We (along with all living things) rely on converting energy from a stored form to something useful that we can use immediately, all the time, just to stay alive. On a larger scale, our highly switched-on society relies on a constant supply of (usually electrical) energy.
At present in Australia, most electrical energy is generated by burning coal or gas to produce steam, the force of which rotates a turbine that then turns the generator, which is a machine that moves magnets and conducting metal wires relative to each other in a synchronised way. This causes electrons move from the conductor down a connecting wire – ie. an electric current.
(As an aside - This is the same process how all diesel electric locomotives running on Australian rail tracks derive their power, the diesel engine turns the turbine which turns the generator and the electricity in turn powers the traction motors at the wheels).
The physical "Law of Conservation of Energy" states that energy can never be created nor destroyed, but merely transformed from one form into another. So when we say "generation of electrical energy", we really mean a transformation from the mechanical (kinetic) energy of the turbines into electrical energy. And of course, the steam is heated by using energy that was stored as fuel, such as when plants which originally used the sun's energy, were compressed under the earth to form coal.
Other processes of making electrical energy directly from the sun and the wind and the waves are improving all the time. But the energy they generate needs to be used immediately or it is "wasted". As a society, we will need to store the energy if we are to rely more on these "sustainable" sources, so that we can continue to use the energy when the sun or wind or waves are not active.
The ephemeral nature of energy.
Close your eyes and imagine a bundle of pure "energy". This image is not one that humans can easily "see". That is why physicists find it convenient to use mathematical equations to describe and predict the way energy works in our world.
John, chapter 3 verse 8 describes it thus: " The wind blows where it wishes, and you hear its sound, but you do not know where it comes from or where it goes. So it is with everyone who is born of the Spirit" (Note that the same Greek word can be translated as either "wind" and "spirit").
Almost all the energy used here on Earth comes originally from the sun, with a few exceptions such as heat from deep underground (that heats the Artesian bore water) and a few micro-organisms that use chemical energy from minerals.
The sun's energy in turn comes from the disruption of the nuclei of atoms in "nuclear reactions". This intense radiation travels through space, and some of it reaches Earth as waves or tiny, fast-travelling particles.
Since mass is a type of "condensed" energy, physicists should really call their law the "Law of Conservation of Mass/Energy".
How nature stores energy.
Plants utilise light from the sun in an amazing process called photosynthesis. The compound chlorophyll channels some of the energy from photons (tiny packets of light energy) in a stepwise fashion to drive a long sequence of chemical reactions, that also use carbon dioxide and water, to eventually produce glucose, then long strands of starch. Oxygen is also produced as a waste product.
This starch is used later by the plant, as needed, in the dark or at any time, so that they have energy to carry out all the reactions for life. It is also used by animals – including us – when we eat plants and the starch is converted in our bodies to glycogen or fat, which are our equivalent slow-release, stored forms of energy.
Mimicking nature using "artificial photosynthesis" reactions is not easy, as the exquisitely controlled biochemical reactions are very hard to copy. However, Australian scientists have found a new way to produce hydrogen gas (an excellent fuel) from a reaction that splits up the hydrogen and oxygen atoms in water (H2O) using sunlight as a primary energy source and a synthetic molecule similar to chlorophyll, which helps the reaction along. Research is still in the early phases.
How our society stores energy – up to now.
All our modern mobile devices rely on batteries (or they wouldn't be "mobile"): from pacemakers, hearing aids and cochlear implants; to phones and laptops; to large cars and planes. There are many different and new types of batteries for various purposes, but none are perfect. Some need to be charged often, others contain dangerous chemicals (there are reports of fires from lithium), and some are large and heavy (such as the lead/acid batteries in our cars).
For industrial situations, Australian companies are currently considering other storage methods such as: flywheels, pumped hydro, compressed air, hot liquids (including hot water systems), and capacitors. Some states in the US are passing laws to mandate some storage capacity when new electricity generation systems are built. (cleanenergycouncil.org.au; businessspectator.com.au; www.businessspectator.com.au)
Are capacitors the "new batteries"?
Although capacitors operate differently from a battery, they are similar in storing electrical energy. They do it passively (once charged up) by using alternate layers of a conductor and an insulator, so they can hold their charge even when the source of current (power or battery) is turned off. They can be designed to release charge slowly to smooth out fluctuations in a power supply; they can be combined with a resistor to make a timer; or their properties can be modified to release the charge all at once.
They are commonly used in flashes on cameras, in TV sets and computers or any device where the power needs to be retained if the device is disconnected. That is why you shouldn't play around with old TV or computers unless you know how to correctly discharge the capacitors first – they might discharge through you! In some cars and heavy trucks capacitors provide the "oomph" for starting the vehicle, and they are used in circuitry to make lasers and many other devices.
However, until now, capacitors have been more cumbersome than equivalent batteries because their "energy density" has been lower. But now, a multinational research team has designed "hybrid" supercapacitors, combining the storage power of some types and the ability of others to release energy when required. They have also used nanotechnology to reduce the size and increase the energy density. They have manufactured of tiny, tiny, tiny 3-D structures of graphene (a form of carbon, a conductor) integrated with minute particles of manganese dioxide (a common mineral and an insulator). The making of their new device does not need any clean room or specialised facilities, uses cheap and abundant materials, and the electrolyte is a safe water-based compound.
I always have faith in the inventiveness of the next generation to solve the problems created by the inventiveness of previous generations!
POST SCRIPT: Rubbish can also store energy - Sweden's recycling system
Here is a late story from Sweden – it now recycles 99% of its waste to produce energy. In fact, it is running out of its own rubbish to use, and is considering importing waste materials from other countries as its energy storage system!
The 1960's Goons radio comedy "The Flying Dustman of Australia" (that I have as a '78 and as a CD) where they are in a hunt for rubbish, may be a case of back to the future! There are many references to rubbish in the Scriptures, perhaps there might a clue in these to aid the Swedes and if our household is typical, none of us would get a power bill for 6 months!
Dr Mark Tronson is a Baptist minister (retired) who served as the Australian cricket team chaplain for 17 years (2000 ret) and established Life After Cricket in 2001. He was recognised by the Olympic Ministry Medal in 2009 presented by Carl Lewis Olympian of the Century. He mentors young writers and has written 24 books, and enjoys writing. He is married to Delma, with four adult children and grand-children.
Mark Tronson's archive of articles can be viewed at http://www.pressserviceinternational.org/mark-tronson.html