Eco-innovation minimizes the carbon footprint of wine production

The study addresses how eco-innovation can minimize the carbon footprint (CF) of wine production and align the industry with the UN Sustainable Development Goals (notably SDG 9). Against a backdrop of substantial global wine output and mounting climate pressures, the paper argues that transitioning from linear to circular economy models is essential. It highlights that conventional LCAs may underestimate total greenhouse gas emissions by overlooking biogenic CO2 from fermentation, wastewater emissions, and soil carbon fluxes. The authors aim to analyze existing winery LCAs, identify overlooked emission sources, and demonstrate how eco-innovations—constructed wetlands (CWs) and a solar-integrated microalgal system (Phycosol)—can close resource loops and reduce CFs while advancing SDGs 6, 9, and 12.

Prior work shows viticulture, winemaking, and bottling as major CF contributors, with packaging, post-fertilization field emissions, electricity use, and logistics as hotspots. Studies (e.g., Navarro et al., Chiriaco et al.) suggest winemaking and bottling can account for up to 85% of total bottle CF, but conventional LCAs often omit biogenic fermentation CO2, wastewater emissions, and soil carbon fluxes, potentially underestimating total GHGs. Reports from California, New Zealand, Australia, and Europe provide sustainability indicators, and multiple studies advocate integrating biogenic carbon accounting into LCAs to better reflect vineyard carbon budgets. Literature on wastewater treatment indicates that conventional activated sludge processes (ASP) are energy- and emissions-intensive, whereas nature-based systems (CWs, high rate algal ponds) show lower environmental impacts. Emerging research on microalgae systems demonstrates potential for CO2 capture, resource recovery, and reduced GHGs compared to traditional routes.

The authors conducted: (1) a mapping of eco-innovation types (Organization, Process, Product, Marketing) to widely used sustainability indicators in the wine industry (biodiversity, energy efficiency, carbon footprint, waste and circularity, logistics, society and community) based on their relevance, frequency in reports, and comprehensiveness; (2) a qualitative mapping of eco-innovations to specific SDG 9 targets and other SDGs using a seven-point interaction scale (from +3 to −3) following established frameworks; (3) a global data analysis of biogenic fermentation CO2 and winery wastewater generation, compiling COD and TN data from 40 studies to estimate CH4 and N2O emissions using IPCC-recommended emission factors; (4) comparative assessment of GHG emissions from different wastewater treatment strategies—ASP, constructed wetlands (CW), and Phycosol (a solar-integrated microalgal system)—including reported CFs for aerobic winery wastewater facilities and process-level CH4/N2O emissions; (5) estimation of carbon sequestration potential in microalgal systems using stoichiometric and mass-balance equations for photoautotrophic and mixotrophic growth (including assumptions on COD, biomass productivity, glucose fraction, and CO2 uptake), and calculation of potential CO2 capture per 750 mL bottle; (6) estimation of Scope 1 and Scope 3 emission reductions from substituting synthetic N fertilizers with microalgal biomass (de-oiled, lipid-extracted, fresh) produced via Phycosol, using default N2O emission factors and embodied emissions in fertilizer production and transport; (7) a techno-economic analysis (TEA) referencing prior LCA/TEA studies to compare capital/operational costs and person-equivalent annual CO2-eq reductions for CW and Phycosol versus conventional ASP. Data supporting figures and tables were compiled into a supplementary dataset (figshare).

