Solar cells combined with geothermal or wind power systems reduces climate and environmental impact

Climate change, driven by increasing greenhouse gas (GHG) emissions, necessitates a transition to sustainable energy sources. Electricity and heat production contribute significantly to global GHG emissions, highlighting the urgency for decarbonization. Sustainability assessments must consider not only GHGs but also other pollutants like toxicity and ecotoxicity. Renewable energy integration offers a solution, enhancing grid reliability, efficiency, and land use. This study evaluates the environmental impact of three integrated renewable power cycles: combined geothermal-wind (CGW), combined solar-geothermal (CSG), and combined solar-wind (CSW), incorporating the emerging perovskite solar cell (PSC) technology. The goal is to provide a comprehensive environmental assessment of these integrated systems to inform sustainable energy strategies and guide investment decisions in a rapidly evolving renewable energy landscape.

Existing literature includes thermodynamic and economic studies on standalone geothermal, solar, and wind power plants. Technical and thermodynamic assessments of combined geothermal, solar, and wind power cycles have also been conducted. Life cycle assessments (LCAs) of individual geothermal, solar (including PSCs), and wind technologies are available. However, research on the environmental effects of combining two renewable power cycles, especially incorporating emerging technologies like PSCs, is limited. This study addresses this gap by providing a detailed LCA of integrated renewable power systems, including the promising but relatively less-studied PSC technology.

This study employs a life cycle assessment (LCA) approach to evaluate the environmental impacts of three integrated renewable power plant configurations: CGW, CSG, and CSW. The LCA considers the entire lifecycle from raw material extraction to electricity generation, encompassing manufacturing, installation, operation, and maintenance (O&M). A perovskite solar cell (PSC) system, with varying lifespans (3, 5, 10, and 15 years) and efficiencies (17% to 35%), is incorporated into the CSG and CSW scenarios to analyze the influence of technological advancements on environmental performance. The OpenLCA tool is used for modeling, with a cradle-to-gate system boundary and a functional unit of 1 kWh of net energy. The ReCiPe 2016 (H) midpoint approach is used for impact assessment. A sensitivity analysis using scenario analysis examines the effects of extending PSC lifespan and improving efficiency. Finally, a scoring method visually compares the environmental performance of all scenarios across four impact categories: Climate Change (CC), Freshwater Ecotoxicity (FE), Ozone Depletion (OD), and Marine Ecotoxicity (ME). These categories were chosen based on their significant influence, as determined by normalized impact assessment results.

The base case scenarios (3-year PSC lifespan, 17% efficiency) revealed that combined solar-wind (CSW) had the lowest CC and OD impacts, while combined geothermal-wind (CGW) had the lowest FE and ME impacts. Extending the PSC lifespan significantly reduced environmental impacts, with the most substantial reductions seen in the CSW scenario (56% decrease in CO2 emissions with a 15-year lifespan compared to a 3-year lifespan). Improving PSC efficiency also yielded significant emissions reductions (37% decrease in the CSW scenario with 35% efficiency compared to 17% efficiency). However, lifespan improvements had a more substantial impact than efficiency enhancements. The contribution analysis revealed that different life cycle stages (e.g., O&M, manufacturing, well drilling) had varying degrees of impact across different impact categories and scenarios. The scoring method showed that CSW cycles generally had the lowest CC and OD impacts, while CSG cycles had the lowest FE impacts. The most sustainable scenarios varied depending on the specific impact category. A detailed breakdown of the contribution of each phase (raw material extraction, manufacturing, M&I, O&M) to the CC and FE impacts is provided with pie charts, showing the dominant contributors for each scenario and impact category. The sensitivity analysis, using lifespan and efficiency changes, quantified the effect of technological advancements on the environmental impact. The analysis highlighted the significant influence of PSC improvements on the overall sustainability of the integrated systems, particularly the reduction in greenhouse gases with improvements in PSC lifespan.

The findings highlight the environmental benefits of integrating renewable energy sources. The results emphasize the significant role of technological advancements in reducing the environmental footprint of integrated renewable energy systems. The substantial reductions in greenhouse gas emissions resulting from increased PSC lifespan and efficiency highlight the importance of investing in research and development for emerging renewable technologies. The study's findings support the integration of multiple renewable sources to create resilient and sustainable energy systems. However, challenges remain, including the intermittency of solar and wind energy and the complexities of grid integration. The limitations of the study, mainly concerning data availability and maturity for PSCs, need to be considered when interpreting the results.

This study provides a comprehensive LCA of integrated renewable energy systems, incorporating the promising PSC technology. The results demonstrate the significant environmental benefits of integrating multiple renewable energy sources and the critical role of technological advancements in minimizing environmental impacts. Future research should focus on enhancing data collection for PSCs, standardizing end-of-life management, and broadening the analysis to include a wider range of technologies and social and regulatory considerations.

The LCA results for PSCs are subject to uncertainties due to the limited data available for this emerging technology, especially regarding large-scale production, material use, and end-of-life management. The study excludes the transportation phase and end-of-life phase due to data limitations. The study's findings are based on specific assumptions regarding PSC lifespan, efficiency, and other system parameters. Variations in these parameters could influence the results.