US Solar Land Use Challenge

• Mojave Desert ecosystem changing due to solar farm expansion
• Blue patches (solar farms) replacing Joshua trees and wildflower fields
• Environmental activists/residents opposing desert solar development
• Solar farms disrupting agricultural land and diverse ecosystems
• Biden 2021 net-zero emissions goal by 2050 requires massive land use

Current Solar Development Patterns

• Study findings on utility-scale solar placement:
  • 50%+ in deserts
  • 33% in croplands
  • 10% in grasslands/forests
  • Only 2.5% in urban areas
• Rural placement cheapest/fastest but creates problems:
  • Bulldozing massive land areas
  • Altering plant/animal migration patterns
  • Local opposition to ruined natural views
  • Farmland preservation concerns

Growing Resistance to Large-Scale Solar

• Joshua Pearce (photovoltaics researcher, University of Western Ontario)
• Progressive resistance across middle US to large-scale solar
• Some resistance funded by fossil fuel companies
• Legitimate local concerns exist
• Solar expansion stalled by protests: Massachusetts, Ohio, California
• Agrovoltaics emerging as compromise solution
• Rural solar requires expensive long-distance transmission lines

Parking Lot Solar Solution

• US parking lots cover 5%+ of developed land
• Decades of car-centric city design created opportunity
• Solar canopies could utilize "wasted space except for parking"
• Most parking lots unused most of the time
• France 2023 policy example:
  • Car parks 80+ spaces must cover 50% with solar canopies
  • Estimated 10 nuclear power plants worth of capacity
• Benefits: cleared land, low biodiversity, close to consumers, shade/weather protection

Cost Barriers and Economic Analysis

• Solar canopies 50-100% more expensive than conventional solar farms
• Higher structural costs due to elevation/wind resistance
• Pearce 2017 Walmart study findings:
  • High solar flux areas (Phoenix) incredibly profitable
  • Low solar flux areas (Michigan) still profitable long-term
  • Depends on electricity costs and solar radiation
  • Most US (except Northern Alaska) has good solar flux
  • Western Pennsylvania systems still economic

Walmart Case Study Results

• 2021 study: All US Walmart Supercenters total capacity 11.1 gigawatts
• Comparable to French parking lot program estimates
• Could power 100 EV charging stations per Walmart location
• Combined with rooftop solar: enough to power stores
• Opportunities: sell power to grid, anchor local microgrids, outage backup
• 25-year warranty makes it capital investment with planetary benefits

Current Implementation and Policy

• Early adopters: airports, universities
• Walmart and Target beginning trials at select stores
• Policy developments:
  • Maryland grants for solar canopies
  • NYC zoning proposal: 8,500+ acres of parking lots eligible
• Not one-size-fits-all solution
• Requires good locations and upfront capital investment capability

Comprehensive Solar Strategy

• Parking lots alone cannot solve land scarcity
• Required combination approach:
  • Rural utility-scale arrays
  • Canopies where feasible
  • Rooftop arrays
  • Highway installations
  • Landfill installations
  • Degraded land usage
• Solar canopies part of large toolbox to reduce fossil fuel reliance
• Future potential: repurposing America's overlooked urban spaces