculates that a battery the size of a shipping container could deliver a megawatt of electricity - enough to power 10,000 100-watt light bulbs - for several hours.

Ken Hickson, the author of "The ABC of Carbon" is Director of ABC Carbon, a climate change and sustainability consultancy. He is also Principal of Carinya Corporate and Commercialisation Pty Ltd, set up to help SMEs grow to meet market opportunities. For the full story of renewable energy, energy efficiency, carbon and climate change, you can read "The ABC of Carbon". It's available from Carbon Market.

You can also visit the website www.abccarbon.com and get a free subscription to his weekly e-newsletter abc carbon express.