If the future is solar, what happens when the sun goes away?

July 17, 2015 | By Jaclyn Brandt

In March, a solar eclipse over Europe created an important look into how a solar-heavy grid would handle an outage -- and the answers gave a look into the future of the grid.

The March eclipse's coverage. Credit: HM Nautical Almanac Office/ENTSOE

The eclipse gave grid operators a chance to test what the future would be like with additional solar on the grid -- if that solar were suddenly taken away. The next two eclipses will hit in 2021 and 2026, when solar capacity is expected to triple from today's rates. to be ready for this, a new report by SolarPower Europe and European Network of Transmission System Operators for Electricity (Entsoe), outlined five areas that need improvement before those dates.

The report, "The Successful Stress Test of Europe's Power Grid – More Ahead," looked at solar and how it would affect grid operators -- and vice versa -- at both the distribution and transmission levels.

The European grid has 90 gigawatts (GW) of solar, and grid operators had a lot to deal with on March 20. The eclipse lasted nearly three hours, and according to the report, "Beyond the lower PV generation during the eclipse, the most important expected challenge was the decrease of generation by 20 GW within 1 hour, and the increase of generation by almost 40 GW after the maximum impact of the eclipse."

Although the initial decrease from the eclipse was expected to be the greatest challenge, the report found that the hard work by the transmission system operators (TSO) to plan for the event, made it go seamlessly -- something that may be daily operating procedure in the future.

"Due to the careful and coordinated planning of the TSOs in advance (from August 2014 until March 2015) and thanks to a good communication before and during the eclipse it was not necessary for TSOs to provide any assistance to each other," the report said. "Even though during this predictable event no issues occurred, it still indicates careful planning and coordination between TSOs in all operation phases will be necessary during similar events."

During the 2021 eclipse, there is expected to be 170 GW of solar PV on the European grid, and during the 2026 eclipse, there is expected to be 250 GW. This will account for 7 percent and 15 percent of European electricity demand, respectively.

"Managing a solar eclipse of a significant scale with 90 gigawatts took a year's meticulous preparation and coordination," the report said. "Managing similar eclipses in 2021 and 2026 with twice and three times as much PV in Europe calls for change and rapid action in key areas."

PV industry, grid operators must work together to survive next big solar eclipses. The report found that changes of PV feed-in are expected in the future due to the increasing amount of installed PV capacity in the grids, and "Such events will be a challenging opportunity for the RSCIs to provide strong support to the TSOs in their task of guaranteeing secure and efficient operation of the interconnected system in every critical grid condition."

For more:
- read the full report

http://www.fierceenergy.com/story/if-future-solar-what-happens-when-sun-goes-away