Tuesday, April 28, 2015

Solar energy passes grid test during solar eclipse


Recently, grid operators across Europe anxiously observed a solar eclipse as it cast a shadow over the continent's vast installed solar photovoltaic (PV) systems. The rare celestial event posed a unique challenge for countries like Germany and Italy that significantly rely on solar energy for electricity production.

While grid operators are accustomed to the inherent intermittency of renewables, never before had a solar event tested the resiliency of a grid on this order of magnitude. Germany produces approximately 7 percent of its electricity from the sun and has over 38 gigawatts (GW) of PV capacity. With the total eclipse located in northern Europe, Berlin experienced an 80 percent eclipse around 11:00 a.m. local time, and with minimal cloud cover, the drop in solar electricity generation was nearly three times faster than a typical sunset, and the ensuing ramp-up was approximately four times more rapid than sunrise.

According to solar generation data provided by SMA, Germany was producing over 13 GW of solar electricity when the eclipse began. Over the course of less than one hour, the solar power on the grid dropped to below 5 GW before rising to over 20 GW at midday. The 15 GW swing over a course of one hour was "almost the most stressful situation which could have been anticipated during the eclipse."

With the present set of predictive tools, astronomers provided utilities and grid operators ample time to prepare for the eclipse. In Germany, the utility companies utilized hydroelectric pump-storage facilities and rapid-start gas turbine assets to stabilize the grid during the eclipse. However, grid operator Terna in Italy implemented a more cautious plan by proactively ceasing operation of it utility-scale (more than 100 kW) solar generation plants for the full day to avoid potential grid stability issues resulting from the two hours of the eclipse. Italy has 18 GW of installed solar power and has the highest solar energy penetration of any European country.

As solar power gains increased penetration in electricity markets around the world, utility companies can find comfort in Europe's successful management of the grid during an unprecedented test of the system. However, while the event demonstrated the grid operator's ability to effectively dispatch a large-magnitude capacity, concerns about solar intermittency will justifiably continue as future electricity swings will not be as predictable.

Utility companies looking to make their solar installations more robust and reliable can pursue two approaches to address irregular power production from the sun. First, they can implement better solar production and predictive weather data to improve response planning. Second, utilities can deploy utility-scale battery storage with near-instantaneous dispatchability, but they must be wary of how capital-intensive these projects will be.



Sent from my iPadmc

No comments:

Post a Comment