Electricity consumers to become electricity producers

Electricity generation from solar and wind energy has been going up at exponential rates in our country in recent years. These sources of electricity are intermittent – only when the sun shines or the wind blows. So storage of energy before distribution as per demand has been posing a problem. 

A study published in Current Science last year pointed out that the problems with inverters are the main cause of inefficient functioning of some of the solar power stations in India. Less costly and more efficient energy storage may soon increase the investment in solar and wind energy projects – if a recent paper on flow batteries in Nature is of any indication. 

Scientists knew that flow batteries where two ionic components are separated by a thin membrane which allows the flow of ions across is a good basis for electrical energy storage devices. But such batteries used metallic compounds and the cost was not worth the efficiency of such batteries. Now a collaborative experiment between American and Dutch scientists have come up with an alternative to metallic electrochemicals for the purpose – quinones.

The technique involves movement of charges across membranes. For the anode, you take quinones which goes through hydroxylation and for the cathode, take bromine which cycles to bromide. Each charge-discharge cycle reduces the efficiency only minimally.

There are many quinones in nature and they can be produced easily. So the cost will be much lesser than the earlier metal based attempts at flow batteries. Moreover, these carbon compounds can hold twice the amount of charge compared to metal based flow batteries. Their efficiency and effectiveness can be modulated by minor changes in different parts of the quinone molecule.

The results come at a time when dye based solar cells are promising to bring down the costs of harvesting solar energy. Combined with low cost, quinone based storage, it may soon be possible that every house becomes a producer of electricity.

Nature, 505, 195–198 (09 January 2014) doi:10.1038/nature12909