MIT Professor of Energy Dr. Daniel Nocera has published a paper explaining a process that they’ve developed for splitting water into hydrogen and oxygen efficiently using solar electricity, and then use that hydrogen and oxygen in a fuel cell to re-generate electricity.

Sounds a bit silly when put like that, but the part that I missed out is that there is a time delay between splitting the water and using it to generate electricity.

Storage
Solar panels on the roof of the house generate electricity while the sun shines on them during the day, but at night they’re not generating anything. Additionally, during the day many houses are using less power since their occupants are out at work. The MIT plan is to use the excess energy from the panels during the day to split water into its two constituent gases, and store those in tanks in the house.

At night, when the panels are not generating any power, the hydrogen and oxygen are fed from the storage tanks into a fuel cell, generating electricity for the house’s night time needs (and water which can be split again the next day).

This video from MIT explains it in more detail:

Why Not Use Batteries?
Good question. Solar installations for off-grid projects will often make use of batteries to solve this problem of time shifting the power. The reason the hydrogen fuel cell idea is interesting comes down to energy density. A lithium-ion battery has a density of around 2.5 MJ/kg; a lead-acid battery is around 0.1 MJ/kg. Hydrogen has a density of 143 MJ/kg. So, storing the energy in the form of hydrogen makes sense as long as you can generate the hydrogen efficiently; and that has been the problem until now. The real breakthrough the MIT team claims to have made is in being able to efficiently split water into hydrogen and oxygen, and to do so using materials that are plentiful.

[Via Earth2Tech]

Tags: fuel cell, hydrogen, mit, nocera, solar, storage

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