How2Day: Solar Energy Storage Devices

Rechargeable lithium batteries are becoming more efficient. lithium battery on white image by Yasen Pramatarov from Fotolia.com
Storing solar power for distribution during the night creates a technical challenge for businesses trying to sell their solar electric energy. There are three primary ways to tackle the issue, all of which hail from very different corners of the scientific world. The conventional approach is to use chargeable battery banks to store electricity by day and release it at night, though newer methods also offer a viable alternative.

According to Woodbank Communications' Electropaedia website, lithium ion battery technology provides an almost perfect cell chemistry for rechargeable applications, making it an ideal choice for solar energy storage and nighttime redistribution. Since the technology was first demonstrated in the 1970s, it is nothing new, but frequent updates and reconfigurations of the technology's basic principles bring about new, more efficient and lighter batteries on a frequent basis; just think about advances in the power capacity of laptop batteries as an example. The only real downside to using rechargeable lithium ion battery banks is that they require a large initial investment to provide the level of storage capacity necessary for large-scale solar projects.

Hydrogen generated via the electrolysis of water is not a new concept and is a frequent object of high school science classroom experiments and demonstrations. According to a 2008 article by Martin LaMonica on CNet.com, MIT researchers have taken this humble classroom experiment to an entirely new level, splitting water to create what can be described as an artificial photosynthesis process. The process at the heart of the system splits water into hydrogen and oxygen, storing them in their own respective tanks and recombining them to generate electricity within the hydrogen fuel cell. The technology is promising, but large-scale projects will have to determine how energy efficient the entire process is. If this new artificial photosynthesis process proves economically viable, it could revolutionize the energy market.

There is also the kinetic energy solution to storing solar energy, which bucks the trend toward high-tech solutions and looks backward to ancient technology for inspiration instead. Designs such as the projects of masters like Leonardo da Vinci, Archimedes and the engineers of the Roman empire all help to influence the design of kinetic energy storage devices. One example of a kinetic energy storage system is to use solar electric energy to drive a water pump filling a water tower during the day, which stores the water's gravitational kinetic potential for later use. When night rolls around, the valve is opened and water flows through a turbine rotating generator, turning the energy back into electricity for distribution. With a solution that is so elegantly simple available, it is a wonder that it is not in wide scale use; it is, however, something easily accessible to the average backyard inventor.

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