Intermittent energy sources
Sunday August 18 Germany set a new renewable record. That day at 2 pm generation from renewable energy sources provided 75 % of all power needed to satisfy the total demand of electric energy.
Less noticed was that Burlington Electric Department, Vermont, in September with the purchase of a 7.4 MW hydroelectric facility achieved its goal of reaching 100 % from renewable energy.
While Germany’s August 18 record was a peak, Burlington’s 100 % is basically on a continuous basis.
What makes Burlington Electric’s achievement additionally impressive is that retail electricity rates in Burlington are less than half of the rates in Germany, 13.7 cents/kWh (time of use rate 2014) versus 36.25 cents/kWh (average 2013).
Operating electric grids with more intermittent renewable energy sources, wind and solar, do not come without challenges. As discussed in my previous blog, The Importance of Strong and Nice Neighbors, the experiences from Denmark and Germany illustrates the value of strong electric ties with neighboring systems.
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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