Capturing the energy from the sun and transferring it to electrical or thermal energy can be used to its fullest potential only if it can be stored. On a cloudy or rainy day or at night, energy needs to be provided to the consumer at any given time or on a continual basis. For this, storage technology needs to be part of the energy system.
So why is storage technology still a challenge? It turns out that at a utility or grid level application, the solution is either too expensive or the energy stored is not transferred back efficiently.
There have been several solutions based on molten salt or oil especially in the solar thermal market. However, the costs add quickly to a very large number. Recently, there was some news on using an inexpensive catalyst from MIT that they it thinks might be a breakthrough. Based on the concept of splitting water and storing the hydrogen, the director of the program in MIT believes that using just more than a gallon of water per household is sufficient to store enough energy from photovoltaic systems. The team aims to replace the conventional fuel cells that currently use an expensive catalyst.
The same is true for an energy harvesting system. Texas Instruments is already in the solar energy harvesting market selling kits for wireless network systems. This kit has a thin film battery that takes care of the storage.
Nagarajan Sridhar
