Operating electric grids with more intermittent renewable energy sources, wind and solar, do not come without challenges. Some examples:

In California with increasing amounts of solar behind the meter it has been recognized that the load curve is changing significantly. The new load curve, based on its shape called the “duck curve”, will set high demands on the system to ramp up and down.

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Germany is by many seen as a leader in renewable energy development. Of the 615 TWh (1 TWh = 1 billion kWh)) produced in 2011 7.5 % was produced by wind and 3.1 % by solar (almost all is photovoltaic, PV). All renewable energy sources added up to 19.9 %. In 2012 the portion of renewable energy produced had grown to 22 %. On October 3 this year (2013) at noon wind and PV reached a record peak of 59.1 %.

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Plug-in electric vehicles (PEV) may not come fast enough to reach President’s Obama’s vision of One Million PEVs in the US by 2015, but they are coming. As of November 30 2013 accumulated since 2010 158 600 PEVs have been sold.  It is an impressive number but still just a fraction of the over 250 million registered passenger cars in the US.

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A need for a National Energy Plan is frequently voiced. The reasons for such a plan vary. Some want it for long-term “stability” to enable financing for large power plants. Others want it for a faster change to renewable energy. Etc.

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