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Organic batteries put clean-electricity future within sight

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By Bob McDonald, Quirks & Quarks

Researchers from Harvard University have created a new organic battery that could be the first step towards keeping large amounts of electricity in storage when we don't need it immediately. 

The organic mega-flow battery uses low-cost organic molecules, instead of expensive metals, to store electrical energy in liquids the way gasoline is kept in a tank.

Electricity is the most versatile and cleanest form of energy there is, but it has been difficult to store in large quantities. Batteries have always suffered from limited capacity because of their size and weight. You can only pour so much electricity into them, so they run dry fairly quickly.

This inability to store large amounts of electricity has been the main stumbling block for renewable energy sources, such as wind and solar power, which only provide energy when the sun is shining or the wind is blowing. We always expect electricity to be there when we flip a switch or plug into a wall, so renewable projects have needed conventional backup sources of power to keep the juice flowing all the time. If the energy from wind and solar could be stored when it's not needed immediately, that electricity would be available at night and on calm days.

The idea behind the flow batteries is to store the electricity in organic compounds called quinones, dissolved in water, that can be held in large tanks. The organics, similar to what is found in rhubarb, are much cheaper and abundant than the metals used in existing batteries, and the amount of charge they hold is limited only by the size of the tanks. 

Storing energy in liquids is not new. That's the beauty of gasoline. It's a liquid, containing a huge amount of energy, that you store in a tank under your car and only use when you start the engine.  

Great idea - except that gasoline is a fossil fuel, and the combustion engine only converts about 20 per cent of the energy in the gas to turn the wheels. That means we throw away 80 per cent of the energy in gasoline, which goes out the tail pipe and radiator as waste heat. 

Ridiculous, when you think about it. Only $10  out of a $50 fill-up is used to move the car. You throw away the other $40. 

Electric motors, on the other hand, use about 90 per cent of the energy put into them. But electric cars have been limited in range by current battery technology that cannot hold as much energy by volume as a tank of gasoline. 

Now, there's the challenge: make a container, the same size and weight as a car's gas tank, that stores an equal amount of electrical energy and can be filled in a few minutes when empty. Such a container does not currently exist. These organic batteries may be an answer.  
At the moment, the researchers are aiming for large storage systems that could be used in conjunction with commercial windmills or solar farms.  Underground tanks would store the electricity to be used when needed.

With improvements, future systems could be scaled down for household use. So, for example, if you had solar panels on the roof of your house, they would charge up a tank of organics the size of a water heater in your basement during the day, which would then provide power over night. Liquid sunshine.

This country is currently obsessed with digging fossil fuels out of the ground and burning them up at an increasing rate. We have been using electricity as soon as we make it, which means generating stations are running constantly, even when the demand is low. That is not sustainable in the long run.

Alternative energy has remained on the fringe because of its intermittent nature and our constant demand for electricity. If we can get away from the idea of using energy as soon as we make it and shift to storing it, so we only use it when we actually need it, then we don't need to produce as much of it. 

This type of organic energy storage is a very positive step towards a clean energy future.
(And if you want to hear about some other cutting-edge ideas for battery storage, listen to our special, "Hoarding Electrons to Power the Future.")