Microclimate-adjusted carbon density modeling improves carbon density estimation for photovoltaic-impacted grasslands...

Area of Science:

• Environmental Science
• Ecology
• Renewable Energy

Background:

• Conventional carbon-pool assessments at photovoltaic (PV) facilities use static land-cover values, neglecting microclimatic changes.
• This limitation is significant in drylands, where PV arrays alter thermal conditions and vegetation responses, impacting carbon dynamics.
• Existing methods fail to capture the nuanced effects of PV installations on local environments.

Purpose of the Study:

• To evaluate carbon-pool changes at PV facilities in Inner Mongolia using both conventional and microclimate-adjusted approaches.
• To introduce and validate a novel method (M2) that incorporates microclimate adjustments (δ_micro) into carbon-pool assessments.
• To compare the accuracy and effectiveness of the microclimate-adjusted approach against traditional methods.

Main Methods:

• Evaluated 189 PV facilities (254 km²) in Inner Mongolia using a conventional static land-cover carbon-density approach (M1).
• Developed and applied a microclimate-adjusted approach (M2) incorporating a signed microclimate adjustment term (δ_micro).
• Conducted field-based evaluations at 42 PV facilities to compare M1 and M2 against measured carbon densities.

Main Results:

• The microclimate adjustment term (δ_micro) varied significantly across land-cover transitions, from +36.2% (bare-land-to-grassland) to -12.6% (grassland-to-bare-land).
• The microclimate-adjusted approach (M2) demonstrated higher agreement with measured carbon densities (R² = 0.730) than the conventional approach (M1, R² = 0.624).
• M2 showed lower site-level absolute errors and significant differences in paired tests (p < 0.05) compared to M1.

Conclusions:

• Microclimate-adjusted accounting significantly improves carbon-pool assessment accuracy at PV facilities, especially in dryland grasslands.
• The findings highlight the importance of considering PV-induced microclimatic modifications for precise environmental impact assessments.
• This approach offers context-sensitive data for vegetation management and land-use screening following PV construction.