Energy Storage
Posted 20/11/2012
Solar Energy Storage Battery at Miyako Island Solar Test Facility
The Holy Grail of the smart grid and our energy solution for the Island will be storage. As soon as you can store the renewable energy you generate you dislocate the demand and supply curves. You can then “store energy” when the renewables are in surplus and release them later when the need is greater.
Hydrogen: We have a Technology Strategy Board grant to place a Hydrogen Refueler on the Island. Based on a electrolysis process that uses renewable energy to split water and release Hydrogen which can then be stored in tanks up to 400 bar and released later when required. Uses include fuel cell vehicles, petrol vehicles that have been converted to hydrogen, hydrogen BBQ’s, hydrogen cookers and the ultimate perhaps hydrogen fuel cells back into the home. There is also an option to put Hydrogen back into the Natural Gas Grid up to 15% thereby greening up the gas supply and acting as a “repository” for surplus renewable energy.
One of the biggest problems in Scotland / Ireland / Germany at present is that they have so much renewable energy that they find it really hard to balance off their loads. One of the keys to energy balancing is being able to put surplus renewables into this kind of a storage facility to act as a buffer. It is even possible to use the “gas grid” as temporary storage i.e. hydrogen generated from renewables into the gas grid when in surplus and then back into energy as “therms” later. This requires very close co-operation with the gas company and to our knowledge has not been done before.
Battery: The technology in batteries is advancing all the time. There are currently EV batteries in development that can take 8,000 charges and re-charge cycles and a full charge from flat in 6 minutes. There is some new technology in liquid metal batteries, which may prove to be a breakthrough, and the team from Cambridge University Eco Racing Team are working with small cell Lithium Ion technology. One of our Partners specialises in battery technologies and we will be hosting a workshop on it at the Summit.
Cryogenic Energy Storage: There are experiments going on with cryogenic storage at the moment BUT to our knowledge there are no commercial applications of it. We are watching this space closely but the liquid-air energy storage system being developed by the Highview team at Leeds University is showing some promise.
Migrating demand: One of the most interesting things about the demand side piece is that by rolling small demand side management curtailments ( i.e. dimming of the lights / switching off appliances ) and joining them up you can migrate demand by short periods ( i.e. ½ hour off peak etc ). This requires some quite intense programming and is not a particularly easy thing to do but in areas where energy is in particularly scarce supply it actually works well.
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