After the Naval Air Warfare Center Weapons Division realized it was losing 30 percent of the efficiency on a test solar array it installed at a facility in Djibouti, Africa, it was time for some problem solving.

Most solar panels in the northern hemisphere are installed facing south and at an angle matching the location’s latitude. Since Djibouti is at just 11 degrees, dust settled easily on the panels.

“The original single containerized living unit project in 2010 was a test to quantify the amount of soiling on the PV panels,” said Matt Malone, an engineer in the Naval Air Warfare Center Weapons Division Renewable Energy Office. “It was known that there was a lot of dust in the area but no actual data had been taken to determine soiling levels.”

The test proved that the soiling diminished solar electricity generation by 30 percent.

To solve for issues with the test project, Malone and his team implemented a few changes.

Some of the panels were turned to face west, which could help them capture more solar energy in the afternoon and evening when electricity demand is at its peak with people returning home and turning on air conditioners and using their computers and other electronics.

Other panels were tilted to 30 degrees to keep the dust from settling on them. And Malone just installed an automatic cleaning system that he said works like a sprinkler system to wash the panels periodically. The system cost about $8,500, adding a little more than 10 percent to the total system cost.

Since all of the changes to the test are new, Malone said there isn’t significant data yet about how the changes will impact the system’s energy output.

The system, as a test, isn’t very big. It provides only a tiny fraction of the Navy's Djibouti facility’s energy needs. But Malone said it still saves the facility from needing to use about 10 gallons of diesel fuel per day for its generators.