Monday, October 29, 2012

A Surprise: The Cost of Backing Up Renewables

Lux Research reports that wind farm output can fluctuate up or down by 3% over a ten-minute interval, 10% over a one-hour interval and 16% over a two-hour interval. Similarly solar panel output can plunge by 50% or more in a few minutes.

As stability in the grid is crucial, this means that some backup energy source, currently estimated at .5% of production, will be needed. As renewable (wind and solar) sources take up more of the burden of electric generation, so the need for backup sources will increase proportionately. In 2009 over 20,132,212 GWh of electricity was produced throughout the world. If renewable sources approach 30% production as planned, the backup storage requirements would be over 100,000 GWh.  Now for the shocker: Typical manufactured energy storage systems cost several million dollars per MWh. That is several billion dollars per GWh.

Per GWh. These are astronomical numbers.

And...AND...unlike the grid sources which can last for a couple of decades, the backup sources have to be replaced every three to seven years. Three to seven years!

Have these numbers been calculated in to the cost of renewables? And who is going to pay it?

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