Will the March 20th Total Solar Eclipse Impact Europe’s Solar Energy Grid?

The first eclipse of 2015 is coming right up on Friday, March 20th, and may provide a unique challenge for solar energy production across Europe.

Sure, we’ve been skeptical about many of the websites touting a ‘blackout’ and Y2K-like doom pertaining to the March 20th total solar eclipse as of late. And while it’s true that comets and eclipses really do bring out the ‘End of the World of the Week’ -types across ye ole web, there’s actually a fascinating story of science at the core of next week’s eclipse and the challenge it poses to energy production.

But first, a brief recap of the eclipse itself. Dubbed the “Equinox Eclipse,” totality only occurs over a swath of the North Atlantic and passes over distant Faroe and Svalbard Islands. Germany and central Europe can expect an approximately 80% partially obscured Sun at the eclipse’s maximum.

The magnitude of the March 20th solar eclipse across Europe. Credit: Michael Zeiler/GreatAmericanEclipse.com

We wrote a full guide with the specifics for observing this eclipse yesterday. But is there a cause for concern when it comes to energy production?

A power grid is a huge balancing act.  As power production decreases from one source, other sources must be brought online to compensate. This is a major challenge — especially in terms of solar energy production.

Residential solar panels in Germany. Credit: Wikimedia Commons/ Sideka Solartechnik.
Residential solar panels in Germany. Credit: Wikimedia Commons/ Sideka Solartechnik.

Germany currently stands at the forefront of solar energy technology, representing a whopping quarter of all solar energy capacity installed worldwide. Germany now relies of solar power for almost 7% of its annual electricity production, and during the sunniest hours, has used solar panels to satisfy up to 50% of the country’s power demand.

We recently caught up with Barry Fischer to discuss the issue. Fischer is the Head Writer at Opower, a software company that uses data to help electric and gas utilities improve their customer experience. Based on Opower’s partnerships with nearly 100 utilities worldwide, the company has amassed  the world’s largest energy dataset of its kind which documents energy consumption patterns across more than 55 million households around the globe.

A study published last week by Opower highlights data from the partial solar eclipse last October over the western United States. There’s little historical precedent for the impact that an eclipse could have on the solar energy grid. For example, during the August 11th, 1999 total solar eclipse which crossed directly over Europe, less than 0.1% of utility electricity was generated using solar power.

Looking at the drop in power production during the October 2014 solar eclipse. Credit: Opower.

What they found was intriguing. Although the 2014 partial solar eclipse only obscured 30 to 50% of the Sun, solar electric production dropped over an afternoon span of nearly three hours before returning to a normal pattern.

Examining data from 5,000 solar-powered homes in the western United States, Opower found that during the eclipse those homes sent 41% less electricity back to the grid than normal. Along with a nearly 1,000 megawatt decline in utility-scale solar power production, these drop-offs were compensated for by grid operators ramping up traditional thermal power plants that were most likely fueled by natural gas.

No serious problems were experienced during the October 23rd, 2014 partial solar eclipse in terms of solar electricity production in the southwestern United States, though it is interesting to note that the impact of the eclipse on solar energy production could be readily detected and measured.

The projected effect of the March 20th eclipse on solar power production. Credit: Opower.

How does the drop and surge in solar power output anticipated for the March 20th eclipse differ from, say, the kind presented by the onset of night, or a cloudy day? “The impact of an eclipse can register broadly – and unusually rapidly – across an entire region,” Fischer told Universe Today. On a small scale, one area many be cloudy, while on a larger regional scale, other areas of clear or partly sunny skies can compensate. An eclipse — even a partial one — is fundamentally different, because the sudden onset and the conclusion are relatively uniform over a large region.

The March 20th event offers an unprecedented chance to study the effects of an eclipse on large-scale solar production up close. A study (in German) by the University of Applied Sciences in Berlin suggests that solar power production will fall at a rate 2.7 times faster than usual as the eclipse progresses over a span of 75 minutes. This is the equivalent of switching off one medium-sized power plant per minute.

The anticipated slingshot might be just as challenging, as  18 gigawatts of power comes back online at the conclusion of the eclipse in just over an hour. And as opposed to the 2014 eclipse over the U.S. which ended towards sunset, the key rebound period for the March 20th eclipse will be around local noon and during a peak production time.

