<blockquote>'Vanadium "redox flow" batteries are indeed stable. They can be discharged and recharged 20,000 times without much loss of performance, and are thought to last decades (they have not been around long enough for this to have been demonstrated in practice).
They can also be enormous, and - in large part thanks to their vanadium content - expensive. The smallest of the "Cellcube" batteries that American Vanadium is producing in partnership with German engineering firm Gildemeister has a footprint the size of a parking bay and costs $100,000.
..
Radvak says that among his target customers are large corporate electricity consumers such as the Metropolitan Transport Authority, which runs New York's subway, and with whom his firm has just signed a pilot deal to supply Cellcube batteries.
Such companies are facing ever higher charges for the electricity they use during the peak hours of the day, and the Canadian claims they can cut their bills by a quarter if they use a battery to draw down the daytime electricity they need during the night, when it is cheapest.
By flattening out demand between the daily peaks and troughs, the batteries also help out the electricity companies.
One of their biggest expenses is investing in the extra power station capacity that is only ever called upon for a few hours each year when the weather, holidays and the time of day all conspire to produce the biggest peak in electricity demand.
That challenge of balancing electricity supply and demand is set to get a whole lot more difficult as ever more solar and wind energy is added to the grid.
..
Rooftop solar panels don't just produce electricity at the "wrong" time of day, they also produce it at a low voltage, which, according to the German renewable energy entrepreneur Alexander Voigt, means it is effectively trapped at the level of the local community.
"Our traditional electricity grid is built in a way that the energy flows from the high voltage to the low voltage, and not the other way round," he says.
That means the solar energy can only be shared among the few households - typically just a village or a town neighbourhood - that happen to share the same transformer station that plugs them into the high-voltage national grid.
Voigt helped set up the vanadium battery company that was later bought up by Gildemeister. He foresees the batteries being built next to transformers, where they can store up each community's daily solar surplus, before releasing it back again in the evening.'
- Laurence Knight,
Vanadium: The metal that may soon be powering your neighbourhood, June 13, 2014</blockquote>
Context<blockquote>
(Germany's Green Energy Revolution) - Wind- und Solaranlagen produzieren erstmals Strom mit über 30.000 MW Leistung</blockquote>