Sahara Dust Heads for Germany as Solar Forecasts Diverge

Dust from the Sahara Desert that’s affecting U.K. air quality will cloud German skies tomorrow and cut reliability of forecasts for solar power generation, according to the weather forecaster MeteoGroup.

The concentration of airborne Saharan dust in southwest Germany will increase more than tenfold, according to University of Athens data. This may throw solar power predictions off by as much as 8,000 megawatts, equivalent to the output of about eight nuclear reactors, Andreas Gassner, a meteorologist at MeteoGroup’s unit in Appenzell, Switzerland, said today.

“The hot desert wind brings a lot of dust from the Sahara to Europe,” Kai Biermann, a forecaster for Deutscher Wetterdienst, said by phone from Hamburg. “It’s a phenomenon that doesn’t happen too often and the dream of every meteorologist but a nightmare for solar plant operators.”

Electricity produced from sun in Germany, Europe’s largest solar producer, increased to 4.7 percent last year from 1.8 percent in 2010, according to data from AG Energiebilanzen eV, an association of energy lobbies and economic research institutes. Power traders rely on solar forecasts to calculate supply and value the price of electricity, while plant operators use the predictions to help calculate income.

Naked Eye

The concentration of Saharan dust, kicked up by sandstorms in the desert 2,000 miles to the south, will rise to 5,687 milligrams a square meter (1.2 square yards) at 6 p.m. Berlin time tomorrow, compared with about 500 milligrams the same time today, the data show. By midday tomorrow, southwest German regions will see the dust before it starts to settle on April 4, especially in the north, according to Gassner.

“It’s striking that it’s visible to the naked eye,” Gassner said. “The dust can lead to either more or less clouds, depending on the humidity and condensation processes in the air, and the solar models can’t deal with this phenomenon properly.”

The price of power for delivery on July 21 fell by 18 percent when solar output in Germany reached a record 24,019 megawatts, exchange data show. Solar production in Germany peaked this week at 20,046 megawatts on March 31 and is forecast to reach a high of 18,954 megawatts today, according to Bloomberg’s solar model.

The pace of new solar installations in Germany has slowed as the nation reforms the support it provides producers. The amount of photovoltaic panels added in 2013 declined 57 percent to 3.3 gigawatts from 7.6 gigawatts in 2012, according to data from the European Photovoltaic Industry Association. One gigawatt, or 1,000 megawatts, is enough to power 2 million European homes.

Dust Direction

The Saharan dust has come into Europe mainly over France and the U.K. and may cause little change in Germany, according to WSI Corp. in Andover, Massachusetts. Peak production will be 24,245 megawatts on April 5, according to the forecaster.

“Our solar forecast did overestimate the production on March 31 slightly but there was quite a bit of cloud across the north of Germany which spread a little further south than expected,” Eleanor O’Neill, a meteorologist at WSI, said by e-mail. “It is largely clear over Germany today and we expect it to remain so with fairly good production.”

A large amount of sand and dust was swept up by 40-mile-per-hour winds in the Sahara Desert in northwest Africa, according to the U.K.’s Met Office. The airborne particles were blown north to the U.K. where they combined with warm air and were deposited during rain showers, the national forecaster said on its website March 31.

Lightsource Renewables Energy Ltd., the U.K.’s largest solar PV plant operator, washes dust and seed particles off its panels when solar output drops by 2 percent, according to Chris Buckland, the technical director at the company based near Salisbury, England.

“We are not seeing any effect at the moment. We will have a look after it stops raining to see if there is any impact,” he said.

Before it's here, it's on the Bloomberg Terminal.