Are Solar Farms heat islands (radiating heat beyond the installation area)
Solar farms have the potential to contribute to heat formation, although their overall impact is generally lower compared to urban areas or industrial zones. Heat islands occur when a specific area experiences significantly higher temperatures than its surrounding regions due to human activities and the built environment.
Solar farms generate heat through two primary mechanisms:
Absorption and re-emission of sunlight: Solar panels absorb sunlight to produce electricity, but a portion of that energy is converted into heat. While modern solar panels are designed to convert sunlight into electricity efficiently, some heat is inevitably generated. This localised heat generation can lead to a slight increase in temperature within the solar farm.
Modification of land surface:
Installing solar farms often involves clearing vegetation and altering the land surface, which can impact the area's energy balance. Vegetation plays a role in temperature regulation through transpiration and shading, but these cooling effects diminish when replaced by solar panels. As a result, the absence of vegetation cover can contribute to localised warming.
It's worth noting that solar farms typically cover large areas and are often situated in open, rural regions where land use is less dense compared to urban areas. Therefore, their contribution to heat islands is usually much lower than that of cities or urbanised regions with extensive infrastructure, concrete, and asphalt surfaces.
Furthermore, solar farms can also provide certain cooling benefits. Solar panels reduce the amount of sunlight reaching the ground, which can lower surface temperatures compared to bare, sunlit land. Additionally, solar panels absorb and convert solar energy, thereby reducing the amount of energy that would otherwise be converted to heat by other human activities, such as fossil fuel-based power generation.
Solar farms can be designed and managed with specific considerations to mitigate potential heat island effects. For example, incorporating vegetative buffers around the perimeter or interspersing the solar panels with low-growing vegetation can help reduce the heat island effect. Additionally, careful site selection, optimising panel orientation and spacing, and implementing cool roof technologies can minimise any localised temperature increases.
Local Heat Island Creation & Global Warming Effects
The vegetative characteristics of the land use, before and after the solar farm development occurs, plays a key role. Most studies have concluded the heating effects are localized with no overall day-to-day warming effect:
http://www.clca.columbia.edu/13_39th%20IEEE%20PVSC_%20VMF_YY_Heat%20Island%20Effect.pdf
https://www.nature.com/articles/srep35070
This has been translated into state planning guidelines in Australia, such as those published by Victoria:
Furthermore, UNSW was commissioned to put together this report for the NSW Government, which lists technical references:
NSW Government’s recently published Large-Scale Solar Energy Guideline represents the most comprehensive set of guidelines published by the Australian states:
The NREL has published a few reports related to the benefits of adding low-growing vegetation under solar panel installations:
https://www.nrel.gov/docs/fy14osti/60240.pdf
https://www.nrel.gov/docs/fy17osti/66218.pdf
Other resources available that describe the advantages of hybrid land use:
General Setback Distances between PV Solar Farms & Residential Dwellings
As this Australian Government statement describes, “Setback distances for large-scale solar arrays are still largely being developed and refined by state governments” https://www.aeic.gov.au/observations-and-recommendations/governance-compliance
In other jurisdictions further afield (for example), Indiana University’s Environmental Resilience Institute recommends a minimum setback distance of 150 feet (46.3 m):
https://eri.iu.edu/documents/in-solar-ordinance-2020-december.pdf