• Conventional farming shows the highest fossil and biogenic CFs per bottle compared with mixed and organic systems; organic generally has lower fossil CF due to reduced synthetic inputs.
• Conventional LCAs likely underestimate winery CF by excluding biogenic fermentation CO2, wastewater emissions, and soil carbon fluxes. Estimated global biogenic fermentation averages 217×10^6 tonnes CO2-eq (range 83–497×10^6 tonnes CO2-eq).
• Wastewater analysis across 40 studies shows wide regional variability; in Europe, CH4 emissions span up to 5726.40 g kg−1 COD and N2O up to 7.391 g kg−1 TN, underscoring the influence of local practices.
• Reported CF for aerobic winery wastewater treatment facilities: 9.86–17.10 kg CO2-eq per m3 of treated wastewater. ASP GHGs observed: 239–282 kg CO2, 0.08 kg N2O, and 0.20–0.40 kg CH4 per m3 treated (case-specific).
• Eco-innovation wastewater options: CWs and Phycosol have lower emissions than ASP. CWs show lower energy/chemical use and high removal rates (up to 10 kg COD m−2 d−1 vs 0.01–0.03 in conventional systems). Phycosol demonstrated up to 94% GHG reduction compared to traditional microalgal routes.
• Comparative modeling (ASP vs CW vs Phycosol) indicates potential emission reduction of 0.09–381.61 g CO2-eq per 750 mL bottle through wastewater treatment strategy choice (Table 3).
• CO2 sequestration via Phycosol: ~2.73 g CO2 L−1 of winery wastewater captured, translating to ~10.90 g CO2 per 750 mL bottle.
• Fertilizer substitution with microalgal biomass (Phycosol) reduces Scope 1 N2O by 12–16 g CO2-eq and avoids Scope 3 fertilizer production/transport emissions of ~5.70–49.30 g CO2-eq per 750 mL bottle. Total potential reduction (Scope 1 + 3) from Phycosol strategies: 28.69–457.81 g CO2-eq per bottle.
• Aggregate impact: Adoption of CW and Phycosol can reduce winery CF by approximately 25–30% per 750 mL bottle, despite wastewater and fermentation sources being <1% of total CF in typical LCAs.
• TEA suggests CW and Phycosol have about two-fold lower capital/operational costs than ASP and can reduce emissions by ~41.36 and 50.22 kg CO2-eq person−1 yr−1, respectively.
• Strong alignment and positive synergies with SDGs 9, 6, and 12, especially targets 6.3, 6.6, 12.4, and 12.5.

The findings demonstrate that integrating eco-innovations that close resource loops—specifically capturing fermentation CO2 and valorizing/treating wastewater—addresses overlooked emissions in conventional LCAs and materially lowers winery CF. By shifting from ASP to CW or Phycosol, wineries can cut direct process emissions, reduce energy and chemical use, and sequester CO2 through microalgal biomass production, which also displaces synthetic fertilizers and associated upstream emissions. Regional variability in wastewater emissions and practices indicates the need for context-specific strategies, but the overall pattern supports nature-based and low-carbon systems as superior to conventional approaches. Incorporating biogenic carbon fluxes and soil carbon sequestration into LCAs yields a more accurate GHG budget and may further lower reported CFs, particularly in organic systems. The synergy with SDGs 6, 9, and 12 underscores the broader sustainability benefits beyond CF reduction, including improved water quality, circular resource use, and sustainable industrialization. Market trends toward sustainable wines reinforce the economic viability of adopting these models.

Eco-innovation—embodied by constructed wetlands and the solar-integrated microalgal Phycosol system—can substantially improve the sustainability profile of wine production. Despite wastewater and fermentation emissions contributing <1% in many LCAs, capturing and valorizing these streams yields a notable CF reduction of about 25–30% per 750 mL bottle while generating co-benefits such as biofertilizers and biogas. Aligning with SDG 9 and synergizing with SDGs 6 and 12, these models promote circularity and resource efficiency, offering environmental and economic advantages. Widespread adoption can aggregate small per-bottle gains into significant industry-wide emission reductions. The authors call on policymakers, industry stakeholders, and researchers to embrace and scale eco-innovations to realize tangible climate and sustainability benefits across the wine sector.

• Conventional LCAs frequently omit biogenic fermentation CO2, wastewater emissions, and soil carbon fluxes, leading to uncertainty in baseline CF estimates and complicating comparisons across studies.
• Emission factors and wastewater characteristics vary widely by region, production techniques, and treatment configurations, introducing variability into GHG estimates.
• The estimated CF reductions attributed to Phycosol and CW depend on operational conditions, influent characteristics, and system design; real-world performance may differ from modeled or literature-based values.
• The efficacy of microalgal biomass as a fertilizer depends on species, growth conditions, and application practices; further research is needed to optimize agronomic performance and quantify long-term soil and N2O responses.
• Reported per-bottle reductions (e.g., 28.69–457.81 g CO2-eq; 25–30% CF decrease) are context-dependent and represent potential ranges rather than universally observed outcomes.