Fischer also noted that “the second half of the partial solar eclipse will also pose a notable challenge” for the grid, as it is flooded with solar power production 3.5 times faster than normal. This phenomenon could also serve as a great model for what could occur daily on a grid that’s increasingly solar power reliant in the future, as energy production ramps up daily at sunrise. Such a reality may be only 15 years away, as Germany projects installed solar capacity to top 66 gigawatts by 2030.

The Crescent Dunes Solar Energy Project outside of Tonopah, Nevada. Credit:  Wikimedia Commons/Amble. Licensed under a CC BY-SA 4.0 license.

What’s the anticipated impact projected for a future eclipse such as, say, the 2017 and 2024 total solar eclipses over the U.S.?

This eclipse may serve as a great dry run for modeling what could occur as reliance on solar energy production grows.

Such is the modern technical society we live in. It’s fascinating to think that eclipses aren’t only a marvelous celestial spectacle, but their effects on power production may actually serve as a model for the smart grids of tomorrow.




A Complete Guide to the March 20th Total Solar Eclipse


The first of two eclipse seasons for the year is upon us this month, and kicks off with the only total solar eclipse for 2015 on Friday, March 20th.

And what a bizarre eclipse it is. Not only does this eclipse begin just 15 hours prior to the March equinox marking the beginning of astronomical spring in the northern hemisphere, but the shadow of totality also beats path through the high Arctic and ends over the North Pole.

An animation of the March 20th eclipse. Credit: NASA/GSFC/AT Sinclair.

Already, umbraphiles — those who chase eclipses — are converging on the two small tracts of terra firma where the umbra of the Moon makes landfall: the Faroe and Svalbard islands. All of Europe, the northern swath of the African continent, north-central Asia and the Middle East will see a partial solar eclipse, and the eclipse will be deeper percentage-wise the farther north you are .

2015 features four eclipses in all: two total lunars and two solars, with one total solar and one partial solar eclipse. Four is the minimum number of eclipses that can occur in a calendar year, and although North America misses out on the solar eclipse action this time ’round, most of the continent gets a front row seat to the two final total lunar eclipses of the ongoing tetrad on April 4th and September 28th.

How rare is a total solar eclipse on the vernal equinox? Well, the last total solar eclipse on the March equinox occurred back in 1662 on March 20th. There was also a hybrid eclipse — an eclipse which was annular along a portion of the track, and total along another — on March 20th, 1681. But you won’t have to wait that long for the next, as another eclipse falls on the northward equinox on March 20th, 2034.

The path of the March 20th eclipse across Europe, including start times for the partial phases, and the path of totality, click to enlarge. For more maps showing the percentage of occlusion, elevation, and more, click here. Credit: Michael Zeiler/GreatAmercianEclipse.com.

Note that in the 21st century, the March equinox falls on March 20th, and will start occasionally falling on March 19th in 2044. We’re also in that wacky time of year where North America has shifted back to ye ‘ole Daylight Saving (or Summer) Time, while Europe makes the change after the eclipse on March 29th. It really can wreak havoc with those cross-time zone plans, we know…

The March 20th eclipse also occurs only a day after lunar perigee, which falls on March 19th at 19:39 UT. This is also one of the closer lunar perigees for 2015 at 357,583 kilometres distant, though the maximum duration of totality for this eclipse is only 2 minutes and 47 seconds just northeast of the Faroe Islands.

Views from selected locales in Europe and Africa. Credit: Stellarium.

This eclipse is number 61 of 71 in solar saros series 120, which runs from 933 to 2754 AD. It’s also the second to last total in the series, with the final total solar eclipse for the saros cycle occurring one saros later on March 30th, 2033.

And speaking of obscure eclipse terminology, check out this neat compendium we came across in research. What’s an Exeligmos? How many Heptons are in a Gregoriana?

The 462 kilometre wide path of the eclipse touches down south of Greenland at 9:13 UT at sunrise, before racing across the North Atlantic towards the pole and departing the Earth at 10:21 UT. The sedate partial phases for the eclipse worldwide start at 7:40 UT, and run out to 11:51 UT.

