Netting has been fitted on the new recycling shed at Moorwell to prevent seagull poo impairing the effectiveness of the solar panels.
Cllr Steve Sims explained at last week's Full Council meeting that the netting will act as a deterrent to birds settling on the roof.
He later told This is Scilly: "Lots of gulls hang around on the roof at the Porthmellon waste site because it remains a very good food source for them. The PV panels were virtually useless because the bird poo was getting caked over them.
"Jet washing wasn't a particularly viable option because of accessibility and the water shortage issues."
Bird droppings can "create hotspots and subsequent failures of cells within panels", resulting in a loss of output, according to PV panel cleaning firm Clean Solar Solutions.
Cllr Sims, who deals with waste and recycling in his capacity as Lead Member for Place, said guano should not be a problem elsewhere to the same extent.
He added: "The problem will get better as the food source is removed due to improving waste management methods."
Photo by CTM Solar Blog.