Solar power installations have become increasingly attractive to pig enterprise managers in various countries, often due to financial support from governments and energy companies. But the history of solar panels on pig farm roofs has been uncertain at times. Early panels often included an aluminium frame that was soon corroded by the acidity of feed dust in the air extracted from the house. Newer frames are of stainless steel to correct this.

However, the dust in air leaving a pig house remains a problem, if the extractors are located close by the panels. A layer of dust across the surface of a panel can seriously limit its operating efficiency unless removed at frequent intervals.

That is why, in some countries where solar power is popular and pigs are typically housed indoors, commercial services now exist to visit farms on a regular basis and wash panels clean -- without the use of chemicals that could leave an undesirable film on the panel’s surface.