Nearby vegetation

Nearby vegetation means plants, grasses and trees growing under, around or next to a PV array. Woody growth in particular can grow into modules and structures and damage them mechanically. Plants under an array are not a problem in themselves. Trouble begins when they grow up through the array, cast shadows on modules or grow into equipment. Shading from vegetation cuts module output by more than the shaded area would suggest. It can also cause hotspots that may damage modules over the long term. Trees on neighbouring land keep growing for years. Check during siting and operation whether they will eventually shade the array. Vegetation also adds biological soiling such as fallen leaves, tree resin and pollen. Along with humid climate and nearby water, it is treated as a sign that widespread fungal soiling losses may recur at a site. Dry, poorly managed vegetation raises fire risk, including fires started by electrical arc faults. Sites in vegetated regions need fire breaks and close control of growth in wetter months. Moderate climates support plant growth all year, so vegetation control is a routine preventive maintenance task there. Exposure is reduced by mowing, grazing animals, or herbicide applied without spraying the modules, and by designing for high ground clearance with low-growth ground cover. Mowing can throw debris that damages modules.

<!-- review notes

• sentence 4: support check: partial - u5 says to consider how tall adjacent trees will be in 20 years during site selection, and u19 says to consider tree growth during operation. Neither says trees keep growing for years, and the 'check during siting and operation' wording is a paraphrase.
• sentence 5: support check: partial - u30 covers fallen leaves, resin and pollen as biological soiling, and u8 says to include bio-soiling in loss assumptions where humid climate, vegetation or water proximity suggest recurrence. The passages do not say 'widespread fungal' soiling losses, and u8 refers to bio-soiling and 'fungal' only loosely.
• sentence 7: support check: partial - u20 says moderate climates are very suitable for vegetation throughout the year, and u19 lists vegetation management as a common preventive maintenance action. Neither says vegetation control is a routine task specifically in moderate climates. -->