What would it look like to sit at the North Pole and watch a total solar eclipse on the first day of Spring? It would be a remarkable sight, as the disk of the Sun skims just above the horizon for the first time since the September 2014 equinox. Does this eclipse occur at sunrise or sunset as seen from the pole? It would be a rare spectacle indeed!

An equinoctal eclipse as simulated from the North Pole. Credit: Stellarium.

Alas, this unique view from the pole will more than likely go undocumented. A similar eclipse was caught in 2003 from the Antarctic, and a few intrepid eclipse chasers, including author David Levy did manage to make the journey down under to witness totality from the polar continent.

Practicing eclipse safety in Africa. Credit: Michael Zeiler/GreatAmericanEclipse.com

Safety is paramount when observing the Sun and a solar eclipse. Eye protection is mandatory during all partial phases across Europe, northern Asia, North Africa and the Middle East. A proper solar filter mask constructed of Baader safety film is easy to construct, and should fit snugly over the front aperture of a telescope. No. 14 welder’s goggles are also dense enough to look at the Sun, as are safety glasses specifically designed for eclipse viewing. Observing the Sun via projection or by using a pinhole projector is safe and easy to do.

A solar filtered scope ready to go in Tucson, Arizona. Credit: photo by author.

Weather is always the big variable in the days leading up to any eclipse. Unfortunately, March in the North Atlantic typically hosts stormy skies, and the low elevation of the eclipse in the sky may hamper observations as well. From the Faroe Islands, the Sun sits 18 degrees above the horizon during totality, while from the Svalbard Islands it’s even lower at 12 degrees in elevation. Much of Svalbard is also mountainous, making for sunless pockets of terrain that will be masked in shadow on eclipse day. Mean cloud amounts for both locales run in the 70% range, and the Eclipser website hosts a great in-depth climatology discussion for this and every eclipse.

The view of totality and the planets as seen from the Faroe Islands. Credit: Starry Night.

But don’t despair: you only need a clear view of the Sun to witness an eclipse!

Solar activity is also another big variable. Witnesses to the October 23rd, 2014 partial solar eclipse over the U.S. southwest will recall that we had a massive and very photogenic sunspot turned Earthward at the time. The Sun has been remarkably calm as of late, though active sunspot region 2297 is developing nicely. It will have rotated to the solar limb come eclipse day, and we should have a good grasp on what solar activity during the eclipse will look like come early next week.

And speaking of which: could an auroral display be in the cards for those brief few minutes of totality? It’s not out of the question, assuming the Sun cooperates.  Of course, the pearly white corona of the Sun still gives off a considerable amount of light during totality, equal to about half the brightness of a Full Moon. Still, witnessing two of nature’s grandest spectacles — a total solar eclipse and the aurora borealis — simultaneously would be an unforgettable sight, and to our knowledge, has never been documented!

We also put together some simulations of the eclipse as seen from Earth and space:

Note that an area of southern Spain may witness a transit of the International Space Station during the partial phase of the eclipse. This projection is tentative, as the orbit of the ISS evolves over time. Be sure to check CALSky for accurate predictions in the days leading up to the eclipse.

The ISS transits the Sun during the eclipse around 9:05 UT as seen from southern Spain. Credit: Starry Night.

Can’t make it to the eclipse? Live in the wrong hemisphere? There are already a few planned webcasts for the March 20th eclipse:

Astronomia Practica plans to post photos in near real time of the eclipse from northern Scotland.

-Slooh has plans to broadcast the eclipse from the Faroe Islands.

-And here’s another webcast from the Faroe Islands and the path of totality courtesy of Kringvarp Føroya:

-Here’s another broadcast planned of the partial stages of the eclipse as seen from the UK.

-And our friends over at the Virtual Telescope Project also plans on webcasting the solar eclipse:

… and speaking of which, there’s also an exciting new Kickstarter project entitled Chasing Shadows which is headed to the Arctic to follow veteran eclipse chaser Geoff Sims (@beyond_beneath of Twitter):

And stay tuned, as North America and the Pacific region will witness another total lunar eclipse on April 4th 2015. And we’ve only got one more total solar eclipse across Southeast Asia in 2016 before the total solar eclipse of August 21st 2017 spanning the U.S.

Let the first eclipse season of 2015 begin!

Next… how will the solar eclipse affect the European solar grid? Expect an article on just that soon!