Can solar energy be stored and run day and night? One of the problems ofsolar power it concerns conservation, when the sun is not there you risk running out of energy. An adequate storage method is still difficult: batteries for storing solar energy are very expensive and worse, they degrade very quickly. But fortunately things are changing, not surprisingly there are various methods that allow you to storing solar energy.
How to store solar energy, the batteries
There are ad hoc batteries on the market that allow you to to store large quantities of solar power. Here are two examples:
- Smart Energy Storage from Panasonic
- Kyocela Solar
How to store solar energy with the photovoltaic diamond
For some years now, ENEL in collaboration with the University of Pisa and the province of Florence has been using a sort of photovoltaic diamond. It is a dodecahedron structure located in Pratolino and can accumulate photovoltaic energy not fed into the grid in the form of hydrogen.
How does it work?
There are 38 photovoltaic panels installed on the structure that produce energy by directly exploiting the sun. The part not used during the day is stored in the form of hydrogen through fuel cells that can be used at night.
During the daytime phase, solar energy is captured by the photovoltaic panels and converted into low voltage electricity (48Vdc) to power the utilities. The unused part of energy is sent to an electrolyser which uses it to divide the water into oxygen and hydrogen subsequently accumulated in a special tank.
During the night phase, the energy produced and stored during the day is used thanks to a fuel cell that transforms the chemical energy contained in hydrogen into electricity. In this way, the continuous supply of utilities will be ensured.
How to store solar energy with compressed air technology
Thanks to the "Light Sail Energy" project led by scientist Danielle Fong, work is being done on the development of a compressed air technology capable of storing renewable energy that is not used.
What does it consist of?
It consists in using the energy produced by Solar Panel to power a compressor that pumps air into a tank. To reuse the energy produced, just let the air out and use it to power an electricity generator. One of the main problems of compressed air energy is its own efficiency since the heat created by the process is still lost. In this perspective, the project of theLight Sail Energy.
To get the most out of this type of power, it was discovered that the only thing to do is to keep the temperature constant both in compression and in expansion, so water is introduced to try to stabilize the temperature. This is the main idea from which the whole project started. The project has entered the practical development phase, it will be possible to deliver the first prototype already by the end of 2013.
How to store solar energy with electrolysis
Researchers at the University of Wisconsin-Madison have found a method to select catalysts to create and store solar energy. The research is published in the journal Angewandte Chemie. This method consists in transforming some substances, such as water, carbon dioxide and others into substances that can store solar energy through an electrolysis process.
The only problem is finding electrocatalysts that are effective, easily available and cheap. The sun is undoubtedly the largest energy source on the planet. It is true the sun does not always shine but we are confident that it will shortly in every home with solar system there will be the possibility to turn on a switch even at night.