To estimate the FFO (Funds From Operations) / Net Debt ratio for ERG S.p.A. as of the end of 2022, we first identify the components provided in the report.

**1. Estimating FFO:**
FFO is typically calculated as EBITDA (Profit/Loss from Operating Activities before Interest, Taxes, Depreciation, and Amortisation) minus cash interest paid and cash taxes paid.
*   **EBITDA (2022):** 499,430,000 EUR
*   **Interest Paid (2022):** 29,146,000 EUR (Cash flow financing)
*   **Income Taxes Paid (2022):** 91,854,000 EUR
*   **FFO Calculation:** 499,430,000 - 29,146,000 - 91,854,000 = 378,430,000 EUR.

**2. Estimating Net Debt:**
Net Debt is calculated as total financial liabilities minus cash and cash equivalents.
*   **Total Financial Liabilities (2023-01-01 / end of 2022):**
    *   Noncurrent financial liabilities: Other Noncurrent Financial Liabilities (1,751,255,000) + Noncurrent Lease Liabilities (150,955,000) = 1,902,210,000 EUR
    *   Current financial liabilities: Current Financial Liabilities At Fair Value (76,644,000) + Other Current Financial Liabilities (389,716,000) + Current Lease Liabilities (6,362,000) = 472,722,000 EUR
    *   Total Gross Debt = 1,902,210,000 + 472,722,000 = 2,374,932,000 EUR
*   **Cash and Cash Equivalents (2023-01-01 / end of 2022):** 392,811,000 EUR
*   **Net Debt Calculation:** 2,374,932,000 - 392,811,000 = 1,982,121,000 EUR.

*(Note: We exclude financial assets held for sale as they are specific to the asset disposal/group classification.)*

**3. FFO / Net Debt Ratio:**
*   Ratio = 378,430,000 / 1,982,121,000 ≈ 0.19092.

<answer>0.19092</answer>